Is tubal ligation a risk factor for low bone density and increased risk of fracture?

Abstract

Objective: Osteoporosis is a major women's health problem, because it is responsible for about 1.3 million fractures in the United States each year. Estrogen deficiency is a major risk factor in the pathogenesis of osteoporosis. Recent evidence has indicated that tubal ligation may cause menstrual dysfunction and estrogen deficiency. This study examined the association between tubal ligation and bone mass in a group of elderly postmenopausal women.

Study design: Subjects were 2215 white women > or = 65 years old participating in the Baltimore center of the Study of Osteoporotic Fractures. Bone mineral density of the proximal and distal radius and the calcaneus was measured by single photon absorptiometry. Multiple regression analysis was performed to determine whether tubal ligation had an independent effect on bone density. The effect of tubal ligation on the risk of hip and osteoporotic fractures was estimated by Cox proportional hazards model.

Results: Women who reported a tubal ligation had lower, although not statistically significant, bone density of the radius and calcaneus. The relative risk of hip (1.05, 95% confidence limit 0.84 to 1.32) and osteoporotic fractures (1.01, 0.80 to 1.29) was not significantly increased in women with tubal ligation.

Conclusion: We conclude that elderly women who had a tubal ligation have small changes in bone density that are not of sufficient magnitude to increase their risk of osteoporotic fractures.

PIP: Osteoporosis is a major women's health problem, responsible for about 1.3 million fractures in the United States each year. Estrogen deficiency is a major risk factor in the pathogenesis of osteoporosis. Recent evidence has indicated that tubal ligation may cause menstrual dysfunction and estrogen deficiency. Bone mineral density of the proximal and distal radius and the calcaneus was measured by single photon absorptiometry. Multiple regression analysis was performed to determine whether tubal ligation had an independent effect on bone density. The effect of tubal ligation on the risk of hip and osteoporotic fractures was estimated by Cox proportional hazards model. A self-administered questionnaire was mailed to all participating women in the Baltimore center of the Study of Osteoporotic Fractures to obtain past experiences with reproduction, lactation, and menstruation. The association between tubal ligation and bone mass was examined in a group of 2215 white women or = 65 years old. 89 women reported having a tubal ligation performed at some point during their reproductive lives. These women were compared with the remaining 2126 nonsterilized women in the cohort. Women with a tubal ligation had lower trabecular (distal radius and os calcis) and cortical (proximal radius) bone density. A 1.4% difference in bone density of the distal radius, 0.5% difference in proximal radius, and 1.5% in os calcis density was observed between women with and without a tubal ligation. However, the difference in bone density level was not statistically significant. The relative risk of hip (1.05) and osteoporotic fractures (1.01) was not significantly increased in women with tubal ligation. 45 women had a hip fracture, and an additional 300 women had fractured other bones since baseline. The risk of hip fracture and any other osteoporotic fracture was not significantly increased in women with tubal ligation after adjustment for body mass index, years since menopause, number of births, estrogen use, and oophorectomy.