Objective: To examine the associations between morning cortisol and adiposity in children at baseline and 9-month follow-up.
Methods: Participants included 649 (301 males, 348 females) children (9.6 +/- 0.9 years) for the cross-sectional analysis and 316 (153 males, 163 females) for the longitudinal analysis. Body mass index (BMI, kg/m2) was calculated from measured height and weight and waist circumference (WC, cm) was measured at the superior border of the iliac crest. Cortisol was assessed via saliva samples collected on a single morning. Cross-sectional and longitudinal analyses were conducted to examine the relationships between cortisol and adiposity.
Results: Approximately 31% were overweight (17.7%) or obese (12.8%). The mean cortisol level was 9.36 +/- 5.64 nmol/L (0.34 +/- 0.20 microg/dL). At baseline, no significant correlations were found between cortisol and BMI or WC (r < 0.07). Baseline cortisol did not correlate with change in BMI z-score (r = -0.03) or WC (r < -0.01) over the follow-up period. When examined by weight status, baseline cortisol was significantly related to changes in WC (r = 0.32) and BMI z-score (r = 0.28) among overweight subjects.
Conclusions: A positive relationship was found between morning cortisol and change in WC over 9 months in overweight children. Future studies should examine the association between 24-h cortisol patterns and direct measures of trunk fat.