Table 1 Characteristics of included studies
From: Vitamin D levels and deficiency with different occupations: a systematic review
Group | Author (year) | Occupational Detail | Number of Subjects | Location/Latitude | Study type | 25-(OH)D | Notes | |
|---|---|---|---|---|---|---|---|---|
Mean ± SD (nmol/L) | % Deficiency | |||||||
Outdoor Workers | ||||||||
Haddad and Chyu (1971) [102] | Lifeguards | 8 | St. Louis, Missouri, USA (38°63′ N) | Descriptive | 160.7 ± 21.7 | |||
Devgun (1981) [85] | Gardeners | 18 | Dundee/Scotland (56°30′N) | Descriptive | 59.4 ± 19.7 | |||
Devgun (1981) [25] | Male outdoor workers | 20 | Scotland (56°30′N) | Descriptive | 62.1 ± 18.8 | |||
Devgun (1983) [103] | 1.Outdoor workers | 9 | Scotland (56°30′N) | Descriptive | 73 (1977), 54 (1979) | Average reported as median | ||
2. Outdoor workers | 9 | 55 (1976), 84 (1977) | Excluded from meta-analysis | |||||
Azizi (2009) [104] | Agriculture, physical education, construction | 122 | Beer Sheva, Israel (31°25′ N) | Case-control | 67.6 ± 21.3 | |||
Norsang (2009) [105] | 1. Farmers | 20 | Shigatse, China (29°19′ N) | Descriptive | 81.0 ± 18.0 | <75 nmol/L: 40% <50 nmol/L: 0% | ||
2. Farmers | 6 | Tingri, China (28°34′N) | 67.0 ± 27.0 | <75 nmol/L: 67% <50 nmol/L: 17% | ||||
3. Farmers | 6 | Chonggye, China (29°02′ N) | 46.0 ± 27.0 | <75 nmol/L: 83% <50 nmol/L: 17% | ||||
Azizi (2012) [91] | Israel National Water Company | |||||||
1. Group 1 | 34 | Israel (31°05 N) | Interventional | 74.4 ± 15.2 | ||||
2. Group 2 | 67 | 98.3 ± 17.2 | ||||||
80.4 ± 27.7 | ||||||||
3. Group 3 | 53 | |||||||
Choi (2011) [106] | Agriculture, Forestry, Fishery | 644 | South Korea (33° - 38°N) | Cross-sectional | 61.3 ± 18.5 | <75 nmol/L: 76.2% <50 nmol/L: 27.8% | ||
Roomi (2015) [55] | Outdoor workers | 15 | Lahore, Pakistan (31°55′N) | Cross-sectional | 31.4 ± 3.8 | |||
Oh (2015) [107] | 1. Craft, equipment, machine operating, and assembling workers | 2812 | South Korea (33° - 38°N) | Cross-sectional | <50 nmol/L: 61.6% | |||
2. Skilled agricultural, forestry, and fishery workers | 2572 | <50 nmol/L: 38.5% | ||||||
Bacchel (2015) [27] | Farmers | 6 | North-West Punjab, India (31°15′N) | Cross-sectional | <75 nmol/L: 50% <25 nmol/L: 50% | |||
Indoor Workers | Devgun (1981) [85] | Laboratory staff | 8 | Dundee, Scotland (56°30′N) | Descriptive | 43.9 ± 17.0 | ||
Devgun (1981) [25] | Indoor workers | 9 | Scotland (56°30′N) | Descriptive | 42.9 ± 15.3 | |||
Maeda (2007) [108] | Plant and office workers | 28 | Sao Paulo, Brazil (23° 34′S) | Descriptive | 94.0 ± 32.6 | |||
Gulvady (2007) [109] | Senior executives | 75 | Mumbai, India (19°08′ N) | Descriptive | <50 nmol/L: 83% | |||
Islam (2008) [110] | Garment factory workers | 200 | Dhaka, Bangledesh (23°81′N) | Descriptive | 36.7 ± 11.2 | <50 nmol/L: 86.5% | ||
Azizi (2009) [104] | Industry, civil service, etc. | 104 | Israel, Beer Sheva (31°25′ N) | Interventional | 57.5 ± 20.8 | |||
Itoh (2011) [28] | Indoor daytime workers | 4 | Kawasaki City, Japan (35°53′N) | Interrupted time series | 49.7 ± 7.9 | |||
Vu (2011) [111] | Office workers | 213 | Brisbane, Australia (27°S) | Descriptive | 62.2 ± 22.5 | <75 nmol/L: 43.3% <50 nmol/L: 42.5% | ||
Choi (2011) [106] | 1. Administration, clerical work | 1047 | Cross-sectional | 45.8 ± 16.5 | <75 nmol/L: 93.4% <50 nmol/L: 87.1% | |||
53.8 ± 18.5 | <75 nmol/L: 87.1% <50 nmol/L: 50% | |||||||
2. Engineering, assembling, and technical work | 572 | South Korea (33° - 38°N) | ||||||
Xiang (2013) [56] | Pregnant indoor workers | 311 | Guiyang, China (26°65′ N) | Descriptive | 36.7 ± 17.0 | <75 nmol/L: 12.5% <50 nmol/L: 83.6% | ||
Cinar (2014) [112] | Premenopausal female and male office workers. | 118 | Ankara, Turkey (39°93′N) | Prospective observational | 52.8 ± 28.4 | <75 nmol/L: 24.2% <50 nmol/L: 54.3% | ||
Jeong (2014) [23] | Managers, experts, specialists, etc. | 2659 | South Korea (35°91′N) | Descriptive | 40.6 ± 18.0 | <50 nmol/L: 80.4% | ||
Sharma (2015) [113] | Office working women | 50 | Udaipur, Rajasthan, India (24°59′N) | Descriptive | 46.7 ± 17.4 | |||
Yosephin (2015) [114] | Garment factory workers | 39 | Indonesia (3°35′N) | Randomized control-trial | 39.5 ± 12.0 | <75 nmol/L: 82% | ||
Roomi (2015) [55] | Indoor workers | 73 | Lahore, Pakistan (31°55′N) | Cross-sectional | 19.0 ± 1.1 | |||
Kwon (2015) [54] | Manufacturing workers | 1054 | Busan, Gyeongnam/South Korea (35°18′N) | Cross-sectional | 22.7 ± 8.1 | <50 nmol/L: 97.2% | Deficiency <25 nmol/L:68.4% | |
Insufficiency: <50 nmol/L: 97.2% | ||||||||
Oh (2015) [107] | 1. Clerks | 2357 | South Korea (33° - 38°N) | Cross-sectional | <50 nmol/L: 74.7% | |||
2. Managers, professionals and related work | 3597 | <50 nmol/L: 74.8% | ||||||
Bacchel (2015) [27] | 1. Public servants | 69 | North-West Punjab, India (31°15′N) | Cross-sectional | <75 nmol/L: 100% <25 nmol/L: 56.5% | |||
2. Professionals (businessmen) working indoors | 13 | <75 nmol/L: 100% <25 nmol/L: 16.7% | ||||||
Shift Workers | Ward (2011) [41] | 1. Shiftworkers with constant regular work hours | 4496 | United Kingdom (55°39′N) | Cohort | 53.0 | <50 nmol/L: 81% | Average reported as geometric mean. Excluded from meta-analysis |
2. Shiftworkers with varying number of hours worked per week | 6136 | 52.3 | <50 nmol/L: 79.4% | |||||
Itoh (2011) [28] | 1. Rotating shift workers without night shift | 4 | Osaka Prefecture, Japan (34.5°N) | Cross-sectional | 63.1 ± 6.3 | |||
2. Rotating shift workers with night shift | 4 | 64.4 ± 8.1 | ||||||
Kim (2013) [115] | Shift workers without day shift | 627 | South Korea (35°91′N) | Descriptive | 40.0 ± 14.7 | |||
Jeong (2014) [23] | Shiftworkers | 969 | South Korea (35°91′N) | Descriptive | 40.0 ± 17.7 | <50 nmol/L: 80.1% | ||
Kwon (2015) [54] | Manufacturing workers | 872 | Busan, Gyeongnam/South Korea (35°18′N) | Cross-sectional | 22.2 ± 8.1 | <25 nmol/L: 71% ≥25 nmol/L: 29% | ||
Romano (2015) [45] | Shiftworkers | 96 | Northern Italy, Milan Province, Lomabardy (45° 30′N) | Cross-sectional | 33.4 ± 13.2 | <75 nmol/L: 24% <50 nmol/L: 66.8% | ||
Lead/Smelter | Greenberg (1986) [79] | Lead and cadmium exposed workers | 37 | Pittsburgh & Cleveland, United States (40°44′N & 41°50′N) | Descriptive | 62.5 ± 24.5 | 5.4% | Mean 1α, 25-(OH)2D: 122.7 ± 36.5 pmol/L. Vitamin D deficiency was not defined. |
Mason (1990) [78] | Lead exposed workers | 63 | United Kingdom (55°39′N) | Cohort | Mean 1α, 25-(OH)2D: 90.5 ± 29.5 pmol/L | |||
Chalkley (1998) [39] | Smelter workers | 19 | England (52°36′N) | Descriptive | Mean: 71.4 Median: 71.0 | 1α, 25-(OH)2D3 Mean: 77.3 pmol/L; Median: 84.0 pmol/L. Excluded from meta-analysis | ||
Kristal-Boneh (1998) [77] | 1. Lead-exposed factory workers (battery and recycling) | 56 | Israel (31°25′ N) | Cross-sectional | 86.0 ± 25.2 | Mean 1α, 25-(OH)2D: 198 ± 64.8 pmol/L | ||
2. Non-lead exposed workers | 90 | 79.0 ± 20.5 | Mean 1α, 25-(OH)2D: 165 ± 42.3 pmol/L | |||||
Potula (2005) [116] | Smelter workers | 73 | Bunker Hill, Idaho, USA (43°91′N) | Descriptive | Mean 1α, 25-(OH)2D: 115.9 ± 38.0 pmol/L | |||
Coal-miners | Shuster (1981) [82] | 1. Underground miners | 101 | Newcastle Upon Tyne (54°98′N) | Cross-sectional | 73.8 ± 73.4 | ||
2. Surface workers | 19 | 82.3 ± 67.6 | ||||||
3. Miners not at work | 6 | 83.5 ± 67.4 | ||||||
Shuster (1982) [81] | 1. Underground miners | 60 | United Kingdom (55°39′N) | Cross-sectional | 58.5 ± 24.3 | |||
2. Surface workers | 28 | 62.6 ± 21.7 | ||||||
Sarikaya (2006) [83] | 1. Underground miners | 50 | Zonguldak, Turkey (41°45′N) | Cross-sectional | 24.5 ± 28.2 | |||
2. Surface workers | 50 | 35.3 ± 29.3 | ||||||
Healthcare Students | Maeda (2007) [108] | Medical students | 44 | Sao Paulo (23° 34′S), Brazil | Descriptive | 81.5 ± 35.8 | ||
Gonzalez-Padilla (2011) [117] | Medical students | 103 | Gran Canaria, Canary Islands (27°92′N) | Descriptive | 69.6 ± 31.0 | <75 nmol/L: 28.6% <50 nmol/L: 32.6% | Paper reported unit as ng/dL but ng/ml was used for calculation | |
Kaehler (2012) [118] | Female healthcare professional students | 215 | Innsbruck, Austria (47°27′N) | Cross-sectional | 50.3 ± 16.6 | <75 nmol/L: 33.5% <50 nmol/L: 55.8% | ||
Al-Elq (2012) [119] | Medical students | 198 | Dammam, Saudi Arabia (26°39′N) | Cross-sectional | 21.2 ± 11.9 | <75 nmol/L: 4% <50 nmol/L: 96% | ||
Manickam (2012) [120] | Medical students and residents | 104 | Chicago, IL, USA (42°N) | Descriptive | 54.0 ± 28.0 | <75 nmol/L: 77% | ||
Zabihiyeganeh (2014) [121] | Medical students | 100 | Tehran, Iran (35° 69′N) | Cross-sectional | 42.0 ± 11.7 | <75 nmol/L: 15% <50 nmol/L: 84% | ||
Milovanovic (2015) [122] | Medical, pharmacy and dental students | 86 | Kragujevac, Serbia (44°N) | Descriptive | 33.1 ± 12.1 | <50 nmol/L: 88.4% | ||
Medical Residents | Haney (2004) [61] | Medical residents | 34 | Portland, OR, USA (45°52′ N) | Interrupted series | 56.4 ± 20.1 | <50 nmol/L: 38% | Paper reported unit as ng/dL but ng/ml was used for calculation |
Maeda (2007) [108] | Medical residents | 49 | Sao Paulo, Brazil (23° 34′S) | Descriptive | 67.1 ± 27.0 | |||
Orlandin Premaor (2014) [123] | Medical residents | 73 | Porto Alegre, Brazil (30°S) | Cross-sectional | 44.7 ± 20.0 | <50 nmol/L: 57.4% | ||
Multani (2010) [76] | Medical residents | 214 | Mumbai, India (19°08′ N) | Cross-sectional | 31.1 ± 18.6 | <50 nmol/L: 87.2% | ||
Singh (2011) [124] | Medical residents | 80 | Varanasi, India (25°N) | Cross-sectional | 22.8 ± 18.2 | <75 nmol/L: 11% <50 nmol/L: 89% | ||
Growdon (2012) [125] | Trainee doctors (Residents) | 102 | Boston, MA, USA (42°36′ N) | Descriptive | 67.0 ± 26.0 | <75 nmol/L: 44% <50 nmol/L: 25% | ||
Mendoza (2013) [126] | Medical residents | 20 | Mexico City, Mexico (19°43′N) | Cross-sectional | 42.4 ± 13.0 | <50 nmol/L: 75% | ||
Ramirez-Vick (2015) [127] | Medical residents | 51 | San Juan, Puerto Rico (18°47′ N) | Descriptive | 54.3 ± 19.4 | <75 nmol/L: 45% <50 nmol/L: 43% | ||
Practising Physicians | Gann (1996) [128] | Male physicians | 414 | United States (37°09′N) | Case-control | Median: 71.1 | <50 nmol/L: 6.5% | |
Goswami (2000) [129] | Physicians and nurses | 19 | Delhi, India (28°61′N) | Descriptive | 13.0 ± 7.9 | Mean 1α, 25-(OH)2D: 93.6 ± 29.0 pmol/L | ||
Kramm (2010) [130] | Physicians | 28 | Madison, Wisconsin (43°07′N) | Descriptive | 80.0 ± 25.0 | <50 nmol/L: 21% | 25-(OH)D deficiency was defined as <62.5 nmol/L | |
Mahdy (2010) [75] | Physicians and nurses | 340 | Doha, Qatar (25°29′N) | Observational | 29.3 | <75 nmol/L: 9.5% <50 nmol/L: 87% | SD was not provided. Excluded from meta-analysis | |
Lee (2011) [131] | Male physicians | 389 | United States (37°09′N) | Case-control | 64.0 | Only control values were used for analysis | ||
Haliloglu (2016) [132] | Medical doctors | Unknown | Istanbul/Turkey (41°N) | Prospective observational | Winter: 42.8 ± 22.5 Summer: 58.1 ± 24.3 | Total number of healthcare workers were 190. Actual number of medical doctors was not provided | ||
Munter (2015) [133] | Hospital- and community-based physicians | 81 | Jerusalem (31.4°N), Israel | Descriptive | 56.2 ± 16.3 | <75 nmol/L: 24.6% <50 nmol/L: 67.6% | ||
Nurses | Platz (2000) [134] | Nurses | 326 | United States (37°09′N) | Case-control | 67.0 ± 25.5 | Mean 1α, 25-(OH)2D: Controls: 77.3 ± 20.6 pmol/L | |
Eliassen (2011) [135] | Nurses | 1218 | United States (37°09′ N) | Case-control | 62.4 ± 24.0 | Only control values used | ||
Hattapornsawan (2012) [136] | Nurses | 217 | Nonthaburi, Thailand (13°86′N) | Cross-sectional | <75 nmol/L: 45.6% <50 nmol/L: 49.8% | |||
Wallingford (2014) [137] | Premenopausal nurses | 83 | Kingston, ON, Canada (44°23′N) | Cross-sectional | 83.5 ± 36.2 | <50 nmol/L: 11.2% | ||
Wang (2014) [138] | Nurses | 584 | United States (37°09′N) | Case-control | 61.1 ± 22.8 | Only control values used | ||
Haliloglu (2016) [132] | Nurses | Unknown | Istanbul/Turkey (41°N) | Prospective observational | 41.8 ± 16.8 | Authors did not report number of subjects | ||
Bertrand (2016) [139] | Nurses | 835 | Boston/USA (42°36′N) | Case-control | 68.0 ± 25.8 | Only control values used | ||
Madani (2015) [140] | Nurses | 200 | Kashan/Iran (33°98′N) | Cross-sectional | 42.4 ± 52.8 | <75 nmol/L: 178 (89%) ≤25 nmol/L: 91 (45.5%) <25–75 nmol/L: 87 (43.5%) | 25-(OH)D 25–75 nmol/L (deficiency); | |
25-(OH)D ≤ 25 nmol/L (severe deficiency) | ||||||||
Other Healthcare Employees | Platz (2000) [59] | Health professionals | 150 | United States (37°09′N) | Cohort | 45.5 ± 15.0 | Mean 1α, 25-(OH)2D: 79.6 ± 15.7 pmol/L | |
Nakamura (2001) [141] | Nursing home employees | 77 | Niigata, Japan (37° 48′ to 59′N) | Cross-sectional | 42.1 ± 15.1 | <50 nmol/L: 26% | Mean 1α, 25-(OH)2D: 111.1 ± 33.6 pmol/L | |
Platz (2004) [142] | Health professionals | 460 | United States (37°09′N) | Case-control | 59.7 ± 20.5 | Mean 1α, 25-(OH)2D: 83.8 ± 17.0 pmol/L. | ||
Arya (2004) [143] | Hospital staff | 92 | Lucknow, 26.55°N, 80.59°E | Descriptive | 30.7 ± 27.2 | <50 nmol/L: 78.3% | Mean 1α, 25-(OH)2D: 97.4 ± 48.2 pmol/L | |
Hanwell (2010) [144] | 1. Hospital workers (in winter) | 47 | South Italy (latitude 40°N) | Descriptive | 38.8 ± 29.0 | <75 nmol/L: 87% <30 nmol/L: 53% | ||
2. Hospital workers (in summer) | 23 | 58.6 ± 16.5 | <75 nmol/L: 78% <30 nmol/L: 4% | |||||
Beloyartseva [29] | Healthcare professionals | 2119 | India, various cities (20°59′N) | Descriptive | 35.8 ± 26.5 | <75 nmol/L: 15% <50 nmol/L: 79% | ||
Plotnikoff (2012) [145] | Health care system employees | 10,646 | Minnesota, United States (46°73′ N) | Prospective observational | 70.1 ± 34.0 | <75 nmol/L: 31.9% <50 nmol/L: 28.9% | ||
Porojnicu[146] | Hospital employees | 105 | Bucharest, Romania (45° N) | Descriptive | <80 nmol/L: 17% <50 nmol/L: 80% | |||
Gannage-Yared (2014) [147] | Hospital employees | 392 | Beirut, Lebanon (33°89′N) | Descriptive | 39.0 ± 19.7 | < 75 nmol/L: 23.5% < 50 nmol/L: 71.4% | ||
Skarphedinsdottir (2014) [148] | 1. Anaesthesia health care staff | 106 | Reykjavik, Iceland (64°08′N) Madison, WI, USA (43°07′N) | Descriptive | 70.5 ± 30.9 | <75 nmol/L: 56.6% <50 nmol/L: 39.6% | ||
2. Anaesthesia health care staff | 124 | 70.0 ± 30.0 | <75 nmol/L: 61.3% <50 nmol/L: 29% | |||||