Diabetes, metformin and incidence of and death from invasive cancer in postmenopausal women: Results from the Women’s Health Initiative

Gong, Z. et al. (2015) International Journal of Cancer

Abstract

Findings from studies of metformin use with risk of cancer incidence and outcome provide mixed results; with few studies examined associations by recency of diabetes diagnosis or duration of medication use. Thus, in the Women’s Health Initiative, we examined these associations and further explored whether associations differ by recency of diabetes and duration of metformin use.

Cox regression models were used to estimate hazard ratios (HR) and their 95% confidence intervals. Diabetes was associated with higher risk of total invasive cancer (HR, 1.13; p<0.001), and of several site-specific cancers (HR, 1.2-1.4, and up to over 2-fold). Diabetes was also associated with higher risk of death from cancer (HR, 1.46; p<0.001). There was no overall difference in cancer incidence by diabetes therapy (p=0.66). However, there was a lower risk of death from cancer for metformin users, compared to users of other medications, relative to women without diabetes, overall (HRs, 1.08 versus 1.45; p=0.007) and for breast cancer (HRs, 0.50 versus 1.29; p=0.05).

Results also suggested that lower cancer risk associated with metformin may be evident only for a longer duration of use in certain cancer sites or subgroup populations. We provide further evidence that postmenopausal women with diabetes are at higher risk of invasive cancer and cancer death. Metformin users, particularly long-term users, may be at lower risk of developing certain cancers and dying from cancer, compared to users of other anti-diabetes medications. Future studies are needed to determine the long-term effect of metformin in cancer risk and survival from cancer.

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s