There are almost 1.1 million professional and voluntary firefighters in the United States (US) . Obesity, an excessive accumulation of body fat , is a key health issue among firefighters who have a high risk for on-duty cardiovascular disease (CVD) mortality [3,4]. In a recent study using the 1997-2002 National Health Interview Surveys (NHISs), firefighters, along with police officers, ranked third in obesity prevalence (30% having a body mass index [BMI] ≥ 30 kg/m2) among 41 US male occupational groups . In earlier NHISs from 1986-1994, these occupations ranked fifth with the prevalence of 18%, so their obesity prevalence has increased in both relative and absolute measures (Fig. 1). Firefighters are among the occupations with the highest prevalence of obesity despite the fact that they are the most active among the 41 male occupational groups and meet the Healthy People 2010 recommended leisure-time physical activity goals .
Despite the high obesity prevalence among firefighters [5,7], epidemiological studies on firefighters and obesity [8-13] have tended to focus on the associations between obesity and physiological covariates (e.g., blood pressures and lipid profiles). Only a few studies [14-17] have investigated occupational and behavioral risk factors for obesity in firefighters. Despite the well-documented preventive effects of regular physical activity and a healthy diet on obesity in general populations [18-26], in the few studies available, the associations between regular physical activity and obesity in firefighters are inconsistent. Two epidemiological studies failed to show a significant association between self-reported physical activity and obesity [14,15], while two experimental studies about supervised exercise training programs [16,17] reported a small, but statistically significant nmda receptor antagonist of weight and body fat percent. The association between healthy diet behavior and obesity was supported in a recent cross-sectional study , but not in a prospective study . To our knowledge, no study has examined the levels of physical activity, food consumption, and the eating behaviors of firefighters at work and during leisure-time in relation to obesity. Gerace and George  reported some socio-demographic and behavioral risk factors for obesity in firefighters (i.e., being unmarried, younger, Black, recent ex-smoker, fast-eater at stations, and financial insecurity) and Elliot et al.  reported beneficial effects of a supportive health climate at work on promoting healthy behaviors and managing weight.
Developing a Theoretical Framework on Work and Obesity in Firefighters
Research Design and Methods
The research is a cross-sectional epidemiological study that builds on and takes advantage of an ongoing OCFA WEFIT examinations and available OCFA records of work schedules and duties. We are recruiting at least 360 OCFA firefighters from a pool of 840 active-duty firefighters scheduled for a WEFIT exam at the UCI COEH. The study involves the following steps in chronological order: 1) building a research advisory committee of researchers and firefighters; 2) conducting focus groups of firefighters to review, assess and adapt work environment and health behavior questionnaires to the firefighter work environment; 3) completion of a self-report survey (n > 360) to assess working conditions and health behaviors (dietary quality, eating behaviors, and physical activity); 4) a sub-study (n = 80) to test the validity of the self-report questionnaire against 48 hours of physical activity monitoring and food records, and to test a one-week test-retest reliability of the self-reported questionnaire; 5) data linkage for data analysis: the survey data, the sub-study data, and OCFA archival data about annual call information by local fire station will be linked to existing WEFIT medical data of the firefighters on weight (BMI and body fat %), clinic blood pressure, and other clinical measures (maximal oxygen consumption [VO2 max], total cholesterol, high-density lipoprotein [HDL], low-density lipoprotein [LDL], and triglycerides); and 6) reconvening the firefighter focus groups to assess and evaluate study findings in order to develop recommendations for reducing weight and obesity in the OCFA. The overall schedule of data collection and research activities is shown in Fig. 3. The study has convened the Advisory Committee and has begun to conduct the focus groups.