Older women need to stay trim to reduce the risk of breast cancer, it has emerged.
Scientists have found breast cancer risk is more affected by total body fat than abdominal fat.
A study, published in Endocrine-Related Cancer, emphasises the importance of maintaining a healthy weight.
The researchers found levels of several breast cancer risk markers were reduced in postmenopausal women, who lost total body fat, rather than just belly fat.
Study leader Evelyn Monninkhof said: “It is known that belly fat increases the risk of several chronic diseases independently of total body fat but, for reducing sex hormone levels, total body fat seems more important.”
The study used a more accurate method of determining fat distribution, rather than waist circumference.
“We obtained two measurements of both fat deposits and biomarkers over time, and we used more accurate DEXA [dual-energy X-ray absorptiometry)] measurements for total body fat, as well as MRI for belly fat,” said Dr Monninkhof.
Researchers at the University Medical Center Utrecht in the Netherlands who examined 243 overweight, postmenopausal women who lost 5kg-6kg of weight over 16 weeks found lower levels of breast cancer markers, including sex hormones and leptin, in total body fat, while a reduction in belly fat was more associated with inflammatory markers.
In recent years, belly fat has been reported to raise the risk of several conditions including cardiovascular disease, type-2 diabetes and colorectal cancers.
Increased levels of several blood markers, including sex hormones testosterone and oestrogen; the ‘fullness’ hormone leptin; and inflammatory factors are associated with breast cancer risk.
While some research has suggested that the markers are mainly produced in fat localised in the belly, other studies have shown weight loss is associated with changes in blood levels of breast cancer markers. Taken together, the findings seem to suggest that body fat could have a major effect on breast cancer markers.
“Our next step is to find out how belly fat and total body fat can best be conquered,” said Dr Monninkhof.
Head of research at the Irish Cancer Society, Robert O’Connor said the research supported much of what was already known: that being overweight increases the risk of some cancers.
“Exercise releases hormones that suppress tumour growth and helps make our immune system more efficient at targeting cancer cells,” said Dr O’Connor.
“Importantly, this latest paper suggests that taking active measures to moderate our weight and be more active reduces the levels of substances in the blood which are linked to higher cancer risk and increases levels of substances which are associated with lower cancer risk.
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