Besides increasing the calcium and phosphorus levels in the extracellular fluid to mineralize new bone, vitamin D also has extra skeletal effects in the body. It modulates the transcription of cell cycle proteins that decreases cell proliferation and increases cell differentiation of a number of specialized cells of the body (e.g. enterocytes, keratinocytes, etc.).[11-13] Vitamin D toxicity can also develop due to more than required supplementation which causes increased calcium levels. Hypercalcaemia causes fatigue, loss of appetite, weight loss, excessive thirst, excessive urination, dehydration, constipation, irritability, nervousness, ringing in the ear (tinnitus, muscle weakness, nausea, vomiting, dizziness, confusion, disorientation, high blood pressure, heart arrhythmias, etc. The consequences of vitamin D deficiency are low calcium and phosphate, increased parathormone(PTH) producing secondary hyperparathyroidism, a further reduction in phosphate levels and increased plasma levels of bone-derived alkaline phosphatase. Clinically, low vitamin D produces poor bone mineralization - rickets in children, osteomalacia in adults. Extra skeletal manifestations of vitamin D deficiency include depression, increased risk of fracture, limb girdle muscle weakness, muscle twitching (fasciculation), pre-eclamsia,etc.[14] Despite ample sunshine in India, 70-100% Indians in different age groups are reported to be vitamin D insufficient or deficient.[15] But this deficiency is according to western reference scale. While osteomalacia and rickets have been studied extensively, there is little information on vitamin D deficiency without obvious bone disease. As per western statistics, vitamin D deficiency is defined as a serum 25(OH)D level <50 nmol/L (<20 ng/mL), whereas a serum 25(OH)D level of >75 nmol/L (>30 ng/mL) is considered to be normal, and a level 2 of 50-75 nmol/L (20-30 ng/mL) defines vitamin D insufficiency. According to this, majority of Indian population are insufficient or deficient yet are asymptomatic. There was a retrospective analysis of the vitamin D levels measured at a major medical center in Hyderabad, India. Vitamin D levels measured as a part of a routine health check were reviewed. A further analysis done on the basis of gender and geographic location of the population in sample of 65 Indian females showed serum 25(OH)D level to be 12.12 ng/mL (range 3-47.5) while in 30 Indian males the mean level was 11.86 ng/mL.[16] In 2000, serum 25(OH)D measured using sensitive and specific assay in apparently healthy subjects in Delhi and showed that significant hypovitaminosis D was present up to 90 per cent population tested.[17] A study from eastern India in Kolkata, West Bengal conducted by Rudrajit Paul et al showed more than half of the study population had Vitamin D deficiency with 53% females and 33% males. In west India in study done in Maharashtra, 95% of total population had hypovitaminosis D.[18] The northern and southern states in India too had similar findings of Vitamin D deficiency in majority of normal population.[19]Subclinical vitamin D deficiency has been reported to be highly prevalent in both urban and rural settings, and across all socioeconomic and geographic strata. According to the western reference scale, 70-100 % Indian population who are found to be vitamin D deficient should have poor bone quality. We hypothesize that the incidence of hypovitaminosis in Indian population is inflated because the western reference scale do not correspond to normal Indian values. Thus studies are required in India to estimate the serum vitamin D levels in normal and healthy population.