Concurrent Use in Taiwan of Chinese Herbal Medicine Therapies among Hormone Users Aged 55 Years to 79 Years and Its Association with Breast Cancer Risk: A Population-Based Study
Table 4
Number (no.) of new cases, population-at-risk, hazard ratios (HR), and 95% confidence intervals (CI) for breast cancer estimated using the multivariate Cox regression model on a random sample from the National Health Insurance Research Database among sample subjects and followed from 1997 to 2008.
Presence of breast cancer during the follow-up period
HT users who did use a Chinese medicine. Number of cases/population
HT users coprescribed a Chinese medicine, Number of cases/population
HT users coprescribed a Chinese medicine/HT users who did not use a Chinese medicine aHR (95% CI)
HT* use at baseline
Estrogen-alone
Current users
3/53
2/117
1.00
Last use 1–3 years previously
0/211
3/249
0.22 (0.05–0.93)
Last use 4-5 years previously
1/192
1/159
0.19 (0.04–1.00)
Last use >=6 years previously
2/710
1/395
0.09 (0.02–0.39)
Progesterone-alone
Current users
3/9
0/0
—
Last use 1–3 years previously
0/23
0/0
—
Last use 4-5 years previously
0/19
0/0
—
Last use >=6 years previously
0/32
0/0
—
Estrogen and progesterone combination
Current users
0/0
0/0
—
Last use 1–3 years previously
0/0
0/0
—
Last use 4-5 years previously
0/0
0/0
—
Last use >=6 years previously
0/0
0/0
—
Mixed type†
Current users
5/69
7/246
1.00
Last use 1–3 years previously
1/69
8/192
0.91 (0.38–2.15)
Last use 4-5 years previously
0/118
0/614
—
Last use >=6 years previously
16/836
11/1,081
0.37 (0.19–0.73)
HT refers to hormonal therapy. †Mixed type refers to the estrogen-alone (E-alone); estrogen together with progesterone (E + P); other preparations, which included progesterone only and vaginal and other local treatments and combinations of the above preparation types. aHR refers to the hazard ratios adjusted by age and number of chronic diseases.
