Secondary hyperparathyroidism and its relationship with sarcopenia in elderly women.

Low dietary intake of calcium and poor vitamin D status during aging can result in mild secondary hyperparathyroidism, which may be associated with low muscle mass and reduced strength in the elderly. The aim of this study was to investigate whether low vitamin D, high parathormone (PTH), or both, are associated with sarcopenia. A total of 105 women, 35 with sarcopenia and 70 without sarcopenia, were enrolled in the present study. Body composition measurements were performed by DXA and sarcopenia was defined as skeletal muscle mass index<5.45 kg/m2 and grip strength lower than 20 kg. Three-day dietary records were taken and adjustments for energy intake made. The estimated average requirement (EAR) method was adopted as a cut-off point for estimating the prevalence of inadequate intake. Serum total calcium, phosphorus, creatinine, intact PTH, and 25(OH)D were measured. Only 1% of the patients met the daily adequate intake for vitamin D and 11% met the daily adequate intake for calcium. Notably, the prevalence of sarcopenia was higher in hyperparathyroidism (25(OH)D<20 ng/mL and PTH>65 pg/dL) than in the absence of hyperparathyroidism (41.2 vs 16.2%, respectively; p=0.046). The odds ratio for sarcopenia in hyperparathyroidism cases was 6.81 (95%CI 1.29-35.9) compared with participants who had low PTH and a high 25(OH)D concentration. The present study showed that vitamin D insufficiency associated with secondary hyperparathyroidism increased the risk of sarcopenia, suggesting that the suppression of hyperparathyroidism by ensuring adequate calcium and vitamin D intake should be considered in interventional studies to confirm potential benefits.