Childhood measles contributes to post-bronchodilator airflow obstruction in middle-aged adults: A cohort study

Background and objective: Chronic obstructive pulmonary disease (COPD) has potential origins in childhood but an association between childhood measles and post-bronchodilator (BD) airflow obstruction (AO) has not yet been shown. We investigated whether childhood measles contributed to post-BD AO through interactions with asthma and/or smoking in a non-immunized middle-aged population. Methods: The population-based Tasmanian Longitudinal Health Study (TAHS) cohort born in 1961 (n =8583) underwent spirometry in 1968 before immunization was introduced. A history of childhood measles infection was obtained from school medical records. During the fifth decade follow-up (n =5729 responses), a subgroup underwent further lung function measurements (n =1389). Relevant main associations and interactions by asthma and/or smoking on post-BD forced expiratory volume in 1s/forced vital capacity (FEV₁/FVC; continuous variable) and AO (FEV₁/FVC<lower limit of normal) were estimated by multiple regression. Results: Sixty-nine percent (n =950) had a history of childhood measles. Childhood measles augmented the combined adverse effect of current clinical asthma and smoking at least 10 pack-years on post-BD FEV₁/FVC ratio in middle age (z-score: -0.70 (95% CI: -1.1 to -0.3) vs -1.36 (-1.6 to -1.1), three-way interaction: P =0.009), especially for those with childhood-onset asthma. For never- and ever-smokers of <10 pack-years who had current asthma symptoms, compared with those without childhood measles, paradoxically, the odds for post-BD AO was not significant in the presence of childhood measles (OR: 12.0 (95% CI: 3.4-42) vs 2.17 (0.9-5.3)). Conclusion: Childhood measles infection appears to compound the associations between smoking, current asthma and post-BD AO. Differences between asthma subgroups provide further insight into the complex aetiology of obstructive lung diseases for middle-aged adults.