Family history of hypertension and the risk of overweight in Japanese children: results from the Toyama Birth Cohort Study.

Background: Family history can be a useful screening tool in the assessment and management of the risk for noncommunicable disease. However, no data have yet been reported on family history of hypertension and its effect on children's overweight.

Methods: A total of 7249 Japanese children enrolled in the Toyama Birth Cohort Study were followed until 2002 (mean age: 12.3 years). Family history of hypertension was ascertained by asking children's parents whether children's biological parents or grandparents had doctor-diagnosed hypertension. Child overweight was defined according to international criteria for age- and sex-specific body mass index.

Results: The prevalence of child overweight at age 12 was 21.7% for males and 15.9% for females. After adjusting for family structure, parental employment status, and lifestyle factors, we found that a maternal family history of hypertension was positively associated with the risk of child overweight at age 12 (adjusted odds ratio [OR] 1.21, 95% confidence interval [CI] 1.04-1.39). The adjusted OR increased from 1.16 (95% CI 0.99-1.35) to 1.42 (95% CI 1.04-1.92) to 4.75 (95% CI 1.35-16.69) as the number of family members with hypertension increased from 1 to 2 to 3, respectively. There was no significant difference in the prevalence of overweight between children with a paternal family history of hypertension and those without.

Conclusions: A maternal family history of hypertension was positively associated with the risk of overweight in children at age 12.