While some studies, like those mentioned, find an association, others do not.

However, not all studies can find a clear association.

Millions of women began taking replacements after studies found an association between good health and their use.

However, in contrast to this, a 2008 study did find an association with poor sleep quality.

However, experimental studies have not always found an association, and the size of the effect can be very modest.

However, the evidence is not definitive as 5 of 17 studies failed to find an association.

Other studies have found an association between smoking and strokes in men.

The third study also found an association, though a somewhat smaller one, between ozone levels and death rates.

They also found an association between estrogen and the number of teeth lost.

A new study finds a strong association between the health of husbands and wives.