Role of gender and pubertal stage on cough sensitivity in childhood and adolescence.

Studies in healthy adult volunteers and patients with chronic cough have shown that women have increased cough sensitivity to inhaled tussigenic stimuli, including capsaicin. The explanation for this phenomenon remains unknown, although the influence of pubertal changes (dimensional, hormonal) may play a role. In the present study we set out to examine the effect of the pubertal status on cough reflex sensitivity in a population of male and female children and adolescents. The study consisted of cough reflex sensitivity (CRS) testing, spirometry, and a children-completed pubertal status questionnaire. The inclusion criteria were no current symptoms of respiratory disease, no respiratory infection in the preceding 2 weeks, no allergic disease, and no other disease that could modulate CRS. All children were non-smokers. For assessing the CRS we used a compressed air-driven nebuliser controlled by a dosimeter with an inspiratory flow regulator valve. Each subject inhaled up to 12 capsaicin aerosol concentrations (0.61-1250 micromol/l) during 400 ms at 1 min intervals. CRS was defined as the lowest capsaicin concentration that evoked minimally 2 coughs. 225 children (median age 13 yr, 103 girls/122 boys) were divided according to the pubertal status (prepubertal, early pubertal, and late pubertal) and gender. We found that CRS [geometric mean (95%CI)] was similar in prepubertal and early pubertal girls and boys. However, CRS was significantly higher in late pubertal girls (n=56) than in boys (n=26) [53.57 (35.62-80.64) micromol/l vs. 119.7 (70.74-208.55) micromol/l; respectively; P=0.017]. We conclude that puberty and gender have a significant influence on the cough threshold to capsaicin. It seems, however, hard to determine what factors are responsible for the observed gender differences in cough reactivity adolescents.