Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

Movie Smoking Ups Teens' Risk Of Starting the Habit: Study

Teens are more likely to start smoking if they see a lot of movie scenes that depict smoking, according to a new study.

It found that youth exposed to a lot of onscreen smoking are about three times more likely to begin smoking than those with less exposure to smoking in movies.

The researchers also analyzed the top-grossing movies from 1991 to 2009 and found that depictions of tobacco use have declined in recent years. However, more than half of the PG-13-rated movies released in 2009 still contained tobacco imagery.

The study appears today in the latest Morbidity and Mortality Weekly Report, published by the U.S. Centers for Disease Control and Prevention.

The authors suggested a number of ways to decrease the negative impact of movie smoking on young people: give R ratings to new movies that portray tobacco use; require that strong anti-tobacco ads be shown before movies that depict smoking; and forbid tobacco brand displays in movies.

-----

Low Levels of Income, Education Increase Women's Diabetes Risk: Study

Poverty and low levels of education appear to be associated with increased risk for type 2 diabetes in women, a new study released Wednesday by Statistics Canada reports.

The two factors are independent of other diabetes risk factors, including the well-documented connection between being overweight/obese and diabetes, CBC News reported.

Lower-income women were much more likely to develop diabetes than those in high-income households. But household income didn't appear to influence diabetes risk in men. Their main risk factors were being overweight/obese and behaviors such as smoking, heavy drinking and physical inactivity.

The 15-year study included 12,333 participants, aged 18 and older, in the National Population Health Survey. Among those who were diabetes-free in 1994-95, 7.2 percent of men and 6.3 percent of women had either developed diabetes or died of the disease by 2008-09, CBC News reported.

-----

Possible Link Between Athletes' Head Injuries and Lou Gehrig's Disease: Study

There appears to be a connection between head injuries in athletes and Lou Gehrig's disease, according to a new study.

Boston University neurology professor Dr. Ann McKee found toxic proteins in the spinal cords of three athletes who suffered head injuries during their careers and later died of Lou Gehrig's disease, also called amyotrophic lateral sclerosis (ALS), the Associated Press reported.

The same toxic proteins have been found in the brains of athletes with chronic traumatic encephalopathy (CTE). This condition is associated with head injuries and patients experience abnormal behavior, cognitive decline and dementia.

McKee launched her study after noticing that ALS appears to affect an unusually high number of football players. People with ALS lose the ability to move and speak as the disease attacks nerve cells in the brain and spinal cord.

She analyzed the brains and spinal cords of former Minnesota Vikings linebacker Wally Hilgenberg, former Southern California linebacker Eric Scoggins, and an unnamed boxer, the AP reported. All of them died of ALS.

The spines of all three athletes contained the toxic proteins. But these proteins were not present in the spines of athletes who had CTE but not ALS, nor in non-athletes who died of ALS.

The study appears in the Journal of Neuropathology and Experimental Neurology.

-----