A 50-year study of breast cancer was launched today with the aim of pinpointing the causes of the disease, which kills 13,000 women in the UK each year.

Researchers hope to recruit 100,000 British women aged over 18 to take part in the study, which will examine genetic, environmental, behavioural and hormonal factors thought to increase the risk of developing breast cancer. It will be the largest, longest running scientific study of breast cancer ever.

Each volunteer will give a blood sample, which will be analysed for hormonal and genetic factors that may affect breast cancer risk, and provide information about their lifestyles. Researchers hope they can find new ways to prevent women developing the disease - one of the major killers of women.

The study, set up by the charity Breakthrough Breast Cancer and the Institute of Cancer Research, is backed by celebrities including former EastEnders actor Michelle Collins, opera singer Lesley Garrett, TV presenter Tara Palmer-Tomkinson, actors Meera Syal, and newsreaders Fiona Bruce and Katie Derham.

Around 40,000 cases of breast cancer are diagnosed in the UK each year, with rates rising in the past decade. But scientists believe that around half of these cases - at least 20,000 a year - could, in principle, be prevented if the causes of the disease were better understood.

The Breakthrough Generations study will be led by Professor Anthony Swerdlow, head of epidemiology at the Institute of Cancer Research, and Professor Alan Ashworth, director of the institute's Breakthrough Toby Robins Breast Cancer Research Centre.

Prof Swerdlow said: "Breast cancer is the most common cancer in women in this country and sadly it leads to many thousands of deaths each year.

"It is important that we find its causes so that future cases can be prevented. The causation of breast cancer is complicated, however, and to help to unravel these complexities the study will therefore need to include very large numbers of women and to continue over many years."

Prof Ashworth added: "There have been real improvements in breast cancer treatment and diagnosis over the last decade, but what's absolutely vital for the future is to prevent the disease occurring in the first place.

"To do this we first need to pinpoint and understand the causes of breast cancer - an area of research that has not received enough attention to date.

"Within a few years, we can expect the first results of the study to emerge, giving us a unique insight into the causes of breast cancer and, eventually, allowing us to work out methods to prevent it occurring in the first place."