Hint on lower risks of cancer

Press, 16 January 1986, Page 25

Hint on lower risks of cancer

NZPA-AP Boston Women who begin athletic training during their youth establish a style of living that significantly lowers their risk of developing cancer of the breasts and reproductive organs, a Harvard study concludes. The researchers said they believe that their work, based on a survey of former college athletes, is the first to examine links between physical activity and the risk of cancer in women.

The study found that lessactive women had about Wi times as much cancer of the uterus, ovary, cervix and vagina as the former college athletes, and nearly twice as much cancer of the breast. These tumours account for more than 40 per cent of all female cancers.

Just why the college athletes go on to have less cancer is not clear. However, the researchers believe that it has something to do with estrogen secretions, which are thought to play a role in the development of female cancers. The athletic women were leaner than the non-athletes, and lean women make less estrogen — and a less potent form of estrogen — than do plump women. There might be a lower risk of cancer, because these athletes might have lower levels of estrogen, said Dr Rose Frisch, who directed the study. “Whatever the reason,” the researchers wrote, “we conclude that long-term athletic training establishes a lifestyle that somehow lowers the risk of breast

cancer and cancers of the reproductive system.” The study, published in the “British Journal of Cancer,” was based on a study of 5398 women who graduated from 10 United States colleges between 1925 and 1981.

Dr Frisch, a researcher at Harvard’s School of Public Health and Centre for Population Studies, said the apparent benefits of physical fitness probably begin early in life.

She noted that 82 per cent of the college athletes were on teams in high school or earlier. Most of the women continued to work out through life. At the time of the survey, three-quarters of the former athletes exercised regularly, compared with

half of the non-athletes. The results suggest that women have to start exercising early in life to obtain the apparent cancer protection. The college athletes competed in such team sports as basketball, crew, field hockey, softball and tennis. “The important point is that it’s something that young people can participate in,” said Dr Frisch.

“It’s moderately intense, regular exercise. It isn’t on the level of marathon running.” The effects of body composition and exercise on estrogen secretions have been the subject of considerable study over the last decade.

An earlier study of Harvard women runners and

swimmers showed that young athletes go through sexual maturity at a later age. Every year of athletic training delays menarche — the first menstrual period — by five months. In the latest study, the athletes had menarche a few months later and menopause a few months earlier than the non-athletes. The variation in cancer rates could not be attributed to differences in the women’s family histories of cancer or their fertility. These factors were similar for both groups. Among the co-authors of the report was Tenley Albright, who won the Olympic gold medal for figure skating in 1956. She is now a physician at New England Baptist Hospital, Boston.