OBESITY IS BIGGER CAUSE OF BREAST CANCER THAN SMOKING OR DRINKING

Women who are dangerously overweight are at a far higher risk even than those who drink heavily or smoke.

Experts have long known that the excesses of a modern, unhealthy lifestyle can dramatically increase the likelihood of breast cancer. But now scientists have shown that obese women have far higher levels of cancer-triggering hormones than those who smoke or drink to excess.

Researchers at Oxford University in the U.K. looked at levels of cancer-triggering hormones including oestrogen and testosterone in 6,300 post-menopausal women.
On average, obese women had oestrogen levels 50% higher than those of normal weight. Testosterone levels were 16% higher.
Experts believe that fat tissue secretes oestrogen and another hormone, insulin, which in turn triggers production of testosterone.

The researchers, who looked at 13 published studies, also found that drinking two and a half units of alcohol a day - one large glass of wine - increased levels of some cancer-triggering hormones by 18%, but had no effect on oestrogen.
And smoking more than 15 cigarettes a day also raised the level of some hormones by a small amount, the study, published in the British Journal of Cancer, found.

A woman’s chance of developing breast cancer depends on a range of other factors including family history, age, time of menopause and whether she has had children. But scientists say that obesity is the biggest avoidable cause of the disease.