Educational inequalities in all-cause and cause-specific mortality among people with gout: a register-based matched cohort study in southern Sweden

The relationship between education attainment and gout, and the mediating role of modifiable risk factors: a Mendelian randomization study

Objective

To investigate the causal relationship between educational attainment (EA) and gout, as well as the potential mediating effects of individual physical status (IPS) such as body mass index (BMI) and systolic blood pressure (SBP) and lifestyle habits (LH) including alcohol intake frequency (drinking), current tobacco smoking (smoking), and time spent watching television (TV).

Methods

Utilizing two-sample Mendelian randomization (MR), we analyzed the causal effects of EA on gout risk, and of IPS (BMI and SBP) and LH (smoking, drinking, and TV time) on gout risk. Multivariable MR (MVMR) was employed to explore and quantify the mediating effects of IPS and LH on the causal relationship between EA and gout risk.

Results

An elevation of educational attainment by one standard deviation (4.2 years) exhibited a protective effect against gout (odds ratio 0.724, 95% confidence interval 0.552-0.950; p = 0.020). We did not observe a causal relationship between smoking and gout, but BMI, SBP, drinking, and TV time were found to be causal risk factors for gout. Moreover, BMI, SBP, drinking, and TV time acted as mediating factors in the causal relationship between EA and gout risk, explaining 27.17, 14.83, 51.33, and 1.10% of the causal effects, respectively.

Conclusion

Our study indicates that having a genetically predicted higher level of EA may provide protection against gout. We found that this relationship is influenced by IPS factors such as BMI and SBP, as well as LH including drinking and TV time.

Association between vegetarian diet and gouty arthritis: A retrospective cohort study

BACKGROUND AND AIMS

A vegetarian diet is rich in vegetables, fruits, and soy products. Although vegetarian diet is beneficial for improving the health outcomes such as body mass index, metabolic syndrome, cardiovascular disease, and mortality rate, the association between a vegetarian diet and gout incidence is not well known.

METHODS AND RESULTS

We linked the MJ Health Survey Data and MJ Biodata 2000 with the National Health Insurance Research Database (NHIRD) and the National Registration of Death (2000-2018). Information on the diet was collected from the MJ Health Survey Data, and the incidence of gouty arthritis was confirmed using the NHIRD. The Kaplan-Meier survival curve and log-rank test were used to compare the differences between vegetarian and non-vegetarian participants. Cox regression models were used to estimate the risk of the incidence of gouty arthritis. Among 76,972 participants, 37,297 (48.46%) were men, 2488 (3.23%) were vegetarians and the mean age was 41.65 ± 14.13 years. The mean baseline uric acid level was 6.14 ± 1.65 mg/dL. A total of 16,897 participants developed gouty arthritis, including 16,447 (22.08%) non-vegetarians and 450 (18.9%) vegetarians over a mean follow-up of 19 years. Significant differences were observed in the Kaplan-Meier survival curves between vegetarians and non-vegetarians (log-rank p < 0.001). Vegetarians had a significantly decreased incidence of gouty arthritis compared with non-vegetarians (hazard ratio = 0.87, 95% confidence interval = 0.78-0.98, p = 0.02) after adjusting for potential confounders.

CONCLUSION

People with a vegetarian diet had a significantly decreased risk of developing gouty arthritis compared with non-vegetarians in Taiwan.

Incident Gout: Risk of Death and Cause-Specific Mortality in Western Sweden: A Prospective, Controlled Inception Cohort Study

Background

Excess mortality in gout has been attributed to cardiovascular diseases (CVD). Considering the decline in CVD mortality in the general population, we wanted to evaluate overall mortality in gout and cause-specific contributions to mortality beyond CVD and temporal trends.

Methods

All incident cases of gout between 2006 and 2015 in western Sweden and 5 population controls per case matched for age, sex, and county were identified. Comorbidities were identified for 5 years preceding the index date. Follow-up ended at death, migration, or end of study on December 2017. Effect of gout on death risk was calculated using COX regression on the whole population and stratified by sex, adjusted for demographics, and comorbidities. Death incidence rates were compared between the two time periods, 2006-2010 and 2011-2015.

Results

We identified 22,055 cases of incident gout and 98,946 controls, median age (Q1, Q3) 69-68 (57, 79/56, 78) years and 67.6-66.5% males. Except for dementia, all comorbidities were significantly more common at baseline among gout cases. Overall, the risk for death in incident gout was neither increased overall nor in men, but women had a 10% elevated risk. In adjusted models for cause-specific mortality, death from CVD, renal disease, and digestive system diseases were significantly increased in the total gout population while death from dementia, cancer, and lung diseases were significantly decreased. There were no significant differences in overall incident death rate ratios between cases and controls in the two time periods examined.

Conclusions

An increased risk for CVD, renal disease, and diseases of the digestive system in patients with gout highlights the importance of addressing CVD risk factors in gout management. Gout was associated with reduced mortality from dementia, which may have implications on urate lowering therapy and possible effects on dementia risk.