Recent studies suggest they may be more common than had been thought.
Most studies, however, suggest they could just as well try something else.
But a new study suggests that where one lives may play an important role.
Current studies suggest that at least five times a week is best.
In the past, some studies suggested increased risk and others did not.
But another reason may be that they have run out of money, a large study suggests.
Perhaps, but don't think too hard if you want to do well, a new study suggests.
A new study suggests that the answer may be yes.
Some studies, though, have suggested an association between the two.
A new study of high school students suggests that they are right.