Dietary Nicotine Intake and Risk of Parkinson Disease: A Prospective Study

Abstract

Abstract Objectives To prospectively examine the association between dietary nicotine intake and subsequent PD risk among never-smokers. Methods The current study was based on never-smoker participants from two large prospective cohorts: the Nurses’ Health Study (n = 31,615) and the Health Professionals’ Follow-up Study (n = 19,523). The studies contained information on dietary nicotine intake from 1986 from validated food frequency questionnaires. Dietary nicotine intake was calculated based on consumption of peppers, tomatoes, processed tomatoes, potatoes, and tea. Incident cases of PD were identified via questionnaires and subsequently confirmed by reviewing medical records. We used Cox proportional hazard models to calculate cohort-specific hazard ratios (HRs), and used fix-effects models to calculate the pooled hazard ratio. Results During 26 years of follow-up, we identified 601 incident PD cases (296 women, and 305 men). After adjusting for potential covariates, the pooled HR for the highest vs. lowest quintile of dietary nicotine intake was 0.70 (95% confidence interval [CI], 0.51–0.94). The significant inverse association was, however, only observed in women (adjusted HR, 0.64; 95% CI, 0.42–0.96), but not in men (adjusted HR, 0.77; 95% CI, 0.50–1.20). Further adjusting for environmental tobacco smoke exposure generated similar significant results in women. Consistently, greater consumption of peppers was associated with lower risk of PD (adjusted HR for ≥5 times/week vs. ≤3 times/month, 0.49; 95% CI, 0.25–0.94) in women but not in men (adjusted HR, 1.04; 95% CI, 0.57–1.90). Conclusions Women with greater consumption of dietary nicotine intake had a lower risk of PD, relative to those with lower consumption. Funding Sources This work was supported by the National Institute of Neurological Disorders and Stroke at the National Institutes of Health (NINDS 1R03NS093245–01A1 to X.G.). The NHS is funded by the National Institute of Health through grant UM1 CA186107. The HPFS cohort is funded by the National Institute of Health through grant UM1 CA 167,552.