Are the levels of uric acid associated with biometeorological conditions?

Association between uric acid and the risk of depressive symptoms in US adults: results from NHANES 2005-2018

BACKGROUND

This study explores the relationship between serum uric acid(UA) levels and depression. UA is the final product of purine metabolism in the human body, possessing certain physiological functions such as blood pressure regulation, antioxidation, DNA protection, and anti-aging, thereby drawing attention for its potential role in preventing and treating depression.

METHODS

This cross-sectional study includes 32,424 participants aged ≥ 20 years from the National Health and Nutrition Examination Survey (NHANES) conducted between 2005 and 2018, generating a nationally representative database. Depressive symptoms were assessed using the Patient Health Questionnaire-9. Serum uric acid concentration was measured using the uricase-peroxidase coupled method, and participants were divided into quartiles of serum uric acid concentration. Weighted data were calculated according to analysis guidelines. The association between serum uric acid and depressive symptoms was analyzed using weighted multivariable logistic regression models and restricted cubic spline regression analyses. Subgroup analyses were also performed.

RESULTS

Among 32,424 participants, 3,421 were defined as having depressive symptoms. The crude prevalence of depressive symptoms was 10.5% (weighted prevalence: 9.086% [95% confidence interval: 9.032-9.139%]). Compared with the first quartile, individuals with higher UA levels had a decreased risk of depressive symptoms by 9% (OR: 0.910, 95% CI: 0.797-10.40), 14.6% (OR: 0.854, 95% CI: 0.741-0.983), and 20.5% (OR: 7795, 95% CI: 0.680-0.930), respectively. Further restricted cubic spline regression analysis revealed a nonlinear association between UA and depressive symptoms, with an inflection point of 319.72 µmol/L. Subgroup multivariable weighted logistic regression analysis found that the association between UA and the risk of depressive symptoms remained consistent across all subgroups, demonstrating high stability and reliability.

CONCLUSION

This study emphasizes a significant nonlinear negative correlation between serum uric acid and depressive symptoms. This suggests that proper control of serum uric acid levels may play a role in preventing and treating depression.

Seasonal variations for newly prescribed urate-lowering drugs for asymptomatic hyperuricemia and gout in Japan

Background: Urate-lowering drugs (ULDs) have been approved for treatment of asymptomatic hyperuricemia and gout in Japan. Although serum urate levels and rates of gout onset are known to have seasonal variations, no survey results regarding the seasonality of ULD prescriptions for asymptomatic hyperuricemia and gout have been reported. Methods: A large-scale database of medical claims in Japan filed between January 2019 and December 2022 was accessed. In addition to total size of the recorded population for each month examined, the numbers of patients every month with newly prescribed ULDs for asymptomatic hyperuricemia and gout were noted, based on the International Classification of Diseases, 10th Revision, codes E79.0 and M10. Results: The results identified 201,008 patients with newly prescribed ULDs (median age 49.0 years, male 95.6%). Of those, 64.0% were prescribed ULDs for asymptomatic hyperuricemia and 36.0% for gout. The proportion of new ULD prescriptions was seasonal, with that significantly (p < 0.001) higher in summer (June-August) [risk ratio (RR) 1.322, 95% CI 1.218 to 1.436] and autumn (September-November) (RR 1.227, 95% CI 1.129-1.335) than in winter (December-February), whereas the proportion in spring (March-May) was not significantly different from winter. There was no significant difference after stratification by drug type (uric acid production inhibitor/uricosuric agent) or size of the medical institution, nor subgrouping by age or sex (p for interaction = 0.739, 0.727, 0.886, and 0.978, respectively). On the other hand, the proportions of new ULD prescriptions for asymptomatic hyperuricemia were significantly lower and for gout significantly higher in spring than winter, while those were similar in summer and autumn for both groups (p for interaction<0.001). Conclusion: The present findings indicate that new prescriptions for ULDs to treat asymptomatic hyperuricemia or gout in Japan show seasonal differences, with higher rates noted in summer and autumn as compared to winter.