Body & Brain

Pack-a-day habits on the wane, plus Haitian cholera and omega-3s in this week’s news

Haitian cholera underestimated
The United Nations might be underestimating the human toll posed by Haiti’s ongoing cholera epidemic, according to researchers at Harvard Medical School and the University of California, San Francisco. Using a mathematical model, the team calculates that nearly 800,000 more cases of cholera could occur before the epidemic ends, killing an additional 11,000 people. Current U.N. estimates predict 400,000 cases and 4,000 deaths occurring between December 2010 and December 2011. Vaccinating 10 percent of the population could avert 63,000 cases, the researchers predict in a study posted online March 16 in the Lancet. —Nathan Seppa

Omega-3s vs. vision loss
Consuming omega-3 fatty acids found in fish might lessen the risk of vision loss caused by age-related macular degeneration, Harvard University researchers report online March 14 in the Archives of Ophthalmology. Starting in 1993, more than 38,000 women filled out questionnaires regarding their health status and lifestyle. After 10 years, 235 had developed age-related macular degeneration. Those eating fish at least once a week were 13 to 62 percent less likely to develop the disorder than those who ate fish less than once a month, the researchers calculate. Researchers took into account confounding factors such as smoking, blood pressure and diabetes. —Nathan Seppa

Heavy smoking declines
Since the first Surgeon General report warning against smoking came out in 1964, the percentage of smokers in the United States has fallen, as has the number of actual cigarettes lit up by those smokers per day, an international team of researchers reports in the March 16 Journal of the American Medical Association. Roughly 23 percent of U.S. adults smoked a pack a day or more in 1965, a rate that fell to 2.6 percent in California by 2007 and to 7.2 percent in the rest of the country. California has led the nation in antismoking programs. Only 4.6 percent of Californians born during the 1970s who had reached age 35 were moderate-to-high-intensity smokers, compared with 13.5 percent nationwide. —Nathan Seppa

New test for Creutzfeldt-Jakob disease
Doctors may soon be able to diagnose a human brain-wasting condition similar to mad cow disease without taking a sample of brain tissue. Creutzfeldt-Jakob disease is caused by an infectious protein called a prion. The disease produces symptoms similar to other forms of dementia, so definitive diagnosis usually requires a brain biopsy or an autopsy after death. Now, researchers at Case Western Reserve University in Cleveland have developed a test that measures levels of an iron-carrying protein in the spinal fluid. Low levels of transferrin protein in the spinal fluid can diagnose the disease with 80 percent accuracy, the researchers report online March 9 in PLoS One. —Tina Hesman Saey

Apple bodies no worse than pears
A new study of more than 220,000 people in 17 countries finds no exaggerated heart risk for apple-shaped people — those who wear their excess fat around the belly. A major international research consortium confirmed what other studies have found: Excess weight increases an individual’s risk of heart attack and stroke. But contrary to a host of research, having that fat aggregated around the waist was no worse than having it amass at the hips or elsewhere, the authors report online March 11 in the Lancet. The findings linked heart risk primarily to factors associated with excess weight: blood pressure, diabetes and high cholesterol. —Janet Raloff