[Birth cohort analysis of obesity in an occupational setting]

The purpose of this study was to analyze the transition of body mass index (BMI) by birth cohort and to determine the relationship between BMI and high blood pressure, for the health management of workers in an industry.

The eligible study subjects were 3,043 male workers at printing and papermaking plants who were 20 to 49 years of age in 1986 and whose annual health checkup information was available for both 1991 and 1996. First, we analyzed the transition of BMI by 5-year birth cohort. Second, we analyzed the relationship between BMI and high blood pressure (systolic blood pressure > = 140 mmHg or diastolic blood pressure > = 90 mmHg) using multiple logistic regression models. In this analysis, we excluded 596 subjects who were diagnosed as having high blood pressure in 1986 and 17 subjects whose alcohol drinking habits were unknown. Consequently, we had 2,430 study subjects.

(1) All the birth cohorts showed that the proportion of obese subjects (BMI > = 26.4) became higher as age advanced. The proportion was higher for younger cohort. (2) By multiple logistic regression models, age at the beginning of the study, BMI, change of BMI in 5 or 10 years, and alcohol drinking habits were related to the risk of having high blood pressure.

In the health management of workers, it is necessary to evaluate the risk by birth cohort. Also, we consider that we need to initiate obesity counseling before the workers become 30 years of age.