A CORRELATION BETWEEN NAIL CHANGES AND BONE HEALTH IN PATIENTS WITH HYPERTHYROIDISM

ABSTRACT Hyperthyroidism, specifically Graves’ disease (GD), has been associated with increased bone resorption. There are only a few studies linking nail and bone changes in patients with hyperthyroidism. Fingernails may be good indicators of metabolic changes occurring in the body, as they are in contact with periosteum of the phalangeal bone. Thus, the mineral composition of the nail plates might be a suitable adjunct to bone densitometry to monitor bone health. In previous studies, Raman spectroscopic data of nail clippings has been shown to correlate with bone changes in postmenopausal osteoporosis. Hence this study was done to ascertain whether nail changes are a surrogate marker for bone health in patients with hyperthyroidism. We analysed 30 patients (> 18 years) of newly diagnosed Graves’ disease (Tc99 proven), or patients with GD with < 1 year duration of treatment with persistently suppressed TSH. Total T3, T4, TSH; serum calcium, phosphorus, Vitamin D, PTH and ALP were done for all patients. BMD DXA (Hologic; hip and lumbar spine) was done for all patients. Raman spectroscopy analysis was carried out using a Sierra Reader (Snowy Range Instruments) using 785 nm excitation with 50 mW power at the sample. Spectra were acquired from 400 to 1700 cm− and position of the disulphide bonds (500 cm-1), Amide I and Amide II intensities noted. Results: Patients were divided into 2 groups for analysis: Group 1: < 40 years (17 patients), and Group 2: >=40 years (13 patients). Mean age was 38.6 years. Median levels of TSH in both the groups was 0.028 miu/ml (0.005-0.114) and 0.006 miu/ml (0.005-0.031) respectively. Median levels of T3 in Group 1 was 2.01 ng/ml (1.57 – 7.9) and in Group 2 was 2.36 ng/ml (1.88 – 4.82), and that of T4 were 8.82 ug/dl (7.49-11.17) and 8.28 ug/dl (7.44-14.26) respectively. Median values of serum calcium, phosphorus, Vitamin D, PTH and ALP were not significantly different across the two groups. The median Tc99 uptake was 4.5% (2.5-7.5) and 5.1% (3.4-7.9) respectively in the two groups. The median BMD measured at the lumbar spine measured by DXA (Hologic) in Group 1 and 2 was 0.880 g/cm2 (0.783-0.906) and 0.794 g/cm2 (0.695-0.893) and at the femoral neck was 0.732 g/cm2 (0.636-0.813) and 0.686 g/cm2 (0.578 – 0.775) respectively. The median Z score for Group 1 patients at the lumbar spine was -1.2 (-1.85 to -0.8) and at the femoral neck was -1.0 (-1.75 to -0.75), while in Group 2, the median T score for these patients at the lumbar spine was -2.1 (-2.6 to -0.85) and at the femoral neck was -1.4 (-2 to -1). As regards the nail changes (analysed in all patients), the position of the Disulphide bond peak at 500 cm-1 was shifted maximally in 17 patients, resulting in negative intensities, while it was weakly positive in the remaining 13; indicating poorer nail quality but better than the former. The median Amide I: Amide II ratio was 0.55 (0.2-0.93), with a ratio of <0.67 indicating poor nail quality. The median BQT values (Bone Quality Test) analysed from the spectra was 19.05 (12.24-23.9), with lower values (<20) indicating poor nail matrix organization. It was observed there was a significant correlation between the Amide I concentration and the BQT (Bone Quality test) parameter (r = 0.745, p = 0.013), indicating that this parameter might be used as a correlate of bone health. Hence, it was observed that nail changes on Raman Spectroscopy were evident in patients with hyperthyroidism, and that they could be potentially used as a surrogate marker for bone health in these patients.