Caffeine May Boost Driver Safety

Long-haul truck drivers who drink coffee or other caffeinated drinks are significantly less likely to have an accident than their uncaffeinated peers.

Australian researchers looked at data on 530 drivers recently involved in a crash, comparing them with 517 who had not had an accident within the past 12 months. All were driving tractor units with one, two or three trailers.

The researchers interviewed all the drivers, gathering information about various health and lifestyle issues, including caffeine consumption over the past month. The study was published online in BMJ.

After adjusting for age, driver experience, distance driven, hours of sleep, naps, night driving and other factors, they found that drivers who consumed caffeine were 63 percent less likely to be involved in a crash.

According to the lead author, Lisa N. Sharwood, a research fellow at the George Institute for Global Health in Sydney, Australia, this does not mean that caffeinated drinks are the answer for road safety.

“Clearly drivers are using caffeinated substances to help them stay awake,” she said. “While this may be useful for a period of time, it should really be seen as part of drivers’ overall fatigue and health management in a quite dangerous industry. It isn’t sustainable to go without sleep. But caffeine is useful as part of a wider strategy.”

Eating walnuts may reduce the risk for Type 2 diabetes in women, a large new study concludes.

Previous studies have suggested an inverse relationship between tree nut consumption and diabetes. Though the findings are correlational, walnuts are uniquely high in omega-3 and omega-6 fatty acids, which may be of particular value in Type 2 diabetes prevention.

The scientists, writing in the April issue of The Journal of Nutrition, used dietary and health data on 138,000 women participating in a large continuing study of women’s health. Beginning in 1999 they collected data on walnut consumption, and followed the women for the next 10 years. They found 5,930 cases of Type 2 diabetes.

Women who ate walnuts tended to weigh less, consume more fish and exercise more than those who did not. But researchers controlled for these and many other factors, and found that compared with women who ate no walnuts, those who consumed 8 ounces of walnuts or more a month reduced their risk for Type 2 diabetes by 24 percent.

“There’s been a lot of research on nuts in general in relation to cardiovascular health,” said the senior author, Dr. Frank B. Hu, a professor of medicine at Harvard. “This is the first on walnuts and diabetes. Walnuts may have some unique benefits.”

The study was supported with grants from the National Institutes of Health and the California Walnut Commission.

Alcohol and Breast Cancer Survival

Alcohol consumption is known to increase the risk for breast cancer. But a new study suggests that moderate drinking has little effect on survival after diagnosis, and may reduce deaths from cardiovascular disease.

Researchers, writing online in The Journal of Clinical Oncology, studied 22,890 women with breast cancer, recording information on alcohol intake before diagnosis and, for a subset of 4,881 of them, after diagnosis as well.

After controlling for age, education, stage of cancer, body mass index, smoking and other factors, they found that breast cancer survival was similar in women who drank alcohol after diagnosis and those who did not. But women who drank moderately before diagnosis — three to six drinks a week — were significantly less likely to die of breast cancer and of cardiovascular disease. Cardiovascular disease, the authors write, is increasingly being recognized as a mortality cause among breast cancer survivors.

The study’s lead author, Polly A. Newcomb, said that the results “suggest that moderate alcohol consumption before or after breast cancer diagnosis is not associated with an increased risk of death from breast cancer.” Dr. Newcomb is a researcher at the Fred Hutchinson Cancer Research Center in Seattle.

The authors note that the study is observational, and it may be that women who drink moderately engage in other healthy practices that the researchers were unable to control for.

Sleep Less, Weigh More

A new study suggests that adolescent obesity could be decreased if teenagers got more sleep, and the heaviest would benefit most.

For a study published last week in Pediatrics, researchers surveyed 1,429 ninth graders, gathering data on height and weight. The children reported their sleep habits on weekdays and weekends to the nearest 15 minutes. The researchers followed the students with interviews every six months over the next four years, updating their data.

Each additional hour of sleep was associated with a reduction in body mass index, but the heaviest children — those above the 90th percentile of B.M.I. — had the greatest benefit, an average 0.28 reduction in B.M.I. for every extra hour. The researchers controlled for physical activity, screen time, sex, race and socioeconomic status.

The authors acknowledge that they had no data on caloric intake, which may increase with less sleep, but it is also possible that less sleep discourages physical activity and affects hormones that regulate energy expenditure.

“Our data can’t tell you what will happen with an individual child,” said the lead author, Jonathan A. Mitchell, a postdoctoral fellow at the University of Pennsylvania. “But based on our observational study, we predict that increasing the duration of sleep to 10 hours from eight would lead to a 4 percent reduction in obesity among U.S. children.”