Background: Recent increases in the prevalence of obesity worldwide are suggested to be caused largely by an environment that promotes sedentariness and excessive food intake.
Objective: We investigated associations of body mass index (BMI) and obesity with physical activity, food choices, alcohol consumption, and smoking history. In addition, we examined the consistency of these associations over time, with the aim of assessing whether the significance of lifestyle variables as correlates of obesity increased over a 15-y period.
Design: Independent cross-sectional surveys were carried out in 1982, 1987, 1992, and 1997. Altogether, 24604 randomly selected men and women (aged 25-64 y) participated in these surveys. The subjects' weights and heights were measured, and data on lifestyle were collected with self-administered questionnaires.
Results: In men and women, perceived general health, leisure-time physical activity, and daily vegetable consumption were inversely associated with obesity, as were bread consumption in women and activity at work in men. Consumption of sausages, milk, and sour milk and heavy work (in women only) were positively associated with obesity. Obesity was also associated with alcohol consumption and smoking history. Most associations were constant over the 15-y period. However, the inverse associations of BMI with physical activity in women and with perceived health in men seemed to strengthen over time.
Conclusions: A physically active lifestyle with abstention from smoking, moderate alcohol consumption, and consumption of healthy foods maximizes the chances of having a normal weight. The significance of avoiding sedentariness increases over time as a factor associated with normal weight.