Using human genetics to understand the epidemiological association between obesity, serum urate, and gout

Risk of Sudden Sensorineural Hearing Loss in Patients with Gout: A Population-Level Study in a South Korean National Health Screening Cohort

Background: Gout, characterized by serum uric acid accumulation, prompts inflammation, leading to tissue damage and comorbidities. Prior studies reported a higher risk of hearing loss in gout patients; however, the specific risk of sudden sensorineural hearing loss (SSNHL) remains unclear. Method: This population-based study assessed SSNHL incidence and risk in patients aged ≥ 40 years with or without gout, excluding those with prior SSNHL, within the Korean National Health Insurance Service Health Screening Cohort (2002-2019). A total of 24,508 gout patients were matched 1:4 with 98,032 controls by age, sex, income, and region. SSNHL incidence was compared, and Kaplan-Meier curves with log-rank tests evaluated cumulative incidence over 200 months. Hazard ratios (HRs) were calculated using stratified Cox models adjusted for patient characteristics. Results: SSNHL incidence was slightly higher in the gout cohort vs. controls (1.70% vs. 1.96%, SD = 0.02). Kaplan-Meier analysis revealed significantly higher cumulative SSNHL incidence in gout patients (p = 0.009). Patients with gout had a significantly higher risk of developing SSNHL in both the unadjusted (HR [95% CI]: 1.14 [1.03-1.27]; p = 0.010) and adjusted Cox models (1.13 [1.02-1.26]; p = 0.021). Subgroup analyses indicated higher risk in gout patients aged <60 years, males, non-smokers, non-drinkers, moderately-high income, normal BMI, Charlson Comorbidity Index score of 0, or fasting blood glucose < 100 mg/dL (all p < 0.05). Conclusions: Korean adults with gout, particularly younger, healthier patients, face increased SSNHL risk. Early, effective gout management may help mitigate this risk.

Mendelian randomization reveals the causal association between gout and hearing impairment in older adults

With the global aging trend escalating, the holistic well-being of the elderly has become a paramount concern within public health. Traditional observational studies often struggle with confounding factors and establishing causality, leaving the relationship between age-related hearing loss (ARHL) and gout largely unexplored. Employing bidirectional two-sample Mendelian randomization (MR) analysis, this investigation elucidated the genetic underpinnings associated with age-related hearing impairment, gout, and urate levels within the IEU Open-GWAS database, thereby uncovering potential causal connections that underlie the intricate interplay between gout, serum urate concentrations, and auditory decline in the geriatric demographic. In the forward MR phase, a cohort of 30 single nucleotide polymorphisms was leveraged to dissect the causal dynamics between ARHL and both gout and urate concentrations. Conversely, in the reverse MR phase, gout and urate levels were posited as the exposome to delineate their impact on hearing acuity, employing an array of models for rigorous validation and sensitivity scrutiny. In the forward MR analysis, a statistically significant correlation was discerned between ARHL and gout (P = .003, odds ratio = 1.01, 95% confidence interval: 1.00-1.02), alongside a notable association with serum urate levels (P = .031, odds ratio = 1.39, 95% confidence interval: 1.03-1.88), intimating that ARHL could potentially influence the incidence of gout and urate concentrations. Conversely, the reverse MR investigation revealed that neither gout nor serum urate levels exerted significant impact on auditory degradation (P > .05), insinuating that these factors might not predominantly contribute to hearing loss. Sensitivity analyses concurred with this inference. This study enriches the comprehension of geriatric health intricacies and unveils that ARHL potentially influences gout and serum urate concentrations. This suggests that monitoring ARHL may play a crucial role in the early identification and management of gout and hyperuricemia, potentially contributing to a comprehensive approach to improving geriatric health outcomes.

Exploring the causal associations of micronutrients on urate levels and the risk of gout: A Mendelian randomization study

BACKGROUND & AIMS

Growing evidence has indicated a potential association between micronutrient levels, urate levels, and the risk of gout. However, the causal association underlying these associations still remains uncertain. Previous observational studies and randomized controlled trials investigating the association between micronutrients, urate levels, and the risk of gout have been limited in their scope and depth. The aim of this study was to utilize Mendelian randomization (MR) to investigate the causal associations between genetically predicted micronutrient levels, urate levels, and the risk of gout.

METHODS

In this study, we conducted a comprehensive examination of 10 specific micronutrients (vitamin B6, vitamin B12, vitamin C, vitamin D, folate, calcium, iron, copper, zinc, and selenium) as potential exposures. Two-sample MR analyses were performed to explore their causal associations with urate levels and the risk of gout. In these analyses, gout data were collected from the Global Biobank Meta-Analysis Initiative (N = 1,069,839, N cases = 30,549) and urate levels data from CKDGen Consortium (N = 288,649) by utilizing publicly available summary statistics from independent cohorts of European ancestry. We performed inverse-variance weighted MR analyses as main analyses, along with a range of sensitivity analyses, such as MR-Egger, weighted median, simple mode, weighted mode, Steiger filtering, MR-PRESSO, and Radial MR analysis, to ensure the robustness of our findings.

RESULTS

The results of our study indicate that there were negative associations between serum vitamin B12 and urate levels, as well as serum folate and the risk of gout. Specifically, we found a negative association between vitamin B12 levels and urate levels, with a β coefficient of -0.324 (95% CI -0.0581 to -0.0066, P = 0.0137) per one standard deviation (SD) increase. Similarly, a negative association was observed between folate levels and gout risk, with an odds ratio of 0.8044 (95% CI 0.6637 to 0.9750, P = 0.0265) per one SD increase. On the other hand, we identified positive associations between serum calcium levels and both urate levels and the risk of gout. Specifically, there was a positive association between serum calcium levels and urate levels (β coefficient: 0.0994, 95% CI 0.0519 to 0.1468, P = 4.11E-05) per one SD increase. Furthermore, a positive association was found between serum calcium levels and the risk of gout, with an odds ratio of 1.1479 (95% CI 1.0460 to 1.2598, P = 0.0036) per one SD increase. These findings were robust in extensive sensitivity analyses. By employing MR-PRESSO and Radial MR to eliminate outliers, the observed associations have been reinforced. No clear associations were found between the other micronutrients and the urate levels, as well as the risk of gout.

CONCLUSION

Our findings provided evidence that there were negative associations between serum vitamin B12 and urate levels, as well as serum folate and the risk of gout, while positive associations existed between the serum calcium levels and urate levels, as well as the risk of gout.