Examining the Role of Race/Ethnicity and Sex in Modifying the Association Between Early Smoking Initiation and Mortality: A 20-Year NHANES Analysis.

Introduction: The authors aim to examine the modifications of the relationship between early smoking initiation and overall mortality by race/ethnicity and sex using data from U.S. adults in the 1999-2018 National Health and Nutrition Examination Surveys. Methods: The authors analyzed data from 10 aggregated National Health and Nutrition Examination Surveys cycles focusing on noninstitutionalized U.S. civilian population aged 20-79 years. Smoking initiation was categorized by age, and the study's primary outcome was all-cause mortality. The authors employed Kaplan-Meier curves and Cox proportional hazards models to investigate the associations and adjusted for race/ethnicity, sex, and survey cycle. The authors also explored effect modification by race/ethnicity and sex. Results: The analysis included 50,549 participants. The authors found that early smoking initiation was significantly associated with increased all-cause mortality across all age categories, with higher hazard ratios for earlier initiation ages. The relationship exhibited variations by race/ethnicity and sex. Non-Hispanic White population showing the highest risk, followed by non-Hispanic Black subpopulation, but race/ethnicity interaction terms was not significant. Significant interaction by sex was observed. Conclusions: Early smoking initiation is significantly associated with increased risk of mortality, with noticeable differences by race/ethnicity and sex. These findings emphasize the need for prevention measures that are sensitive to demographic variations.