Fig. 1

Differences in body composition changes in males (M) and females (F) during puberty have different mediating effects on total airway resistance (Rrs5). Pubertal status refers to logarithmic testosterone levels in males and breast development by Tanner stage in females. Body composition is based on the muscle-fat ratio in males and body mass index (BMI) in females. The blue and pink colored lines represent males and females, respectively. The solid line indicates a positive relationship, whereas a dotted line indicates a negative relationship. Higher testosterone levels in males correlated with a higher muscle-fat ratio, which had a synergic mediating effect (aβ =  − 0.03, proportion = 19%) on lowering airway resistance. Conversely, a higher BMI in females had a negative effect (aβ = 0.14, proportion =  − 51%) on airway resistance. ^#Generalized linear regression with gamma function adjusted for confounding factors. ^¶ Mediation package with adjustment for confounding factors. Confounding factors included height, prematurity (< 37 weeks’ gestation), low birth weight (< 2500 g), passive smoking, aeroallergen sensitization, history of wheezing episode, and 25-OH vitamin D levels. Rrs5, resistance at 5 Hz; CI, confidence interval