For centuries the painful condition of gout has been associated with a rich diet but a new study that suggests genetics may be more to blame could help shatter long-held misconceptions, say researchers.
Research, published in the British Medical Journal, suggests genes are more important than food and drink when it comes to the development of high blood urate levels, which often precede gout.
“Our results challenge widely held community perceptions that hyperuricaemia is primarily caused by diet”
The findings challenge the commonly held belief that gout – which mainly affects men aged 40 and over – is caused by diet and may go some way to reducing stigma that can prevent sufferers from seeking help, say experts.
Gout is caused by excess uric acid in the blood – known as hyperuricaemia – which forms into crystals that collect around the joints, causing extreme pain and swelling.
Recent studies indicate consuming certain food and drinks may increase the risk of developing the condition, while others such as fruit, vegetables and coffee can help reduce the risk of gout.
Studies also suggest genetic factors play an important role so a team of researchers based in New Zealand set out look at how both diet and genes might influence the development of gout.
They analysed dietary surveys completed by 8,414 men and 8,346 women from five US studies. Blood urate levels and genetic profiles were also recorded for participants.
“The study provides important evidence that much of patients’ predisposition to hyperuricaemia and gout is non-modifiable”
Lorraine Watson and Edward Roddy
When the research team looked at people’s diets they identified seven items associated with raised blood urate levels such as meat, alcohol and sugary soft drinks and eight linked with reduced urate levels, including egg, skimmed milk and brown bread.
However, they found each of these foods explained less than 1% of variation in urate levels.
When people’s diets were given an overall score, a healthier diet was linked to lower urate levels while those with a diet crammed with unhealthy foods were more likely to have higher urate levels.
But again, the researchers found the diet scores explained very little – 0.3% – of variation.
In contrast, genetic analysis revealed that common genetic factors explained almost a quarter – 23.9% – of variation in urate levels.
The fact the study only looked at people from a European background who did not actually have gout may mean the findings do not apply to other populations or those with gout, the researchers warned.
Nevertheless they said their findings were important when it came to demonstrating the relative contribution of diet and inherited genetic factors to hyperuricaemia.
“Our results challenge widely held community perceptions that hyperuricaemia is primarily caused by diet, showing for the first time that genetic variants have a much greater contribution to hyperuricaemia than dietary exposure,” the paper said.
The Gout by James Gillray
In a linked editorial in the BMJ, researchers at Keele University highlighted the stigma faced by gout sufferers who are often made to feel the condition is basically their fault by clinicians and others.
“People with gout often experience stigma from the societal misconception that gout is a condition caused by dietary habits and an unhealthy lifestyle, a view which is also pervasive among healthcare professionals,” said research fellow Lorraine Watson and reader Edward Roddy from the university.
“As a result, patients known to have gout are often reluctant to seek help for fear that they will not be taken seriously or will be blamed for their lifestyle habits, meaning that practitioners are often unaware that patients have troublesome symptoms,” they said.
When patients develop gout, they are frequently given inaccurate or conflicting information “which trivialises gout and misrepresents its causes and treatment” with opportunities to start treatment missed, they added.
They pair the new study could help bust myths and ensure people received appropriate advice and care.
“The study provides important evidence that much of patients’ predisposition to hyperuricaemia and gout is non-modifiable, countering these harmful but well established views and practices and providing an opportunity to address these serious barriers to reducing the burden of this common and easily treatable condition,” they concluded.