Vitamin D has effects on many tissues, and hypovitaminosis D is frequent. In a French survey conducted among 1587 adults, vitamin D insufficiency (<30ng/ml) has been reported in 80% of subjects, including 43% with moderate deficiency (<20ng/ml) and 5% with severe deficiency (<10ng/ml).

Because of the possible consequences of hypovitaminosis D (osteomalacia in adults…), the number of vitamin D determination has increased ten-fold since 2005 in France, reaching 4.5 million € in 2011, and with it the costs for health insurance. However, there is currently no consensus on the strategy for detection, diagnosis and treatment of hypovitaminosis D.

We propose to develop a predictive clinical score of hypovitaminosis D based on the accurate assessment of solar exposure, vitamin D intakes and hypovitaminosis D risk factors collected through a self-administered questionnaire.

Inclusion Criteria:

- Men and women aged 18 to 70 years old

Exclusion Criteria:

• Participation in a study related to vitamin D
• Taking at least 80 000 IU vitamin D in the last 3 months as a single dose
• Pregnancy or breast-feeding
• Renal failure : severe renal impairment, dialysis, having kidney transplant
• Known hepatic impairment
• Gastrointestinal disorders: Celiac disease, Crohn's disease, ulcerative colitis, bariatric surgery, gastrointestinal surgery with stoma
• Known primary hypo/hyperparathyroidism
• Bone cancer/metastases current or in the last 2 years
• Treatment with antiepileptics
• Long-term treatment with glucocorticoids (> 3 months)
• Treatment with antiretroviral
• Legal incapacity or limited legal capacity
• Non-recipient of French Social Security