The Journal of Nutrition, Health & Aging© Volume 18, Number 1, 2014

EXAMINING CHANGE IN SOCIAL SUPPORT AND FRUIT AND VEGETABLE CONSUMPTION IN AFRICAN AMERICAN ADULTS C.W. O’Neal1, K.a.S. WiCKrama1, P.a. ralStON2, J.Z. iliCh3, C.m. harriS4, C. COCCia5, i. YOuNg-ClarK2, J. lemaCKS6

1. human Development and Family Science; university of georgia, athens, ga 30602; 2. Center on Better health and life for underserved Populations; Florida State university, C2200 university Center, tallahassee, Fl 32306-2641; 3. Nutrition, Food, and exercise Science; Florida State university, tallahassee, Fl 32306; 4. institute of Public health; Florida a&m university, College of Pharmacy & Pharmaceutical Sciences, tallahassee, Fl 32307; 5. human Sciences; texas a&m university-Kingsville, human Sciences Building, Kingsville, tX 78363; 6. Nutrition and Food Systems, university of Southern mississippi, hattiesburg, mS 39406. Corresponding author: Catherine W. O’Neal, human Development and Family Science; university of georgia, 107 Family Science Center ii; athens, ga 30602, [email protected]; (706) 542-2972

Abstract: Objective: to examine (a) inter-individual variation in african americans’ fruit and vegetable social support, behavior, and consumption trajectories by estimating latent growth curves (lgCs) and (b) the associations between these trajectories over time. Design: as part of a larger intervention study, data were collected from mid-life and older african americans yearly for three years. the study incorporated a quasiexperimental design with random selection of participants, stratifying for age and gender. Setting: Six churches in North Florida. Participants: two hundred and thirty one (73% women; median age range of 57-63) older african americans. Measurements: a structured questionnaire elicited personal data as well as information on dietary social support, eating-related behaviors, and fruit and vegetable dietary intake. Results: age was positively associated with initial social support but negatively associated with the rate of change in social support. more important, the rate of change in dietary social support predicted eating-related behavior trajectories, which influenced the rate of change in fruit and vegetable consumption over time after controlling for the intervention. Conclusion: these findings illustrate the mediating role of eating-related behaviors and the inter-locking nature of social support, behavior and consumption trajectories. this research has implications for future research as well as community interventions and programs.

Key words: african americans, eating behavior, social support.

Introduction

african americans consume diets that are higher in fat and lower in fruits and vegetables than Caucasians (1). the diet of african americans is particularly important as it likely contributes to their health disadvantage, which accelerates in later years (2). Previous research suggests domain-specific social support (i.e., social support related to a particular behavior) is central to african americans’ performance of health promoting behaviors (3, 4, 5). however, little is known about the individual trajectories of fruit and vegetable consumption and associated factors, such as social support, as individuals age and the association between these trajectories during aging. thus, the purpose of the current study is to use longitudinal data from a three-year period to analyze change in social support related to eating behavior and dietary intake at the individual level (i.e., growth trajectories) by examining inter-individual variation in these trajectories and the associations between these trajectories over time. Eating Behavior

the current study examines fruit and vegetable-related behaviors, such as food planning, preparation, and selfmonitoring, as predecessors of fruit and vegetable consumption following a few existing studies suggesting that consumptionrelated behaviors, such as planning meals in advance and tracking fruit and vegetable intake, are associated with eating

Received January 30, 2013 Accepted for publication April 24, 2013

more fruits and vegetables (6, 7). Fruit and vegetable behaviors, such as preparation and tracking intake, may be particularly important for the fruit and vegetable consumption of african americans for two reasons. First, they are at increased risk for structural constraints which affect food access, availability, and preparation (8, 9, 10, 11). Second, cultural values in african american families often influence their food preparation and eating practices, resulting in the above-average consumption of high calorie foods (12). thus, food consumption is likely determined by related behaviors, such as buying, preparing, and monitoring food selections (13). Social Support

Social support is pivotal to a number of health related outcomes, including fruit and vegetable intake, particularly for african americans (4, 5, 14, 15). however, we hypothesize that this influence occurs through the impact of social support on fruit and vegetable-related behaviors, such as planning to eat fruits and vegetables, preparing these healthier food options, and tracking fruit and vegetable intake. Social support provides the necessary psychological resources, such as motivation and enthusiasm (16). Social support also provides sources of instrumental support. For instance, individuals may cook healthier foods when they have someone to help them peel vegetables and/or give them meal ideas.

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thus, we hypothesize that the rate of change of domainspecific social support will predict fruit and vegetable behavior trajectories and, in turn, these behavior trajectories will explain the rate of change in fruit and vegetable consumption after controlling for the influence of the intervention. Method

Participants Data were collected from african american adults who participated in a study to reduce cardiovascular risk conducted in six North Florida churches (17). the sample included individuals who provided responses to the questionnaire for at least two of the first three waves (n = 231) (sample size for waves 1, 2, and 3 = 223, 257, and 240, respectively; note: new participants were allowed to enroll at wave 2 with an average response rate of 93.3%). Waves of data collection were approximately one year apart. respondents included men and women (73% female, 27% male). respondents’ educational attainment ranged from some high school (n = 23; 10.0%) to Ph.D./m.D./J.D. (n = 5; 2.2%) with a median of some college experience (n = 64; 27.8%). at Wave 1, participants reported ages ranging from 43-49 (n = 40; 19%) to over 91 (n = 1; 0.5%) with a median age range of 57-63 years (25.2%). On average, respondents were married (n = 103; 45.0%) with two children (n = 58; 25.4%).

Measures Social Support for Fruit and Vegetable Consumption. Five items from the processes of change instrument (18) assessed domain-specific social support (i.e., social support related to eating fruit and vegetables) in the previous month for each of the three waves. Participants rated their agreement to the items using a 5-point scale ranging from “never” to “repeatedly.” Sample items include: “i had someone i could rely on to support my decision to eat more vegetables and fruits” and “i spent time with people who encouraged me to eat more vegetables and fruits.” items were summed, and higher scores indicate the presence of more social support. internal consistencies (Cronbach’s alpha) for waves 1, 2, and 3 were .823, .829, and .825, respectively. Fruit and Vegetable Behavior. at each of the three waves, six items from the processes of change instrument (18) assessed participants’ planning, preparation, and tracking behaviors in the past month for fruit and vegetable consumption. responses were indicated on a 5-point scale ranging from “never” to “repeatedly.” Sample items include: “i planned my meals in advance so i would be able to eat more vegetables and fruits,” “i peeled fruits and vegetables ahead of time so i could eat them whenever i wanted to,” and “i kept track of the number of fruits and vegetables i ate each day.” responses to these six items were summed with higher scores indicating more positive behaviors (α for waves 1, 2, and 3 = .781, .726, and .811, respectively).

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Fruit and Vegetable Consumption. two items were summed to assess respondents’ fruit and vegetable consumption at each of the three time points. respondents were asked how many servings of fruits and vegetables they usually eat each day. response categories ranged from 1 = “one or less” to 5 = “five or more.” the second item was taken from the processes of change instrument (18). respondents indicated how often in the past month they “snacked on vegetables or fruits instead of going hungry” with response options ranging from 0 = “never” to 5 = “repeatedly.” Correlational analyses indicated these two items were significantly correlated at each wave (.310, .162, and .134, p < .05 for waves 1, 2, and 3, respectively). intervention (control variable). approximately half of the sample received an intervention comprised of three phases (emphasizing health awareness, knowledge/clinical learning, and taking charge of your health). each phase lasted approximately six months. the intervention occurred between the first and third data collection points. the independent change due to social support is the focus of the current paper. Consequently, the intervention was included solely as a control variable. Subsequent papers will describe the intervention effect in detail.

Statistical Analyses using three repeated measures, we examined individuals’ fruit and vegetable social support, behavior, and consumption trajectories by estimating latent growth curves (lgCs) with initial levels and slopes (rate of change) as latent constructs (19). although the trajectories for each individual vary in initial level and rate of change, these can be aggregated to create mean and variance values for the initial level and slope. a significant variance in a change parameter implies different rates of change among individuals in the sample. in the present study, for instance, a significant variance in the slope parameters for fruit and vegetable social support suggests that some african american adults show greater increases or decreases in fruit and vegetable social support from wave 1 to wave 3 (a period of two years) than other adults in the sample. Consequently, variables that explain this variation can then be examined (20). For example, we use the age of african american adults to predict the initial level and rate of change of social support. also, we examine the influence of the initial level and rate of change of fruit and vegetable social support trajectories on the initial level and rate of change of fruit and vegetable behavior trajectories, respectively. Similarly, the association between fruit and behavior trajectories and consumption trajectories is also examined. estimation of latent growth curve models was conducted in a structural equation modeling framework with amOS statistical software (21). With data at three time points, we examined the linear shape of trajectories. Full information maximum likelihood (Fiml) was used to manage missing data for all study variables. goodness-of-fit was assessed using the chisquare statistic divided by the degrees of freedom, the

The Journal of Nutrition, Health & Aging© Volume 18, Number 1, 2014

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comparative fit index (CFi), and the root mean square error of approximation (rmSea). Results

at time 1, overall, participants reported “occasional” fruit and vegetable social support (m = 14.047, SD = 5.044) and “seldom” to “occasional” fruit and vegetable behaviors (m = 16.150, SD = 4.713). regarding consumption, averages indicated respondents “occasionally” had fruits or vegetables for snacks (m = 3.26, SD = 1.039) and consumed approximately two fruits or vegetables per day (m = 2.319, SD = 1.082). as shown in Figure 1, age (β = .206, t = 2.570) positively predicted the initial level of fruit and vegetable social support of adult african americans and negatively predicted the rate of change in fruit and vegetable social support (β = -.19, t = 1.978). thus, older african americans reported more fruit and vegetable social support at time 1, but they experienced greater deterioration, or fewer increases, in fruit and vegetable social support over time. using mean splits, we examined the average social support trajectory for older and younger african american adults to more closely examine how these trajectories varied by age (see Figure 2, Panel a). On average, older african americans experienced declining fruit and vegetable social support over time whereas younger individuals experienced increasing social support with time. Participants’ initial level of fruit and vegetable social support influenced their initial level of fruit and vegetable behaviors (β = .626, t = 6.556), which, in turn, explained variation in the initial consumption level of fruits and

vegetables (β = .739, t = 9.007). that is, those who have higher starting values for fruit and vegetable social support trajectories also have higher starting values for fruit and vegetable behavior, and those with higher starting values for behavior tend to have higher starting values for fruit and vegetable consumption. more important, african americans’ fruit and vegetable social support trajectories (or rate of change) predicted change in their fruit and vegetable behavior (β = .679, t = 2.944). the rate of change in fruit and vegetable behaviors explained variation in fruit and vegetable consumption trajectories (β = .796, t = 4.028). thus, across the total sample, participants who reported increasing fruit and vegetable social support over time exhibited increasingly positive fruit and vegetable behaviors. in turn, increases in positive fruit and vegetable behaviors over time were associated with greater increases in fruit and vegetable consumption (see Figure 2, Panel B). however, the negative influence of age on the rate of change for fruit and vegetable social support and an examination of the mean trajectories in social support after disaggregating by age showed changes in social support occur differentially for younger and older groups (see Figure 2, Panel a). these analyses controlled for the treatment intervention because approximately half of the respondents participated in an intervention project during the length of the study. these findings remained after controlling for the treatment intervention. Participants in the treatment group had a marginally lower initial level of fruit and vegetable consumption (β = -.155, t = -1.807). there was a positive effect of the treatment on fruit and vegetable consumption trajectories (β = .366, t = 2.333) indicating that over time those in the

Figure 1 influence of age on the trajectories of fruit/vegetable (F/V) social support, F/V behavior, and F/V consumption after controlling for the intervention and marital status

* p < .05. ** p < .01.

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Figure 2 Panel a. mean trajectories of fruit and vegetable social support for younger and older african american adults. Panel B. estimated average growth trajectories for three attributes

* p < .05. ** p < .01. *** p < .001.

treatment group experienced greater improvement, or fewer declines, in their consumption of fruits and vegetables compared to individuals in the control group. Overall, this model fit the data well (χ2/df = 1.88, CFi = .91, rmSea = .05). Discussion

the findings from this study expose the inter-locking nature of fruit and vegetable social support, eating-related behavior, and consumption trajectories. Our latent growth curve analysis indicated that change in domain-specific social support was associated with change in fruit and vegetable behavior trajectories. in turn, when older african americans exhibited more fruit and vegetable behavior over time (i.e., growth trajectories) their consumption trajectories also increased. although numerous studies have emphasized the association between social support and a variety of health behaviors, such as dietary intake, little existing research has examined the factors linking social support to health behaviors (6, 22); as expected, we found that fruit and vegetable behaviors served as a linking mechanism to explain how fruit and vegetable social support influenced african americans adults’ consumption of fruits and vegetables. Domain-specific social support likely increases african american adults’ fruit and vegetable-related behaviors by providing psychological and structural resources that make these behaviors possible (16, 22). moreover, it is interesting that older african americans, on average, reported higher initial levels of fruit and vegetable social support but decreasing social support as they age compared to younger african american adults. Supplementary analyses detailing the average social support separately for younger and older participants over time indicated a positive rate of change for younger participants but a negative rate of change for older participants. thus, it appears that although an

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overall increase existed in social support over time, it increases as african americans age only until a certain point, when it then begins to decrease over time. this may contribute to divergent health disparities among african americans in their later years. Future longitudinal studies examining a longer time span are necessary to more fully elucidate how domain-specific social support changes over adulthood and into old age. there are several limitations which should be noted. Our sample was drawn from churches, and, therefore, the findings may not generalize to individuals who do not attend church. Furthermore, we relied on self-report data only, and other methods, such as multiple 24-hour dietary recalls, may reach different conclusions. replication using more comprehensive measures of fruit and vegetable intake that have been validated for use in older african american samples would improve upon the current study. Despite these limitations, the present study makes a valuable contribution regarding eating-related social support, behavior, and consumption trajectories of adult african american individuals and the association between these trajectories over time. these findings provide evidence of social and behavioral determinants that are relevant to the health behaviors of african americans, a racial/ethnic group with known health disadvantages (2). therefore, the importance of social determinants, such as domain-specific social support, should not be overlooked for interventions and programs aimed at improving the health behaviors of this population as they may increase african american adults’ implementation of positive eating-related behaviors, which have consequences for their dietary intake. Furthermore, programs may increase the benefits of social support by emphasizing the psychological and structural assistance related to eating behaviors provided by social support.

Funding Statement: the project described was supported by award Number

The Journal of Nutrition, Health & Aging© Volume 18, Number 1, 2014

EXAMINING CHANGE IN SOCIAL SUPPORT AND FRUIT AND VEGETABLE CONSUMPTION

r24mD002807 (Penny a. ralston, Principal investigator) from the National institute on minority health and health Disparities. the content is solely the responsibility of the authors and does not necessarily represent the official views of the National institute on minority health and health Disparities or the National institutes of health.

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Examining change in social support and fruit and vegetable consumption in African American adults.

To examine (a) inter-individual variation in African Americans' fruit and vegetable social support, behavior, and consumption trajectories by estimati...
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