Three years have passed since a case of Type 3 wild polio virus has been detected in the world, which means that particular viral subtype has most likely disappeared forever, the World Health Organization announced.

Its demise could speed up the drive to eliminate polio, which has gone on for 27 years and costs more than $1 billion a year. The last known Type 3 polio case was an 11-month-old boy in northern Nigeria who became paralyzed on Nov. 10, 2012.

Stimulants may have PTSD links

Stimulant medications used to treat attention deficit problems and keep service members alert during long stretches of combat might increase vulnerability to post-traumatic stress disorder, a study suggests.

Defense Department researchers analyzing data from nearly 26,000 service members found that those with prescriptions for the stimulants were five times more likely to have PTSD.

Drugs such as Adderall and Ritalin raise concentrations of the brain chemical norepinephrine, which has been shown to result in more vivid and persistent memories of emotionally charged situations. Traumatic memories are a hallmark of PTSD.

More good news about coffee

A large study has found that drinking coffee is associated with a reduced risk of dying from heart disease and certain other causes.

Researchers followed more than 200,000 doctors and nurses for up to 30 years. The study is in Circulation.

Compared with abstainers, nonsmokers who drank a cup of coffee a day had a 6 percent reduced risk of death, one to three cups an 8 percent reduced risk, three to five cups a 15 percent reduced risk, and more than five cups a 12 percent reduced risk. There was little difference whether they drank caffeinated or decaffeinated coffee.

Coffee drinking was linked to a reduced risk of death from heart disease, stroke, diabetes, neurological diseases and suicide, although not from cancer. The lead author, Dr. Ming Ding, of the Harvard School of Public Health, cautioned, "Our study is observational, so it's hard to know if the positive effect is causal or not."

Sleeping in may not be healthy

Sleeping later on weekends may be bad for you. Researchers have found that the greater the mismatch in sleep timing between weekdays and weekends, the higher the metabolic risk. Sleeping late on days off was linked to lower HDL, or good, cholesterol, higher triglycerides, higher insulin resistance and higher body mass index. The study was in the Journal of Clinical Endocrinology & Metabolism.

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