Abstract
Background: We have reported previously in the Multiethnic Cohort study (MEC) that the incidence of lung cancer varies across races/ethnicities. Compared to whites, for the same number of cigarettes smoke, African Americans and Native Hawaiians have a higher risk of lung cancer, whereas Latinos and Japanese Americans have a lower risk of disease. Chronic obstructive pulmonary disease (COPD) is a well-established risk factor for lung cancer. The differences in COPD risk across populations while accounting for known risk factors have not been evaluated.
Methods: Using data from the MEC, restricted to participants enrolled in Medicare fee-for-service program (n=120,607), we investigated the association of known risk factors with risk of COPD across five racial/ethnic populations, including age, sex, education, BMI, physical activity, marital status, asthma, smoking history, ethnic-specific smoking cessation rates, and occupational exposures, mutually adjusting for the other variables. Stratified analyses were conducted by smoking status.
Results: A total of 24,730 COPD cases were identified in the MEC between 1999 and 2014. Compared to whites, African Americans and Native Hawaiians had an 8% lower risk of COPD risk (RRs=0.92; 95% CI: 0.87-0.97 for African Americans and 95% CI: 0.86-0.97 for Native Hawaiians). Risk was found to be even lower in Latinos (RR=0.83; 95% CI: 0.79-0.88) and Japanese Americans (RR=0.68; 95% CI: 0.65-0.70). While the overall order of risk correlated with self-reported quantity of cigarettes smoked, disaggregation by smoking status revealed underlying ethnic disparities (p-heterogeneity<0.001). In current smokers (n=4,610), after adjusting for age, sex, education, BMI, physical activity, marital status, asthma, and occupational exposures, COPD risk was lower in Native Hawaiians (RR=0.78; 95% CI: 0.7-0.88), Japanese Americans (RR=0.63; 95% CI: 0.58-0.69) and Latinos (RR=0.69; 95% CI: 0.62-0.77) compared to whites and no difference was found in African Americans (RR=0.96; 95% CI: 0.86-1.06). Among former smokers (n=8,715), after adjusting for the same variables, compared to whites, African Americans (RR=0.89; 95% CI: 0.82-0.96), Japanese Americans (RR=0.69; 95% CI: 0.65-0.73) and Latinos (RR=0.83; 95% CI: 0.77-0.89) had a lower risk of COPD; no difference in risk was found for Native Hawaiians (RR=0.97; 95% CI: 0.89-1.07). Among never smokers (n=6,972), when compared to whites, only Japanese Americans had a lower risk of disease (RR=0.71; 95% CI: 0.66-0.76). African Americans (RR=0.93; 95% CI: 0.84-1.01), Native Hawaiians (RR=0.96; 95% CI: 0.86-1.08) and Latinos (RR=0.95; 95% CI: 0.87-1.03) were all found to have a similar COPD risk as whites.
Conclusions: Our findings demonstrate that the racial/ethnic patterns for COPD risk are not consistent with those observed with lung cancer risk. Reasons for these differences are being investigated. Also, our findings suggest that the disparities in COPD risk may be different by smoking status.
Citation Format: Sungshim L. Park, Iona Cheng, Anna H. Wu, Jackie Porcel, Lynne R. Wilkens, Loic Le Marchand, V. Wendy Setiawan. Ethnic differences of chronic obstructive pulmonary disease (COPD) in the Multiethnic Cohort study [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C096.
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