African Americans are at known higher risk of bronchial asthma (BA) than whites, but data are sparse about possible black/white disparity in risk of COPD. Information is also sparse about Asian/white disparity for both BA and COPD.
We performed a cohort study among 126,263 persons who supplied data, including self-classified ethnicity, at examinations in 1978–85. These included ∼55% whites, ∼27% African Americans, ∼11% Asian Americans, and ∼4% Hispanics. Endpoints were subsequent primary hospitalization for BA among 726 persons and, excluding those with any diagnosis of BA, for COPD among 753 persons. To estimate BA and COPD risk, we used Cox proportional hazards models adjusted for age, sex, body mass index, education, smoking and alcohol intake.
With whites as referent, the relative risks (RR), 95% confidence intervals (CI) for BA were: blacks = 1.7 (1.4–2.0), Asians = 1.5 (1.2–2.0), & Hispanics = 0.9 (0.6–1.4). The increased BA risk in Asians was concentrated in Filipinos (RR=2.5 [1.7–3.6]. For COPD RR's vs whites were black =0.8 (0.7–1.0), Asian = 0.5 (0.3–0.7), and Hispanic –0.6 (0.3–1.0). The lower risk of COPD among Asians was present in each specific Asian ethnicity: e.g., Chinese (RR=0.3), Japanese (RR=0.4), Filipinos (RR=0.8) and other Asians (RR=0.4). The lower Asian COPD risk was also consistent in the sexes and multiple strata, including smoking categories, and COPD diagnostic subgroups (chronic bronchitis and other COPD diagnoses).
There are striking ethnic disparities in the risk of BA and COPD, especially for Asian Americans who have high BA risk and low COPD risk. While incomplete control for smoking habit differences or other environmental factors may be responsible for the Asian/white COPD risk difference, it is possible that Asians may have a genetic trait protective against COPD.
Asian Americans have a lower risk of developing COPD compared to whites.
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