Watch the weight

The worldwide incidence for obesity is increasing. Apart from being associated with increased risks of developing diabetes mellitus, ischaemic heart disease, back problems and joint diseases, obesity is also a risk factor for the development of cancer.

A study from the University of Texas M D Anderson Cancer Center compared 841 patients with pancreatic adenocarcinoma with 754 healthy individuals to see if there is an association between obesity and increased risk of pancreatic cancer (JAMA 2009; 301: 2553 – 2562). Overweight individuals (BMI 25 – 29.9), aged 14 to 39 years, and obese individuals (BMI ≥ 30), aged 20 to 49 years, respectively had a 67% and 158% increased risk of pancreatic cancer. The association was stronger in men than in women. Those who were overweight or obese from the ages of 20 to 49 years had an earlier onset of pancreatic cancer by 2 – 6 years. When non-obese individuals with pancreatic cancer were compared to obese individuals with pancreatic cancer, aged 30 to 79 years, the non-obese individuals had longer overall survival irrespective of the cancer disease stage and tumour resection status.

Once you have become overweight or obese, would losing weight reverse the increased risk of cancer? The Swedish Obese Subjects (SOS) study recently published its study involving 2010 obese patients (BMI ≥ 34 in men and ≥ 38 in women) who underwent weight reduction surgery (bariatric surgery) and 2037 contemporaneously matched obese controls (Lancet Oncol 2009; 10: 653 – 662). The median follow-up time was 10.9 years. Over 10 years, bariatric surgery led to a sustained weight reduction of 19.9 kg while in controls there was a weight gain of 1.3 kg. The risk of developing cancer was reduced by 33% in those who underwent bariatric surgery. However, the risk reduction by bariatric surgery was only seen in women but not in men.

These two studies demonstrate that being overweight or obese will increase your risk of developing cancer. While surgery to help you lose weight can reduce your risk of developing cancer, the goal in life surely is not to become overweight or obese in the first place.

Watch your weight. Keep fit and keep trim.