Smoking can extinguish a good night's sleep

February 11, 2008

Here's another good reason to put away those cigarettes - a new study shows that smoking can lead to unhealthy sleep patterns, making you feel groggier the next day. Scientists have long speculated that smokers have poorer sleep quality than nonsmokers because of conditions associated with the habit, such as sleep apnea and lung disease. Now, research from Johns Hopkins University School of Medicine led by Dr. Naresh M. Punjabi, shows that smoking might be the culprit for decreased sleep quality. Researchers chose 40 smokers and 40 nonsmokers who were otherwise healthy. They sent them to bed with EEG machines that pick up sleep patterns in the brain. Using mathematical models, researchers were able to determine that smokers tended to spend more time in light sleep and less time in deep sleep - with the result that nearly one-quarter of smokers, compared with only 5 percent of nonsmokers, said they weren't getting restful sleep.

BOTTOM LINE: "If smokers have sleep disturbances, smoking probably has an important contribution," Punjabi said.

CAUTIONS: "We didn't look at former smokers," Punjabi said, so this study has no way of predicting whether quitting smoking might help restore normal sleep habits.

WHAT'S NEXT: Researchers plan to follow the patients over the next five years to see whether sleep is affected over the long term.

WHERE TO FIND IT: Chest, February.

SUSHRUT JANGI

Plaque found in the brains of an Alzheimer's patient can develop in just 24 hours and may be a cause rather than a symptom of the disease, according to a new study that contradicts widely held theories about the neurodegenerative disorder. Scientists thought that plaques lesions on the brain caused by a build up of the protein amyloid-beta developed slowly as a result of the disease. But new images of brain tissue in living mice show that the plaques form in just one day, and neuronal deterioration begins soon afterward, said Dr. Bradley Hyman, senior author and director of the Alzheimer's Unit at MassGeneral Institute for Neurodegenerative Disease. Hyman and collaborators at the Washington University School of Medicine used a technique called multiphoton confocal microscopy to watch the brains of mice genetically engineered to develop amyloid plaques. The images were taken daily and weekly, allowing scientists to track plaque development in real-time without damaging brain tissue. Once plaque developed, immune cells called microglia rushed to the site and within a week, the plaques stabilized and growth stopped. "Our study shows that the simple formation of plaque leads to an alteration in its surrounding environment that leads to changes in neurons and their ability to communicate with one another," Hyman said. "So, it's the accumulation of individual plaques that causes damage."

BOTTOM LINE: This study adds weight to the idea that the formation of plaques in the brain is a cause - rather than an effect - of Alzheimer's. Better understanding plaque growth will help researchers develop drugs to stop it.

CAUTIONS: Researchers used mice genetically engineered to develop Alzheimer's, but there is no guarantee that these findings would hold true for humans.

WHAT'S NEXT: Scientists want to know why plaques form when and where they do, and more about the role immune cells play in plaque stabilization.

WHERE TO FIND IT: Nature, Feb. 7

KELLI WHITLOCK BURTON