A new study shows for the first time on a large scale that gout does indeed run in families. The study, published recently online in the journal Annals of the Rheumatic Diseases, also shows gender differences in gout risk from the impact of genetic and environmental factors.

“The composition of risk is different in men and women, but both genders are at higher risk if they have family history [of the disease],” explains the study’s lead author Chang-Fu Kuo, a PhD candidate at the University of Nottingham in the United Kingdom and a practicing rheumatologist in Taiwan. “And genes determine part of the risk but environmental factors shared by families – like diet habits – determine much more.”

Gout is a type of inflammatory arthritis that results from high levels of uric acid in the blood, or hyperuricemia. This can result in needle-like urate crystals accumulating in and around joints. Gout attacks (flares) cause sudden, severe pain, swelling and tenderness, usually in one joint – typically the joint of the big toe, although it less frequently affects some other joint in the foot, ankle, knee, hand, wrist or elbow. In more advance disease, it can affect multiple joints and sometimes the soft tissue and tendons.

Dr. Kuo says gout has long been observed to cluster in families, but previous evidence for a family link came mostly from small case series or case reports, not population-based studies. So he and his team of researchers sought to confirm the familial connection on a larger scale.

His study, conducted in Taiwan, which has one of the highest estimated rates of gout in the world, relied on a health insurance database with information on nearly all residents of the country.

The researchers found that out of more than 22 million residents, approximately 1 million had physician-diagnosed gout.

Both men and women with a first-degree relative – a sibling, parent or offspring – with gout were nearly two times more likely than someone in the general population to develop the disease. Having a twin with gout raised a person’s risk eight-fold. This risk was what the researchers call “dose dependent,” meaning that with each additional first-degree relative with gout a person had, that person’s risk increased even more.

Men with a second-degree relative – a nephew, niece, uncle, aunt, grandparent or grandchild – with the condition were 1.25 times more likely than someone in the general population to develop gout, and women with a second-degree relative were 1.4 times more likely to develop it.

Part of this genetic risk is thought to be linked to genes that control “renal urate clearance” – the elimination of crystal-causing uric acid from the blood by the kidneys.