Dietary Calcium Intake in Patients Evaluated for Bone Fragility, with a Focus on Women Receiving Adjuvant Endocrine Therapy for Breast Cancer: A Single-Center Cross-Sectional Study

Background/Objectives: Adequate dietary calcium intake is essential for bone health. Despite this, calcium intake is still insufficient in many countries of the world. The study aims to provide information about dietary calcium intake of specific populations with bone fragility, with a particular focus on patients at risk of secondary osteoporosis due to adjuvant endocrine therapy (AET) for breast cancer (BC). Methods: Data from 132 patients referred for the first time to the Osteoporosis and Bone Metabolism Diseases outpatient clinic of the Division of Endocrinology of the Azienda Ospedaliero-Universitaria delle Marche (Ancona, Italy) were collected. Dietary calcium intake was assessed with a 7-day food frequency questionnaire; biochemical and densitometric parameters, osteoporosis etiology, and previous fragility fractures were also reported. Results: Patients were predominantly postmenopausal women, with severe osteoporosis (43.2%) or at risk of secondary osteoporosis (40.9%); 64.8% of patients evaluated for secondary osteoporosis were women on AET for BC. Total mean dietary calcium intake was 959 ± 396 mg/day. A lower intake was observed in younger patients with postmenopausal osteoporosis (848 ± 471 mg/day, p = 0.03). Patients with normal bone mineral density (631 ± 131 mg/day), without fragility fractures (906 ± 361), and evaluated for secondary osteoporosis (900 ± 364 mg/day) tended to have lower mean dietary calcium intake although without reaching statistical significance. Mean calcium intake was also lower than the recommended threshold in women on AET for BC (854 ± 345 mg/day). Conclusions: Patients with bone fragility should be more encouraged to increase their dietary calcium intake. Attention must be paid to women with BC on AET, who have high fracture risk and should not be discouraged a priori from consuming selected dairy products (low-fat and fermented ones) and alternative calcium dietary sources.