VanWormer, Jeffrey J.2011-03-292011-03-292011-01https://hdl.handle.net/11299/102002University of Minnesota Ph.D. dissertation. January 2011. Major: Epidemiology. Advisors: Jennifer A. Linde, PhD, & Robert W. Jeffery, PhD. 1 computer file (PDF); xi, 90 pages, appendix A.INTRODUCTION: Rising obesity rates are a threat to the American public's health. To date, however, few studies have used an environment focused weight gain prevention intervention approach, which is arguably more appropriate than individual weight loss counseling interventions. The HealthWorks trial recently implemented a worksite environment intervention (e.g., modifications to cafeterias/vending, activity social environment) aimed at reducing weight gain over two years among adults. METHODS: This dissertation includes three secondary data analyses from the broader HealthWorks trial in order to: (1) determine if baseline physical activity level is associated with enrollment in worksite walking club events, (2) assess if self-weighing frequency is associated with weight maintenance, and (3) assess if weight change is associated with workplace absenteeism. Physical activity and self-weighing were two of the key lifestyle changes targeted in the HealthWorks trial and reduced workplace absenteeism was one of the economic outcomes believed to result from a successful intervention. Six worksites (N=1,747 individuals) were randomized to either a treatment or control arm. Multivariate regression models were used for all analyses. RESULTS: In paper #1, baseline physical activity level was not a significant predictor of worksite walking club participation, but several covariates (i.e., age, sex, social support, worksite) remained in the final models as significant predictors. In paper #2, there was a significant interaction between follow-up self-weighing frequency and baseline BMI category. Specifically, adjusted weight change ranged from a mean±SE -4.5±0.8 kg among obese daily self-weighers to 2.2±0.4 kg for participants at a healthy BMI who reported self-weighing monthly or less. In paper #3, weight change was not a significant predictor of workplace absenteeism, but several covariates (i.e., sex, depression, smoking, BMI) remained in the final models as significant predictors of workplace absenteeism. CONCLUSIONS: The collective findings suggest that over two years: (1) worksite walking clubs are generally appealing across varying levels of physical activity, (2) self-weighing may be most beneficial for obese individuals who increase their self-weighing frequency over time, and (3) weight loss may not meaningfully decrease workplace illness absence days. More intense efforts on the primary prevention of weight gain that decreases the proportion of newly obese employees, perhaps via broad-based physical activity programs and stronger emphases on frequent self-weighing, may be necessary to achieve long-term weight change and economic benefits for employers.en-USAbsenteeismPhysical activitySelf-weighingWeight gain preventionWorksiteEpidemiologyThesis or Dissertation