Age-related changes in parathyroid hormone and 25 hydroxycholecalciferol levels.

Serum parathyroid hormone and 25 hydroxyvitamin D were measured in 124 normal subjects aged from 20 to 90 years. There was a significant progressive increase in serum parathyroid levels with age associated with a progressive decrease in total serum calcium. After the sixth decade there was a significant reduction of 25 hydroxyvitamin D serum levels. In each age group, there were no significant differences between men and women in all parameters measured. In normal elderly subjects there is an age-related decline of calcium absorption associated with reduced calcium intake and sun exposure leading to secondary hyperparathyroidism. These results emphasize the importance of calcium and vitamin D supplementation in elderly European population, not only in long-stay patients but in ambulatory normal people after 60 years.