Influence of nutritional factors on calcium-regulating hormones and bone loss

The relationships between nutritional factors, calcium regulating hormones, and bone density were evaluated in three groups of normal subjects in rural southeast Kansas. Dietary intake of calcium (Ca), phosphorous (P), protein, and vitamin D; and serum 25OHD, Ca, P, parathyroid hormone (iPTH), and bone density (distal 1/3 radius) were measured in 29 elderly women, 35 elderly men, and 50 perimenopausal women. Measurements were repeated 5 years and 4 years later respectively in 16 elderly women and 15 elderly men. The r values for significant regression correlations for each group were as follows: perimenopausal: bone density and dietary Ca:P--r = .29, iPTH and 25OHD--r = -.38; elderly women: 25OHD and dietary Vitamin D(D)--r = .58, change in bone density (delta BD) and initial bone density (BDI)--r = -.71, delta BD and serum 25OHD--r = -.60, serum calcium and age--r = -.42; elderly men: Serum 25OHD and D--r = .61, iPTH and 25OHD--r = -.43, iPTH and serum phosphorous--r = .59.

The more adequate the state of vitamin D nutriture, the lower the serum iPTH in perimenopausal women and elderly men and the less bone loss in elderly women. The Ca:P ratio in the diet may be important in maintaining bone density in perimenopausal women.