COPD Risk in Middle-Age: The 3-Way Interaction of Asthma, Smoking, and Measles
Although a previous measles infection alone may not have an independent effect on COPD risk, it appears to augment the combined effect of asthma and smoking.
The association between smoking, current asthma, and post-bronchodilator airflow obstruction may be compounded by measles infection during childhood, according to a study published in Respirology.
Researchers conducted a retrospective review of data from the prospective population-based Tasmanian Longitudinal Health Study (TAHS) to determine whether being infected with measles during childhood in a non-immunized middle-age population contributed to post-bronchodilator airflow obstruction through interactions with asthma and/or smoking. A total of 8583 participants were included in the study. Individuals who had a spirometry study in 1968 (n=7312) were retraced and resurveyed for this study (n=5729). Mean participant age was 44.9, and 51% were men. A total of 950 participants (69%) reported having had childhood measles.
A 2-way interaction was observed between smoking and asthma on post-bronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio. However, the results were only notable in participants with a reported history of childhood measles (z-score: –0.70; 95% CI, –1.1 to –0.3) vs –1.36; 95% CI, –1.6 to –1.1; 3-way interaction P =.009).
Of note, the 3- way interaction was found to be statistically significant only in individuals diagnosed with early-onset current clinical asthma compared with late-onset asthma (P =.011 and P =.198, respectively). When participants who did not have childhood measles were compared with participants who did and were assessed in combination with never and ever-smokers of <10 pack-years with current asthma symptoms, the odds of post-bronchodilator airflow obstruction was not found to be statistically significant (odds ratio [OR], 12.0; 95% CI, 3.4-42 vs OR, 2.17; 95% CI, 0.9-5.3). Researchers also found that while only 5.7% of participants had smoked ≥10 pack-years, had measles, and had current adult asthma, this comprised 19% (95% CI, 13%-28%) of participants with post-bronchodilator airflow obstruction in the total TAHS population. There were no associations identified between childhood measles and spirometry at age 7.
Researchers concluded that although measles did not independently influence post-bronchodilator airflow obstruction in middle-age adults, the strong 3-way interaction between measles, smoking ≥10 pack-years, and current asthma led to a decrease in post-bronchodilator FEV1/FVC ratio and increased the odds of “spirometrically defined COPD.” This suggests that the history of measles infection augments the 3-way interaction observed between smoking, current asthma, and measles.
Therefore, clinicians should carefully assess each individual's infectious disease history, smoking habits, and asthma history to early identify individuals at a higher risk for COPD during middle-age.
Perret JL, Matheson MC, Gurrin LC, et al. Childhood measles contributes to post-bronchodilator airflow obstruction in middle-aged adults: a cohort study [published online March 20, 2018]. Respirology. doi:10.1111/resp.13297