Menopause Not at Fault In Hyperparathyroidism


MONTREAL — The higher incidence of primary hyperparathyroidism in women, compared with men, appears to be unrelated to the onset of menopause, according to a study of more than 11,000 patients who were surgically treated for the condition.

Previous studies have reported a female-to-male ratio ranging from 3:1 to 5:1 for the condition, and the disproportionate number of women, particularly those over the age of 50, “has been attributed, at least in part, to changes in estrogen and other hormones that occur at the onset of menopause,” said Dr. Barbra Miller, who presented results of a new analysis at a meeting sponsored by the International Society of Surgery.

Dr. Miller, of the University of Michigan Health System in Ann Arbor, said her analysis shows a gradual increase in the female-to-male ratio starting around the age of 26 years and plateauing around the age of 50 years. “We saw no significant change in ratio after the age of 50. This tells us that if hormonal changes were responsible for an increase in females' having primary hyperparathyroidism, we should see a divergence around the age of 50, and instead we see a plateau where the ratio stabilizes,” she said.

The study analyzed 10,190 patients (74% female) from the Nationwide Inpatient Sample (a 20% random sample of all hospital discharges containing multiple data points between 1995 and 1999) and 1,066 patients (74% female) from the University of Michigan endocrine surgery database (1999–2005).

“Since there is no national database that accurately reflects the incidence of primary hyperparathyroidism in the United States, we used surgically treated hyperparathyroidism as a surrogate marker for the condition,” said Dr. Miller, acknowledging that this was one of the study's limitations, along with the fact that the analysis did not capture patients treated nonsurgically.

Both data sets showed an overall female-to-male incidence ratio of 2.8:1, with the ratio beginning a slow divergence at 1.6:1 around the age of 26 years, and continuing until it reached 3:1 at around age 50 years, she said.

The peak incidence for both genders occurred between the ages of 56 and 60 years, reaching 13% among women and 12.2% among men.

“This study sheds new light on the age and sex distribution of primary hyperparathyroidism, and should stimulate new hypotheses regarding the female-to-male ratio,” concluded Dr. Miller.

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