03/29/2002 02:12:52 PM
By Robert Short
There is a positive association between smoking and dementia, when seen in the context of Parkinson's Disease.
The surprising conclusion comes from a study of a 180 non-demented patients with Parkinson's disease in New York. The mean age of the patients was 71 years at the study start and they were followed up for a mean of 3.6 years. In that time, 52 of the 180 patients (29 percent) became demented. This did not seem to be related to head injury risk ratio, hypertension or diabetes mellitus, according to Cox models.
However, patients who reported having 'ever smoked' were at increased risk for the development of dementia compared with 'nonsmokers' (risk ratio 2.0; P=0.05). 'Current smoking' was significantly associated with dementia occurring (risk ratio 4.5; P=0.02). 'Past smoking' approached significance (risk ratio 1.9;P=0.07).
The result surprised the researchers. Lead author Gilberto Levy, MD said, 'Although an inverse association between smoking and Parkinson's Disease has been reported in several studies, our study showed a positive association between smoking and dementia in the setting of Parkinson's Disease. The association of smoking with incident dementia in Parkinson's Disease deserves further study'.
Dr Levy is based at the Gertrude H Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, USA.
ACTUAL STUDY ABSTRACT
|Do risk factors for Alzheimer's disease predict dementia in Parkinson's disease? An exploratory study|
|Gilberto Levy, MD 1, Ming-Xin Tang, PhD 1 4 5, Lucien J. Cote, MD 2, Elan D. Louis, MD, MS 1 2, Brenda Alfaro, MA 1 2, Helen Mejia, MA 1 2, Yaakov Stern, PhD 1 2 3 5, Karen Marder, MD, MPH 1 2 5 *|
|1Gertrude H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, USA |
2Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
3Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, New York, USA
4Division of Biostatistics, School of Public Health, Columbia University, New York, New York, USA
5The Taub Institute for Research on Alzheimer's Disease and The Aging Brain, Columbia University, New York, New York, USA
|email: Karen Marder ([email protected])|
*Correspondence to Karen Marder, G.H. Sergievsky Center, 630 West 168th Street, New York, New York, 10032
|Parkinson's disease; dementia; epidemiology; smoking|
|The extent to which concomitant Alzheimer's disease (AD) is etiologically related to the development of dementia in Parkinson's disease (PD) remains controversial. We explored the association of four risk factors associated with AD, including head injury, smoking, hypertension, and diabetes mellitus, with incident dementia in PD. A cohort of 180 nondemented PD patients from the Washington Heights community in northern Manhattan, New York, completed a risk factor questionnaire at baseline and was followed annually with neurological and neuropsychological evaluations. The association of baseline variables with incident dementia was analyzed by using Cox proportional hazards models. All analyses controlled for age at baseline, gender, years of education, duration of PD, and total Unified Parkinson's Disease Rating Scale (UPDRS) motor score at baseline. Of 180 patients (mean age, 71.0 ± 10.3 years), 52 (29%) became demented during a mean follow-up period of 3.6 ± 2.2 years. Head injury risk ratio ([RR] 0.9; 95% confidence interval [CI], 0.4-2.2; P = 0.9), hypertension (RR, 0.7; 95% CI, 0.4-1.4, P = 0.3), and diabetes mellitus (RR, 0.8; 95% CI, 0.3-2.3; P = 0.7) were not significantly associated with incident dementia in the Cox models. Patients who reported having ever smoked were at increased risk for the development of dementia compared with nonsmokers (RR, 2.0; 95% CI, 1.0-3.9; P = 0.05). Current smoking was significantly associated with incident dementia (RR, 4.5; 95% CI, 1.2-16.4; P = 0.02), whereas past smoking approached significance (RR, 1.9; 95% CI, 0.9-3.7; P = 0.07). Although an inverse association between smoking and PD has been reported in several studies, our study showed a positive association between smoking and dementia in the setting of PD. The association of smoking with incident dementia in PD deserves further study. © 2002 Movement Disorder Society.|
Received: 22 March 2001; Revised: 8 August 2001; Accepted: 21 August 2001