Relationship of menopause to skeletal and muscle mass.

Cross-sectional and longitudinal changes in body composition with age were examined in white women to determine the relationship of body cell mass to menopause and of body fat to bone mass. There was statistical evidence for a curvilinear component to loss of total body potassium with negligible rates of loss before menopause. Longitudinal measurements also indicated a relationship between the proximity to menopause and the rate of loss of potassium. Total body potassium was significantly related to total body calcium and bone density of the spine, radius, and femoral neck. Total body fat was not related to any of these measurements. We found no evidence that adiposity plays a major role in protecting against bone loss.

Coexisting hyperparathyroidism with thyrotoxicosis.

The coexistence of hyperparathyroidism complicating thyrotoxicosis is quite rare. We report the case of one patient who presented with thyrotoxicosis, (total thyroxine of 15.1 micrograms/dl (5-13), free thyroxine index of 18 (4-15) and triiodothyronine by RIA of 305 ng/dl (70-230) and asymptomatic hypercalcemia of 15 mg/dl (8.5-10.6), who was also initially noted to have an elevated (C-terminal) serum immunoreactive parathyroid hormone (iPTH) level of 8,800 pg/ml (50-340). With propylthiouracil and propranolol, however, this patient became normocalcemic with a decrease in iPTH values to 714 pg/ml. As the patient was tapered from medication, after being rendered euthyroid, a recurrence of hypercalcemia with rising iPTH levels occurred. PTH levels should be helpful in defining coexisting hyperparathyroidism in patients with thyrotoxicosis since in the latter iPTH is usually suppressed. Our findings support the recommendation that in patients suspected of having both hyperparathyroidism and hyperthyroidism, a diagnosis of the former can only be made with certainty after the patient has been rendered euthyroid with persistently elevated serum calcium and iPTH levels. While there are no clinical features which permit the easy identification of patients who present with dual lesions, the determination of iPTH values may be the most consistently helpful test initially, whereas other parameters such as vitamin D, serum phosphate are less reliable.

Biochemical short-term changes produced by hormonal replacement therapy.

Seventy-one white women within 6 months to 6 years postmenopause were randomly assigned to three treatment groups: (a) placebo, (b) calcium, (c) cyclic estrogen-progestin plus calcium. Calcium was given as calcium carbonate with meals to attain an intake of 1,700 mg daily in the latter two groups. All women received 400 IU of vitamin D daily. Samples were obtained at baseline and after 2 months therapy. The hormonal treatment group had a decline in serum calcium, osteocalcin and urinary hydroxyproline and an increase in levels of calcitonin, parathyroid hormone and calcitriol. The increase in the latter two measurements could have resulted from the drop in serum calcium, it is also possible that the increase in calcitonin levels was a result of calcium supplementation. Although all these changes were statistically significant for the estrogen treatment group when considered alone, analysis of variance including the 3 groups demonstrated significance for the estrogen group for the parameters of skeletal metabolism but not for the changes in the calciotrophic hormones. There was an increase in serum calcium (p = 0.05) in the calcium augmentation group. It would be of interest to determine the effects of higher intakes of calcium in both the calcium and the estrogen treatment groups and to further explore differences in effects on bone remodeling between the two treatment approaches as well as the possibility of a additive effects. Early effects of estrogen replacement reduce bone remodeling whereas calcium supplementation to 1,700 mg per day of Ca CO3 did not appear to affect the parameters of bone remodeling.