No studies have linked the medications to the act itself.
Many studies link population growth with emissions and the effect of climate change.
No studies directly link cell phone use to brain cancer.
Despite numerous studies linking walking to better health, many people cannot seem to bring themselves to do even that.
But the study could not specifically link the high rate to contaminated water.
However, several studies have linked drinking tea to a lower risk of cancer for some people.
In 1971 a Soviet study linked the dye to cancer.
Recent medical studies have linked it to brain damage and depression.
But studies have linked low levels of vitamin D to depression among older men and women.
And recent studies have linked the chemical to hormonal changes.