Calcium intake, bone mineral density, and fragility fractures: evidence from an Italian outpatient population.

Abstract

The principal aim of the present study was to focus on the effects of dietary calcium intake on bone mineral density (BMD) and fragility fractures in a representative sample of an adult Italian outpatient population. The study group consisted of 1000 consecutive adult Italian subjects [838 women (F) and 162 men (M)] referred to the Bone Metabolic Diseases Unit for the evaluation of their bone metabolism. Daily dietary calcium intake was assessed using a specific food frequency questionnaire (FFQ). Other evaluations included fracture risk, lumbar and femoral BMD, heel ultrasound, fragility fractures, plasma concentration of parathyroid hormone ([PTH]) and 25-hydroxy-vitamin D ([25(OH)D]), and urinary calcium. Only 10.4% of the subjects (n=104; 71 F and 33 M) had a daily calcium intake adequate for adults (≥1000mg/day). No correlation was found between calcium intake and BMD. The transition from a daily dietary calcium intake <400mg/day to a daily dietary calcium intake ≥400mg/day was associated with a reduced fracture probability ratio at any site [from 42 to 21% (p<0.05)]. Subjects with one or more vertebral fractures had a significantly lower dietary calcium intake (<400mg/day) than did subjects without vertebral fractures, and they practiced physical activity only occasionally (p=0.030). Daily dietary calcium intake is lower than the recommended daily intake in an Italian ambulatory population, and a higher fracture risk appears to be associated with a reduced calcium intake. An age-adequate daily calcium intake, combined with regular physical activity, is strongly recommended in order to counteract fragility fractures.