[Association between hair cortisol concentration and overweight and obesity in 6-9 years old childhood]

Objective: To determine the possible relations between hair cortisol concentration (HCC) as a biomarker of chronic stress and childhood overweight and obesity. Methods: Children from grade 1 to 3 from 2 primary schools in Bengbu were invited to participate in the study; and those who suffer from mental disorders, endocrine diseases and those who took hormone drugs were excluded. Parental questionnaire was implemented to collect information on physical activity, screen time, sleep duration, sugar-beverage consumption, as well as socio-economic status. Height and weight were examined. Eligible hair samples from 1 263 children (598 boys and 665 girls) were obtained, and the cortisol content was determined. Multivariate logistic regression model analysis was recruited to examine the association between HCC quartiles and overweight and obesity among boys and girls, respectively. Results: HCC in P(50) (P(25)-P(75)) among girls and boys was separately 11.86 (10.57-13.15) and 11.71 (10.54-13.09) µg/kg (Z=-0.886, P=0.376); HCC in P(50) (P(25)-P(75)) among non-overweight, overweight and obesity boys was separately 11.62 (10.45-12.82), 12.24 (10.88-13.55) and 12.30 (10.99-13.53) µg/kg (χ(2)=8.24, P=0.016); HCC in P(50) (P(25)-P(75)) among non-overweight, overweight and obesity girls was separately 11.35 (10.06-12.62), 12.07 (11.04-13.21) and 12.59 (11.12-13.63) µg/kg (χ(2)=36.16, P<0.001). After age, physical activity, screen time, sleep duration, sugared beverages and socio-economic status adjusted, compared with HCC in Q1 level, girls whose HCC in Q2, Q3 Q4 level had higher rates in overweight, with OR (95%CI) at 1.10 (1.04-3.32), 2.59 (1.51-4.45) and 3.16 (1.79-5.57), respectively. Girls with HCC in Q3 and Q4 level had higher rates in obesity, with OR (95%CI) at 2.22 (1.16-4.26) and 5.62 (3.04-10.41). Among boys, highest quartiles in HCC was risk factor for overweight, OR (95%CI) was 2.14 (1.18-3.90). Conclusion: Hair cortisol had a significant relation with overweight and obesity in 6-9 years old childhood especially among girls.