Normalized dyslipidaemia after parathyroidectomy in mild primary hyperparathyroidism: population-based study over five years.

OBJECTIVE: Postmenopausal women are at increased risk of primary hyperparathyroidism (pHPT). Secondary dyslipidaemia in pHPT has attracted little attention, although morbidity and mortality associated with cardiovascular diseases have been reported to be increased in these patients.

DESIGN: A population-based screening programme was used to recruit postmenopausal women with mild, asymptomatic pHPT (mean serum calcium 2.57 +/- 0.12 mmol/l) and matched controls. MEASUREMENTS AND PATIENTS: Serum lipids, lipoprotein fractions and influences of treatment for the parathyroid disease were studied in 87 case-control pairs (mean age 67 years), 69 of whom completed a 5-year follow-up period.

RESULTS: pHPT was characterized by decreased serum high-density lipoprotein (HDL)-cholesterol, increased total triglycerides, very-low-density lipoprotein (VLDL)-triglycerides and VLDL-cholesterol levels and an elevated atherogenic index. The differences were more pronounced in the cases with serum parathyroid hormone levels in the normal range and were inversely correlated to the serum parathyroid hormone level. Parathyroidectomy, with or without additive hormone replacement therapy, normalized the dyslipidaemia. Five-year surveillance of pHPT without treatment was associated with a maintained increase in total triglycerides and the atherogenic index and a decrease in HDL-cholesterol levels.

CONCLUSION: Proatherosclerotic dyslipidaemia characterizes mild pHPT and is effectively reversed by parathyroidectomy. As dyslipidaemia might contribute to the increased risk of cardiovascular diseases and death observed in pHPT, the findings favour operative intervention rather than conservative surveillance in mild, asymptomatic pHPT in postmenopausal females.