Into Thin Air
You’re less likely to get lung cancer—whether you smoke or not—if you make your home at high altitude. That’s according to a new study co-authored by Kamen Simeonov, an MD-PhD student at the Perelman School of Medicine. Using regression analysis on cancer rates in the western United States, Simeonov found that every additional kilometer in elevation is associated with a 12 percent decrease in the incidence of lung cancer—a drop of 7.23 cases per 100,000 people. This relationship didn’t hold up for breast, prostate, or colorectal cancer, suggesting that there may be something protective about the thin air up there.
“Lower atmospheric pressure at higher elevations results in less inhaled oxygen, sometimes as much as one-third less than in low-elevation areas,” Simeonov noted. Recent findings suggest that incompletely metabolizing oxygen when you breathe may injure and mutate cells, paving the way for lung cancer.
While previous studies have explored this relationship, this one, published online on PeerJ, has assessed it the most comprehensively, collecting data from a geographic area more than three times larger than previous studies and controlling for previously under-addressed confounding variables.
Alzheimer’s and Antidepressants
The commonly prescribed antidepressant citalopram appears to decrease the formation of beta-amyloid peptides—which clump together in the brain to form plaques that are a hallmark of Alzheimer’s Disease. A pair of studies led by Yvette Sheline, professor of psychiatry, radiology, and neurology and director of the Center for Neuromodulation in Depression and Stress at the Perelman School of Medicine, investigated the effect of the medication, a selective serotonin reuptake inhibitor (SSRI), on beta-amyloid concentrations first in mice and then in a small group of healthy adults.
As reported last May in Science Translational Medicine, a four-week course of the drug halted the growth of existing amyloid plaques in the brains of mice, and reduced the formation of new ones by 78 percent compared to a control group. Human subjects given two doses of citalopram exhibited spinal-fluid concentrations of beta-amyloid that were 38 percent lower than those registered by a control group.
“We are a long way from making a statement regarding the ability of SSRIs to prevent the cognitive decline associated with [Alzheimer’s],” said Sheline. But the reduction of beta amyloid levels has been one of the main avenues of research on the disease.
All Work and No Sleep
Paid work and long commutes are the most common thieves of sleep, according to a new study. Researchers from the sleep and chronobiology division of the Perelman School of Medicine analyzed the responses of 124,517 Americans to a time-use survey conducted between 2003 and 2011. They found that across almost all demographic categories, “short sleepers”—those who said they slept 6 hours or less per night—worked 1.55 more hours on weekdays and 1.86 more hours on weekends and holidays than their better-rested peers. Socializing, grooming, and watching TV were also associated with less sleep, but to a lesser extent.
“The evidence that time spent working was the most prominent sleep thief was overwhelming,” said lead author Mathias Basner, an assistant professor of sleep and chronobiology.
Short sleepers also tended to travel more, and to do so earlier in the morning and later into the evening, suggesting that most of these sleep-deprived workers were commuting. Basner suggests that shortening commute times and increasing the flexibility of work start times could go a long way toward reducing Americans’ chronic sleep loss.
The American Academy of Sleep Medicine recommends that adults get 7-9 hours of sleep a night for optimal health and productivity.