Age-related differences in vitamin D status in Polish centenarians compared with 65-year-olds

INTRODUCTION Vitamin D status is known to change with age. However, little is known about vitamin D status in centenarians. OBJECTIVES The aim of the study was to assess vitamin D status and correlations among the levels of parathyroid hormone (PTH), 25-hydroxycholecalciferol (25[OH]D), 1,25-dihydroxycholecalciferol (1,25[OH]D), calcium, inorganic phosphorus, and alkaline phosphatase (ALP) activity in centenarians. PATIENTS AND METHODS The study group included 97 participants: 81 women and 16 men (median [interquartile range [IQR]) age, 101.4 [100.5-102.16] years). Centenarians were visited at their homes where examinations were conducted and blood samples collected. The control group consisted of 57 elderly subjects: 35 women and 22 men (median [IQR] age, 65.9 [65.3-66.5] years). The concentrations of PTH, 25(OH)D, and 1,25(OH)D were measured in frozen plasma samples, and calcium, phosphorus, and ALP levels, in serum samples. RESULTS The median calcium level was 8.88 mg/dl in centenarians versus 9.52 mg/dl in 65-year-old subjects (P <0.01); ALP, 223 IU versus 190 IU (P = 0.01); phosphorus, 3.01 mg/dl versus 3.23 mg/dl (P = 0.13); PTH, 45.59 pg/ml versus 29.27 pg/ml (P <0.01); 25(OH)D, 7.39 ng/ml versus 19.81 ng/ml (P <0.01); 1,25(OH)D, 57.5 pmol/l versus 78.6 pmol/l (P <0.01). Only centenarians demonstrated correlations among the measured laboratory parameters. CONCLUSIONS Considering lower 25(OH)D, 1,25(OH)D, and calcium concentrations in the majority of centenarians, as well as the negative correlation between vitamin D active metabolites and PTH, vitamin D and calcium should be systematically supplemented in the oldest of the elderly.