WOMEN who go up a skirt size every decade between their mid 20s and mid 60s have a 33 per cent greater risk of breast cancer, a study claims today.
Overall weight gain during adulthood is known to increase the risk of the illness but the research indicates a thickening waist could be “particularly harmful”, indicating the key value of staving off a bulge around the middle, researchers said.
Their work, published in the online journal BMJ Open, examined the health of 93,000 women all aged over 50 in England taking part in the UK Collaborative Trial of Ovarian Cancer Screening.
During the monitoring period, 1,090 women developed breast cancer.
Researchers said that as expected infertility treatment, family history of breast or ovarian cancer and use of hormone replacement therapy were all significantly linked with a heightened risk of being diagnosed with the disease, while pregnancies were protective.
But they said after taking account of other influential factors, increases in skirt size emerged as the strongest predictor of breast cancer risk after the menopause.
Analysis revealed that going up one skirt size every 10 years was associated with a 33 per cent greater risk of developing breast cancer after the menopause. Going up two skirt sizes over the same period was associated with a 77 per cent greater risk.
Researchers from London and Manchester estimated that the risk of post-menopausal breast cancer rises from one in 61 to one in 51 with each increase in skirt size every 10 years.
Women who reduced their skirt size decreased their risk of the illness although three in four of the women involved in the study saw theirs increase. Women taking part in the research said their average skirt size was 12 at the age of 25. When they entered the study at an average age of 64, it was 14.
The study authors said no definitive conclusions could be drawn about the impact of skirt size from the study.
But they said an expanding waistline had been linked to other others including those of the pancreas, lining of the womb, and ovaries, possibly because midriff fat is more harmful. Extra fat is known to boost levels of the female hormone oestrogen on which many breast cancer cells rely for fuel.
Tom Stansfeld, of Cancer Research UK, said: “This study relied on women remembering what size they were at least 30 years ago which could be unreliable. Also, dress sizes have changed over the years so it’s hard to be sure what each size really means.
“Evidence tells us the most important things you can do to reduce breast cancer risk, especially after the menopause, is to keep a healthy weight, be physically active as often as you can, and cut down on alcohol.
“Keeping a healthy weight is important to help reduce breast cancer risk after the menopause, and looking at skirt sizes to help women understand this is interesting, but knowing if you’re overweight is more important.”
Simon Vincent, of Breakthrough Breast Cancer, said: “This study highlights an easy way to monitor your weight gain over time. Women are more likely to remember their skirt size when they were younger than their body-mass index.”
Grete Brauten-Smith, of Breast Cancer Care, said lifestyle changes did not guarantee cancer prevention. She said: “Being female and getting older remain the most significant risks for developing the disease.”