Saturday, March 14, 2009
The Guardian UK has an article about concerning the million women study being conducted by scientists at Oxford University. Sarah Boseley writes,
Oh, the lure of a glass of chilled white wine at the end of a hard day. Or a goblet of luscious red by a leaping fire on a winter's evening. Or a gin and tonic, poured over cracking ice and lemon. Can't you hear it calling as you tramp home, tired, head buzzing with the day? Well, maybe not any more - if you heeded the recent study which warned that even a small glass of wine a day increases a woman's risk of breast cancer.
In all likelihood, most women just shrugged and reached for the corkscrew. There are, after all, so many conflicting stories about what is good and bad for you these days. Unfortunately, this is not some easily dismissed, pie-in-the-sky trial involving a couple of hundred people. It is the Million Women Study, run by some very senior scientists at Oxford University. In research, size really does matter - and this is the biggest project of its kind on the planet. . .
The survey was started by Professor Valerie Beral, head of Oxford University's cancer epidemiology unit. When she began planning it in 1993, she quickly realised the study would have to be massive to answer the thorny and still controversial questions over HRT and possible links to cancers and other diseases. But enrolling a million women meant they would be able to tackle a lot of other issues too, and the answers are slowly coming in. And yes, she says, it is intended to provide a definitive blueprint for women's health, spotlighting all the issues from the pill, to alcohol, to diet, to childbearing, to the menopause. "That's what we plan to do, slowly and reliably over time," says Beral. "We're interested in not creating false stories, so it is totally reliable information - the sort of information that women want to know about their health." . . . .
With this much data, the scientists will be able to investigate a whole range of issues. Maybe those who enjoy painting or music in their spare time or who go to church are less stressed and happier than those with little social activity to report. And are those who say they eat five portions of fruit and vegetables a day really healthier? . . . .
Even so, Professor Sheila Bird of the MRC's biostatistics unit and the Royal Statistical Society, sounds a cautious note. Big in itself does not necessarily mean free of bias. One in four of the population in the age group signed up - but, she asks, "How different are the quarter who volunteered from the rest?" First they accepted breast screening and then they agreed to be part of the Million Women Study. Does that mean, for instance, that they are middle-class women more concerned about breast cancer?
Avoiding and then adjusting for any such bias, however, is at the heart of the work of the Oxford cancer epidemiology unit. And Walker points out that the Million Women Study is under constant scrutiny from the best scientists in this field - facing rigorous peer review, first to get funding from Cancer Research UK and the MRC, and then to get each scientific paper published as they are completed. The findings have all appeared in leading medical journals, such as the Lancet.
So what do the study's findings really mean for each of us as individuals? Should we all be following Beral's developing blueprint to the letter? The answer is, not necessarily. We may all run an increased risk of cancer if we drink, but how serious that is depends on how high or low a risk we had to start with. Walker puts it well: "What they are coming out with is risks across the population that they are studying. Each of us as individuals will have been born with a greater or lesser risk of a cancer because of the genes we have inherited and, on top of that, our lifestyle has to be factored in. "We may have only one vice and it may be drinking three glasses a night, but if we had 10 children before the age of 30, it is not going to make much difference. One needs the whole picture."
And each of us may have a different perspective on acceptable risk. As a herd, we have a 9.5% chance of getting breast cancer before we are 75. Drinking every day raises that risk to 10.6%. If we think we have no other major risk factors lurking, such as a mother or sister who died of the disease, but we believe a drink a day significantly improves our life, we might choose to go with the extra risk. The great thing about the Million Women Study is that it is giving us the information with which to make an informed choice . . . .