Hormone replacement therapy in relation to risk of cataract extraction: a prospective study of women.

OBJECTIVE

To investigate the association between hormone replacement therapy (HRT) and the incidence of cataract extraction among postmenopausal women.

DESIGN

Population-based, prospective cohort study.

PARTICIPANTS

A total of 30 861 postmenopausal women participating in the Swedish Mammography Cohort, age 49 to 83 years, who completed a self-administered questionnaire in 1997 about hormone status, HRT, and lifestyle factors.

METHODS

The women were followed from September 1997 through October 2005. The cohort was matched with registers of cataract extraction in the study area.

MAIN OUTCOME MEASURES

Incident operative extraction of age-related cataract.

RESULTS

We identified 4324 incident cases of cataract extractions during 98 months of follow-up. In multivariate adjusted analysis, ever use of HRT was associated with a 14% increased risk of cataract extraction (rate ratio [RR], 1.14; 95% confidence interval [CI], 1.07-1.21) compared with those who never used HRT. Current use of HRT was associated with an 18% increased risk of cataract extraction (RR, 1.18; 95% CI, 1.10-1.26). A significant linear trend was observed where increasing duration of HRT usage resulted in an increased risk of cataract extraction (P for trend = 0.006). Multivariate RR for current HRT usage for >10 years was 1.20 (95% CI, 1.06-1.36; P for trend = 0.001). Among women drinking on average >1 drink of alcohol per day, current HRT users had a 42% increased risk (RR, 1.42; 95% CI, 1.11-1.80) for cataract extraction, compared with women who neither used HRT nor alcohol. The risk of cataract extraction among current users of HRT was similar among current smokers and those who never smoked.

CONCLUSIONS

Our prospective, population-based study indicates that postmenopausal women using HRT for a long period of time may be at an increased risk for cataract extraction, especially those drinking >1 alcoholic drink daily.