Prevalence and determinants of vitamin D deficiency in healthy French adults: the VARIETE study

The U.S. Institute of Medicine considers that a serum 25-hydroxyvitamin D (25OHD) concentration >20 ng/mL corresponds to optimal vitamin D status in the general population. Old studies of vitamin D status in the French general population have demonstrated high prevalence of insufficiency. We measured serum 25OHD, 1,25(OH)₂D, PTH, calcium, phosphorus, and creatinine levels in 892 French Caucasian healthy subjects (463 men, 429 women) aged from 18 to 89 years. The 25OHD concentration was similar in men (24.1 ± 8.2 ng/mL) and women (23.4 ± 8.0 ng/mL). 25OHD concentrations of <10, <12, <20, and <30 ng/mL were found in respectively 6.3, 9.9, 34.6, and 80.3 % of subjects. Residence in northern France (odds ratio [OR] 1.91), blood sampling between January and March (OR 7.74), BMI ≥24 kg/m² (OR 1.81), and age 60 years or more (OR 1.99) were significant determinants of hypovitaminosis D (25OHD <20 ng/mL). The serum 25OHD level correlated positively with 1,25(OH)₂D and negatively with PTH. 25OHD values below 20 ng/mL were associated with lower 1,25(OH)₂D levels, and 25OHD values below 27 ng/mL were associated with higher PTH levels. Many French healthy adults have a 25OHD concentration <20 ng/mL, especially during winter months. Actions to improve the vitamin D status of the French general population are urgently needed.