New evidence from two large British studies suggests that women in their forties can lower their risk of dying from breast cancer by having regular mammograms.

For women in their forties, the question of when to begin having mammograms has been controversial. There is ample evidence that among women aged 50 or older, regular mammograms reduce breast cancer deaths by about 30 percent, and the National Cancer Institute recommends having the test every one to two years starting at 50. The NCI offers the same advice to women in their forties, but some studies have not found that mammograms prevent breast cancer deaths in that age group.

However, the new British data suggest that for women aged 45 to 49, mammography offers about the same reduction in mortality as for women 50 and older.

One study, the U.K. Trial of Early Detection of Breast Cancer, collected data on more than 236,000 women aged 45 to 64 who were treated at eight British health centers.

Patients at two of the centers were offered mammograms every two years, those at two other centers were taught breast self-examination (BSE), and patients at the other four centers (the control group) received routine care. Sixteen years after the study began, the death rate from breast cancer was 27 percent lower in the women screened with mammograms than in the control group. Deaths were not reduced among the women taught BSE.

About 23,000 women entered the study while in their forties, and "we didn't find any less of a benefit" from mammograms in that age group, said Derek Coleman of the Institute of Cancer Research in London.

In a study in Edinburgh, more than 54,000 women were randomly assigned to receive mammograms every two years or routine care. The results after 14 years, when adjusted for differences in socioeconomic status between the two groups, showed a 21 percent reduction in breast cancer deaths in the mammography patients, which was of "borderline" statistical significance. Among women aged 45 to 49 at the start of the study, mammography reduced breast cancer deaths by 30 percent.

The British national health insurance program currently provides mammograms for women every three years, starting at age 50.

In a commentary accompanying the studies in Saturday's issue of The Lancet, Brown University's Kay Dickersin argues that the debate over mammograms for women in their forties is no longer about science, but "about politics, money, fear and a sense of helplessness in the face of a dreaded disease." For the typical woman, the benefits are marginal. Screening 10,000 women in their forties annually with mammograms for ten years, she notes, would "on average extend all 10,000 women's lives by 2.5 days. However, it is impossible to say what would happen in a given individual."

--Susan Okie


Men who are overweight at age 25 are more likely in middle age to develop Type 2 diabetes, the most common form of the disease, than thinner men, researchers at Johns Hopkins Medical Institutions reported recently.

The results come from a long-term study of 913 male physicians. It is one of the first studies to examine the potential impact of body weight in the decades before middle age, when diabetes often develops, and could assist researchers in developing programs aimed at preventing the condition, which is a major cause of death and disability.

Lead researcher Frederick L. Brancati and his colleagues studied the weights of former Hopkins male medical students beginning in the class of 1948 and continuing through 1964. Because so few women were enrolled at the time, only male medical students were eligible for the study, which was devised in 1947 by physician Caroline Bedell Thomas to examine the origins of heart disease.

During medical school each participant underwent a detailed physical exam and medical history. After they left Hopkins, participants received regular questionnaires about their weight and were asked about other factors such as smoking, exercise and their use of medications. Each man's body mass index was calculated at ages 25, 35 and 45. A 5-foot-11 man who weighed 179 pounds would have a body mass index of 25.

Overall, the group was predominantly white and most were lean: their body mass indexes at age 25 averaged 23.2, at 35 the average was 23.9 and by age 45 it was 24.1.

The researchers discovered that men who were overweight at age 25--those who had a body mass index of 25 or greater--were almost four times more likely to develop diabetes after age 50 than men who were not overweight.

The reasons for the relationship of overweight in early adulthood and the development of diabetes decades later may be biological, the authors suggest. "One possible explanation is that early adulthood marks the end of a critical period for the development of metabolism," they noted in the study, which was published in the May 10 issue of the Archives of Internal Medicine.

Another possibility is that the effect of excess weight on insulin resistance is cumulative, much like the ingestion of tobacco smoke on the development of lung cancer.

Diabetes prevention programs, the researchers concluded, should be targeted at a younger population: overweight young adults. "The rising prevalence of overweight in young adults today," they conclude, "may accelerate the incidence of diabetes well into the next century."

--Sandra G. Boodman