Effects of ten year body weight variability on cardiovascular risk factors in Japanese middle-aged men and women.

OBJECTIVE: The purpose of the present study was to determine the effects of weight variability on cardiovascular risk factors (CRF) based on a large sample of community-resident Japanese males and females.
METHOD: A total of 3564 men and 1955 women, all Japanese, aged 30-69 y in the baseline year (1987), were followed-up for up to 10 y (end-point in 1996). Height, body weight, systolic and diastolic blood pressure, fasting serum total cholesterol, triglyceride and fasting plasma glucose were measured as an annual health check-up. At least six times in 10 y, body mass index (BMI) mean was calculated as an index of the BMI level of each subject (BMI mean). Direction and magnitude of the change in a subject's BMI was determined by a regression slope of BMI values over time (BMI slope). BMI fluctuation was defined as the root mean square error (BMI RMSE) of a regression line. The slopes of the five CRF were calculated using each regression equation over time.
RESULTS: The BMI slope strongly correlated to each CRF slope independent of baseline age, baseline CRF value, smoking habit, BMI mean and BMI RMSE. BMI RMSE did not correlate to any CRF slopes.
CONCLUSION: This study indicates that weight gain and weight loss have a much greater effect on CRF change than does weight fluctuation in Japanese middle-aged men and women.