Global vitamin D levels in relation to age, gender, skin pigmentation and latitude: An ecologic meta-regression analysis

Department of Endocrinology and Metabolism C, Aarhus Amtssygehus, Aarhus University Hospital, Aarhus, Denmark.
Osteoporosis International (Impact Factor: 4.17). 05/2008; 20(1):133-40. DOI: 10.1007/s00198-008-0626-y
Source: PubMed

ABSTRACT We performed a meta-analysis of cross-sectional studies on serum 25(OH)D status globally. Serum 25(OH)D levels on average were 54 nmol/l, were higher in women than men, and higher in Caucasians than in non-Caucasians. There was no trend in serum 25(OH)D level with latitude. Vitamin D deficiency was widespread.
We studied vitamin D status (expressed as serum 25-hydroxy-vitamin D [25(OH)D]) in native subjects worldwide.
Meta-analysis and meta-regression of studies reporting on 25(OH)D in healthy subjects retrieved from Pubmed, Embase and Web of Science using the terms "serum", "25-hydroxy-vitamin D", "cholecalciferol", and "human". A total of 394 studies were included.
The mean 25(OH)D level was 54 nmol/l (95% CI: 52-57 nmol/l). Women had borderline significantly higher 25(OH)D levels than men, and Caucasians had higher levels than non-Caucasians. 25(OH)D levels were higher in subjects aged >15 years than in younger subjects. Unadjusted there was no significant decrease in 25(OH)D with latitude (slope of curve -0.03 +/- 0.12 nmol/l per degree latitude north or south of equator, p = 0.8). There was a significant decline with latitude for Caucasians (-0.69 +/- 0.30 nmol/l per degree, p = 0.02), but not for non-Caucasians (0.03 +/- 0.39 nmol/l per degree, p = 0.14). After adjustment for age, gender, and ethnicity, no overall correlation was present between 25(OH)D and latitude (-0.29 +/- 0.24 nmol/l per degree, p = 0.23).
There was no overall influence of latitude on 25(OH)D. However, in separate analyses 25(OH)D decreased with latitude in Caucasians but not in non-Caucasians. A widespread global vitamin D insufficiency was present compared with proposed threshold levels.

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Available from: Peter Vestergaard, Aug 15, 2015
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    • "The effect of latitude and season on vitamin D concentrations is well documented in humans, where people living closer to the equator have higher vitamin D concentrations due to longer periods of sunlight (Hagenau et al., 2009; Mithal et al., 2009). Of interest and supporting the importance of sunlight exposure, the highest rates of hypovitaminosis D and rickets in the world are reported in the Middle East and Africa (Hagenau et al., 2009; Mithal et al., 2009). This is explained by ethnicity, cultural and religious practices (body covering, veils), prolonged breastfeeding, and inhabitants with darker skin color. "
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    ABSTRACT: Vitamin D is essential in calcium and phosphorus regulation, bone physiology, cell proliferation and epithelial integrity. Literature on vitamin D in growing horses is sparse, and the effect of age on vitamin D has not been evaluated in equids in the United States or in tropical countries. The goal of this study was to determine if there was an effect of age on serum 25(OH)D3 concentrations in equids in the US (Ohio/Kentucky) and Thailand (Chiang Rai and Kanchanaburi) during the same time of the year. Blood samples were collected from healthy ponies (n=21) and Thoroughbred foals (n=13), yearlings (n=10), and horses (n=20) in Thailand and from Thoroughbred foals (n=10) and horses (n=17) in the US. Serum concentrations of 25(OH)D3, calcium and phosphorus were measured. In both countries, serum 25(OH)D3 concentrations were lower in foals than in yearlings and adult horses. Serum 25(OH)D3 concentrations were higher in horses than in ponies in Thailand, but were not different between horses from either country. Calcium concentrations were not different between groups or location. In both countries, phosphorus concentrations were higher in foals than in older groups; however, were not different between ponies and horses. This study shows that independent of geography there are age-related differences in 25(OH)D3 concentrations in horses and further confirms that 25(OH)D3 concentrations are lower in horses compared to other species. The information will serve as the basis for future clinical studies and to help understand better the pathophysiology of equine disorders associated with calcium and phosphorus dysregulation.
    The Veterinary Journal 03/2014; 199(3). DOI:10.1016/j.tvjl.2014.01.002 · 2.17 Impact Factor
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    • "Calcium metabolism is under control through the coordinated actions of parathyroid hormone (PTH) and activated vitamin D, and the most common cause of hypocalcemia in primary care is vitamin D deficiency [3]. Vitamin D deficiency is increasing worldwide [4] [5] [6] [7] [8], and it has been drawing much attention in the association of various diseases including cancer, cardiovascular disease, endocrine and metabolic diseases, and infectious and autoimmune diseases [9] [10] [11] [12] [13]. In addition, it has been more recently suggested that vitamin D deficiency is associated with Graves' disease [14] [15] [16]. "
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    04/2013; 2013:512671. DOI:10.1155/2013/512671
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    • "It has recently been suggested that hypovitaminosis D is widespread in mid-and high-latitude countries [Holick, 2007, 2011; Hagenau et al. 2009; Pierrot-Deseilligny and Souberbielle, 2011] and it is nowadays generally accepted that this insufficiency may constitute one of the risk factors for multiple sclerosis (MS) [Ascherio and Munger, 2007; Ebers, 2008; Ascherio et al. 2010; Pierrot-Deseilligny and Souberbielle, 2010; Hanwell and Banwell, 2011; Ramagopalan et al. 2011]. Furthermore, several studies in MS patients have shown that vitamin D plays an anti-inflammatory and immunomodulatory role via diverse immunological mechanisms [Mahon et al. 2003; Correale et al. 2009, 2010; Royal et al. 2009; Bartosik-Psujek et al. 2010; Smolders et al. 2008a, 2009, 2010, 2011b; Lysandropoulos et al. 2011], potentially resulting in beneficial effects after the start of the disease. "
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    Therapeutic Advances in Neurological Disorders 07/2012; 5(4):187-98. DOI:10.1177/1756285612447090
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