Table 2.
The study design and basic details of the studies included in the systematic review.
| Ref. | Authors, Year | Study Design | Country/Location | Studied Group | Time |
|---|---|---|---|---|---|
| [29] | Vieth et al., 2004 | Blinded, randomized trial | Canada/Toronto | Outpatients of endocrinology clinic with 25(OH)D < 61 nmol/L (Study 1) | Winter 2001–2002 (Study 1) |
| Outpatients of endocrinology clinic with 25(OH)D < 51 nmol/L (Study 2) | Winter 2002–2003 (Study 2) | ||||
| [30] | Shipowick et al., 2009 | Quasi-experimental pilot study | United States of America/Washington | Female patients treated at a medical clinic for vitamin D deficiency or insufficiency | Not specified |
| [31] | Bertone-Johnson et al., 2011 | Cross-sectional prospective analysis within Women’s Health Initiative Observational Study (WHI OS) | United States of America | Women aged 50–79 participating in WHI OS | 1993–1998 |
| [32] | Sanders et al., 2011 | Double-blind, randomized, placebo-controlled trial within Vital D study | Australia/Barwon and Mornington Peninsula regions | Community-dwelling women aged at least 70 years participating in Vital D study | 2005–2008 |
| [33] | Kjaergaard et al., 2012 | Nested case-control study and randomized clinical trial | Norway/Tromsø | Adults 30–75 years old with serum 25(OH)D levels below the 20 percentile (55 nmol/L) or above the 75 percentile (70 nmol/L) from the sixth Tromsø study | October 2009–November 2010 |
| [34] | Cheema and Chaudhry, 2016 | Prospective study | United Kingdom | Patients admitted with a fall with or without sustaining a fragility fracture post fall | Not specified |
| [35] | Patil et al., 2016 | Randomized double-blind, placebo-controlled intervention trial with vitamin D and exercise (DEX trial) | Finland | Older Finnish women participating in DEX trial | 2010–2013 |
| [36] | Vaziri et al., 2016 | Randomized controlled trial | Iran/Shiraz | Pregnant women under prenatal care in Hafez hospital | November 2014–October 2015 |
| [37] | Choukri et al., 2018 | Double-blind, placebo-controlled, randomized clinical trial | New Zealand/Dunedin | Healthy women aged 18–40 years | February–October 2013 |
| [38] | Jorde and Kubiak, 2018 | Randomized controlled trial within Tromsø study population | Norway/Tromsø | Adults aged 40–80 years participating in Tromsø Study | 2015–2016 |
| [39] | Krokosz et al., 2018 | Double-blind, placebo-controlled, randomized study | Poland | Experienced marathon and ultramarathon male runners (aged 31–50 years) taking part in a 100 km track run | Not specified |
| [40] | de Koning et al., 2019 | Randomized placebo-controlled clinical trial within D-Vitaal Study | Netherlands/Amsterdam | Community-dwelling older individuals with functional limitations participating in D-Vitaal Study | 2013–2016 |
| [41] | Gugger et al., 2019 | 1-year double-blind randomized clinical trial | Switzerland/Zurich | Community-dwelling older adults with a prior low-trauma fall in the previous year | January 2010–May 2011 |
| [42] | Lipowski et al., 2019 | Intervention program | Poland/Gdansk | Elderly women participating in a Nordic walking training program | October 2018 * |
* data provided on request. 25-hydroxyvitamin D (25(OH)D).