SEASONAL CHANGES IN THE BIOCHEMICAL INDICES OF VITAMIN D DEFICIENCY IN THE ELDERLY: A COMPARISON OF PEOPLE IN RESIDENTIAL HOMES, LONG-STAY WARDS AND ATTENDING A DAY HOSPITAL

Abstract

The seasonal changes in the biochemical indices of vitamin D nutrition have been measured in elderly people with differing requirements for institutionalized care. Residents of local authority homes (LAH) showed an increase in serum 25-hydroxyvitamin D₃ [25(OH)D₃] between spring and autumn (means 14–17 nmol/1, P3 9.5 and 9.5 nmol/1] and in day-hospital attenders [(GDH) 25 and 26.8 nmol/1]. Significant differences (PP3 amongst the three groups. A significant linear relationship (r=0.84, P=0.036) was found between mean serum 25-hydroxyvitamin D₂[25(OH)D₂] and dietary vitamin D₂. The intake of vitamin D was suboptimal in all groups. The incidence of 25-hydroxyvitamin D deficiency [25(OH)D<12.5 nmol/1] varied from 11.7% of residents in LAH in autumn to 47% of GW patients in spring; but hypocalcaemia occurred less often (LAH 1.3% in autumn, GW 4.7% in spring). The diet assumes a greater role in protecting against vitamin D deficiency when the total 25(OH)D is low. Because most diets contain insufficient amounts of vitamin D, elderly institutionalized people will remain at high risk of developing vitamin D deficiency unless specific preventative measures are adopted.