BACKGROUND: Human and animal studies, albeit not fully consistent, suggest that vitamin D may reduce risk of Parkinson's disease (PD). Ultraviolet radiation converts vitamin D precursor to the active form. This study examined the hypothesis that working outdoors is associated with a decreased risk of PD. METHODS: PD cases were enrolled from Group Health Cooperative, a health maintenance organization in the Puget Sound region in western Washington State, and the University of Washington Neurology Clinic in Seattle. Participants included 447 non-Hispanic Caucasian newly diagnosed PD cases diagnosed between 1992 and 2008 and 578 unrelated neurologically normal controls enrolled in Group Health Cooperative, frequency matched by race/ethnicity, age and gender. Subjects' amount of outdoor work was estimated from self-reported occupational histories. Jobs were categorized by degree of time spent working outdoors. A ten-year lag interval was included to account for disease latency. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression, with adjustment for age, gender, and smoking. RESULTS: Outdoor work was inversely associated with risk of PD (outdoor only compared to indoor only): OR = 0.74, 95% CI 0.44-1.25. However, there was no trend in relation to portion of the workday spent laboring outdoors and PD risk. CONCLUSION: Occupational sunlight exposure and other correlates of outdoor work is not likely to have a substantial role in the etiology of PD.
BACKGROUND:Human and animal studies, albeit not fully consistent, suggest that vitamin D may reduce risk of Parkinson's disease (PD). Ultraviolet radiation converts vitamin D precursor to the active form. This study examined the hypothesis that working outdoors is associated with a decreased risk of PD. METHODS:PD cases were enrolled from Group Health Cooperative, a health maintenance organization in the Puget Sound region in western Washington State, and the University of Washington Neurology Clinic in Seattle. Participants included 447 non-Hispanic Caucasian newly diagnosed PD cases diagnosed between 1992 and 2008 and 578 unrelated neurologically normal controls enrolled in Group Health Cooperative, frequency matched by race/ethnicity, age and gender. Subjects' amount of outdoor work was estimated from self-reported occupational histories. Jobs were categorized by degree of time spent working outdoors. A ten-year lag interval was included to account for disease latency. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression, with adjustment for age, gender, and smoking. RESULTS: Outdoor work was inversely associated with risk of PD (outdoor only compared to indoor only): OR = 0.74, 95% CI 0.44-1.25. However, there was no trend in relation to portion of the workday spent laboring outdoors and PD risk. CONCLUSION: Occupational sunlight exposure and other correlates of outdoor work is not likely to have a substantial role in the etiology of PD.
Authors: Jordan A Firestone; Jessica I Lundin; Karen M Powers; Terri Smith-Weller; Gary M Franklin; Phillip D Swanson; W T Longstreth; Harvey Checkoway Journal: Am J Ind Med Date: 2010-03 Impact factor: 2.214
Authors: Line Kenborg; Christina F Lassen; Beate Ritz; Eva S Schernhammer; Johnni Hansen; Nicole M Gatto; Jørgen H Olsen Journal: Occup Environ Med Date: 2010-09-30 Impact factor: 4.402
Authors: Harvey Checkoway; Karen Powers; Terri Smith-Weller; Gary M Franklin; W T Longstreth; Phillip D Swanson Journal: Am J Epidemiol Date: 2002-04-15 Impact factor: 4.897