Hypovitaminosis D in developing countries—prevalence, risk factors and outcomes

Abstract

Hypovitaminosis D is a prevalent disorder in developing countries. Clinical manifestations of hypovitaminosis D include musculoskeletal disorders, such as nonspecific muscle pain, poor muscle strength and low BMD, as well as nonmusculoskeletal disorders, such as an increased risk of respiratory infections, diabetes mellitus and possibly cardiovascular diseases. In developing countries, the prevalence of hypovitaminosis D varies widely by and within regions; prevalence ranges between 30-90%, according to the cut-off value used within specific regions, and is independent of latitude. A high prevalence of the disorder exists in China and Mongolia, especially in children, of whom up to 50% are reported to have serum 25-hydroxyvitamin D levels <12.5 nmol/l. Despite ample sunshine throughout the year, one-third to one-half of individuals living in Sub-Saharan Africa and the Middle East have serum 25-hydroxyvitamin D levels <25 nmol/l, according to studies published in the past decade. Hypovitaminosis D is also prevalent in children and the elderly living in Latin America. Risk factors for hypovitaminosis D in developing countries are similar to those reported in Western countries and include extremes of age, female sex, winter season, dark skin pigmentation, malnutrition, lack of sun exposure, a covered clothing style and obesity. Clinical trials to assess the effect of vitamin D supplementation on classical and nonclassical clinical outcomes in developing countries are needed.

Arterial stiffness and 25-hydroxyvitamin D levels in chronic kidney disease patients

“…22 Vitamin D deficiency in females was significantly higher in our study, in accordance with previous studies. 23,28 This may be attributable to the covered clothing style worn by Turkish females due to cultural factors.…”

“…8,15,26,27 In Middle Eastern and South Asian developing countries, levels of 25(OH)D < 10 ng/mL were reported in 50% of the population and higher risk was noted among females. 28 Of females aged 24-77 years living in Rabat, 91% had lower than 30 ng/mL 25(OH)D, and female sex was considered a predictor of 25(OH)D deficiency. 29 Reports of 25(OH)D deficiency in females tend to be particularly common in the Asia/Pacific and Middle East/Africa regions, possibly due to women wearing a more covered clothing style compared to females in other parts of the world.…”

Vitamin D in Neurological Diseases: A Rationale for a Pathogenic Impact

“…Latitude, season, cultural norms, religious practices, low awareness, low knowledge/health literacy, indoor lifestyles, urban living, skin pigmentation, malnutrition, diet, co-morbidities like tuberculosis, and drugs may contribute to vitamin D deficiency especially in the in the developing world, moreover, blacks tend to have lower levels of 25(OH)D compared to whites [2,3]. It has been widely demonstrated that Vitamin D is also involved in different non-skeletal functions, including hypertension, diabetes, multiple sclerosis, Alzheimer's disease, Parkinson's disease, and Stroke [4,5,6,7].…”

Serum 25-hydroxyvitamin D levels correlate with EGFR mutational status in pulmonary adenocarcinoma

“…In particular, cautious interpretation is required regarding the prognostic value of vitamin D (Giovannucci et al 2006, Mei et al 2007, Dizdar et al 2008. Similarly, on the basis of results from previous studies indicating that females have low vitamin D levels compared with males (Arabi et al 2010, Choi et al 2011, the sex difference might explain the inverse association of vitamin D level and EGFR mutational status. However, it should be emphasized that the significance of vitamin D levels with respect to EGFR mutations was maintained after adjustment for other factors including sex in this study (Table 2).…”