Unequal Effects of Educational Attainment on Workplace Exposure to Second-Hand Smoke by Race and Ethnicity; Minorities' Diminished Returns in the National Health Interview Survey (NHIS).

Background: One of the mechanisms by which high educational attainment promotes populations' health is through reducing exposure to environmental risk factors such as second-hand smoke. Minorities' Diminished Returns theory, however, posits that the protective effect of educational attainment may be smaller for racial and ethnic minority individuals particularly Blacks and Hispanics compared to Whites.

Aims: To explore racial and ethnic differences in the association between educational attainment and second-hand smoke exposure at work in a national sample of American adults.

Methods: Data came from the National Health Interview Survey (NHIS 2015), a cross-sectional study that included 15,726 employed adults. The independent variable was educational attainment, the dependent variables were any and daily second-hand smoke exposure at workplace, age and gender were covariates, and race and ethnicity were the moderators.

Results: Overall, higher educational attainment was associated with lower odds of any and daily second-hand smoke exposure at work. Race and ethnicity both interacted with educational attainment suggesting that the protective effects of educational attainment on reducing the odds of any and daily second-hand smoke exposure at work are systemically smaller for Blacks and Hispanics than Whites.

Conclusions: In the United States, race and ethnicity bound the health gains that follow educational attainment. While educational attainment helps individuals avoid environmental risk factors such as second-hand smoke, this is more valid for Whites than Blacks and Hispanics. The result is additional risk of cancer and tobacco related disease in highly educated Blacks and Hispanics. The results are important given racial and ethnic minorities are the largest growing section of the US population. We should not assume that educational attainment is similarly protective across all racial and ethnic groups. In this context, educational attainment may increase, rather than reduce, health disparities.