Cluster headache causes extreme pain, but its origins remain unclear. New research links the disorder to genetics, inflammation, and tobacco smoke exposure. Unlike an ordinary headache, a cluster attack typically erupts without warning and causes excruciating pain around one eye. Episodes can last from 15 minutes to three hours and often return at similar times [...]

A kidney test result that appears perfectly normal may still reveal hidden danger, according to a major new study involving more than a million adults. Even small differences in kidney function, including values that still fall within the normal range, may reveal who is at greater risk of developing chronic kidney disease. That is the [...]