INTRODUCTION: Obesity has been associated with asthma, however the reverse relation has recently been observed among children.
OBJECTIVE: To investigate whether asthma contributes to obesity incidence in adults.
METHODS: The ECRHS is a cohort study with two follow-ups around, 10-years (ECRHS-II) and 20-years (ECRHS-III) after enrolment. Participants with obesity (BMI>30kg/m2) at baseline were excluded (n=957), leaving 8618 non-obese subjects who participated in at least one follow-up. Asthmatics were described if the subjects reported ever having asthma and had an asthma attack or woke up by an attack of shortness of breath in last 12 months or on current asthma medication. We evaluated the association between: (1) asthma at baseline (ECRHS-I) and obesity at ECRHS-II; and (2) newly reported asthma at ECRHS-II and obesity at ECRHS-III.
RESULTS: 10.2% of asthmatics at baseline developed obesity after 10 years compared to 7.7% of non-asthmatics (Age, sex & country-adjusted relative risk: 1.26; 95% confidence interval: 1.03-1.55). Further adjustment for BMI at baseline slightly reduced this risk (RR:1.2; 95%CI: 1.0-1.4). Obesity risk was highest for those developing asthma in adulthood (RR:1.37; 95%CI: 1.01-1.86) compared to those with childhood onset asthma (RR: 1.13; 95%CI: 0.83-1.53). Asthmatics who were non-atopic at baseline had a higher risk of developing obesity at 1st follow up (RR: 1.47; 95%CI: 1.15-1.86). Similar trend was observed in newly reported asthmatics in ECRHS-II and increased obesity risk at the final follow up ECRHS-III (RR: 1.22; 95%CI: 0.86-1.73).
CONCLUSION: These results suggest that asthmatics are at a higher risk of developing obesity.
