Michael Mosley reveals why health tests aren’t always good for us

In this week’s Horizon, Mosley is scanned and screened to find out whether too much knowledge could be harmful

Michael Mosley’s father died 12 years ago, aged 74. Though he’d been treated for prostate cancer, it was heart failure that killed him. Mosley had tried to dissuade his father from undergoing the invasive surgery recommended by cancer doctors. “I advised him not to have anything more done about it, but he couldn’t bear the thought of having a tumour inside him and so he had the surgery. But it left him both impotent and incontinent.”

He died two years after that treatment. “It is possible that the treatment slowed or delayed the progress of the disease, but it is equally possible – in fact more likely – that the tumour was slow growing and would never have interfered with his life. He could have lived with the cancer and not suffered all the indignity and inconvenience of wandering around with incontinence pads for what remained of his life.”

What the case of Mosley’s father highlights – and it’s why he’s talking about it today – are the dilemmas thrown up by the increasing ease with which we can look at our bodies and attempt to predict our medical futures. This scrutiny, through screening, scanning and testing, undoubtedly saves lives. But there’s a body of opinion that says it also leads to over diagnosis that such health tests actually feed a neurosis about falling ill, filling GP surgeries and hospital clinics with the worried well. 

“There are a lot of tests out there that are useless and probably quite unreliable,” says Mosley. “For instance, I think there are an awful lot of allergy tests that have absolutely no substance to them. And a lot of the private stuff is quite unregulated, so you don’t know whether the test is reliable and whether the information you’re receiving is also reliable.”

For this week’s Horizon documentary, Mosley underwent a battery of such tests in an attempt to establish their usefulness. They ranged from a simple blood pressure test by his own GP, through DNA profiling, to a cancer-seeking scope inserted into his bowel. 

Seen in the round, Mosley thinks such tests are a good thing. The crucial point is knowing which results to act on and which to ignore. It has to be said, he’s probably better equipped than most of us to reach those decisions…

“I do believe that knowledge is power, so I like to know more about myself and I can then start doing something about it. And that’s one of the central questions: if you know what’s going on, is it more likely to make you feel depressed and want to give up or will it empower you to do something about it? Does know the facts alter how you live your life? if it doesn’t then these tests are useless.”

In Mosley’s case he chose to ignore one set of results and is still pondering the outcome of another. His GP tests revealed that he had a ten per cent risk – considered low to moderate – of having a heart attack in the next ten years.

Statins would lower the risk but for him it isn’t that straightforward. “My reservation currently is the fact that statins raise your risk of diabetes. So that’s where I’m slightly stuck.

“In my case I’ll probably go on a course of statins for a couple of months and see what happens to my blood sugars. But it underlines the great complexity of all this.”

Likewise with the DNA screening he had done. Though he admitted relief at the result that he had a low risk of Alzheimer’s, he refused to look at his Parkinson’s score. “I think these tests are only helpful if you think you will be able to alter the outcome in some way. As far as Parkinson’s is concerned I’m not aware of anything that you can do to change the outcome. So I chose not to find out the results.”