Hormonal Relationships to Bone Mass in Elderly Spanish Men as Influenced by Dietary Calcium and Vitamin D

We aim to evaluate whether calcium and vitamin D intake is associated with 25-hydroxyvitamin D (25-OH-Vitamin D₃) and parathyroid hormone (PTH) serum concentrations or is associated with either the phalangeal dual energy X-ray absorptiometry (pDXA) or the quantitative bone ultrasound (QUS) in independent elderly men. Serum PTH and 25-OH-Vitamin D₃ were measured in 195 healthy elderly men (mean age: 73.31 ± 5.10 year). Food intake was quantified using a dietetic scale. Participants with 25-OH-Vitamin D₃ levels ≥ 30 ng/mL (75 nmol/L) and a calcium intake of 800–1200 mg/day exhibited the lowest PTH levels (41.49 ± 16.72 ng/mL). The highest PTH levels (75.60 ± 14.16 ng/mL) were observed in the <30 ng/mL group 25-OH-Vitamin D₃ with a calcium intake >1200 mg/day. No significant differences in the serum PTH levels based on the serum 25-OH-Vitamin D3 levels were observed among participants with a calcium intake of 800–1200 mg/day. Serum PTH was inversely correlated with serum 25-OH-Vitamin D₃ in the entire patient sample (r = −0.288, p = 0.019). No differences in any of the three densitometry techniques were observed between any of the age groups in the 800–1200 mg/day and >1200 mg/day calcium intake groups. PTH levels correlate negatively with serum 25-OH-Vitamin D₃ levels, and neither calcium nor vitamin D intake exert a strong influence on either of the two parameters.