Abstract
Background: Observational studies suggest that obesity is associated with increased risk of asthma. However, it is unknown whether this could be explained by wheezing.
Objective: We tested the hypothesis that observational and genetic high body mass index(BMI) are associated with wheezing and asthma.
Methods: We genotyped 86,019 individuals aged 20-100 years from the Copenhagen General Population Study for FTO(rs9939609), MC4R(rs17782313), and TMEM18(rs6548238); 13,908 individuals experienced wheezing and 5,612 had asthma. Wheezing was self-reported, and asthma was ascertained through self-report, hospital contacts with asthma, and/or receiving medication for asthma.
Results: In observational analyses versus BMI of 18.5-22.4kg/m2, odds ratios(ORs) for wheezing were 2.68(95% confidence interval:2.49-2.88) for BMI of 30-34.9kg/m2, 4.20(3.79-4.66) for 35-39.9kg/m2, and 6.45(5.46-7.61) for BMI≥40kg/m2. Corresponding ORs for asthma were 1.46(1.32-1.62), 1.60(1.37-1.88), and 2.05(1.61-2.62), respectively. Compared with BMI allele score 0-2, score 3 and 4-6 were associated with 0.30 and 0.67kg/m2 higher BMI. In genetic analyses versus allele score 0-2, ORs for wheezing were 1.05(1.01-1.10) and 1.11(1.06-1.17) for allele score 3 and 4-6. Corresponding ORs for asthma were 1.02(0.95-1.08) and 1.02(0.95-1.10). Genetically determined ORs per unit higher BMI were 1.17(1.09-1.25) for wheezing and 1.03(0.93-1.14) for asthma. Corresponding observational ORs were 1.10(1.09-1.10) and 1.03(1.03-1.04).
Conclusions: Genetically high BMI was associated with wheezing, but not with asthma. Thus, these findings suggest that asthma may be misdiagnosed based on wheezing in many obese individuals.
- Copyright ©ERS 2015
