RT Journal Article SR Electronic T1 Outdoor work and risk for Parkinson's disease: a population-based case–control study JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP 273 OP 278 DO 10.1136/oem.2010.057448 VO 68 IS 4 A1 Line Kenborg A1 Christina F Lassen A1 Beate Ritz A1 Eva S Schernhammer A1 Johnni Hansen A1 Nicole M Gatto A1 Jørgen H Olsen YR 2011 UL http://oem.bmj.com/content/68/4/273.abstract AB Objectives Sunlight 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.Methods We 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.Results Relying 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.Conclusions Our 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.