Demographic and lifestyle predictors of body mass index among offshore oil industry workers: cross-sectional and longitudinal findings.
BACKGROUND: Significant overweight among offshore workers on North Sea oil and gas installations has been linked to high calorie intake, lack of active leisure-time pursuits, and environmental factors conducive to weight gain. However, the prevalence of overweight among offshore workers has not been examined in recent data, and no longitudinal studies of body mass index (BMI) in this occupational group have been reported. Aims The present study sought to examine BMI levels in a sample of UK offshore personnel, and to evaluate demographic factors, smoking and work-related physical activity as predictors of BMI, and 5 year change in BMI. METHODS: Survey data (including age, education, marital status, work-related physical activity and height/weight) were collected in 1995 from male workers on 17 North Sea installations (n = 1581, 83% response rate); follow-up data were obtained in 2000 (n = 354, 34.9% of the potential sample). RESULTS: Overall mean BMI was 25.6 (2.8) kg/m(2): rates of obesity (BMI > 30) and overweight (BMI = 25-30) were 7.5 and 47.3%, respectively. Mean age was 38.7 (8.9) years; linear and quadratic age terms predicted BMI. Age-adjusted BMI values were very similar to those reported from other offshore studies over the past 15 years. Age, marital status, education, smoking and physical activity significantly predicted baseline BMI, but only age (and some interactive effects) predicted 5 year BMI change. CONCLUSIONS: The present age-adjusted BMI values were closely similar to those found offshore in the mid-1980s, but also to recent national data; thus, North Sea personnel do not appear to reflect current population trends towards increased BMI levels. This result accords with the emphasis now given to health promotion (particularly dietary change) on offshore installations; the present findings also highlight the need to focus these initiatives on workers with sedentary jobs and/or low education.