The association between serum uric acid and asymptomatic intracranial arterial stenosis in middle-aged Koreans.

BACKGROUND AND AIMS: Intracranial arterial stenosis (ICAS) is one of the most common causes of stroke, especially in Asians. Hyperuricemia has been associated with an increased risk of comorbidities such as metabolic syndrome or cardiovascular diseases. However, there are few studies focusing on the association between serum uric acid (SUA) levels and asymptomatic ICAS. The aim of this study was to explore the association between SUA and the prevalence of ICAS in middle-aged Korean health screening examinees. METHODS AND RESULTS: A cross-sectional study was performed on 9417 males and 7755 females who underwent a comprehensive health examination including transcranial Doppler (TCD) ultrasonography. The association of SUA and ICAS was analyzed using multivariate logistic regression. The prevalence of ICAS among the total examinee population was 3.55%. In females, the multivariate-adjusted odds ratio for ICAS was 1.52 (confidence interval 1.13-2.04) in the 3rd quartile of SUA and 1.45 (1.05-2.00) in the highest quartile, compared to the reference (P for trend 0.008). This trend was evident in all clinically relevant subgroups evaluated, including women with low inflammation status. SUA was not significantly associated with the prevalence of ICAS among males. In a sensitivity analysis, the multivariate-adjusted odds ratio of middle cerebral artery stenosis in females was 1.60 (1.09-2.37) in the highest quartile compared to the reference (P for trend 0.023). CONCLUSIONS: Higher SUA level was associated with increased risk of ICAS among middle-aged females but not males. A further cohort study is warranted to elucidate the effect of SUA on asymptomatic ICAS.

Prevalence of multiple sclerosis in Korea.

OBJECTIVE: The aim of this study was to estimate the prevalence of multiple sclerosis (MS) in Korea through a nationwide survey. METHODS: We estimated the prevalence of MS in Korea using several sources collected between 2000 and 2005: verified cases from 38 major referral hospitals across the nation, the National Health Insurance (NHI) payment request data from NHI Corporation of Korea, and the national mortality dataset from Statistics Korea. We established a network of neurologists from 38 major referral hospitals and performed a nationwide hospital survey for MS cases. The diagnoses of MS were validated according to the McDonald criteria. The diagnostic validity of each hospital was evaluated from hospital survey data to reduce the uncertainty of NHI data and was applied to estimate the prevalence using novel statistical methods. RESULTS: The estimated numbers of MS cases in Korea through 2 different statistical methods which adjust NHI data by the diagnostic validity of each hospital were very similar: 1,681 (95% confidence interval [CI] 1,490-1,902) by the stratification method and 1,640 (95% CI 1,402-1,789) by the linear regression method. The crude MS prevalence was 3.5-3.6 cases per 100,000 individuals. The estimated female-to-male ratio was 1.26. CONCLUSION: This study is the first nationwide survey for the prevalence of MS in Korea utilizing a national database in complementary way. We found an increase in the prevalence of MS that is consistent with reports from neighboring Asian countries.