Obesity, leptin and blood pressure among children in Taiwan: the Taipei Children's Heart Study.

BACKGROUND

Obesity is associated with the occurrence of hypertension; however, the mechanisms of obesity-induced high blood pressure (BP) remain unclear. Leptin, the obese (ob) gene product, is associated with the occurrence of obesity and related disorders in humans. The purpose of this study was to evaluate the association between plasma leptin and BP among children.

METHODS

After multistage sampling, we randomly selected 1265 children (618 boys and 647 girls) with a mean age of 13.3 years (12 to 16 years old) in this cross-sectional survey. Obesity measurements included body mass index (BMI) and waist-to-hip circumference ratio (WHR). Plasma leptin levels were measured by radioimmunoassay.

RESULTS

The mean and median plasma leptin levels were 4.1 and 2.4 ng/mL among boys and 10.1 and 8.8 ng/mL among girls. Children in the highest quintile of leptin level (mean, 11.1 and 19.7 ng/mL for boys and girls, respectively) had higher body weight, BMI, WHR, BP, and insulin levels than children in the lowest quintile (mean, 1.1 and 3.9 ng/mL for boys and girls, respectively). Boys had a higher BMI, WHR, and BP levels, yet had lower leptin levels than girls. In both genders, BMI and plasma leptin levels were significantly positively correlated with BP. In multivariate regression analyses, plasma leptin levels were positively associated with BP; however, this association became insignificant among girls and even inversely associated with systolic BP among boys after adjusting for BMI.

CONCLUSIONS

Obesity is positively associated with BP among school children in Taiwan; however, the role of plasma leptin on the development of obesity-related hypertension is still controversial among school children.