Bowel cancer, coffee and diabetes: Two new studies

By Dr. Ananya Mandal, MDAug 31 2011

Diabetes and bowel cancer risk

Australian researchers have identified a link between type 2 diabetes in men and a significantly increased risk of bowel cancer, triggering calls for diabetics to have regular checks.

For the study the team looked at almost 1,300 people with type 2 diabetes, recruited in the 1990s as part of the Fremantle Diabetes Study, for up to 17 years, then compared results with Australian Institute of Health and Welfare statistics. They found that men aged 55 to 84 with type 2 diabetes were 87 per cent more likely than the general population to develop bowel cancer.

Study author Tim Davis, a Professor of Medicine at the University of Western Australia, presented the findings at the Australian Diabetes Society annual scientific meeting in Perth yesterday. He said more research was needed to explain the link. “It might be that the risk factors for the two conditions, including obesity, are the same and that they develop independently of each other or it may be that factors associated with diabetes trigger bowel cancer,” Professor Davis said. Prof Davis said that based on the study findings, fecal occult blood testing every one or two years should be considered for men aged over 55 attending diabetes clinics.

Bowel Cancer Australia chief executive Julien Wiggens said the study added to existing evidence linking the two common diseases.

About one in 12 Australians will be diagnosed with bowel cancer before the age of 85. If detected early, 90 per cent of cases are treated successfully. Doctors believe genetic and lifestyle factors such as being overweight and having a poor diet play key roles in the development of type 2 diabetes. While there is no cure, the condition can be managed by eating a healthy diet, taking regular exercise and medication.

Coffee and diabetes risk

The risk of developing type 2 diabetes appears to decrease with increasing consumption of both boiled and filtered coffee, according to a study from the Norwegian Institute of Public Health. Researchers warn however that this does not mean that one should drink as much coffee as possible because high coffee consumption can cause other health problems.

The team of researchers examined the association between consumption of boiled coffee and filter coffee at ages 40-45 and the development of type 2 diabetes at ages 45-60.

Several studies have found a beneficial relationship between coffee consumption and type 2 diabetes, but this is the first time such a large study has looked at this association. The study used information about coffee consumption by 360 000 diabetes-free women and men from health studies conducted between 1985 and 1999. By linking with the Norwegian Prescription Database at the Norwegian Institute of Public Health, one could identify how many people used medicines for type 2 diabetes in the period 2004-2007.

“This study found that the risk of developing type 2 diabetes decreased with increasing coffee consumption in approximately the same degree for boiled and filtered coffee,” said researcher Vidar Hjellvik at the Norwegian Institute of Public Health. Those who drank nine cups of boiled coffee or more had a 35 per cent lower risk of developing type 2 diabetes than those with the same age, body mass index, smoking habits, education, and physical activity levels who drank less than one cup daily. For those who drank the equivalent amount of filter coffee, there was a risk reduction of 38 per cent.

”Everyone is different and can tolerate varying amounts of caffeine. Some can drink 30 cups a day while most people stick to one or two cups. This is partly to do with genes. We have different abilities to metabolise caffeine in the body and those who convert it slowly can tolerate less. If everyone drank four to five cups of coffee per day, we would probably end up with a whole host of other problems, such as insomnia“ said Helle Margrete Meltzer, Department Director at the Norwegian Institute of Public Health. ”Each of us usually knows how much we can tolerate,” says Meltzer. “Most people notice when they cross their own threshold. They recognise the restlessness, anxiety, palpitations and nervousness.