Parkinson's disease research in a prospective cohort in China

Introduction: China has the largest population of Parkinson's disease (PD) patients; however few etiological studies of PD have been conducted in China.

Methods: The Shanghai Women's Health Study recruited 74,941 women in urban Shanghai, aged 40 to 70, from 1996 to 2000. Self-reported PD cases were invited for a neurological examination and diagnoses were made by a movement disorder specialist.

Results: This cohort had very few smokers (2.7%), alcohol drinkers (2.3%), and post-menopausal hormone users (4.3%); however, tea drinking (29.9%) and exposure to tobacco smoke from husbands (61.8%) were common. A total of 301 participants reported PD diagnosis during the follow-up. The diagnosis was confirmed in 76 (57%) of the 133 clinically examined patients. An additional 19 (53%) PD cases were identified out of 36 participants who self-confirmed the diagnosis and provided a history on PD symptoms and treatments. As expected, increasing age was strongly associated with PD risk. Further, PD risk appears to be inversely associated with exposures to second-hand tobacco smoke from husbands and tea drinking, and positively with education, although none of these reached statistical significance. The age-adjusted odds ratio (OR) was 0.7 (95% confidence interval: 0.4-1.1) for participants whose husbands were current smokers at baseline and 0.8 (0.5-1.3) for ever tea-drinkers. Compared with primary education or lower, the age-adjusted OR was 1.3 (0.7-2.4) for middle school and 1.6 (1.0-2.7) for high school or above.

Conclusion: PD research in this unique cohort is feasible and, with extended follow-up, will allow for prospective PD etiological research in China.