High dietary nicotine intake lowers risk of Parkinson disease in women

Greater consumption of dietary nicotine reduces the risk of Parkinson’s disease (PD) in women, results of a study have shown.

This 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). These cohorts had available information on dietary nicotine intake from 1986 from validate food frequency questionnaires.

The investigators calculated dietary nicotine based on consumption of peppers, tomatoes, processed tomatoes, potatoes, and tea. Questionnaires were utilized to identify incident PD cases, which were subsequently confirmed by reviewing medical records. Cohort-specific hazard ratios (HRs) and pooled HR were calculated using Cox proportional hazard models and fixed-effects models, respectively.

A total of 601 incident PD cases (305 men and 296 women) were identified during 26 years of follow-up. The pooled HR after adjusting for potential covariates was 0.70 (95 percent confidence interval [CI], 0.51–0.94) for the highest vs lowest quintile of dietary nicotine intake. However, the inverse association was only observed in women (adjusted HR, 0.64, 95 percent CI, 0.42_0.96), not in men (adjusted HR, 0.77, 95 percent CI, 0.50–1.20).

Similar significant results in women were observed after further adjustments for environmental tobacco smoke exposure, family history of PD, and use of ibuprofen.

Notably, high peppers intake correlated with a lower risk of PD (adjusted HR for ≥5 times/week compared with ≤3 times/month, 0.49, 95 percent CI, 0.25–0.94) in women but not in men (adjusted HR, 1.04, 95 percent CI, 0.57–1.90).