Vitamin D inadequacy: the Italian picture

Introduction

The standard method used to assess vitamin D status is the measurement of 25-hydroxyvitamin D (25OHD) serum concen­tration, the major circulating metabolite of vitamin D. Opinions regarding the optimal concentration of serum 25OHD vary widely. Generally in Italian studies a cut-off of 30 nmol/L has been used because concentrations of 25OHD below 30 nmol/L were associated with secondary hyperparathyroidism, in­creased bone turnover, and decreased bone mineral density at the hip, even if many recent studies have shown that serum concentrations of at least 50-75 nmol/L are necessary to maxi­mize intestinal calcium absorption and minimize perturbations in parathyroid hormone (PTH), calcium, and phosphorus homeostasis.

Numerous epidemiological studies have assessed the preva­lence of low serum 25OHD concentrations and have indicated that vitamin D inadequacy is a common problem worldwide. Differences in the prevalence of vitamin D inadequacy have been related to a variety of factors, including physiological changes with age, race, body mass index, sun exposure, lati­tude, and dietary vitamin D intake.

Several studies have compared vitamin D status in different populations and geographical regions, but these comparisons are frequently complicated by differences in assays. Here we review the available data on the prevalence and con­sequences of hypovitaminosis D (defined as serum 25OHD level below 30 nmol/L) in Italy and some of the strategies for its prevention. When you need your medication buy cialis professional