Epidemiological Evidence for the Disruption of Ionized Calcium Homeostasis in the Elderly

Abstract 

Ionized calcium (Ca²⁺), phosphate, albumin, total calcium, and pH measurements taken from participants in a large population-based epidemiological study were examined to determine the change in physiological variation with age for persons over 43 years old. Only Ca²⁺ showed a statistically significant increase in SD with age (p < 0.0001). The Ca²⁺ coefficients of variation (CV) increased from 2.92% in the youngest age group (43–54 years) to 3.69% in the oldest age group (75–86 years of age). In females, the increase in Ca²⁺ variability was nearly complete by age 55. Males also showed a significant (p = 0.006) increase in SD between the 43–54 age group and the 55–64 age group, however, Ca²⁺ variability did not plateau after age 55 in men as it did in women. In the 43–54 (p = 0.04) and 55–64 (p = 0.03) age group men showed significantly better physiological control of Ca²⁺ than women. Phosphate showed a slight decrease in CV with age. These data suggest that Ca²⁺ homeostasis is disrupted in the same age groups that are most vulnerable to osteoporosis.

Keywords:  Ionized calcium, phosphate, homeostasis, gerontology, osteoporosis, sex differences