Pecova and colleagues conducted a pilot study to ascertain the link between cough reflex sensitivity and body mass index (BMI) among children who have chronic cough. 

Overall, 41 children with symptoms of chronic cough underwent cough reflex sensitivity measurement. The relation of cough reflex sensitivity (CKR) due to BMI was evaluated. Investigators defined cough reflex sensitivity as the lowest capsaicin concentration that could incite two (C2) or five (C5) coughs. 

Participants inhaled saline randomly mediated in 12 inhalations of additive capsaicin aerosol concentrations (0.61-1250 µmol/l). Each administration of saline and capsaicin aerosol was carried out at intervals of 1 min with an inhalation time of 400 ms. Investigators counted the number of coughs within 30 s of aerosol administration. The end-point of this cough challenge was the capsaicin concentration that could incite atleast 5 coughs (C5) or when the maximum capsaicin concentration of 1250 µmol/l was reached.

Cough reflex sensitivity (median, with the Inter-Quartile Range) for C2 and C5 was 19.5 (73.4) micromol/l and 78.1 (605.5) µmol/l, respectively. Researchers found no significant difference between obese andnon-obese subjects in concentrations of capsaicin that caused two (C2) coughs and five coughs (C5). Additionally, there was no statistically significant difference between obese atopic and non-obese atopic children for C2 and C5 value.

However, cough reflex sensitivity (C5) had a statistically significant negative relation, though weak, with BMI. Increase in BMI of one unit was found to be associated with -34.959 µmol/l reduction inthe value of C5. 

C2 and BMI did not have a statistically significant association. The median value of CKR (C2 and C5) in boys and in girls was not statistically significantly different. 

Conclusion - A rise in BMI in children having chronic cough is tied to decrease of cough reflex sensitivity (C5 value).

Source: Pecova R, Sojak J, Durdik P, et al. Relationship between cough reflex sensitivity and body mass index in children with chronic cough - a pilot study. Physiol Res. 2020 Dec 31;69(Suppl 3):S463-S470.