Dietary calcium intake in a cohort of individuals evaluated for low bone mineral density: a multicenter Italian study

BACKGROUND: A low calcium intake is a well-known factor that influences the bone mineral density (BMD) maintenance. In the presence of inadequate calcium intake, secondary hyperparathyroidism develops, leading to an increased bone turnover and fracture risk.AIMS: To assess the dietary calcium intake in relation with osteoporosis and fragility fracture in a cohort of Italian individuals evaluated for low BMD.METHODS: A 7-day food-frequency questionnaire was administered to 1793 individuals, who were consecutively referred at the Centers of the Italian Society for Osteoporosis, Mineral Metabolism and Skeletal Diseases (SIOMMMS) for low BMD.RESULTS: In 30.3% and 20.9% of subjects, the calcium intake was inadequate (<700mg/day) and adequate (>1200mg/day), respectively. As compared with patients with adequate calcium intake, those with inadequate calcium intake were younger (65.5±10.8 vs 63.9±11.5years, p=0.03) and they more frequently reported adverse reactions to food (3.2% vs 7.2% p=0.01) and previous major fragility fractures (20.8% vs 27.0%, p=0.03). Patients with calcium intake<700mg/day showed a higher prevalence of diabetes mellitus, idiopathic hypercalciuria and food allergy/intolerance (8.1%, 5.1%, 7.2%, respectively) than patients with calcium intake>700mg/day (5.3%, 3.0%, 4.1%, respectively, p<0.04 for all comparisons), also after adjusting for age, gender and body mass index. In 30.3% of fractured subjects, the calcium intake was<700mg/day.DISCUSSION: In Italy, a low calcium intake is highly prevalent in individuals at risk for low BMD. Importantly, an inadequate calcium intake is highly prevalent even in patients with history of fragility fractures.CONCLUSIONS: Only about a fifth of patients being assessed for low BMD in an Italian SIOMMMS referral Centre have an adequate calcium intake.