Effects of Short-term Variation in Body Mass Index on Blood Pressure in Middle-aged Japanese Male Workers

Abstract

We attempted to perform multilevel analyses to explore whether a year-to-year weight variation causes any corresponding effects on blood pressure (BP) among middle-aged Japanese workers. Subjects were 4547 healthy male workers 40-59 in age from whom serial data of systolic and diastolic BP were collected during health checkups conducted in the years 1997-2000. The effects on BP of a time-varying body mass index (BMI) that was rescaled to center around the individual-specific mean of 4 examinations on BP were investigated by statistical analysis with multilevel modeling to adjust for the wide variability among individuals. A significant relationship between the time-varying BMI and both systolic and diastolic BP was confirmed. None of the interaction terms for BMI × potential effect modifiers (smoking history, drinking status, leisure-time physical activity, and preference for salty taste) included in the subanalysis model showed any significant modifying effect. Our result indicated that the year-to-year weight variation, though usually in a much narrower range than the between-individual variation, has a strong impact on the corresponding BP. This result supports the public health significance of interventions in short-term weight control to prevent the development of hypertension among an otherwise healthy workplace population.