Risk and impact of chronic cough in obese individuals from the general population

Thorax. 2021 Jul 6;thoraxjnl-2020-216351. doi: 10.1136/thoraxjnl-2020-216351. Online ahead of print.

Abstract

Background: Obese individuals may be at higher risk of chronic cough. We investigated the risk and impact of chronic cough in obese individuals from the general population.

Methods: We recorded chronic cough, body mass index (BMI) and other related clinical conditions in 44 554 adults from the Copenhagen General Population Study. Individuals with asthma and/or chronic obstructive pulmonary disease were excluded (n=10 977). BMI was divided into: underweight (BMI <18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), obese (30.0-34.9 kg/m2) and severely obese (≥35.0 kg/m2).

Results: Among 33 577 adults from the general population, 27 829 (83%) were non-obese and 5748 (17%) were obese. Compared with individuals with normal weight, multivariable adjusted ORs for chronic cough risk were 1.4 (95% CI 1.2 to 1.6) in overweight, 1.9 (95% CI 1.7 to 2.2) in obese and 2.6 (95% CI 2.1 to 3.2) in severely obese individuals. Mediation analyses showed that chronic cough due to obesity was up to 23% mediated by gastro-oesophageal reflux disease (GERD). Other mediators included low vegetable intake with 10% and occupational exposure with 8%. Among obese individuals, those with versus without chronic cough had worse accompanying respiratory symptoms, more often comorbidities including GERD and diabetes, greater healthcare utilisations, lower lung function and higher blood inflammation (all p<0.05).

Conclusion: There is dose-response relationship between BMI and chronic cough, and chronic cough risk is twofold to threefold higher in obese individuals from the general population. This increased risk was partly mediated by GERD, low vegetable intake and occupational exposure, supporting that there may be benefit to gain by ameliorating some of these factors in obese individuals with chronic cough.

Keywords: clinical epidemiology; cough/mechanisms/pharmacology.