Iris Publishers - Current Trends in Clinical & Medical Sciences (CTCMS)
A Latent Growth Model Evaluation of the Comprehensive, Integrated HIV Prevention Program Effect on Excessive Alcohol Risk Awareness and Excessive Alcohol Consumption Risk
Authored by Meya YB Mongkuo
It has been almost four decades
when HIV infection became a severe public health problem. Since then,
infectious disease experts worldwide have been working without finding a
vaccine to immune people from the disease. So the focus has shifted from
developing a vaccine to identifying the most effective evidence-based
prevention strategies to slow the spread of the disease. In 2017 an estimated
5.1 million or 14.8% of young adults aged 18 to 25 were diagnosed with
substance use disorder [1,2]. Other researchers have focused on identifying
evidence-based risk and protective factors and prevention strategies to slow
the disease [3-8]. Research has found excessive alcohol consumption destabilize
the normal functioning of virtually all vital organs that regulate behavior,
including the nervous system, the immune system, the digestive system, the
endocrine system, and the circulatory system [3,9]. These hormones control
metabolism and energy levels, electrolyte balance, growth and development,
reproduction, responses to and appropriate coping with changes in the internal
and external environments, such as changes in temperature and the electrolyte
composition of body fluids, and response to stress, anxiety, and injury
[3,5-8,10].
Both acute and chronic alcohol
consumption induces hormonal disturbance of the endocrine system that disrupts
the body’s ability to maintain homeostasis leading to various disorders,
including cardiovascular diseases, reproductive deficits, immune dysfunction,
certain cancers, bone disease, and psychological and behavioral disorders.
Research has also found that indulgence in excessive alcohol consumption does
not only harm the hypothalamicpituitary- adrenal (HPA) axis, but practically
all the hormonal systems of the body, including the
hypothalamic-pituitary-gonadal (HPG) axis Sakar DK, Gibbs DM [5], the
hypothalamic-pituitarythyroid (HPT) axis [11], hypothalamic-pituitary-growth
hormone/ insulin-like growth factor-1 (GH/IGF-1) axis [13-15], and the
hypothalamic-posterior pituitary (HPP) axis [3,4,17-19].
A recent review of studies on
youth and adolescents also suggests that hypothalamic-pituitary-adrenal (HPA)
axis dysfunction and exposure to stress are critical components that interact
to convey risk for developing attention deficit disorder (AUD) [20]. For
example, several randomized clinical trials (RCT) have found that excessive
alcohol consumption harms the normal functioning of the nervous and endocrine
systems, both of which are responsible for proper communication between various
organs and cells of the body to maintain a stable internal environment or
homeostasis [21- 22]. Interference of the normal functions of these
communication systems sets in motion a series of adverse physiological
activities, including disruption of the hormonal control of metabolism and energy
levels, electrolyte balance, growth and development, and reproduction of the
body. These disruptions, in turn, inhibits the body’s ability to respond to
effectively and appropriately adapt to changes in body temperature or the
electrolyte composition of the body’s fluids, response to stress and injury,
and psychological and behavioral disorders [1, 22-24]. As for the nervous
system, excessive consumption of alcohol disrupts the vital hormonal flow of
the hypothalamic-pituitary-adrenal HPP axis that is responsible for cognitive
brain functioning. The HPP axis includes two neuropeptides called arginine
vasopressin (AVP) and oxytocin.
Other research has focused on the
progressive alterations in the HPA axis function crucial for understanding the
underlying brain mechanisms of substance use, including excessive alcohol
consumption disorders. These studies found that in contrast to mood and
affective disorders, alcohol dependence has a biphasic effect on HPA axis
dynamics as a person traverses through the various phases of heavy hazardous
drinking, including dependent alcohol, withdrawal, abstinence, and relapse.
Generally speaking, these developmental stages seem to be mirrored by a shift
between hyper- and hypo-responsiveness of the HPA axis to stressful events
[25]. For example, hyper-responsiveness has been identified in people with a
family history of alcoholism [8,10], a population that is at increased risk for
alcohol dependence (Windle 1997). Thisfinding raises the question of whether
heightened stress responsivity is clinically meaningful to the development of
alcoholism. This view is supported by studies showing that cortisol
responsivity correlates with the activity of the regulatory function of the
nervous system called the mesolimbic dopaminergic pathway, which is a central
neural reward pathway [8,26]. The transition to alcohol dependence leads to
compensatory allostatic mechanisms result in injury to HPA axis function and
elevation of stress peptide levels (e.g., corticotropin-releasing factor (CRF)
in brain regions outside the hypothalamus. Allostasis refers to the process
through which various biological processes attempt to restore homeostasis when
an organism is threatened by multiple types of stress in the internal or
external environment [3,27]. Allostatic responses can involve alterations in
the HPA axis function, the nervous system, various signaling molecules in the
body, or other systems. Allostatic changes in HPA axis function have been
posited to, among other things, injure brain reward pathways, contribute to
depressed mood (i.e., dysphoria) and craving, and further contribute to the
maintenance of problem drinking behavior.
A close examination of the
physiology of the hypothalamicpituitary- adrenal (HPA) axis reveals that the
body responds to stress with automatic, allostatic processes aimed at returning
critical systems to a set point within a narrow range of operation that ensures
survival [3,4]. These automatic processes consist of multiple behavioral and
physiological components. Perhaps the best-studied element in the stress
response in humans and mammals is the activation of the HPA axis. This line of
inquiry has found that the neurons in the paraventricular nucleus (PVN) of the
hypothalamus release two neurohormones-CRF and arginine vasopressin (AVP)-into
the blood vessels connecting the hypothalamus and the pituitary gland (i.e.,
hypophysial portal blood). Both hormones stimulate the anterior pituitary gland
to produce and secrete adrenocorticotropic hormone (ACTH) into the general
circulation. The ACTH, in turn, induces glucocorticoid synthesis and release
from the adrenal glands located atop the kidneys.
The main glucocorticoid in humans
is cortisol, which frequently is used as model systems to investigate the
relationship between stress and alcohol use, which is corticosterone.
Hypothalamic activation of the HPA axis modulated a variety of brain signaling
(i.e., neurotransmitter) systems. Some of these systems have inhibitory effects
(e.g., g-aminobutyric acid [GABA] and opioids), whereas others have excitatory
effects (e.g., norepinephrine and serotonin) on the PVN. These effects suggest
that the central nervous system (CNS) and the hormone (i.e., endocrine) system
are tightly interconnected to coordinate glucocorticoid activity [28]. The HPA
system carefully modulates through negative-feedback loops designed to maintain
predetermined hormone levels (i.e., setpoints) and homeostasis. To this end,
Hermann [28] asserts that secretion of CRF, AVP, and ACTH in part controlled by
sensitive negative feedback exerted by cortisol at the level of the anterior
pituitary gland, PVN, and hippocampus.
Iovino [18] suggest that there are
two types of receptors for cortisol-mineralocorticoid (type-I) and
glucocorticoid (type- II) receptors-both of which participate in the negative
feedback mechanisms. Cortisol binds more strongly (i.e., has higher binding
affinity) for the mineralocorticoid receptors (MRS)1 than the glucocorticoid
receptors (GRs). Because of this difference in a critical relationship, the MRS
help maintain the relatively low cortisol levels circulating in the blood
during the regular daily (i.e., circadian) rhythm. Only when the cortisol
concentration is high (e.g., during a stressful situation) does it bind to the
GRs with lower affinity; the resulting activation of the GRs terminates the
stress response. This delicate negative feedback control mechanism maintains
the secretion of ACTH and cortisol within a relatively narrow bandwidth [29].
This process is a critical homeostatic mechanism because it regulates too much
or too little exposure AVP secreted in response to osmotic stimuli. Also, it
restricts the concentration of dissolved molecules (i.e., osmolality) in the
blood fluid by retaining water in the body and constricting blood vessels
[18,29]. Some AVP is released directly in the brain, and research suggests that
it play an essential role in social behavior, sexual motivation and pair
bonding, as well as maternal response to stress (Dorin et al. 2003; Ehrenreich
et al. 2010).
Excessive alcohol consumption
lowers the level of AVP to the brain leading to impaired cognitive performance
(Laczi 1987). Like AVP, oxytocin is produced by both magnocellular and
parvocellular neurons of the hypothalamus and functions both as a peripheral
hormone and a signaling molecule in the central nervous system Buijs [30] to
regulate adaption of the body to respond effectively to internal physiological
and environmental changes or disruptions. Research on people with a history of
excessive alcohol consumption shows that hyperresponsiveness of the stress
response is mediated by the HPPA axis [8], leading to mental health problems.
Research on animals found acute ethanol administration to rats increased plasma
ACTH and corticosterone levels by enhancing CRF release from the hypothalamus
[31-32]. Chronic alcohol consumption is associated with anxiety-producing
(i.e., anxiogenic) Behavior [33]. Collectively, these studies show that
excessive or chronic alcohol consumption attenuates basal ACTH and corticosterone
levels and increases stressful and anxiogenic behaviors. Other studies have
found an association between excessive alcohol consumption and depression among
young adults [34-36].
Rate of excessive alcohol
consumption in Cumberland, North Carolina
The Center for Disease Control and
Prevention (CDC) reports that Cumberland County’s rate of people drinking five
or more drinks of alcohol in one seating of 11.2% is higher than North Carolina
State’s rate of 10.5%. Disease prevalence data and study findings suggest that
our target populations have a more severe than expected alcohol abuse problem
that makes them vulnerable to alcohol-related HIV infection. The CDC also
estimates that Cumberland County’s rate of people drinking five or more drinks
of alcohol in one seating of 11.2% is higher than North Carolina State’s rate
of 10.5% [2]. The North Carolina Department of Health and Human Service (NCHHS)
reports that Cumberland County continues to battle against sexually transmitted
diseases. North Carolina Department of Health and Human Services reports that
in 2013, there 1,339 persons living with HIV infection (PLWHI) in Cumberland
County. Of this total, 866 had HIV, and 473 had AIDS. There were 158 PLWHI
young adults ages 15-24 years old, representing 0.6% with a corresponding HIV
infection rate of 27.7 per 100,000 population in Region 5, which includes
Cumberland County. This HIV infection rate is higher than North Carolina’s rate
of 25.7 per 100,000 people. Desegregating the PLWHI.rate by regionshows that
the rate in Region 5, which includes Cumberland County by
race/ethnicity,reveals that except for Hispanics and Asian/Pacific Islanders,
the rate of PLWHI for Region 5 was higher than that of North Carolina, with the
PHLI.Rate and percent of Americans of 4.9% and 189.6 per 100,000 population
areseven times higher than North Carolina’s 0.7% and 175.2 per 100,000 people;
African Americans were 69.4% and 710.4 per 100,000 people compared to North
Carolina’s 65.4% and 857.8 per 100,000 people. This prevalence data suggest
that higher than expected level of HIV infection among our target populations,
and hence a need for evidence-based intervention.
Rate of HIV infection in
cumberland county, north carolina
North Carolina Department of
Health and Human Services report that in 2013, Cumberland County had 97 newly
diagnosed HIV infections, which rank 3rd among all North Carolina Counties in
newly diagnosed HIV infection rate with 26.0% HIV infections per 100,000
population (97 cases) compared to NC. rate of 15% per 100,000 people. From 1983
to 2013, Cumberland County had a cumulative number of HIV cases of 2,087, which
ranks 6th out 100 Counties in North Carolina. During the same period, the
County had 910 increasing cases of AIDS, which ranks 6th among the 100 counties
in North Carolina. North Carolina State Center for Health Statistics (NCSCHS)
reported that during the period 2007- 2011, Cumberland County’s HIV rate of
infection of 27.3/100,000 population was 1.54 times higher than the State of
North Carolina’s HIV infection rate of 17.7 per 100,000 people. Also, NCSCHS
reported that during 2007-2011, Cumberland County’s total AIDS rate of
3.4p/100,000 population was 1.7 times higher than North Carolina State’s
overall AIDS rate of 2.0 p/100,000 population and 13% higher than all its peer
counties, except for one (Mecklenburg County) in the State of North Carolina.
Theoretical Framework
Theoretical approaches to
prevention have three primary assumptions. First, they view prevention as a
proactive process by which conditions that promote the well-being of an
individual. Prevention activities empower individuals and communities to meet
the challenges of life events and transitions by creating conditions and
reinforcing individual and collective behaviors that lead to healthy
communities and lifestyles. Second, prevention requires multiple processes on
multiple levels to protect, enhance, and restore the health and well‐being of
high sexual risk populations. Such as minority young adults in Cumberland
County. Third, prevention involves an understanding of risk and protective
factors that vary among individuals, age groups, racial and ethnic groups,
communities, and geographic areas.
Theories, models, and data that
allow for the explanation and understanding of sexual risk and protective
factors at several levels of social aggregation-community, school, peers,
family, and the individual’s characteristics-provide a rational approach to
designing appropriate prevention strategies and programs. Risk factors exist in
clusters rather than in isolation. Research has shown that these multiple risk
factors have a synergistic effect (i.e., the interactions between these risk
factors have a more significant impact than any single risk factor) alone. For
example, some of the behaviors that put people at heightened risk of
contracting and spreading HIV are excessive alcohol consumption, illicit
substance, and tobacco use, and having sex with multiple sex partners.
The Comprehensive HIVPrevention
Program (CIHPP)
CIHPP is essentially a derivative
of Bronfenbrenner’s [37] ecological epistemology framework, which asserts that
health risk behaviors such as excessive alcohol consumption, involves complex
interactions between social and biological factors [38] March &Susser,
2006; Dalhberg& Krug, 2002; [39] Schiberner et al., 2001. This approach to
health risk behavior prevention is considered the most effective evidence-informed
strategy to prevent the spread of HIV and other infectious diseases among
at-risk populations. This framework emanates from Jessor’s [40] problem
behavior theory (PBT), which proposes interrelated concentric domains of risk
factors beginning with the individual level, the neighborhood or community
level, and societal level [37,39]. Specifically, the states that young adult
health risk factors consist of a personality system, social environment, and
behavior. The approach extends to the domain of psychosocial theory that views
health risk behaviors as co-occurring [40-41] among young adults. Hence,
assessing the effectiveness of prevention programs should include examining the
association between externalizing problems (such as alcohol consumption) and
internalizing problems (such as depression, anxiety, cognitive impairment, and
disruptive behavior). Therefore, as suggested by [37], effective prevention
strategies should identify and address the prevention of sexually transmitted
infections among high-risk individuals and communities at all four levels
(i.e., individual, interpersonal, organization, and societal).
The individual level is considered
the microsystem where individuals work within their family and home
environment, school and peers, work-peer networks, peer support, family
support, parental mentoring, and parental involvement in health risk behaviors
networks. [37,40-42]. This individual-level characteristic is nested within the
broader community, consisting of community norms, attitudes regarding health
risk behavior, cultural standards, gender norms, spiritual and religious norms,
and ideological and political norms. The prevalence of individual-level health
risk behaviors may include having multiple sex partners, having sex without
condoms, having concurrence partnerships, sharing infected needles, and readily
available alcohol, illicit substance, and tobacco. The prevalence of
interpersonal risk behavior is social and sexual network structure (i.e.,
network size, density, mixing, and turnover) and compositional factors (i.e.,
characteristics of network members) that influence vulnerable to HIV infection
and transmission such as minority young adults HIV transmission [43].
Community-level risk factors
include the density of alcohol, tobacco, illicit substance and tobacco outlets,
and community social and economic disadvantages, crime, and homelessness [44-
47]. Societal level sexual risk factors consist of public policies that shape
the environment of the community, such as policies that promote high density of
alcohol and other risky sexual behavior products outlets in poor and minority
neighborhoods, leading to segmentation of drinkers in hot spots for HIV risk
behaviors and HIV transmission [46]. Also, societal health risks may include
institutional racism, stigma, segregation, formal and informal public policies,
and religious and cultural norm [44,47].
The macro-policy level may also
include the biological and physiological status of essential systems of the
body that regulate behavior, including the nervous system, endocrine system,
the digestive system, immune system, and renal system. The macropolicy level
consists of advertisements and marketing policies related to health risk
behaviors [37,39]. Hence, effective prevention strategies and procedures should
include considering all these multiple interrelated spheres of influence on
behavior to achieve desired health outcomes.
The ecological epidemiology
framework of the comprehensive HIV prevention program germane to our study implies
identifying the prevalence of HIV infection and transmission rates in the
target population by conducting needs assessments of measurable constructs at
each level or domain of influence, at cross-level connections at both the micro
and macro levels, as well as by examining the macrosocial and microsocial or
protective factors (risk regulators) that can either constrain or promote the
occurrence of individual-level behavior associated with the risk of HIV
infection [48]. The needs assessments, in turn, provide objective data for
developing a strategic HIV prevention plan for the target population and
community. So far, no research that we know of have has validated the
psychometric properties of the expected outcome of CHIPP, as well as an
evaluation of the desired results of this prevention intervention strategy,
including an increase in excessive alcohol consumption risk awareness, decrease
in excessive alcohol consumption. So far, there has been no study that we know
of has determined the change in behavior in the behavior of participants over
time using the latent growth curve model within the framework of structural
equation modeling.
Purpose of the Study
The purpose of this study is to
begin a line of inquiry to fill this gap in research by examining the
effectiveness of the Comprehensive Integrated HIV Prevention Program in raising
awareness and decreased the involvement of risky sexual behaviors among
minority young adults. We expect that the study to provide public policymakers,
stakeholders, and practitioners with reliable and valid policy-relevant
information relied upon in designing efficient and effective public policies to
reduce the spread of HIV infection among this vulnerable population.
Research question
This study sought to provide an
empirically-ground answer to the following two research questions:
• What is the effectiveness of the
comprehensive, integrated HIV prevention program in raising excessive alcohol
consumption risk awareness of minority young adults?
• What is the excessiveness of the
comprehensive, integrated HIV prevention program in reducing excessive alcohol
consumption of minority young adults?
• Research Hypothesis
• The Comprehensive Integrated HIV
Prevention Program (CIHPP) effectively increases excessive alcohol consumption
risk awareness of minority young adults.
• The (CIHPP) is effective in
reduces excessive alcohol consumption among minority young adults.
Materials and Method
Research design
The study used a pre-experimental
One-shot latent growth curve (LGC) model case Study Design) [49-53]. Figure 1
displays a schematic representation of the design. Treatment Post-test X OT1
OT2…. OTn.
Where X is the participation level
of minority young adults in the comprehensive, integrated HIV prevention
program, O2 is the level of minority young adults’excessive alcohol consumption
risk awareness and excessive alcohol consumption. A limitation of this type of
research design is the lack of a control group. However, latent growth curve
modeling within the framework of the structural equation model modulates this
limitation by having six main advantages over the traditional longitudinal
research design. Specifically, the LGC modeling approach to evaluating change
has six important unique features that make it superior to other longitudinal
procedures in assessing domain outcomes change over time. First, the method can
accommodate anywhere from three to thirty waves of longitudinal data equally
well. Indeed, Willett (1988,1989) has shown that the more waves of data
collected, the more precise the estimated growth trajectory and higher will be
the reliability of the measurement of change. Second, there is no requirement
of the time between each wave of assessments to be equivalent, which suggests
that the LGC modeling approach can comfortably accommodate irregularly spaced
measurements with the caveat that the same set of occasions measures
participants.
Third, personal change can be
represented by either a linear growth or a non-linear growth trajectory,
although linearity is usually assumed. The assumption is tested, and the model
respecified to address curvilinearity if need be. Fourth, in contrast to
traditional longitudinal methods used in measuring change, the LGC allows not
only for estimating measurement error and accounts for autocorrelation but also
for fluctuation across the time when the test for the assumptions of
independence and homoscedasticity is untenable. Fifth, the multiple predictors
of change can be included in LGC as fixed or time-varying [54]. Finally, the
independence of measurement error variances and homoscedasticity of measurement
can be tested by comparing nested models [54].
Participants and Procedure
Participants in this study were a
random sample of minority young adults (18-24 years old) living in a high
prevalent community in the southeastern United States who volunteered to
participate in the study. Upon getting the Institutional Review Board’s (IRB)
approval of the study questionnaire and proposal, culturally and linguistically
appropriate announcements and advertisements were was send out to residents of
the high HIV prevalence community through various minority young adult outlets,
including social media, radio, print media, community organizations,
word-ofmouth, and distribution of flyers inviting them to attend community
health events and participate is a healthy living event.
Minority young adults who
volunteered to participate in the study were informed that a survey would be
conducted periodically over 24 months to obtain their opinion about key risky
behaviors, such as excessive alcohol consumption risk awareness, excessive
alcohol consumption, that may predispose people to HIV infection. The minority
young adults who agreed to participate were given a linguistically and
culturally appropriate consent form to read, sign, and return. The consent
stated that their participation in the survey was strictly voluntary; they may
either opt not to participate in the study or not provide a response to any of
the statements; their identity will not appear in any report; a $30 gift card
will be given to them as an incentive for fully participating in the surveys.
The minority young adults who agreed to participate in the study were provided
with a linguistically appropriate consent form to read, sign, and date. The
consent form explained to the community residents that their participation was
voluntary and that their identity would be kept strictly confidential, and
their names would not appear in any report.
The survey instrument used in this
study is the National Minority Substance/HIV Prevention Initiative Adult
Questionnaire approved on March 15, 2016, by the United States Office of
Management and Budget, containing a total of health risk-related constructs and
over 56 items. The Questionnaire included over 100 constructs, 70 measurement
items, and demographic information of the participants. Upon the Institutional
Review Board (IRB) approval, we administered the survey to the participants who
volunteered, read, and signed the consent form. We adhered to all American
Psychological Association research guidelines. The survey was anonymous in that
no identifying information was connected to individual participants or included
in the study data set. The participants completed the study in less than 25
minutes during the HIV prevention events and returned them before leaving. A
total of 518 minority young adults participated in the survey, and 498 of them
completed the entire survey representing a 96 percent response rate. A small
sample of the to check for internal consistency reliability of the items
measuring the three constructs of interest using Cronbach’s Alpha Reliability
test. The test produced five items measuring excessive alcohol risk awareness,
and two items measuring excessive alcohol consumption.
Measures
The items measuring excessive
alcohol consumption risk awareness and alcohol consumption were: Alcohol
consumption risk awareness was measured by three items such as “How much do
people harm themselves physically or in other ways when they have five or more
drinks of an alcoholic beverage once or twice a week? The items were scored on
an ordinal Likert Scale ranging from 0 days = 0 to 30 days = 30. Excessive
alcohol consumption was measured by five items, such as, “Have you ever felt
bad or guilty about your drinking? The questions were scored on an ordinal
Likert Scale ranging from 0 days = 0 to 30 days = 30.
Statistical Analysis
This study used the latent growth
curve modeling (LGC) within the SEM framework to evaluate the intraindividual
and interindividual change of excessive alcohol consumption risk awareness and
excessive alcohol consumption CIHPP participant overtime. The hierarchical
levels to use in assessing invariance consist of
• Configural Invariance test to
determine if the same factor structure exists in all groups.
• Metric Invariance to test
whether the loading estimates are equal in all group, which allows comparisons
of relationships.
• Scalar Invariance to verify
whether the intercept terms for all equations are similar in all groups which
allow for comparisons of means.
• Factor Covariance Invariance to
test whether the covariances matrix among latent constructs is the same in all
groups.
• Factor Variance Invariance to
test whether the factor variances are the same in all groups.
• Error Variance Invariance to
test whether error variance terms are the same in all groups.
The analytic method used to assess
the psychometric properties of the National Minority SA/HIV Prevention
Initiative Adult Questionnaire (NMSPIAQ) consists of four interrelated SEM
procedures. First, Exploratory Factor Analysis (EFA) to assess the
factorability of each factor and evaluate the internal consistency (i.e.,
Cronbach’s alpha) of the psychometric properties of NMSPIAQ using SPSS version
26.0. Second, single group Confirmatory Factor Analysis (CFA) of NMSPIAQ
determines the construct and content validity of NMSPIAQ. Third, a series of
Multi-group C.F.A. to test the invariance of NMSPIAQ across static factors
groups. Fourth, Latent Growth Curve (LGC) modeling within the SEM framework
using Analysis of Moment Structure (AMOS) version 26.0 to answer questions
about systematic intra-individual BOP innate and inter-individual BOP innates
differences in change over time of a minority young adult’s likelihood of
excessive alcohol consumption. AMOS statistical software version 26.0 was used
to conduct the second through the fourth analysis. A description of each of
these procedures is presented below.
Exploratory factor analysis - The
first phase of the data analysis involved assessing the reliability or internal
consistency of the primary CIHPP outcome constructs by performing an
exploratory factor analysis (EFA) to determine the meaningful factor loading
structure of the items or observed variables were measuring the CIHPP outcome
constructs. The EFA began by checking the assumptions necessary for proceeding
with factor analysis. The check involved assessing the degree of
intercorrelation of the items from both the overall and individual variables
perspectives. The overall measure of intercorrelation was evaluated by
• Computing the partial
correlation or anti-image correlation among the variables, with small values
indicating the existence of “true” factors in the data [55].
• Performing Bartlett’s Test of
Sphericity, with significant approximate chi-square (χ) indicative of
significant correlation among at least some of the construct’s observed
variables;
• Estimating the
Kaiser-Meyer-Olkin Measure of Sampling Adequacy (MSA) value, with MSA values
above .50 considered acceptable to proceed with factor analysis [55].
The variable-specific measure of
intercorrelation was assessed by estimating the Kaiser-Meyer-Olkin (KMO)
measure of sampling adequacy (MSA) value for each observed variable or item
with values below .50 considered to be unacceptable [55-56]. The variable with
the lowest MSA value was deleted, and the factor analysis was repeated. This
process continued until all the observed variables had acceptable MSA values,
and a decision was made to proceed with factor analysis. Principal component factor
analysis applying the varimax rotation was used to reduce or organize the item
pool into a smaller number of interpretable factors. The number of factors was
determined by joint consideration of Cattell’s (1966) scree plot, a priori, and
the percentage of factors to be extracted criteria [55]. The latent root
residual (eigenvalue) criterion was considered inappropriate if the number of
observed variables fells below or outside the acceptable range of 20 to 50
[55]. [57] principle of simple structure using pattern coefficients of absolute
0.35 as the lower bound of influential per factor and interpretability of the
solution used to determine the final solution Lambert & Durant, 1974; [55].
After rotation, variables with crossloading and communalities lower than .50
were deleted [55].
The second step of the analysis
involved reviewing the items measuring each dynamic factor by calculating the
internal consistency estimates (Cronbach’s alpha) for the items representing
each factor retained from the exploratory factor analysis procedure. Cronbach’s
alpha of 0.6 was considered the minimum acceptable level of internal
consistency for using a factor [55]. For factors with Cronbach’s alpha below
this minimum benchmark, the internal consistency of the factor was improved by
identifying and removing items with low item-test correlation and item-rest
correlation. The factor was deleted if no improvement in the reliability score
occurred.
Single group confirmatory factor
analysis
After establishing the reliability
of the CIHPP expected outcomes constructs, the constructs were validated by
performing a single group CFA. This validation involved testing for the
factorial stability of each CIHPP outcome construct. This test aimed to
determine the extent to which items designed to measure each CIHPP outcome
factor (i.e., latent construct) do so. Because the analysis was performed on
original data and not data summary, missing data were accommodated using the
full information maximum likelihood (FIML) procedure. This procedure allowed
the maximum likelihood estimation to be performed on a dataset containing
missing data, without any form of imputation [58]. Several indices were used to
evaluate the goodness of fit of the 6-factor orthogonal CIHPP measurement
model.
The guidelines for determining
model fit consisted of adjusting each index cutoff values based on model
characteristics as suggested by simulation research that considers different
sample size, model complexity, and degree of error in the model specification as
a basis for determining how various accurate indices performed [55,59]. The
model’s absolute fit was assessed using chi-square statistic, χ2, with low,
insignificant χ2 considered a good fit [55]. The incremental fit was evaluated
using Root Mean Square Errors of Approximation (RMSEA) with a value less than
0.8 indicating a relatively good fit, along with Comparative Fit Index (CFI)
and Tucker-Lewis Index (TLI) with a value of 0.97 or greater considered
desirable [55, 59-60]. Convergent validity among items was determined by
estimating the unstandardized factor loadings and Cronbach’s alpha with
significant loadings and alpha of 0.70 or higher considered good reliability
[55]. Construct validity of the model was evaluated by examining the completely
standardized factor loadings with approximately factor loadings of 0.5 or
higher and construct reliability (Cronbach’s alpha) equal or greater than 0.7
considered to be a good fit [55]. Also, a parametric test of the significance
of each estimated (free) coefficient was performed. Insignificant loadings with
low standardized loading estimates were deleted from the model.
The completely standardized
loadings were examined for offending estimates to assess problems with the
model, such as loadings above 1.0. Any identified offending estimates were
dropped from the model. Finally, internal consistency estimates (Cronbach’s
alpha) were calculated for the item representing the CIHPP outcome factor
retained. Cronbach’s alpha of 0.7 was considered as a minimum acceptable level
of internal consistency for retaining the factor [55]. For factors with
Cronbach’s alpha below this minimum threshold, an attempt to improve the
internal consistency was made by identifying and removing items with low
item-test correlation and item-rest correlation (Nunnally & Bernstein,
1994). If no improvement of the reliability score occurred, the factor was
deleted from the model of the construct. The likelihood that the model’s
parameter estimates from the original sample will crossvalidate across in
future samples was assessed by examining the [61] consistent version of the AIC
(CAIC) with lower values of the hypothesized compared to the independent and
saturated models considered to be an appropriate fit. The likelihood that the
model cross-validates across similar-sized samples from the same population was
determined by examining the Expected Cross- Validation Index (ECVI) with an
ECVIvalue for the hypothesized model lower compared to both the independent and
saturated models considered to represent the best fit to the data. Finally,
[62] Critical N (CN) was examined to determine if the study’s sample size is
sufficient to yield an adequate model fit for a χ2 test [59] with a value over
200 for both .05 and .01 CN indicative of the CIHPP outcome measurement model
adequately representing the sample data [49]. The normality of the distribution
of the variables in the model was assessed by Mardia’s (1970; 1974) normalized
estimate of multivariate kurtosis with a value of 5 or less reflexive of normal
distribution. Multivariate outliers were detected by computation of the squared
Mahalanobis distance (D2) for each case with D2 values standings distinctively
apart from all the other D2-values indicative of an outliers
Multi-group analysis
After validating the factorial
structure of NMSPIAQ, we proceeded to conduct a series of multiple groups CFA
to test the invariance of CIHPP outcome factors across static factors groups.
The multiple-group analysis of this study involved performing three types of
CFA. First, examining the factorial invariance of CIHPP outcome factor scales
(1st Order CFA Model). Second, testing the invariance of dynamic factor mean
structure. Third, testing the invariance of CIHPP factors causal structure. The
central concern of measurement invariance was testing measurement equivalence
across groups [63]. We conducted the test at two types of models that
frequently used: first-order models and second-order models (Little,1997).
These tests are the recommended procedures for testing measurement invariance
across a hierarchical series of models, and their common purpose is maximizing
the interpretability of the results sought at each step of the hierarchy [64].
Latent growth curve (LGC) modeling
The LGC modeling within the SEM
framework was relied upon to evaluate the excessive alcohol consumption risk
awareness and excessive alcohol consumption of each minority young adult
periodically, including indicators of progress and regression of time-invariant
predictors CIHPP outcome domains in case of the presence of heterogeneity of
dynamic factor variance. Unlike like the usual “scape shots” approach of taking
the status of outcome domains of interest before and after an intervention such
as CIHPP time-invariant and dynamic factors, the LGC model captures the actual
development of the processes and outcome domains of interest following a
trajectory over time to reveal the intricacies of intra-individual and
inter-individual changes of the study participants. Therefore, the approach
capitalizes on the richness of continuous multi-wave data to provide a somewhat
superior program evaluation approach for answering questions about systematic
intra-individual and inter-individual change among minority young adult CIHPP
participants during 24 months [65- 67].
The next step was to assess an
increase or decline in change over time for one or more CIHPP domain of
interest. A representative sample of the participants was tested systematically
over time, and their status in each CIHPP domain outcome was measured on
several temporal-spaced occasions based on four conditions [65]. First, the
outcome variable of the domain of interest must be an interval level of
measurement [68-69]. Second, while the time lag between occasions can maybe
evenly or unevenly spaced, both the number and spacing of these assessments
must be the same for all CIHPP participants. Third, when the focus is on
individual CIHPP participants, data must be obtained for each CIHPP participant
on three or more occasions, and change is structured as an LGC model, with
analyses conducted using the SEM procedure. Finally, the sample size must be
large (i.e., a minimum 200) enough to allow for the detection of person-level
effects [65] Bootsma, 2005; Bootsma & Hoogland, 2001). Our proposed LCG
model met all of these four conditions.
The basic building block of the
LGC model comprised of two sub-models referred to as Level 1 model and Level 2
model [65]. Level 1 model is a within-person regression model representing an
individual’s change over time of the outcome variables, which in our case are
the five CIHPP outcome domains mentioned earlier. Level 2 model is the
between-person model that focuses on inter-individual differences in CIHPP
outcome factors change over time. Level 1 (i.e., intraindividual minority young
adult change) focuses on capturing the measurement model, which is the portion
of the model that incorporates only linkages between the observed variables of
the measurement instrument and their underlying observed or latent construct or
factor (i.e., likelihood of excessive alcohol consumption). As in any
measurement model, the primary interest is the strength of the factor loading
or regression paths linking the observed variable to the unobserved variable.
The only parts of the model that are relevant in the modeling of
intraindividual change are the regression paths linking the observed variables
to the unobserved factor (both intercept and slope), the factor variances and
covariances, and the related measurement errors associated with these observed
variables. This part of the modeling is an ordinary factor analysis model with
the following two distinctive features. First, all the loadings are fixed
(i.e., there are no unknown factor loadings). Second, the pattern of fixed
loadings plus the mean structure allows us to interpret the factors as
intercept and slope factors. As in all factor models, the present case argues
that each minority young adult’s likelihood of excessive alcohol consumption at
each temporal time point (i.e., Time 1=0; Time 2=1; Time 3 = 2), are a function
of three distinct components:
• A factor loading matrix of
constants (1:1:1) and known time values (0:1:2) that remain invariant across
all individual BOP innates, multiplied by.
• A latent growth curve vector
containing particular minority young adult-specific and unknown factors called
particular CIHPP participant growth parameter (Intercept, Slope), plus.
• A vector of individual minority
young adult-specific and unknown errors of measurement [49]. Whereas a latent
growth curve vector represents the within-person actual change in the
likelihood of excessive alcohol consumption over time, the error vector
represents the within-person likelihood of excessive alcohol consumption
“noise” that serves to erode these actual change values [65].
Level 2 argues that, over and
above the hypothesized linear change in CIHPP outcome domains over time,
trajectories will necessarily vary across CIHPP participants due to differences
in intercepts and slopes. Within the framework of SEM, this portion of the
model reflects the “structural model” component, which in general portrays
relationships among unobserved factors and postulated relations among their
associated residuals. However, within the more specific LGC model, this
structure is limited to the means of the Intercept and Slope factors and their
related variances, which represent deviations from the means. The means carry
information on individual differences in intercept and slope values. The
specification of these parameters, then, makes possible the estimation of
interindividual differences in change. AMOS 26.0 Graphics were used to test the
latent Growth Curve Model 1 and Model 2. AMOS was also used to test the LGC.
Models with static factors as a time-invariant predictor of change. This test
aimed to determine if the static variable can explain statistically significant
heterogeneity in the individual growth trajectories (i.e., intercept and slope)
of CIHPP outcome domains as time-invariant predictors of change. Specifically,
this later test aimed at answering two questions. First, “Do the CIHPP outcome
domains differ for the subsets of a static factor at time 1?” second, “Do the
CIHPP outcome domains change over time differ over time for a subset of a
static?” The answer to these questions used the predictor “static factor,” or
variable incorporated into the Level 2 (or structural) path of the model. This
predictor model represented an extension of our final best-fitting multiple domain
model (Model 3).
The following four new structural
model components were included in the measurement models. First, the regression
paths that flow from the static factors to the intercept and slope factors
associated with CIHPP outcome domains are of primary interest in this predictor
model as they hold the key in answering the question of whether the trajectory
of CIHPP outcome domains differs for the subset groups of the static factor.
Second, there is now a latent residual associated with each of the intercept
and slope factors. This addition is a requirement as these factors are now
dependent variables in the model due to the regression paths generated from the
predictor variables of the static factors. Given that dependent variables
cannot be estimated in SEM, the latent factor residuals served as proxies for
the intercept and slope factors in capturing the variances. These residuals
represented variation in the intercepts and slopes after all variability in
their prediction by the static factors has been explained [67]. Third, the
covariances link the appropriate residuals rather than the factors themselves.
Finally, the means of the residuals were fixed to 0.0.
The first step in building the LGC
model involved determining the direction and extent of change in outcomes of
each CIHPP participant’s scores over the specified time of participation in the
CIHPP programming. Following [49] protocol for determining and testing the LGC
model, the shape of the growth trajectory was known in advance and the LGC
assumption of modeling linearity, which states that the specified model should
include the following two growth parameters: (a) an intercept representing an
individual CIHPP participant’s domain outcome score on the outcome variable at
time 1, and (b) slope parameters representing an individual CIHPP participant’s
rate of change throughout the period. In our study, the intercept described a
CIHPP participant’s CIHPP excessive alcohol consumption awareness and excessive
alcohol consumption scores at the beginning of the intervention; and the slope
represented the rate of change of the two constructs of interest scores over
the 24-month transition. The hypothesized link between the individual growth
parameter (i.e., the intercept and the slope) of levels one and level two
models were considered analysis of change in the CIHPP process and outcome
domains.
The first step in building the LGC
model involved determining the direction and extent of change in outcomes of
each CIHPP participant’s scores over the specified time of participation in the
CIHPP programming. Following [49] protocol for determining and testing the LGC
model, the shape of the growth trajectory was known in advance and the LGC
assumption of modeling linearity, which states that the specified model should
include the following two growth parameters: (a) an intercept representing an
individual CIHPP participant’s domain outcome score on the outcome variable at
time 1, and (b) slope parameters representing an individual CIHPP participant’s
rate of change throughout the period. In our study, the intercept described a
CIHPP participant’s CIHPP excessive alcohol consumption awareness and excessive
alcohol consumption scores at the beginning of the intervention; and the slope
represented the rate of change of the two constructs of interest scores over
the 24-month transition. The hypothesized link between the individual growth
parameter (i.e., the intercept and the slope) of levels one and level two
models were considered analysis of change in the CIHPP process and outcome
domains.
Results
The results of this study consist
of estimates of mean, covariance, and variance of the latent growth curve model
of two CIHPP effectiveness in raising excessive alcohol consumption risk
awareness and reducing excessive alcohol consumption. The results of each of
these CIHPP outcome domains are presenting below.
Effectiveness in Reducing
Excessive alcohol consumption risk awareness latent growth curve model results
Mean estimate: Results of the
analysis indicate that the mean estimate of excessive alcohol consumption for
the intercept and the slope are statistically significant. The results reveal
that the average score for excessive alcohol consumption risk awareness
increased (2.863) significantly over the 24-months periods, as indicated by the
value of 0.374; p = 001. (Table 1-1).
Covariance estimate: Table 1-2
shows the results of the covariance estimate between the intercept and slope
factors for excessive alcohol consumption risk awareness. The results indicate
that the covariance between the intercept and slope factor for excessive
alcohol consumption risk awareness was statistically significant (p = .001).
The positive estimate of .774 suggests that minority young adults exhibited a
rate of increase in their excessive alcohol consumption awareness over the 24
months. This finding indicates that the CIHPP was effective in raising the
excessive alcohol consumption risk perception of young adults under study.
Variance estimate: The variance
estimate related to the intercept and slope for excessive alcohol consumption
risk awareness is statistically significant (p=.001).This finding reveals
substantial inter-individual differences in the original score of excessive
alcohol risk perception between the young adults at the beginning of the
implementation of the CIHPP and its change over time, as the young adult
progressed from the beginning of the CIHPP intervention through the 24 months.
Such evidence provides powerful support for further investigation of
variability related to the growth trajectory. Specifically, incorporating
time-invariant change into the model explains the participants’’ excessive
variability of alcohol consumption risk awareness. This incorporation involves
testing the latent growth curve model with the demographic or static variable
as a time-invariant predictor of change [49]. This study incorporated gender in
the LGC model as a predictor of growth. Table 1-3 displays the result.
Excessive alcohol consumption risk
latent growth curve model results
Mean estimate: The results
indicate that the mean estimate of excessive alcohol consumption risk for the
intercept and the slope are statistically significant. Specifically, the
findings reveal that the average score for excessive alcohol consumption
(-5.016) decreased significantly over the three 6-months periods as indicated
by the value of 20/662; p=001. Hence, we can conclude that CIHPP was effective
in reducing excessive alcohol consumption among minority young adults. Table
2-1.Covariance estimate: The covariance between the intercept and slope factor
for excessive alcohol consumption risk was not statistically significant (p=
.189). The positive sign suggests that young adults exhibited a high rate of
increase in their alcohol consumption over the 24 months. This finding
indicates that the Comprehensive, integrated HIV prevention program was not
effective in decreasing the excessive alcohol consumption of young adults under
study. Table 2-2.
Variance estimate: The variance
estimate related to the intercept and slope for excessive alcohol consumption
risk is statistically significant (p=.001). This finding reveals substantial
inter-individual differences in the original score of excessive alcohol risk
perception between the young adults at the beginning of the implementation of
the CIHPP and its change over time, as the young adult progressed from the
beginning of the CIHPP intervention through the 24 months. Such evidence
provides powerful support for further investigation of variability related to
the growth trajectory. Specifically, incorporating time-invariant change into
the model can explain the participant’s variability of alcohol consumption risk
awareness. This incorporation involves testing the latent growth curve model
with the demographic or static variable as a time-invariant predictor of change
[49]. This study incorporated gender in the LGC model as a predictor of growth.
Table 2-3 present the results of the variance estimate.
Regression Weight with Gender as
Predictor: Gender was found not to be a statistically significant predictor of
excessive alcohol consumption risk predictor of both initial status (-.001) at
p = .981 and rate of change (.018) at p = .811. This finding suggests that
there was no meaningful difference in excessive alcohol consumption risk
between minority young adult males and females both at the beginning of CIHPP
and the rate of change during the 24 months intervention period. Table 2-4. Conclusions
The Comprehensive, integrated HIV prevention program
effectively raised the excessive alcohol consumption risk awareness of minority
young adults under study. There is a significant interindividual difference in
the original score of excessive alcohol risk perception between the young
adults at the beginning of the implementation of the CIHPP and its change over
time, as the young adult progressed from the beginning of the CIHPP
intervention through the 24 months. Female young adult’s excessive alcohol
consumption risk awareness was more significant than male minority young
adults. In summation, The CIHPP effectively increased the awareness of
excessive alcohol consumption risk of minority young adults. The alcohol
awareness of young female adults was higher than the male minority young adult
during the 24 months implementation of the CIHPP. Hence, hypothesis
1.confirmed.
Regarding excessive alcohol consumption risk, the CIHPP
effectively decreased excessive alcohol consumption among minority young
adults. Hence, hypothesis 2 is confirmed. There was inter-individual
differences or heterogeneity in alcohol consumption among the minority young
adults between minority young adult at the beginning of CIHPP intervention and
through the 24 months. However, there was no meaningful difference in excessive
alcohol consumption between minority young adult males and females, both at the
beginning of CIHPP and the rate of change during the 24 months intervention
period. In other words, the interindividual difference was not attributable to
gender. Collectively, the result of this study is consistent with previous studies
[38,48] March &Susser, 2006; [39,70].
Study Limitations
The study used one static variable, gender, as a
predictor of excessive alcohol consumption awareness and excessive alcohol
consumption risk. To more precisely evaluate interindividual change, we
recommend that future studies use two or more static valuables. Also, the
sample for this study was drawn from one jurisdiction, only making external
validity questionable. Therefore, as a contribution to theory building, future
studies two conduct the research in similar in two or more jurisdictions with
similar populations. Finally, this study used a sample size of 498 minority
young adults. Although this sample meets the recommended minimum threshold of a
sample size of 200 for structural equation modeling [49], the sensitivity of
statistical significance testing to sample size [71], we recommend that future
studies should use effect size instead [72-92].
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