Health-related behavior and the use of hormone replacement therapy

To study health-related differences between hormone replacement therapy (HRT) users and nonusers among colorectal cases and women without diagnosed cancer.

Data from the Saskatchewan Health population-based databases were used to ascertain the use of HRT, oral contraceptives (OCs), cardiovascular system (CVS) drugs, central nervous system (CNS) drugs, prescribed NSAIDs and vitamins among 3338 women diagnosed with colorectal cancer and 13025 women without diagnosed cancer. Physician visits and sigmoidoscopy procedures were also determined.

Among women without diagnosed cancer, HRT was associated with CVS drugs (OR = 1.23, 95%CI: 1.10-1.37), CNS drugs (OR = 1.96, 95% CI: 1.72-2.23), other hormones (OR = 1.12, 95% CI: 1.01-1.24), prescribed vitamins (OR = 1.37, 95% CI: 1.22-1.55), NSAIDs (OR = 1.41, 95% CI: 1.18-1.68), having had a sigmoidoscopy 3-5 years prior to index dates (OR = 1.33, 95% CI: 1.12-1.59) and 15 or more visits to physicians during the 5th year prior to assigned index date (OR = 2.0, 95% CI: 1.77-2.35). Similar results were observed among women diagnosed with colorectal cancer, but HRT use was not associated with having had a sigmoidoscopy.

Health-related characteristics of HRT users and nonusers are identified and described. Some of these factors may contribute to selection bias in studies examining the health benefits of HRT.