[Vitamin D deficiency prediction by patient questionnaire and secondary hyperparathyroidism in a cohort of 526 healthy subjects in their fifties].

Introduction: Can vitamin D deficiency be predicted by patient questionnaire? Does it lead to secondary hyperparathyroidism that may cause excessive bone resorption? We studied non-osteoporotic subjects in their fifties, in whom vitamin D levels are often tested.

Patients And Methods: Patients hospitalised for degenerative osteoarthritis or consulting for assessment of menopause, without renal failure and not treated with vitamin D, completed a questionnaire on sun exposure and underwent measurement of serum calcium, creatinine, 25OH vitamin D, PTH and CTX.

Results: Five hundred and twenty-six subjects, mean age 54.6 years (71% women), were investigated throughout the year. 25OH vitamin D levels were correlated with sun exposure and varied according to the month of the year, unlike PTH and CTX levels. From November to May, over 90% of subjects had 25OH vitamin D levels<30ng/mL. Of the subjects who did not expose their face, arms and legs to the sun for at least 20min/day, 94% had 25OH vitamin D levels<30ng/mL. PTH levels were negatively correlated with those of 25OH vitamin D. Serum CTX levels were not correlated with PTH or 25OH vitamin D. Only 13% of subjects presented with secondary hyperparathyroidism, characterised by serum calcium<2.55mmol/L and PTH>65pg/mL, associated with increased CTX levels.

Conclusion: Vitamin D deficiency can be predicted by patient questionnaire. It very rarely leads to secondary hyperparathyroidism.