Diabetes Increases Risk for Cancer Among Asians

Previous studies have shown a relationship between type 2 diabetes and the risk of developing cancer. Such studies have been restricted mostly in Western populations; however, with the increase in incidence in diabetes in Asian countries, there is a need to understand the risk for cancer in these populations. Asians have always shown a greater predisposition towards developing cancer, with an increased susceptibility to insulin resistance, when compared to Europeans. While there have been previous studies conducted on Asians, they suffer from the following roadblock

• Only one or a few types of cancers were included
• Only a small sample of patients with diabetes were included
• Other important risk factors like obesity were not controlled for

The current study, led by Dr. Yu used data from the Asia Cohort Consortium (ACC), which combines 29 cohorts to understand the influence of the environment, genes and disease in a population of people more than 1 million. Out of these cohorts, only 19 were chosen, which resulted in

• 658,611 East Asians
• 112,686 South Asians from Singapore, Taiwan, South Korea, India, Japan, Bangladesh and China

The average age of the participants were around 54 years, with 37,343 cancer deaths identified during a period of follow-up which lasted 12.7 years. The study involved a large sample size therefore it captured the diversity of the Asian populations, while there was stratification that was possible based on age, smoking status, sex as well as alcohol consumption. This was a landmark study as it was the first study to analyze the influence of type 2 diabetes on cancer risk among South Asians.

The study findings showed that

• There was a 26% increase in the risk of death due to any cancer among people with diabetes, including factors like alcohol consumption, body mass index (BMI) and smoking
• There was statistical association between type 2 diabetes and death due to specific cancers
• There was an increased risk of death due to cancers of the breast, bile duct, liver, pancreas and the colorectum, when associated with diabetes
• The risk of death was doubled in cancers of the thyroid, kidney and the liver, when associated with diabetes
• There was 2.7 times increased risk of death due to endometrial cancer when associated with diabetes
• There was 1.7 times increased risk of death due to breast cancer when associated with diabetes

This increase in death risk is compared with the risk associated with an individual who does not have diabetes.

Increased Risk of Death Among Asians

The risk of death due to site-specific cancers like thyroid, kidney and prostate cancer was higher among Asians than among people of European origin. Moreover, the risk of death due to cancer was found to be greater among participants who were less than 60 years of age.

The scientists involved in the study stated that

• The effect of type 2 diabetes on the risk of death due to overall cancer, breast cancer and digestive cancer was similar to the risk associated with the Western population.
• The enormity of the data analyzed showed that type 2 diabetes should be considered as a serious risk factor for cancer, especially liver cancer which had a high incidence in Asians.

There should be a mandatory cancer screening for people who have been diagnosed with type 2 diabetes, which would aid in early identification of the disease and a reduction in the risk of death.

Increase in Body Fat

The American Institute of Cancer Research found that hyperinsulinemia, cancer and type 2 diabetes all shared a common high-risk factor- high body fat. A high body fat resulted in hormonal changes which led to an increase in the risk for cancer and for type 2 diabetes. There are many tumors that have insulin receptors and many studies have shown that insulin is important in the development of cancer. However, there is no direct link associated with insulin and cancer. The scientists believe that there could be other pathways that are triggered by insulin in the growth and proliferation of cancer.

Earlier studies show that maintaining an optimum body weight and body fat are essential to lowering risk of diabetes as well as cancer. Since there is a common pathway that triggers diabetes and cancer, lowering the risk factors will lower the risk for both the conditions.

References :

1. Yu Chen et al. Association between type 2 diabetes and risk of cancer mortality: a pooled analysis of over 771,000 individuals in the Asia Cohort Consortium, Diabetologia (2017). DOI: 10.1007/s00125-017-4229-z
2. The Diabetes-Cancer Connection - (http://preventcancer.aicr.org/site/News2?page=NewsArticle&id=13631&news_iv_ctrl=0&abbr=res_)

Source: Medindia