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* Osteomalacia, a bone-thinning disorder that occurs exclusively in adults and is characterized by proximal muscle weakness and bone fragility. The effects of osteomalacia are thought to contribute to chronic musculoskeletal pain, there is no persuasive evidence of lower vitamin D status in chronic pain sufferers. Adequate vitamin D may also be associated with healthy hair follicle growth cycles. There are also associations between low 25(OH)D levels and peripheral vascular disease, certain cancers, multiple sclerosis, rheumatoid arthritis, juvenile diabetes, Parkinson's and Alzheimer's disease. However these associations were found in observational studies and vitamin D vitamin supplements have not been demonstrated to reduce the risks of these diseases. Research conducted in the United Kingdom and the United States shows that dark-skinned people living in Western societies may not be getting enough vitamin D from the sun. This is particularly true among people of Asian descent, with worse levels of deficiency among Asian women. This is partly due to the fact that dark-skinned people are less efficient at making vitamin D, but among some groups it may be attributed to cultural practices of covering up exposed skin. Other groups that are at risk for vitamin D deficiency include children under five, pregnant and breast-feeding women, anyone who is housebound, and seniors who are less able to make vitamin D from their skin — particularly those who don’t get out much, or people living in care homes where they don’t sit outdoors.
In healthy adults, sustained intake of 1250 micrograms/day (50,000 IU) can produce overt toxicity after several months; those with certain medical conditions are far more sensitive to vitamin D and develop hypercalcaemia in response to any increase in vitamin D nutrition, while maternal hypercalcaemia during pregnancy may increase fetal sensitivity to effects of vitamin D and lead to a syndrome of mental retardation and facial deformities. Pregnant or breastfeeding women should consult a doctor before taking a vitamin D supplement. For infants (birth to 12 months) the tolerable Upper Limit (maximum amount that
Overdose by ingestion