title: Smoking and Parkinson's disease: explanatory hypothesis.
abstract: A systematic review was conducted to estimate the pooled risk of smoking for Parkinson's disease in Chinese populations. The four identified case-control studies had odds ratios with 95% confidence intervals nearly or overlapping unity. Pooled odds ratio of these studies was 0.77 with 95% confidence interval 0.60 to 0.97. It was suggested that smoking induces debrisoquine 4-hydroxylase, which is responsible for the metabolism of antipsychotic drugs and the detoxification of certain environmental toxins known to cause dopaminergic neural damage. This could be the explanation of these contradictory results as cytochrome P-450 CYP2D6 debrisoquine hydroxylase gene polymorphism is known to be much lower in Chinese than in Caucasian people. This systematic review raises concerns about generalization of the conclusion previously settled by many cohort and case-control studies.
authors.affiliation: Department of Preventive Medicine and Public Health, Faculty of Medicine, University of Córdoba, Avda. Menéndez Pidal, s/n 14004 Córdoba, Spain. fm2faahm@lucano.uco.es
authors.forename: Mohamed Farouk
authors.initials: MF
authors.lastname: Allam
authors.forename: Amparo
authors.initials: A
authors.lastname: Serrano del Castillo
authors.forename: Rafael
authors.initials: R
authors.lastname: Fernández-Crehuet Navajas
mesh_terms: D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D016001:Confidence Intervals; D019389:Cytochrome P-450 CYP2D6 / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006801:Humans; D015201:Meta-Analysis as Topic; D016017:Odds Ratio; D010300:Parkinson Disease / Q000453:epidemiology* / Q000209:etiology / Q000378:metabolism; D011083:Polycyclic Compounds / Q000378:metabolism / Q000633:toxicity; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*
chemical_list: D011083:Polycyclic Compounds; D003577:Cytochrome P-450 Enzyme System; D019389:Cytochrome P-450 CYP2D6