Eating red or processed meat is linked with an increased risk of breast cancer, a British statistical study says, and the highest risks are associated with the greatest consumption of the meat.

"Women generally consuming most total meat, red and processed meat were at the highest increased risk, compared with non-meat consumers," researchers from the University of Leeds reported in a study released Wednesday.

The study published in the British Journal of Cancer "indicates relationships with certain meats and breast cancer in both pre- and postmenopausal women."

It calls for a larger study.

The researchers gathered diet data on 33,725 British women between 1995 and 1998, and found that by 2004, a total of 678 — 283 premenopausal and 395 postmenopausal — had been diagnosed with breast cancer.

Among nearly 8,890 vegetarian women, 149 (1.7 per cent), got breast cancer. The figure rose to 185 cases among the 8,281 women (2.2 per cent) who reported eating the most meat — more than 103 grams of beef, pork or lamb a day.

"The findings are most striking for postmenopausal women," the university said in a news release. "Those with the highest intake of red meat, the equivalent to one portion a day (more than 57 grams) run a 56 per cent greater risk of breast cancer than those who eat none.

"Women who eat the most processed meat, such as bacon, sausages, ham or pies, run a 64 per cent greater risk of breast cancer than those who eat none."

The study assessed daily intakes of four main meat types: red, poultry, offal and processed (sausages, pies).

"There were no statistically significant linear associations with consumption of poultry or offal in either pre- or postmenopausal women," the researchers said.

Maureen Taylor, the CBC's national medical reporter, cautioned that "this study does not point to cause and effect." There's nothing to indicate what in meat might be a problem, she said.

Moderation is the key

Toronto doctor Mike Evans said the study "is a great first step in showing this link."

But he cautioned that it may not be as definitive as it seems, because of all the other variables.

The report noted that women who ate a lot of meat were more likely to be smokers, had the highest total energy intake, the highest body mass index (a measure to assess if a person is overweight or obese), were more likely to have left school by age 14 and were the least likely to have professional or managerial jobs.

Evans said he would not recommend swearing off red meat. "What I tell people is everything in moderation," he told CBC News.  

Evans is a family physician with a practice in Toronto and an associate professor in the department of family and community medicine at the University of Toronto.