Use of Insulin and Mortality from Breast Cancer among Taiwanese Women with Diabetes.

Chin-Hsiao Tseng

doi:10.1155/2015/678756

Abstract

Background. To evaluate whether insulin use was predictive for mortality from breast cancer in Taiwanese women with diabetes mellitus. Methods. A total of 48,880 diabetic women were followed up to determine the mortality from breast cancer during 1995–2006. Cox models were used, considering the following independent variables: age, sex, diabetes type, diabetes duration, body mass index, smoking, insulin use, and area of residence. Insulin use was also considered for its duration of use at cutoffs of 3 years and 5 years. Results. Age was a significant predictor in all analyses. The multivariable-adjusted hazard ratio (95% confidence interval, P value) for insulin use without considering the duration of use was not statistically significant (1.339 [0.782–2.293, P = 0.2878]). Compared with nonusers, insulin users showed the following adjusted hazard ratios for insulin use <3 years, ≥3 years, <5 years, and ≥5 years: 0.567 (0.179–1.791, P = 0.3333), 2.006 (1.102–3.653, P = 0.0228), 1.045 (0.505–2.162, P = 0.9048), and 1.899 (0.934–3.860, P = 0.0763). Conclusions. Insulin use (mainly human insulin) for ≥3 years may be associated with a higher risk of breast cancer mortality.

Highlights

Patients with diabetes may suffer from a higher risk of cancer involving the liver, pancreas, endometrium, colorectum, bladder, and breasts [1]
Epidemiological studies suggest that the link between diabetes and breast cancer may be attributed to the aberration in glucose metabolism and the presence of insulin resistance [8]
Sensitivity analyses conducted after excluding patients who died of breast cancer within 5 years and 7 years of diabetes onset, separately, did not remarkably change the adjusted hazard ratios

Summary

Introduction

Patients with diabetes may suffer from a higher risk of cancer involving the liver, pancreas, endometrium, colorectum, bladder, and breasts [1]. The use of antidiabetic drugs may be associated with a higher risk of various types of cancer [2,3,4,5,6]. We reported that female patients with diabetes in Taiwan had a significantly higher risk, ranging from 1.37-fold to 2.43-fold in different age groups, of mortality from breast cancer, compared with the general population [7]. To evaluate whether insulin use was predictive for mortality from breast cancer in Taiwanese women with diabetes mellitus. The multivariable-adjusted hazard ratio (95% confidence interval, P value) for insulin use without considering the duration of use was not statistically significant (1.339 [0.782–2.293, P = 0.2878]). Insulin use (mainly human insulin) for ≥3 years may be associated with a higher risk of breast cancer mortality

Objectives

Methods

Results