Serum Uric Acid Levels Tied to Hip Fracture Risks in Older People

By David Douglas

April 19, 2021

NEW YORK (Reuters Health) - Increased levels of uric acid may signal a higher risk of hip fracture, according to a large population-based cohort study by researchers in Europe.

"Our results suggest that uric acid could be useful as an easily measurable blood serum marker for long-term risk of osteoporotic hip fractures, particularly in men," Dr. Wolfgang Brozek of the Agency for Preventive and Social Medicine, in Bregenz, Austria, told Reuters Health by email.

Moreover, he added, "The association between elevated serum uric acid and increased hip fracture risk was notably independent of renal and malignant disease."

In a paper in Maturitas, Dr. Brozek and colleagues note that previous findings have been somewhat conflicting. While increased serum uric acid (SUA) levels have been tied to higher bone-mineral density (BMD) and reduced risk of incident fractures at various skeletal sites in both sexes, the association with hip fractures has been "inconsistent."

To investigate further, the researchers examined data obtained during a free voluntary health monitoring and promotion program covering 1985 to 2005. This was conducted in the Austrian province of Vorarlberg and involved about 185,000 people, around two-thirds of the population.

After collecting baseline data, the team followed more than 42,000 women and close to 36,000 men aged 50 years or more for the occurrence of hip fractures between 2003 and 2013. Information on cancer and end-stage kidney disease was obtained from local registries. Follow-up for women lasted a median of 18.9 years and for men, 17.5 years.

In women, higher SUA levels were associated with a moderate increase in hip fracture risk. In a fully adjusted regression model, risk rose by a significant 6% for every unit increase in SUA.

There was also a significantly increased risk in the highest versus the lowest quartile (hazard ratio, 1.17). However, this was not the case for hyperuricemic versus normouricemic levels. An additional analysis excluding all women with known end-stage kidney disease gave almost identical results.

In men, however, an increase in SUA levels was associated with a greater rise in the risk of hip fractures than in women. After adjustment there was a significant 15% increase in risk for every unit of SUA increase.

Hip fracture risk in the highest quartile was 50% higher than in the lowest (HR, 1.50). Results after exclusion of patients with end-stage kidney disease were similar.

Among other covariates, say the researchers, "diabetes and current smoking were positively, and cholesterol and BMI inversely associated with risk for hip fractures in women and men alike."

"Collectively," the team concludes, "we have demonstrated that high levels of serum uric acid and hyperuricemia are associated with increased risk of hip fractures occurring after the age of 50 years."

They add, "It remains to be clarified by which mechanisms bone is affected by uric acid."

SOURCE: Maturitas, online March 8, 2021.