Weight variability effects: a prospective analysis from the Stanford Five-City Project.

For determination of the effects of weight variability on cardiovascular risk factors, a random community sample of 269 men and 361 women aged 25-74 years, drawn from the Stanford Five-City Project, was followed for up to 10 years (1979-1989). Systolic and diastolic blood pressure, total and high density lipoprotein cholesterol, and pulse were measured. Body mass index slope (BMI-slope) was determined by regressing five BMI values on time for each individual. BMI variability was defined as the root mean square error (BMI-RMSE) of a regression line fitted to each individual's BMI values over time. The slopes of the five cardiovascular risk factors were most strongly related to the baseline value of each risk factor and BMI-slope in both men and women. Neither BMI-RMSE nor the interaction of BMI-RMSE with BMI-slope was related to risk factor slopes. In this population, BMI variability had little impact on cardiovascular risk factors compared with BMI-slope and baseline BMI.