Lifestyle factors and medical history
On the 1989 baseline questionnaire, study participants reported their current weight and height and their weight at age
18 (19). Participants were asked to update their weight on all biennial questionnaires. Body mass index (BMI, kg/m )
was calculated from reported height and weight data. BMI was derived for ages at which weight was not reported (ie,
between age 18 and age at the baseline questionnaire) from a formula using weight at age 18 and weights reported on
biennial questionnaires, as well as somatograms at ages 20, 30, and 40 to assign BMI at each age starting at 18 years
and through the end of the study period.