Hypertension and risk of uterine leiomyomata in US black women.

BACKGROUND Previous studies have found a positive association between hypertension and risk of hysterectomy-confirmed uterine leiomyomata (UL). The association of hypertension with UL confirmed by ultrasound or other surgery is less clear. METHODS The present study evaluated the association of hypertension with UL incidence according to confirmation method (hysterectomy, other surgery or ultrasound) in the Black Women's Health Study, 1997-2007. We collected prospective data every 2 years on physician-diagnosed hypertension and UL in 22 530 premenopausal women. Validation sub-studies confirmed 99 and 96% of hypertension and UL self-reported diagnoses, respectively. Cox regression was used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for the association of hypertension and UL, adjusting for potential confounders. RESULTS During 172 162 person-years of follow-up, there were 6447 incident cases of UL confirmed by ultrasound (n = 5111), hysterectomy (n = 670) or other surgery (n = 666). Treated hypertension was associated with UL confirmed by hysterectomy (IRR = 1.32, 95% CI: 1.06, 1.63), but it was not associated with UL confirmed by ultrasound (IRR = 1.05, 95% CI: 0.96, 1.16) or other surgery (IRR = 1.13, 95% CI: 0.88, 1.46). CONCLUSIONS Treated hypertension was associated with UL confirmed by hysterectomy, but not UL confirmed by other methods (other surgery or ultrasound). These data suggest it is premature to conclude that hypertension is related to an increased risk of UL. Additional studies are needed to assess whether the association with hysterectomy-confirmed UL can be explained by other sources of bias, such as patient or physician preferences for specific types of medical care.