Joint Association of Education and Neighborhood Socioeconomic Status with Smoking Behavior: The Multiethnic Cohort Study

Background: Cigarette smoking is the leading cause of preventable mortality. Both neighborhood- and individual-level socioeconomic status (SES) are inversely associated with smoking. However, their joint effect on smoking behavior has not been evaluated.

Methods: This cross-sectional study examined the association of education and neighborhood SES (nSES) with smoking among 166,475 Multiethnic Cohort (MEC) participants (African American, Japanese American, Latino, Native Hawaiian, White individuals) recruited between 1993-1996 from Hawaii and LA County. nSES was based on a composite score of 1990 US Census data and assigned to geocoded addresses; nSES quintiles were based on region-specific distributions. The joint education/nSES variable had four categories: high nSES (Quintiles 4-5)/high education (> high school), high nSES/low education (≤ high school), low nSES (Quintiles 1- 3)/high education, and low nSES/low education. Poisson regression estimated state-specific prevalence ratios (PR) for current smoking versus non-smoking across joint SES categories, with subgroup analyses by sex and race/ethnicity.

Results: In California, compared to MEC participants with high nSES/high education, the PR for smoking was highest for low nSES/low education (PR = 1.50), followed by low nSES/high education (PR = 1.33) and high nSES/low education (PR = 1.29). All pairwise comparisons between PR were statistically different (p < 0.0001), except high nSES/low education vs. low nSES/high education. In Hawaii, compared to high nSES/high education, the PR for smoking was also highest for low nSES/low education (PR = 1.41), but followed by high nSES/low education (PR = 1.36), then low nSES/high education (PR = 1.20). All pairwise comparisons were statistically different (p < 0.0001), except high nSES/low education vs. low nSES/low education. These patterns were consistent across sex and race/ethnicity within each state.

Conclusion: In California and Hawaii, individuals with low education living in low SES neighborhoods had the highest smoking prevalence. However, regional differences were noted: in California, both low education and low nSES increased smoking prevalence; whereas in Hawaii, low education had a greater impact.