Obesity and kidney cancer rise
The incidence of kidney cancer has risen 38% in men over the last 10 years and much of this rise is due to obesity, according to Cancer Research UK (CRUK).
In the UK, around 5500 people were diagnosed with kidney cancer each year in the mid-1990s, but this has now more than doubled, reaching about 11900 a year.
The bulk of the rise is in renal cell carcinoma and this now accounts for just over 8 in 10 kidney cancers. Renal cell carcinoma is known to be linked to obesity.
‘It’s clear that people who have a higher BMI have a higher risk of developing kidney cancer. This has been demonstrated in numerous studies,’ says Dr Mattias Johansson from the International Agency for Research on Cancer (IARC). ‘Someone who is obese has up to twice the risk compared to those who are a healthy weight, making it one of the most important risk factors of kidney cancer.’
Why obesity is linked to kidney cancer is not clear although according to Dr Mattias, data from his group suggests that high levels of insulin in the body due to excess weight may be one of the drivers.
Researchers also think that insulin-like growth factor-1 (IGF-1) is implicated. Some studies have shown that IGF-1 encourages kidney cell growth, potentially telling cells to divide, and in some cases, leading to cancer.
In its Science Blog, CRUK points to a study in men that in relation to kidney cancer risk, fat might start to have an impact on health from an early age. Being overweight in late adolescence was associated with an increased risk of kidney cancer later in life.