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.

Recently at the delicatessen counter of a supermarket, I heard a mother asked her teenage son “Would you like some salami for lunch?”. After receiving an affirmative reply the mother promptly asked for 20 slices of salami. The teenage boy was shorter than me but he was 3 times as broad and deep as me! In other words, he was overweight, if not obese, with a sizeable belly.

Obesity has reached an epidemic proportion worldwide and the incidence of metabolic syndrome (MetS) seems to be paralleling obesity. Metabolic syndrome is strongly linked to insulin resistance, abdominal obesity, diabetes mellitus and dyslipidaemia. The adipose tissue (or more commonly known as fat) in the body can be divided into subcutaneous adipose tissue and visceral adipose tissue (VAT). Overweight and obese people have increased amount of VAT. One of the many sites for VAT accumulation is the liver and this can give rise to a condition called nonalcoholic fatty liver disease (NAFLD). When inflammation sets in, the condition is called nonalcoholic steatohepatits (NASH). If left unchecked, NASH can lead to progressive liver fibrosis and eventual liver cirrhosis. There is increasing evidence that people with visceral fat accumulation have an increased risk of developing primary liver cancer or hepatocellular carcinoma (HCC). Will visceral fat accumulation cause increased risk of HCC recurrence after curative treatment in patients with suspected NASH?

Researchers from the University of Tokyo studied 62 patients with HCC on a background of suspected NASH (Gut 2009; 58: 839 – 844). The visceral fat area (VFA) was determined by CT images at the time of HCC diagnosis. The patients were divided into two groups based on the VFA:- high VFA group (VFA > 130 sq. cm in males, > 90 sq. cm in females) and control group (VFA < 130 sq. cm in males and < 90 sq. cm in females). Using percutaneous radiofrequency ablation, all patients were treated with a curative intent between 1999 and 2006. These patients were followed up until HCC recurrence. The cumulative recurrence rates at 1, 2 and 3 years in the VFA group were 15.9%, 56.5% and 75.1% , respectively. These are significantly higher values than those found in the controls, being 9.7%, 31.1% and 43.1%, respectively.  The researchers concluded that visceral fat accumulation is an independent risk factor for HCC recurrence after curative treatment in patients with suspected NASH.

While I applaud the mother who wanted to look after her child well, perhaps she has been looking after him far too well for his own good. Saddling an adolescent with excess / excessive weight is equivalent to storing up future health problems for the child. When he / she attains adulthood and starts developing diabetes mellitus, arthritis in the hips and knees, he / she might think differently about the excessive amount of food you have been feeding him / her.