Being obese is known to be associated with increased health problems. These include diabetes, heart diseases, sleep apnoea and joint problems to name a few. It is also known that obese women have an increased risk of breast cancer. Is this association true for other cancers too?

Researchers from several universities from both sides of the Atlantic analysed the pooled data from the National Cancer Institute Pancreatic Cancer Cohort Consortium (PanScan) to look at possible association between obesity and risk of pancreatic cancer. The study included 2170 cases of pancreatic cancer and 2209 controls (Arch Intern Med 2010; 170: 791 – 802). They recorded body mass index (BMI) [< 18.5 underweight, 18.5 – 24.9 normal weight, 25.0 – 29.9 overweight, 30.0 – 34.9 obese and 35.0 severely obese], waist circumference and waist to hip ratio. In men, the risk of pancreatic cancer in those with the highest quartile of BMI is increased by 33% as compared to those with the lowest quartile BMI. In women the increased risk is 34%. An increased waist to hip ratio, between the highest and lowest quartile, was also associated with an 87% increased risk of pancreatic cancer in women.

We have two types of cholesterol in our body: ‘good’ cholesterol, namely high-density lipoprotein cholesterol (HDL-C), and ‘bad’ cholesterol called low-density lipoprotein cholesterol (LDL-C). We know that people with adequate levels of HDL-C are protected from heart disease. Does having more good cholesterol also protect you from cancer?

Researchers from Tufts University in Boston, USA, examined the relationship between HDL-C levels and the risk of developing cancer in 24 large randomised controlled trials (RCTs) of lipid-altering interventions (J Am Coll Cardiol 2010; 55: 2846 – 2854). The study found that there was a significant inverse association between baseline HDL-C levels and the rate of incident cancer. In other words, the higher the HDL-C level, the lower is the risk of cancer. After controlling for variables such as LDL-C level, age, BMI, sex and smoking status, the study found that for every 10 mg/dL increase in HDL-cholesterol, there is a 36% lower risk of developing cancer.

Most individuals put on weight because they eat more than they need. Whether you manage to lose weight or not depends on your motivation and determination. Participants in the reality show ‘The Biggest Loser’ manage to lose significant amounts of weight because they are being motivated to do so. Not everyone will get the chance to go on the show in order to be motivated. However, is the knowledge that becoming obese will increase your risk of developing cancer not enough to motivate you to keep trim?

Hepatocellular carcinoma is a common cancer worldwide. The incidence in the East is very much higher due to endemic chronic hepatitis B virus (HBV) infection in the population. The incidence of HCC has been increasing steadily in USA and the major risk factor for HCC in US is chronic hepatitis C virus (HCV) infection. In 1975, the total incidence of HCC was approximately 1.59 per 100,000 person-years. By 2006, this had reached 4.82 per 100,000 person-years and this increase has been attributed to the increasing numbers of Asian immigrants in the United States. However, a presentation at the recent 101^st Annual Meeting of the American Association for Cancer Research (AACR) has come up with a surprising culprit (Abstract 1816, presented Arpil 19, 2010).

Researchers from the National Cancer Institute (NCI) reviewed data from the NCI SEER database. The case population studied consisted of 5607 people diagnosed with HCC. They examined the odds ratio of an individual developing HCC with the risk factors of HCV infection, HBV infection, alcohol-related disease, rare metabolic disease, diabetes and obesity. (Odds ratio tells you how much more likely it is that you are going to develop the condition compared with someone without the risk factor.) HCV infection has the highest odds ratio of 44.26 (ie 44 x more likely than a non HCV infected person). The odds ratios for HBV infection, alcohol-related disease, rare metabolic disorder, diabetes and obesity were 13.37, 4.43, 3.51, 2.37 and 1.53, respectively. However, the researchers found that diabetes was associated with the greatest percentage of cases (33.5%). The other associations were alcohol-related disorders (23.9%), HCV infection (20.7%), HBV infection (5.7%), rare metabolic disorders (3.1%) and obesity (2.7%).

The incidence of obesity and diabetes mellitus is increasing worldwide and the Asian population has not been spared. While chronic HBV infection is the most important risk factor for HCC in Asia, the general population and clinicians need to be aware that diabetes and obesity are also associated with HCC. The above study found that 67.9% of Asians with HCC had one or more of the identified risk factors. Both obesity and diabetes can be helped by adopting a prudent life style - maintaining a healthy body starts with you!

Happy 2010! Time for the traditional new year resolution. So what will it be for you? Losing some weight is a popular one. However, many fail to achieve this as the year wears on. Perhaps the following research finding might give you more impetus to try harder this year.

Researchers from Boston University studied the incidence of type 2 diabetes in relation to restaurant meal consumption among 44.072 African American women who were not diabetic at entry to the study (Am J Clin Nutr 2009 Dec 16, epub). These women completed a questionnaire every 2 years, from 1995, for 10 years. Compared to women who never eat fast food burgers and fried chicken, women who eat 2 or more burgers meals per week has a 40% increased risk of developing diabetes. Similarly for women who eat 2 or more fried chicken meals per week, the increased risk was 68%. The increased risk of type 2 diabetes is associated with weight gain and obesity.

Yes, it is the fault of the dreaded condition – getting fat- again! Getting fat has a lot to answer for in our society and in our world. Perhaps you should really stick to your new year resolution this year and constructively lose some weight.

Happy New Year!