VITAMIN-D STATUS IN PRIMARY HYPERPARATHYROIDISM IN INDIA

OBJECTIVES Primary hyperparathyroidism is a syndrome with variable cli nical expression, presenting as asymptomatic hypercalcaemia in Western countries and with predominant bone disease in developing countries. Vitamin D deficiency has been implicated as the cause of bone disease. There is a paucity of information on the vitamin D (25-OHD3) status o f patients with primary hyperparathyroidism presenting with bone disea se. The present study aims to evaluate the vitamin D status in patient s with primary hyperparathyroidism and to correlate it with the bone d isease. DESIGN Twenty consecutive patients with primary hyperparathyro idism admitted to the endocrinology and metabolism wards of the All In dia Institute of Medical Sciences were analysed to assess their clinic al, radiological and biochemical features, as well as parathyroid horm one (mid-molecular, PTH-MM) and 25-OHD3 levels. MEASUREMENTS PTH-MM le vels and 25-OHD3 levels were measured using RIA kits. RESULTS Bone dis ease (osteitis fibrosa cystica) was the mode of presentation in 90%. R adiologically, sub-periosteal resorption was present in 90% of the tot al group of patients, brown tumours in 60%, and pathological fractures in 40%. Renal stones and/or nephrocalcinosis was present in 50% of pa tients. Mean serum calcium, phosphate and alkaline phosphatase concent rations (mean of 3 days values) were 2.72 +/- 0.24 mmol/l; 1.01 +/- 0. 28 mmol/l and 425 +/- 249 IU/I respectively. The 24-hour (mean of 3 da ys values) urine calcium and phosphate excretions were 8.0 +/- 4.2 mmo l and 19.0 +/- 13 mmol. Only 50% of the patients had hypercalcaemia(> 2.7 mmol/l). However, 90% of the whole group of patients had hypercalc iuria, The mean serum creatinine concentration of patients with hyperc alcaemia was 108 +/- 38 mu mol/l and of those with normocalcaemia 89 /- 33 mu mol/l. The mean serum PTH-MM was 438 +/- 350 pmol/l (the dete ction limit for the kit was 34 pmol/l). Ultrasound examination detecte d adenomas in 72% of the cases and computerized tomography of the neck localized adenomas in 71% of the cases. The median weight of the aden oma was 4.6 g (range 0.125-25 g). Two patients had coexistent hyperpla sia of the other parathyroid glands and two had recurrent adenomas. 25 -OHD3 levels were assessed in all 20 patients under fasting conditions . The mean value of 25-OHD3 observed (8.4 +/- 5.1 mu g/l) was comparab le to the mean value measured in 14 healthy age and sex matched contro ls (8.3 +/- 2.5 mu g/l). CONCLUSION Patients with primary hyperparathy roidism in India presented with bone and renal diseases; half were nor mocalcaemic. All the patients had hypercalcuria despite the bone disea se. The PTH-MM levels were increased and 25-OHD3 levels were low. The predominant bone disease is probably due to prolonged primary hyperpar athyroidism coexisting with low calcium intake and/or 25-OHD3 deficien cy. The mean weight of the adenoma was higher than that reported for p atients in the Western literature.