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Since 1995, researchers at The Chinese University of Hong Kong (CUHK) have enrolled more than 10,000 people with diabetes into the Hong Kong Diabetes Registry. By analyzing this comprehensive registry, CUHK researchers reported that more than 20% of the people with diabetes died with cancer, a figure comparable to cardiovascular diseases. Compared to age and sex-matched non-diabetic subjects, people with diabetes have a 30% increased risk of cancer, mainly due to cancer in the liver and gastrointestinal tracts.

A team of CUHK researchers, led by Prof. Juliana Chan, Director, Hong Kong Institute of Diabetes and Obesity, and lead author, Dr Xilin Yang, Research Assistant Professor at the Department of Medicine and Therapeutics of CUHK, found that for every 1% increase in glycated hemoglobin (an indicator of average blood glucose control in the last 8 weeks), there was a 26% increased risk of all-site cancer. In this analysis consisting of 2,906 type 2 diabetic patients with no known history of cancer at the time of recruitment between 1996 and 2005, the authors examined the rate of cancer in 971 patients newly started on insulin treatment compared to 1,935 patients, matched for age and smoking status but with no insulin treatment. After a follow-up period of 5 years, for every 100 patients followed up for 1 year, 5 patients developed cancer. On the other hand, in 100 patients treated with insulin, only 1 patient developed cancer every year. After adjusting all risk factors and concurrent medications, patients treated with insulin had up to an 80% risk reduction in developing cancer compared to those with no insulin treatment. The above study was published on the website of the leading diabetes journal, Diabetes, in May 2010.

Prof. Ronald Ma, Associate Professor at the Department of Medicine and Therapeutics of CUHK, remarked, ‘Our findings suggest that not only do people with diabetes have a higher risk of cancer, poor glycemic control in diabetic patients also increases cancer risk. While more studies are needed to clarify the cause underlying these findings, our results strongly suggest that by improving glycemic control, including the early use of insulin, cancer risk can be substantially reduced in these subjects’.

Latest figures from the mainland China show that 1 in 4 people have or are at risk of diabetes. In a national survey of 40,000 people, 9.7% have diabetes and 15.5% have prediabetes. Apart from causing major organ damage, the increased risk of cancer in people with diabetes is now increasingly recognized. ‘These figures are alarming. Over 50% of global deaths are due to diabetes, cancer and heart disease. With better technology, people are less likely to die from heart disease and are living longer. Cancer has now become one of the leading causes of death in diabetic patients. In our analysis, the mean age of our diabetic patients was only 57 with an average disease duration of 5 years. In other words, 50% of the patients were diagnosed at their mid age. At the age of 60, as many as 5% of these subjects have developed cancer, i.e. a 1% increase per year,’ remarked Prof. Juliana Chan.

‘Patients with diabetes often do not have symptoms and are not aware of the importance of controlling glucose to near-normal levels. Our findings of a lower cancer risk in patients with better glucose control should alert high risk subjects for diabetes to get tested and treated early. Diabetic patients should also have added incentives to control their condition,’ concluded Prof. Chan.

Comprehensive diabetes assessment service is now available in most Hospital Authority clinics and some General Out-patient Clinics in Hong Kong. People with diabetes can also go to the CUHK Yao Chung Kit Diabetes Assessment Centre, supported by a recurring donation, for a low-cost service to assess their risk profiles. Please contact the Centre for further information.

CUHK Yao Chung Kit Diabetes Assessment Centre
Tel: 2647-8806
Fax: 2947-8495
Email: yckdac@cuhk.edu.hk
Website: http://yckdac.hkido.cuhk.edu.hk