London - Being slim is not enough to ward off breast cancer.
According to experts, it’s exercise that is crucial – whatever your weight.
A study has found that being unfit raises a woman’s risk of the disease, whether she is fat or thin.
The researchers warned that women who are slim should not be complacent, because it is also important to be active.
Even ordinary, everyday activities such as carrying the shopping home and playing with children will help, the world’s leading obesity conference heard.
And the Swedish researchers said it is “never too late” to become more active.
They quizzed more than 19 000 women with an average age of 56 about their health and habits, including how much exercise they got, and then checked on their health again 13 years later.
Around 900 of the participants had been diagnosed with breast cancer in that time.
Analysis showed their odds of developing the disease were clearly linked to how active they were.
Those who did the least exercise were 40 percent more likely to have developed breast cancer than those who did the most, the International Congress on Obesity heard.
Crucially, the link with exercise applied whatever their weight.
Researcher Ylva Trolle Lagerros, an obesity doctor from the Karolinska Institute in Stockholm, said: “You can still reduce your risk of breast cancer by being physically active, even if you are of normal weight.”
She added that women did not necessarily need to sweat it out in the gym to see a benefit – everyday activities such as walking to work, playing with grandchildren and gardening all count.
The professor said: “Usually what you do in the gym is only a small part of your total activity for the day. Your body doesn’t really care if you are carrying groceries home or if you are at the gym, it is the total amount of exercise in the day that matters, independent of where you get it.”
The study did not look at why being unfit raises the odds of Britain’s most common cancer. But possible reasons include exercise lowering levels of sex hormones and immune system compounds linked to the disease.
However, weight is still an important factor.
Professor Trolle Lagerros found that being overweight raised a woman’s risk of the disease, even if she exercised. Being obese raised the odds of breast cancer by 58 percent, while merely being overweight increased the likelihood by 20 percent. The women at greatest risk of all were inactive and obese. Their risk of breast cancer was double that of fit, slim women.
Breast cancer is Britain’s most common cancer, with almost 50 000 women diagnosed a year.
It is the second biggest cancer killer among women after lung cancer, claiming almost 1 000 lives a month.
Professor Trolle Lagerros said: “One in eight women will be diagnosed with breast cancer in their lifetime.
“Our study shows that post-menopausal women can decrease their risk of breast cancer through exercise and weight loss – which is a clear public health message.”
Professor David Haslam, chairman of the National Obesity Forum, said exercise is already linked to protecting against bowel cancer.
He said: “It all goes to show that sitting around is really bad for you, even if you are slim.”
Dr Indi Ghangrekar, of Cancer Research UK, said: “Previous research has clearly shown that keeping a healthy weight and being physically active are both great ways to help reduce the risk of breast cancer.
“The good news is that the two go hand in hand – being active is a great way to help manage your weight.
“Aim to do at least two and half hours of moderate activity a week, which can be broken down to smaller chunks and doesn’t have to involve the gym – a brisk walk or some gardening can count.
“As well as keeping a healthy weight and being physically active, cutting down on alcohol can also help reduce breast cancer risk.” - Daily Mail