Association between smoke exposure and headache among U.S adolescents: a cross-sectional study from the NHANES 1999-2004

Abstract Background Headaches are increasingly common among adolescents, with smoking considered a contributing risk factor. Cotinine, a nicotine metabolite, serves as an objective measure of smoke exposure. However, there is limited clinical data on the relationship between serum cotinine levels and headaches in adolescents. Methods A cross-sectional study design was applied, and participants aged 12 to 19 years from the National Health and Nutrition Examination Survey (NHANES) 1999–2004 were included in the analysis. Headache data were obtained through interviews and self-reports. Smoke exposure levels were categorized as unexposed, low secondhand smoke (SHS) exposure, high SHS exposure, and active smoking groups based on serum cotinine levels. The main analyses employed weighted multivariable logistic regression models, accounting for the complex multi-stage sampling design of NHANES. Additionally, a restricted cubic spline model was used to investigate the non-linear relationship between serum cotinine levels and headache. Furthermore, a subgroup analysis was conducted. Results The analysis included 5590 adolescents aged 12 to 19 years, among whom 1442 (24.99%) experienced headaches. After adjusting for all covariates, a positive association was found between log2-transformed serum cotinine and headaches (odds ratio, R=1.04 (1.01, 1.07), P = 0.008). Adolescents with high SHS exposure (serum cotinine levels of 0.316 –10 ng/ml) and those in the active smoking group (serum cotinine≥10 ng/ml) had a higher risk of experiencing headaches compared to the unexposed group (serum cotinine < 0.05 ng/ml) [OR = 1.42 (1.07, 1.90), OR = 1.55 (1.06, 2.27), P for trend = 0.006]. A linear dose-response relationship was observed between log2-transformed serum cotinine and the risk of headaches (P non-linearity > 0.05). Subgroup analysis revealed that the positive associations remained regardless of gender and varied depending on age and central obesity. Conclusion In conclusion, higher smoke exposure, as measured by elevated cotinine levels, was significantly associated with an increased risk of headaches among adolescents. Future research should focus on identifying effective strategies to eliminate smoke exposure and discourage tobacco use in adolescents prevent in adolescents to prevent headaches.