Associations Between Weight-Related Measurements and Pubertal Markers in Norwegian Girls: The Bergen Growth Study 2.

CONTEXT

Previous studies that have documented the association between puberty and overweight and obesity have typically used body mass index (BMI) as a measure of weight status, and menarche as outcome. Other markers of body weight or pubertal development are less studied.

OBJECTIVE

To characterize associations between weight-related anthropometric measurements and pubertal markers in Norwegian girls.

METHODS

A total of 646 schoolgirls aged 6 to 16 years from the Bergen Growth Study 2 were included. Pubertal status was assessed with ultrasound staging of breast development (USB), Tanner pubic hair stage, and menarche. Reproductive hormones were analyzed with liquid chromatography-tandem mass spectrometry and immunoassays. BMI, waist circumference, subscapular skinfolds (SSF), and percentage body fat measured by bioelectrical impedance (%BF) were converted to z-scores to study associations with pubertal status with logistic/linear regression adjusted for age (all pubertal markers) and Cox regression (menarche).

RESULTS

For all stages of breast development and all weight-related variables, girls with relatively low (< -1z) levels of anthropometric measurements were less likely (age-adjusted odds ratio [AOR] <1) and girls with high z-score levels were more likely (AOR >1) to have reached a particular stage compared to average-weight peers. Comparable associations were found for menarche. Pubarche was not significantly associated with weight-related measurements. Interestingly, serum concentrations of estrogens were lower in pubertal girls (USB2-5) with increasing SSF and %BF z-scores.

CONCLUSION

Associations between all included weight-related anthropometric measurements and breast development and menarche, but not pubarche, were found strong and consistent. Our findings indicate complex associations between reproductive hormones and weight status.