Table 2.
Main characteristics of eligible studies for the analysis of vitamin D supplementation, outdoor work and risk of PD.
| References | Year | Country | Study Type | Participants | Average Age (years) | OR, 95% CI High Versus Low Category | Adjustments | ||
|---|---|---|---|---|---|---|---|---|---|
| PD | Control | PD | Control | ||||||
| Vitamin D supplementation | |||||||||
| Miyake [18] | 2011 | Japan | case-control | 249 | 368 | 68.5 | 66.6 | 0.82 (0.46–1.47) | age, sex, region of residence, pack-years of smoking, years of education, body mass index and dietary factors including cholesterol, dietary glycemic index, vitamin E, β-carotene, vitamin B6, caffeine, iron, and alcohol |
| Zhu [19] | 2014 | China | case-control | 209 | 210 | 64.6 ± 9.4 | 66.0 ± 8.1 | 0.54 (0.30–0.96) | age, sex, smoking, alcohol use, education, and BMI |
| Outdoor work | |||||||||
| Kenborg [20] | 2011 | USA | case-control | 3819 | 19,282 | 71.2 | - | 0.72 (0.63–0.82) | age, chronic obstructive pulmonary disease, comorbidity, place of birth, and social class |
| Kwon [21] | 2013 | USA | case-control | 447 | 578 | 66 | 68 | 0.74 (0.44–1.25) | age, sex, and smoking |