More time spent moving and less time sitting seem to reduce the incidence of breast cancer, finds a new study partially funded by the governments of Canada and Quebec.
If we could convince a cohort of 100 women to adopt an active lifestyle, there would be 41% fewer cases of breast cancer in this group than in a group of 100 sedentary women, the researchers measured. This reduction was 38% if the women engaged in vigorous physical activity at least three days a week, compared to fully sedentary women. “Per hundred people doing moderate-intensity physical activity? the equivalent of a brisk walk, isn’t that a marathon? there are 40% of these 100 people who are not going to have breast cancer compared to a population which does not have it, ”summarized Kaoutar Ennour-Idrissi, who is a doctoral candidate in epidemiology at Laval University.
“If a population is very, very encouraged to do physical activity, then everyone gets involved, we will have 40% fewer cases of breast cancer. It is not for a particular person, but in a population. In contrast, a sedentary lifestyle was associated with a 104% increased risk of triple-negative breast cancer. The study authors looked at nearly 131,000 women of European descent, including about 75,000 who had breast cancer. They used a sophisticated analysis method that allows them to exclude the influence of factors such as a family history of breast cancer, which gives even more robustness to their results.
Previous observational studies have shown an association between physical inactivity and an increased risk of breast cancer. “We’re going to find people who are going to say to us, ‘Ah, but I’ve been active all my life, I’ve exercised, I’ve taken care of my health all my life. However, I was sick,’ said Ms. Ennour-Idrissi. This means that for a particular person, we cannot know which factors are the most contributing factors. But if we change the behavior of a population, we will reduce 40% of cancers. From a public health point of view, this is very important. That being said, personal risk can be reduced by adopting an active lifestyle, watching your diet, not smoking and reducing our alcohol intake, she added.
“When you drive a car on a highway, when you respect the speed limit, when you put on your seatbelt, when you are attentive, when you are not tired, when you try to put all the chances on our side so as not to have any accidents, well, we significantly reduce our risk, illustrated Ms. Ennour-Idrissi. Of course, there are things you can’t control. What I mean is that we put all the chances on our side. The study was partially funded by Genome Canada, Genome Quebec, the Canadian Institutes of Health Research, the Canadian Cancer Society and the Quebec Breast Cancer Foundation. Researchers from McGill and Laval universities also contributed.
The conclusions of this study are published by the “British Journal of Sports Medicine”.
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