Carotid wall thickness and years since bilateral oophorectomy: the Los Angeles Atherosclerosis Study

Evidence that coronary heart disease risk increases with surgical menopause is consistent. However, findings concerning atherosclerosis and surgical menopause are inconsistent. The Los Angeles Atherosclerosis Study (1995-1996) assessed the cross-sectional relation at baseline between years since bilateral oophorectomy and common carotid artery intima-media thickness (IMT). Participants included 269 employed California women asymptomatic for cardiovascular disease and aged 45-60 years. Ninety-seven women reported a hysterectomy: 42 without oophorectomy or a unilateral oophorectomy and 55 with a concurrent bilateral oophorectomy. IMT was measured bilaterally with B-mode ultrasound and was regressed on age, height, and years since hysterectomy in each group. Among women who had undergone bilateral oophorectomy, IMT was significantly related to years since hysterectomy (beta = 0.042 (standard error, 0.018) mm/10 years, p = 0.02). However, IMT was unrelated to years since hysterectomy in the no bilateral oophorectomy group (beta = 0.005 (standard error, 0.023) mm/10 years, p = 0.82). Adjustment for high density lipoprotein or low density lipoprotein cholesterol attenuated the association between IMT and years since hysterectomy by about a fourth in the bilateral oophorectomy group. Since over 90% of this group had a history of hormone replacement therapy use, the finding that years since bilateral oophorectomy was associated with increasing atherosclerosis conflicts with a well-known finding that such therapy reverses the adverse effect of bilateral oophorectomy on coronary heart disease.