ABSTRACT
Epidemiological studies of weight change will share the challenges of obesity studies; large numbers of participants and longterm follow-up are required, and there are inherent problems in measuring lifestyle predictors such as diet or physical activity. Two groups of predictors were considered: early life predictors, where the outcome was a body-mass index (BMI) trajectory from 7 to 42 years, and childhood predictors, where the outcome was a BMI trajectory from 16 to 42 years. Social class had no influence on BMI at age 7 years in either males or females. However, in both sexes, there was a significant effect on the slope of the trajectory, such that, in males from social classes IV and V, BMI increased at a higher rate, 0.046 kg/m2/year, than in males from social classes I and II. Analyses of obesity and BMI in the 1958 birth cohort have used logistic and linear regression techniques to examine relationships between predictors and body fatness.
