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ARTICLES: A. Vieregge, M. Sieberer, H. Jacobs, J. M. Hagenah, and P. Vieregge Transdermal nicotine in PD: A randomized, double-blind, placebo-controlled study Neurology 2001; 57: 1032-1035 [Abstract] [Full text] [PDF]

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Smoking and Parkinson's disease

Mohamed Farouk Allam   (15 October 2001)

Reply to Allam

Vieregge   (15 October 2001)

Smoking and Parkinson's disease 15 October 2001
Mohamed Farouk Allam, Research fellow Preventive Medicine and Public Health, Faculty of Medicine, University of Cordoba, Spain Send Correspondence to journal: Re: Smoking and Parkinson's disease farouk_allam{at}hotmail.com Mohamed Farouk Allam	The relation between Parkinson’s disease (the second most frequent neurodegenerative disease in the elderly for the time being) and smoking is controversial. Vieregge et al. [1] studied the effectiveness of transdermal nicotine patches as an add-on treatment for symptoms of Parkinson’s disease. The authors found no significant drug effects after their double-blind placebo -controlled trial. Similar findings were previously reported. [2]. It was also reported in a narrative review of observational studies, that there was an inverse association between Parkinson’s disease and smoking [3]. I think that this protective effect should be excluded, or at least not generalized, on seeing the results of experimental and recent observational studies. First, many recent case-control studies did not confirm the inverse association. The results of the pooling of five European population-based case-control studies found no overall association between cigarette smoking and PD [4]. The authors reanalyzed their results according to age of patients, and ever smoking was protective only in the lowest quartile age groups [4]. Second, the standardized mortality rate (SMR) of the last follow-up results on male British doctors is against the possible inverse association. The forty years' observations reported annual mortality in ever smokers of 16 per 100.000, meanwhile in lifelong non-smokers 20 per 100.000 [5]. The calculated SMR is of 0.80 (95% CI = 0.41-1.54). Finally, all prospective studies reported were restricted to men. The authors considered risk estimates of Hammond and Hirayama studies for both genders [3]. Both studies followed up cohorts of both genders but reported risk estimates for men only. Hirayama attributed his stratified analysis to the low frequency of smoking in women of his Japanese cohort. Another report (Wolf et al 1991) based on Framingham study results , one of the most respectable well designed cohort studies, could not identify such inverse association except after stratifying their results by gender. Again, only men showed the protective effect of smoking against Parkinson’s disease (p< 0.05). It is suggested that the apparent protective effect of smoking might be misleading, as smoking is less frequent in women, yet the incidence of Parkinson’s disease is the same. These inconsistent findings may be due to an etiological heterogeneity and raise concerns about the conclusion previously settled by many observational studies. References [1] Vieregge A, Sieberer M, Jacobs H, Hagenah JM, Vieregge P. Transdermal nicotine in PD. A randomized, double-blind, placebo-controlled study. Neurology 2001;57:1032-5. [2] Clemens P, Baron JA, Coffey D, Reeves A. The short term effect of nicotine chewing gum in patients with Parkinson’s disease. Psychopharmacology (Berl) 1995;117(2):253-6. [3] Morens DM, Grandinetti A, Reed D, White LR, Ross GW. Cigarette smoking and protection from Parkinson’s disease: false association or etiologic clue? Neurology 1995;45:1041-51. [4] Tzourio C, Rocca WA, Breteler MM, Baldereschi M, Dartigues JF. Lopez-Pousa S, Manubens-Bertran J.-M, Alperovitch A. Smoking and Parkinson's disease. An age-dependent risk effect? Neurology 1997;49(5):1267-72. [5] Doll R, Peto R, Wheatley K, Gray R, Sutherland I. Mortality in Relation to Smoking: 40 Years' Observations on Male British Doctors. BMJ 1994;309(6959):901-11.
Reply to Allam 15 October 2001
Vieregge, Neurologist Send Correspondence to journal: Re: Reply to Allam peter.vieregge{at}klinikum-lippe.de Vieregge	There are no new data in Mr. Allam´s comments on epidemiological findings of smoking in PD. All what we know from many studies is that patients with PD, when asked about prior smoking habits, do answer that they were less likely to smoke cigarettes than the respective controls. Whether prospective studies not designed for this particular question are at all suitable to clarify the association is debatable. Our intention was simply to test a possible therapeutic approach that took into account the methodologic drawbacks of some earlier studies.