Lifestyle, weight perception and change in body mass index of Japanese workers: MY Health Up Study.

OBJECTIVES

To investigate the effect of weight perception and lifestyle on body mass index (BMI) over a 2-year period.

STUDY DESIGN

Longitudinal study to compare the change in BMI (kg/m(2)) according to weight perception and lifestyle at baseline.

METHODS

Study subjects were 6029 men and 18,567 women aged 20-69 years who worked at a large financial firm in Japan. Subjects' weight and height were measured in 2004 and 2006. The data in 2004 were used as baseline data. Weight perception and lifestyle factors, including eating, physical exercise, hours of sleep, smoking and alcohol consumption, were determined by a self-administered questionnaire in 2004.

RESULTS

The age-adjusted mean change in BMI over the 2-year period was -0.0593 among men and 0.0890 among women. In men, subjects who perceived themselves to be overweight had a reduced BMI 2 years later compared with subjects who perceived themselves to be 'just right' or underweight. Multiple regression analysis of lifestyle factors, adjusted for age and BMI at baseline, indicated that less time spent commuting, not having a hobby, not having a fixed lunch time, consumption of sweets, smoking and colleagues' smoking were associated with increased BMI among men. Fewer hours of sleep, no fixed lunch time and frequent soft drink consumption were associated with increased BMI among women.

CONCLUSIONS

A perception of being overweight was associated with a decrease in BMI for Japanese male workers. Positive lifestyle factors associated with a decrease in BMI in both men and women include having a fixed lunch time and being older. These factors should therefore be highlighted in future health promotion activities in workplaces.