Prevalence of vitamin D inadequacy in European postmenopausal women

Inadequate vitamin D level is associated with secondary hyperparathyroidism and increased bone turnover and bone loss, which in turn increases fracture risk. The objective of this study is to assess the prevalence of inadequate serum vitamin D levels in postmenopausal European women. There are no clear international agreements on what constitutes a level of vitamin D inadequacy, but recent publications suggest that the circulating level of vitamin D should be over 80 nmol/L or at least between 50 and 80 nmol/L.

Assessment of 25-hydroxyvitamin D [25(OH)D] was performed in 8532 European postmenopausal women with osteoporosis or osteopenia. European countries included France, Belgium, Denmark, Italy, Poland, Hungary, United Kingdom, Spain and Germany. Two cut-offs of 25(OH)D inadequacy were fixed : < 80 nmol/L and < 50 nmol/L.

Mean (SD) age of the patients was 74.2 (7.1) years, body mass index was 25.7 (4.1) kg/m(2). Level of 25(OH)D was 61.0 (27.2) nmol/L. There was a highly significant difference of 25(OH)D level across European countries (p < 0.0001). The lowest level of 25(OH)D was found in France [51.5 (26.1) nmol/L] and the highest in Spain [85.2 (33.3) nmol/L]. In the whole study population, the prevalence of 25(OH)D inadequacy was 79.6% and 32.1% when considering cut-offs of 80 and 50 nmol/L, respectively and when considering patients aged less than 65 years, the prevalence reached 86% (cut-off of 80 nmol/L) and 45% (cut-off of 50 nmol/L).

This study indicates a high prevalence of vitamin D [25(OH)D] inadequacy in European postmenopausal women. The prevalence could be even higher in some particular countries. A greater awareness of the importance of vitamin D inadequacy is needed to address this public health problem.