UC Irvine

Psychosocial and environmental work factors and their effects on obesity and cardiovascular disease risk among firefighters

By

Javier Garcia Rivas

Doctor of Philosophy in Public Health

University of California, Irvine, 2019

Professor BongKyoo Choi, Chair

During the last two decades, US firefighters have gradually gotten heavier to become the third heaviest occupational group in the country and workplace has been identified as a salient environmental factor which contributes to the development of obesity among this occupational group. Nevertheless, few studies have studied the impact of the work environment and individual characteristics integrated in a socio-ecological model design.

The long term goal of this investigation is to make a contribution to the research of individual, occupational and environmental factors that play a role in the development of obesity in firefighters. The specific aims of this study were to 1) determine the association between worksite food environmental factors and obesity among male firefighters who work 24-hour shifts. 2) investigate the relationship between health-related (nutrition and physical exercise) self-efficacy and weight outcomes i.e. body mass index, waist circumference and body fat percent. Concurrently, analyze important occupational preceding variables (e.g. institutional, supervisor and coworker support) that facilitate/hamper self-efficacy; and 3) compare four sedentary behavior measures (number of steps, <100 and <150 counts per minute threshold in actigraphy, sitting time by posture sensor inclinometer and self-reported sedentary work) with regards to obesity and CVD risk factors.

The present study found an indirect association between environmental fast-food density and obesity indicators in male firefighters. The association was mediated by station- and individual-level eating behaviors. Secondly, organizational support was the most important occupational predictor of exercise and nutrition self-efficacy. However, only exercise self-efficacy was directly associated negatively with all three obesity indicators (Waist circumference, BMI and Body Fat Percent). Finally, self-reported sedentary work was identified as the best predictor of CVD risk factors when compared to other physical activity and sedentary behavior measures. Sitting time assessed by inclinometry was also an important predictor of systolic blood pressure and HDL cholesterol. Other measures of occupational inactivity (step count and sedentary behavior assessed by actigraphy) did not perform well as predictive tools.

The present dissertation offers an integral theoretical approach to a public health issue based on an occupational health perspective in order to prevent weight-related diseases and improve the health of firefighters.