Outdoor work and risk for Parkinson's disease: a population-based case–control study

• Published in: Occupational and environmental medicine (London, England) Vol. 68; no. 4; pp. 273 - 278
• Main Authors: Kenborg, Line, Lassen, Christina F, Ritz, Beate, Schernhammer, Eva S, Hansen, Johnni, Gatto, Nicole M, Olsen, Jørgen H
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.04.2011; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adult; Age Distribution; Aged; Aged, 80 and over; Biological and medical sciences; Cancer; Case studies; case-control studies; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Denmark - epidemiology; Disease risk; Employment; Epidemiologic Methods; Epidemiology; Humans; Job titles; Lip Neoplasms - epidemiology; Lung neoplasms; Lung Neoplasms - epidemiology; Male; Medical sciences; Middle Aged; Nervous system (semeiology, syndromes); Nervous system as a whole; Neurology; Occupational Exposure - analysis; occupations; Occupations - statistics & numerical data; Outdoors; Parkinson disease; Parkinson Disease - epidemiology; Parkinson Disease - prevention & control; Parkinson's disease; Pension funds; Personal identification numbers; Population control; Social Class; Sunlight; Vitamin D; Workplace; Denmark; Human; Nervous system diseases; Parkinson disease; Case control study; Epidemiology; Cerebral disorder; Outside air; Vitamin D; Central nervous system disease; Risk factor; Work; Population; Degenerative disease; Extrapyramidal syndrome
• ISSN: 1351-0711; 1470-7926; 1470-7926
• DOI: 10.1136/oem.2010.057448

ObjectivesSunlight is the main contributor to vitamin D in humans. Since inadequate levels of vitamin D have been linked to increased risks for neurodegenerative diseases, we examined whether outdoor work is associated with a reduced risk for Parkinson's disease in a population-based case–control study of Danish men.MethodsWe identified 3819 men with a primary diagnosis of Parkinson's disease in the period 1995–2006 in the Danish National Hospital Register and selected 19 282 age- and sex-matched population controls at random from the Central Population Register. Information on work history was ascertained from the Danish Supplementary Pension Fund and the Central Population Register. Based on trade grouping codes and job titles, we evaluated the extent of outdoor work of study subjects as a proxy of exposure to sunlight.ResultsRelying on trade grouping codes, we estimated ORs for study subjects with moderate, frequent and maximal outdoor work compared with exclusive indoor work of 0.90 (95% CI 0.78 to 1.02), 0.86 (95% CI 0.75 to 0.99) and 0.72 (95% CI 0.63 to 0.82), respectively, for Parkinson's disease. Reduced risks were also found for Parkinson's disease among outdoor workers based on study subjects' job titles.ConclusionsOur findings suggest that men working outdoors have a lower risk for Parkinson's disease. Further studies of measured vitamin D levels in outdoor workers are warranted to clarify a potential inverse association between vitamin D and the risk for Parkinson's disease.