NC1028: Promoting healthful eating to prevent excessive weight gain in young adults (NC219)
Statement of Issues and Justification
STATEMENT OF THE PROBLEM: Risks of cardiovascular disease, hypertension, and type 2 diabetes are exacerbated by excessive weight gain. Development of specific strategies is needed to promote healthful eating among young adults, an age group with high risk of weight gain and unique interests in diet/health issues. To date, few interventions have been designed for obesity prevention among young adults. This multi-state research group is currently designing an intervention to prevent weight gain and promote healthy diet/exercise choices among young adult college students. The experimental intervention will utilize principles of community-based participatory research (CBPR), a collaborative approach to research that equitably involves & community members, organizational representatives, and researchers in all aspects of the research process'(1).In previous research, we have been successful at developing theory-based education strategies for low-income young adults between the ages of 18-24. In comparison to a control group receiving a minimal standard treatment, young adults ate more servings of fruits and vegetables when exposed to a tailored intervention with practical age-appropriate messages. However, young adults were more likely to drop from the intervention study if they had very low incomes (<$800/month), were of ethnic minority status and/or were parents. The new intervention will utilize principles of CBPR to increase relevance and accessibility and reduce the attrition we found in our previous research. .
JUSTIFICATION:
Extent of the problem
Recent data from the US Centers for Disease Control and Prevention show continued escalation of the prevalence and severity of obesity in all age, gender and socioeconomic segments of the population, costing the US an estimated $75 billion annually (2). Obesity has increased dramatically since 1991, and now approximately 64% of American adults are overweight or obese (3, 4). Recent epidemiological studies have documented that young adulthood is a critical time in which adverse changes in body weight are likely to occur, and that men and women aged 18-25 are a subset of young adults at particularly high risk for weight gain (5, 6, 7). Being mildly or moderately overweight at age 20-22 years is linked with substantial incidence of obesity by age 35-37 years (8,9). This high-risk age group extends across all racial and ethnic groups, however the rate of weight gain is higher in Blacks, Americans Indians, and Hispanics than non-Hispanic whites (5).
Investigators from the Coronary Artery Risk Development in Young Adults (CARDIA) found young adults gained an average of 0.69 plus or minus 1.19 kg/yr over 10 years (5). The rate of weight gain appeared to slow in subsequent decades to an average of around 0.5 kg/yr (10). While genetic factors undoubtedly contribute to obesity development (11,12), they cannot explain the escalation in recent years nor differences in rate of weight gain by age (13). A chronic state of positive energy balance must exist for weight gain to occur, which is made possible by increased energy intake relative to energy expenditure(12). The Diabetes Prevention Program (DPP) demonstrated that healthy eating and physical activity can achieve modest weight loss among older adults (>=25 years) at high risk of developing diabetes. This study utilized a clinical approach to providing extensive education on nutrition, physical activity, and behavior modification (14).
There are many serious health implications of overweight and obesity, making excess body weight one of the leading causes of preventable death in the U.S.(15) and a serious concern for the nation's health care system and overall economy (12,16). Weight reduction helps to reduce the risk and severity of the most prevalent chronic disease conditions, requiring as little as 5-10% weight loss (2). The Institute of Medicine (IOM) provided guidelines for effective weight loss programs, recommending the combination of diet, exercise and behavior modification (12). In a review of 12 weight loss trials completed between 1990 and 2000, which followed IOM guidelines, average weight loss was 10.4 kg (17). Intensive treatment including diet, exercise and behavior modification has been effective in generating a 5-10% weight loss for those completing a year of treatment (17). However, most overweight individuals are either not prepared or are not able to participate in such programs (7, 18) or if they start, more than one-third will fail to complete treatment and follow-up (19, 20). Even if obese persons participate and complete treatment, they are unlikely to lose sufficient weight to return to a normal weight range(12). Less intensive approaches have produced only minimal or modest weight loss (20, 21).
Few interventions have been designed with an obesity-prevention outcome for college-age individuals. In a review published in 2000, only one randomized controlled trial (RCT) was effective for weight gain prevention (22). The initial Pound of Prevention Intervention study (23) found that treatment consisting of a substantial contingency contract ($120) along with newsletters and a group educational program was more effective in preventing weight gain over 12 months (82%) than a control group (56%). However, in an attempt to replicate results without contingency contracting in a larger more diverse sample, there was no difference between groups at either 12 or 36 months; all groups gained an average of 0.5 kg/yr (24). Leermarkers et al. conducted an investigation of home- or clinic-based diet and exercise programs vs. a no-treatment control to prevent weight gain in young adult men with a BMI of 22-30 (25). Both programs were effective in producing an average weight loss of 1.6 kg over four months compared to the mean gain of 0.2 kg in control subjects; however the sample size was small (n=74) and there was no follow-up. The Midwest Exercise Trial (26) sought to determine whether a 16-month controlled, supervised exercise program could prevent weight gain in sedentary overweight young adults. The exercise group expended approximately 2000 kcal/week in exercise while the controls were instructed to maintain their usual physical activity patterns throughout the study. Results showed that without dietary changes, exercise facilitated a 5.2 kg weight loss in men while the exercising women avoided the 3 kg weight gain seen in the control group. Although the sample completing the study was small (n=67) and attrition high (44%), this study demonstrated that a high level of exercise could prevent weight gain in young adults without dietary restriction. The National Weight Control Registry that tracks reported strategies used by adults to achieve and maintain extensive weight loss also reported the value of routine exercise (REF). The recent STRIDDE (Studies of Targeted Risk Reduction Interventions Through Defined Exercise) investigation (27) found that in non-dieting overweight subjects the equivalent of walking 30 minutes per day was sufficient to prevent weight gain over the course of the eight-month program. These findings indicate the importance of moderate exercise for weight gain prevention.
The Women's Healthy Lifestyle program found that an intensive, individualized traditional diet (TD) approach designed to accomplish modest weight loss was effective in preventing net gain over 5 years (mean=-0.1 kg) compared to the control group (mean=+2.5 kg) (28). In addition, although not designed as a weight gain prevention program, the Diabetes Prevention Program also found modest weight loss and behavioral skill development prevented net gain over time (29). Although results of these programs have been promising, most of these programs utilized diet and/or exercise to generate an initial weight loss in order to prevent net gain over time. Like most TD programs, the initial weight loss was followed by some degree of weight gain. Only two of the programs (25, 26) focused on young adults and both programs had small, homogeneous samples. Clearly, there is a need for a more focused study for primary prevention of weight gain in young adults.
The American Public Health Association has a detailed policy statement supporting CBPR in public health (30). To better understand the social and environmental determinants of health we need to move away from the traditional research model. Rather than passive involvement of research participants, CBPR calls for active collaboration with the community to more effectively solve their problems. Communities need to set priorities for how to handle their problems including obesity (31). CBPR is typically used with a definable local community, but can also be used across a broad community, such as a collection of college campuses. CBPR has been used successfully for the development and implementation of the large scale California Health Interview Survey so that the information collected would best meet the needs of agencies/populations using the resulting data. Advisory boards involving 145 people representing the 60 agencies who used the results were involved in each step of the process (32). PRECEDE-PROCEED (33) is a CBPR model that can be used with local or very broad communities to untangle and understand the complex behavioral and environmental factors that influence health and quality of life. To achieve broad and sustained change in environmental forces and behavioral patterns, it is necessary to use a participatory model to both plan and implement multiple strategies (34).
Benefits
Using participatory research investigators work side-by-side with the target audience to understand, develop, and create interventions desired by the target audience. The process will uncover the necessary background information and knowledge to understand how issues important to young adults such as environment and quality of life affect their diet, activity, and life style choices. Grant funding will be pursued for this participatory research and for the resulting intervention projects, as well as smaller state/local projects. The ultimate outcome of this work will be educationally appropriate materials and interventions that meet the young adult groups' needs in their acquisition of healthful eating and prevention of weight gain. The collective power of the multiple states collaborating throughout the entire participatory process will significantly contribute to the understanding of how to best meet young adults' needs as they strive to prevent weight gain and adopt healthful habits. The outcomes from this work address health promotion priorities of USDA and other agencies such as NIH. Need for cooperative work
Need for cooperative work
In previous studies (NC200, NC219, NC219 renewal multi-state research) the NC219 research team has established a strong record of collaborative research demonstrated by a publication record with multiple authors from different institutions (see Critical Review). This groups has been successful at leveraging grant funding, including an Initiative for Future Agriculture and Food Systems (IFAFS) grant and two National Research Initiative (NRI) grants. NC219 researchers developed significant depth in the understanding of young adult food choice behavior and differences by gender and stages of readiness to change. The cooperation of a multi-state project benefits the proposed research by offering access to a wider variety of young adults than possible at a single institution. In previous work, some regional differences in demographics and in food choice behavior were evident. Racial and ethnic group representation also varied. Our collaborative relationship permits development of a much larger and more intricate project than possible within any one state alone. For example, last year, NC219 researchers in 10 states completed a behavioral intervention for low income young adults using extension/education/research partnerships. Over 2000 economically disadvantaged young adults were recruited and enrolled in a 12-month intervention study. The focus was on underserved populations of non-college young adults. Attrition rates were higher for participants with education dhigh school, experimental group assignment, non-white ethnicity or race, male gender, living with children, and income < $ 800/month (Chi squared, 6df =288, P<.001, Cox R2 =.132). With NRI support, NC219 researchers from 8 states are currently collaborating to develop a web-based intervention for weight gain prevention in college students.
The proposed study will use CBPR to expand the scope of the NRI intervention and address the quality of life, health, behavioral, environmental, and educational needs identified by college students. Our long range plan is to build on the NRI and CBPR with college students to extend to economically-disadvantaged young adults. Multi-state collaboration, by researchers and young adults as proposed for the current study, will provide experience in collaborative, community-based research that will complement the NRI-funded web-based intervention. The relationships that we have previously developed with Extension and other community partners will aid in achieving our long-range goal of using CBPR to provide integrated interventions to hard-to-reach populations of young adults. The larger and more diverse sample afforded through cooperative work increases the power and ability to generalize the results of research findings.
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