Health and Fitness News and Notes Health and Fitness News and Notes

Children who are overweight or obese are at increased risk for asthma, researchers report.

A retrospective study, published in Pediatrics, included 507,496 children followed for an average of four years. None of the children had incidents of asthma before the start of the study.

The researchers divided the children into three groups: overweight, defined as the 85th to 94th percentile for weight; obese, the 95th percentile or higher; and normal weight, the 25th to 64th percentile.

The study controlled for age, race, health insurance, food allergies, medications and other factors, and found that compared with children of normal weight, the overweight were 17 percent more likely to have been given a diagnosis of asthma and to take an asthma medication. The obese were 30 percent more likely.

The researchers estimate that 23 to 27 percent of asthma cases in obese children can be attributed to the obesity itself. Among all the children, 10 to 13 percent of asthma cases were attributable to obesity.

“Asthma is the most common chronic disease of childhood, the most common reason kids lose time in school, and the most common reason for hospitalization,” said the lead author, Dr. Jason E. Lang, an associate professor of pediatrics at Duke University. “There aren’t many preventable risk factors for it, and this study suggests that obesity may be one of them. So it’s really important to keep kids at a healthy weight.”

Cardiologists are generally convinced that blood pressure inevitably increases with age. Now a new study calls this belief into question.

Researchers studied two communities in a remote area of the Venezuelan rain forest that can only be reached by air. The Yanomami are among the most isolated and least assimilated people in the world. Nearby live the Yekwana people, also quite isolated, but with an airstrip that allows for the regular delivery of Western food and medicine.

The study, in JAMA cardiology, included 72 Yanomami and 83 Yekwana men, women and children ages 1 to 60. While the two groups were similar in other respects, average blood pressure among the Yanomami was 95/63, whereas in the Yekwana it was 104/66.

By the time they reached age 60, blood pressure among the Yanomami was unchanged, while the Yekwana average had risen to 114/73.

The lead author, Noel T. Mueller, an assistant professor of epidemiology at Johns Hopkins University, said that while it may not be feasible to follow a Yanomami diet, just cutting our salt intake in half could prevent an estimated 15 million cases of hypertension in the United States.

“That blood pressure rises over age is probably not a natural phenomenon, but a cumulative effect of exposure to the Western diet,” he said. “Following a healthful diet low in processed food and salt can help reduce the risk for hypertension.”

Taking omega-3 supplements during pregnancy may lower the risk for preterm birth, a review of studies has found.

The analysis, in the Cochrane Reviews, considered 70 randomized trials that included almost 20,000 women. A few studied fish consumption, but most tested supplements of omega-3 fatty acids, the fats found in fish.

The researchers found high-quality evidence that, compared with women who did not take omega-3s, those who took supplements had an 11 percent lower risk of giving birth before 37 weeks of gestation, and a 42 percent lower risk of a birth before 34 weeks.

They also found high-quality evidence that omega-3s reduced the risk of low birth weight by 10 percent, and moderate-quality evidence that it reduced the risk of perinatal death by 25 percent.

There was insufficient evidence to draw any conclusions about the effect of omega-3s on serious adverse outcomes among mothers — induction post-term, admission to intensive care, or postnatal depression.

The lead author, Philippa Middleton of the South Australian Health and Medical Research Institute, said the consequences of premature birth, both short- and long-term, are severe, and it is the world’s leading cause of death among children under 5.

“One of the reasons this is a very big deal is that there’s little else out there that deals with premature birth,” she said. “Omega-3 supplementation is one thing that will make a huge difference to the prematurity rate.”