Logo: to the web site of Uppsala University

OBJECTIVE: Case reports have described associations between calcium metabolism disturbances and primary hyperparathyroidism with preeclampsia, suggesting parathyroid involvement in preeclampsia etiology. This study examines whether parathyroid adenoma, the main cause of hyperparathyroidism, diagnosed and treated before pregnancy is associated with preeclampsia. DESIGN: We conducted a register-based study to assess the association between parathyroid adenoma and subsequent preeclampsia. SETTING: Births among Sweden's general population were studied. POPULATION: The study population included 52 women with a diagnosis of parathyroid adenoma and 519 without, all of whom had a subsequent singleton pregnancy between 1973 and 1997. METHODS: We performed a conditional logistic regression investigating the association of parathyroid adenoma with subsequent preeclampsia in the first singleton pregnancy with adjustment for potential confounding factors. MAIN OUTCOME MEASURE: The main outcome was a diagnosis of preeclampsia that does not include women with prior chronic hypertension. To ensure that treatment of parathyroid adenoma was completed before pregnancy, those with a diagnosis of parathyroid adenoma made less than 2 yr before delivery (and the matched comparison women) were excluded. RESULTS: Statistically, parathyroid adenoma prior to delivery is significantly (P < 0.001) associated with preeclampsia, producing an adjusted odds ratio of 6.89 (95% confidence interval, 2.30, 20.58). CONCLUSION: A history of parathyroid adenoma should be viewed as a risk for preeclampsia.

Background: A condition resembling secondary hyperparathyroidism (HPT), including raised levels of PTH and normal levels of serum calcium, has been reported in obesity. A plausible reason may be vitamin D deficiency, but conflicting data have been reported. Objective: Our objective was to investigate calcium homeostasis in obese individuals with emphasis on the function of the parathyroid glands. Design and Intervention: Morbidly obese patients (mean body mass index = 46.6 +/- 6) were examined for their status of calcium homeostasis. A subset was thoroughly investigated with calcium-citrate (CiCa) clamping. Patients: Of 108 morbidly obese patients, 11 underwent CiCa clamping as well as 21 healthy volunteers of normal weight and 15 with primary HPT (pHPT). Large patient cohorts of normal individuals and pHPT patients were also used as comparisons. Outcome Measures and Results: All obese individuals had normal serum calcium and creatinine levels. Mean levels of 25-OH-vitamin D-3 in serum were low, 53 nmol/liter (reference range 75-250 nmol/liter). Mean intact plasma PTH was 5.1 pmol/liter (reference range 1.1-6.9 pmol/liter). There was a significant positive correlation between PTH and duration of obesity. CiCa clamping in obese subjects revealed a remarkably high sensitivity for calcium and a left-shifted relation between plasma calcium and PTH (set point) compared with the normal population. CiCa clamping in pHPT patients demonstrated a right-shifted PTH-Ca curve. Conclusion: Although vitamin D levels in the obese individuals were low, few displayed overt signs of secondary HPT. The CiCa clamping implied a disturbance in the calcium homeostasis comparable to early renal insufficiency, with a left-shifted Ca-PTH curve and a lower set point compared with the normal population.