— Air Pollution and Mortality
Increases in exposure to air pollution even at levels generally considered acceptable are associated with an increase in deaths among the elderly.
Previous studies have suggested an association, but most have been based on small populations in metropolitan areas. This new study, in JAMA, used Medicare files and nationwide air pollution data to estimate 24-hour exposure in people who died from 2000 to 2012.
The researchers found that for each day-to-day increase of 10 micrograms per square meter in fine pariculate matter (PM 2.5), the small particles of soot that easily enter the lungs and bloodstream, there was a 1.05 percent increase in deaths. For each 10 parts per billion increase in ozone, a main component of smog, there was a 0.51 percent increase.
The effect was greater for low-income people, African-Americans, women and those older than 70, and the risk remained significant even at levels below what the Environmental Protection Agency considers safe.
“This translates to PM 2.5 causing an extra 20,000 deaths a year,” said the study’s co-author, Joel D. Schwartz, a professor at Harvard. “Separately, a 10 parts per billion decrease in ozone would save 10,000 lives per year.”
This amounts to more deaths per year than caused by AIDS, Schwartz said. “But unlike AIDS, we know the cure: scrubbers on coal-burning power plants that don’t have them, and reduction in nitrogen oxide emissions.”
— Vitamin D, Calcium and Bones
Vitamin D and calcium supplements are widely used for the prevention of bone fractures in older adults, but a large analysis confirms earlier reports they do not work.
Chinese researchers pooled data from 33 randomized, placebo-controlled trials with more than 51,000 participants to look for an association between taking the supplements and a lowered risk of fracture. The analysis, in JAMA, found none.
Some of the studies looked at calcium and vitamin D separately, others with the two supplements combined. Follow-ups varied from three months to as long as seven years.
Overall, the researchers found no association of vitamin D or calcium supplements, or both, with the frequency of hip, spine or total fractures. Nor was there any association of fracture with baseline vitamin D blood levels or with the dose of the supplements.
The authors acknowledge that some trials did not include baseline vitamin D levels for all participants, and that other researchers might use stricter criteria for classifying a study as high quality.
Still, they conclude, “These findings do not support the routine use of these supplements in community-dwelling older people.”
— Fish and the Growing Brain
Children who eat fish tend to sleep better and score higher on IQ tests, a new study has found.
Using self-administered questionnaires, researchers collected information on fish consumption among 541 Chinese boys and girls ages 9 to 11. Parents reported their children’s sleep duration, how often they awoke at night, daytime sleepiness and other sleep patterns. At age 12, the children took IQ tests.
Compared with the one-quarter of children who ate fish twice a month or less, those who had it twice a week or more scored an average of 4.8 points higher on IQ tests.
The study, in Scientific Reports, also found that the more fish a child ate, the fewer the sleep problems. There may be a chain of effects: Fish consumption is associated with better sleep, and better sleep is associated with better cognitive performance. The study controlled for sex, parental education, maternal age at childbirth, breast-feeding duration and other factors.
“Fish helps with sleep, and this results in higher IQ,” said lead author Jianghong Liu, a professor in the school of nursing at the University of Pennsylvania. “If parents want their kids to be healthy and high performing in school, they should put fish on the table.”
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