Chronic sleep loss can be risky

Even a good night’s sleep doesn’t totally compensate for many weeks of sleep loss. And it’s the late-night period when the accumulation of sleep loss may be most apparent.

Researchers at Brigham and Women’s Hospital examined the effect of weeks of insufficient sleep on performance. They scheduled nine healthy volunteers to live for three weeks on a schedule consisting of 43-hour periods in which they were awake for 33 of those hours. That equals about 5.6 hours of sleep for every 24 hours. They looked at how the volunteers performed on cognitive reaction tasks from chronic sleep loss and disrupted circadian rhythms.

The study showed that after waking from a 10-hour sleep, the subjects’ performance was good, but it deteriorated as each 33-hour waking period went on. Indeed, an individual with chronic sleep loss who worked extended hours into the night can have reaction times about 10 times slower than normal, increasing the risk of accidents and mistakes.

The study is published in the journal Science Translational Medicine.

-- Shari Roan

Vitamin D alone might not be enough

Vitamin D might not lower the risk of bone fractures unless it’s taken with calcium.

Previous research on vitamin D’s effects have been conflicting. Some studies have found supplements reduce the risk of fractures, but others haven’t. Researchers in Denmark analyzed seven studies on the question. The studies included a total of 68,517 people whose average age was 70.

The study concluded that vitamin D given alone in doses of 10 to 20 micrograms per day is not effective in fracture prevention. But when calcium and vitamin D were given together, the fracture rates were reduced.

The analysis, however, compared vitamin D with no treatment or vitamin D plus calcium versus no treatment. There was no direct comparison of vitamin D alone and vitamin D plus calcium.

The authors of the new study, published in the British Medical Journal, acknowledge that additional vitamin D studies are needed.

-- Shari Roan

Newborns: To snip or not to snip

Circumcision. It’s a delicate procedure and a loaded word, filled with connotations of pain, religious significance and hotly debated health benefits.

Some commentary in the current issue of the Archives of Pediatrics and Adolescent Medicine shows that medical professionals are not quite ready to come down on one side or the other. “Recommendations for routine newborn circumcision will need to wait for well-designed studies that verify its cost-effectiveness for the individual and/or society,” the editorial said.

-- Amina Khan