Table 2.
Included studies for deficiency rate of 25(OH)D
| Authors | Publication year | Country/city | Design | Controls | Match | Number
|
NOS scores | References | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Controls/COPD | Mild | Moderate | Severe | ||||||||
| Lee et al | 2014 | USA | Cohort | No COPD | None | 5877/1869 | 932 | NA | 937 | 8 | 21 |
| Xiaomei et al | 2014 | People’s Republic of China | Cohort | Without COPD | Age and sex | 50/50 | NA | NA | NA | 7 | 19 |
| Persson et al | 2012 | Bergen | Cohort | Without COPD | Sex | 134/133 | NA | NA | NA | 7 | 34 |
| Janssens et al | 2010 | Belgium | Cohort | Healthy smokers | Sex | 152/262 | 70 | 87 | 192 | 7 | 20 |
| Zhou et al | 2012 | People’s Republic of China | Case-control | Healthy | Age and sex | 181/193 | NA | NA | NA | 6 | 30 |
| Duckers et al | 2011 | UK | Case-control | Healthy | Age and sex | 30/30 | NA | NA | NA | 6 | 33 |
| Jung et al | 2015 | Korea | Cohort | NA | NA | NA | 24 | 105 | 169 | 5 | 35 |
| Persson et al | 2015 | Bergen | Cohort | NA | NA | NA | NA | 201 | 216 | 7 | 36 |
| Romme et al | 2013 | Netherlands | Cohort | NA | NA | NA | NA | 42 | 109 | 6 | 37 |
Abbreviations: 25(OH)D, 25-hydroxyvitamin D; NA, not applicable; NOS, Newcastle–Ottawa Scale.