The second study was a Norwegian study of high-risk men.
A major Norwegian study was launched in 1972.
This was challenged by a Norwegian study released in 2005, which suggested that lobsters cannot feel pain due to their diminished nervous capacity.
But a Norwegian study shows that genetics may also play a role.
The increased proportion of medium-aged stands of trees created by modern forestry techniques have benefited the species, according to a Norwegian study.
These rates were five times higher than those estimated by an earlier Norwegian study - the only other known research describing EM incidence.
The women in the Norwegian study exercised vigorously enough to raise their heart rates and break into a sweat.
In a 2009 Norwegian study results were somewhat inconclusive at seven years.
A Norwegian study of 2001 found no association with paternal age after adjustment for maternal age.