|Michelle Roberts. Not a clue.|
Michelle Roberts, the BBC's worst health journalist, has taken to the airwaves to talk about Angelina Jolie's double mastectomy. Jolie decided to undergo the operation because she has inherited genes that make her very prone to breast cancer. Her mother died of the disease at the age of 56 and doctors say her DNA means that she has an 87 per cent chance of developing the disease.
I have written before about the BBC's determination to portray smoking, drinking and obesity as the leading causes of breast cancer, despite these being, at most, quite modest risks for the disease. Michelle Roberts was personally responsible for a particularly awful piece of journalism in 2011 which claimed, quite wrongly, that obesity was the "leading driver" of breast cancer.
Roberts could not allow the Jolie story to pass without bringing "lifestyle factors" into it and so appeared on camera—carefully flagged up as "a qualified doctor"—to talk her nonsense.
"In [Jolie's] case, DNA she inherited from her mum meant she was at 87 per cent increased risk of developing the disease in her lifetime and that's why she decided to have a double mastectomy."
No, no, no. She did not have an increased risk of 87 per cent. She had an absolute risk of 87 per cent, as the BBC themselves reported:
She said her doctors estimated she had an 87% risk of breast cancer and a 50% risk of ovarian cancer... Her chances of developing breast cancer have now dropped from 87% to under 5%, she said.
It beggars belief that the BBC's online health editor does not understand the difference between relative risk and absolute risk. Having made this pitiful error, she then moves on to her pet belief that "the vast majority of breast cancers" are caused by "behaviours such as smoking and conditions like obesity".
"Most cases of breast cancer are not caused by faulty genes such as these. Many more cases of breast cancer are caused by things like smoking and obesity—things that we all have the power to prevent."
There are lots of risk factors for breast cancer, including delayed childbirth and not breastfeeding (as this more considered BBC article points out). So why specifically mention smoking and obesity? It is questionable whether smoking increases the risk of breast cancer at all. The NHS doesn't include it in its list of risk factors and a comprehensive meta-analysis of 53 studies published in the British Journal of Cancer concluded that "smoking has little or no independent effect on the risk of developing breast cancer" (results shown below).
A relationship between obesity and breast cancer has been found more regularly, but the risk seems to be relatively small. This meta-analysis found that obesity was associated with a 25 per cent increase in postmenopausal breast cancer and this meta-analysis found a 15 per cent increase in postmenopausal breast cancer and no association with premenopausal breast cancer.
Even if the 87 per cent risk Roberts mentions was relative rather than absolute it would still be much larger than the 15-25 per cent increased risk associated with obesity and obviously much larger than the "little or no" risk associated with smoking. But since the 87 per cent risk is absolute, Jolie's breast cancer risk was off the scale compared to smokers and fatties.
The guiding principle of the Beeb's health reporting is that people shouldn't engage in bad habits so it's okay to misrepresent the facts in an effort to make us change our ways. If that means downplaying major risk factors and exaggerating minor risk factors, then so be it. It is the triumph of morality over medicine. It is not journalism. It is propaganda.