Inequalities in enrollment of women and racial minorities in trials testing uric acid lowering drugs

AIMS

We investigated sex and racial inequalities in clinical trials testing serum uric acid (SUA) lowering drugs and analyzed the temporal trends of participation among the pre-specified demographic groups. Data were collected from publications of clinical trials testing SUA-lowering drugs. Linear regression analysis was performed to assess the relation between drug approval year and proportion of women and minorities enrolled in clinical studies.

DATA SYNTHESIS

The mean percentage enrollment of women in clinical trials significantly decreased over the time (r = -0.43, P-value = 0.02). Moreover, there was a statistically significant difference in mean percentage enrollment of women among trials testing different SUA-lowering drugs, with the highest representation in rasburicase (71.1%) and the lowest representation of women in dotinurad (0.8%). Over the time, also the mean percentage enrollment of racial minorities decreased, passing from 8.7% to 2.2% in a 10-year period. Women were proportionally underrepresented compared with their share of the population with asymptomatic hyperuricemia, overall (participation-to-prevalence ratio (PPR) = 0.34), in trials testing xanthine oxiase inhibitors (PPR = 0.38) and uricosurics (PPR = 0.29), and in trials with febuxostat, allopurinol, pegloticase, halofenate/arhalofenate, verinurad, lesinurad and dotinurad. Women were proportionally underreppresented also compared with their share of the population with gout, overall (PPR = 0.69) and in trials testing XOIs (PPR = 0.69), uricosurics (PPR = 0.68), and all SUA-lowering drugs excepted for rasburicase, pegloticase and topiroxostat.

CONCLUSIONS

Our analysis shows that women and racial and ethnical minorities are underrepresented in controlled clinical trials testing SUA-lowering drugs, with similar pattern across drug classes.

Association of Empirical Dietary Atherogenic Indices with All-Cause and Cause-Specific Mortality in a Multi-Ethnic Adult Population of the United States

Serum uric acid (SUA) and apolipoprotein B (apoB) are markers of the risk of morbidity and mortality. However, no study has investigated their role, simultaneously with nutritional factors, on the risk of mortality. We calculated the dietary uricaemia score (DUS) and the dietary atherogenic score (DAS) and evaluated their associations with the risk of all-cause and cause-specific mortality. Data from the NHANES 1999-2010 study were used. Vital status through the 31 December 2011 was ascertained. Reduced rank regression models followed by stepwise linear regression analyses were applied on 39 macro/micronutrients to identify a dietary pattern most predictive of SUA (DUS) and apoB (DAS). Overall, 20,256 participants were included (mean age: 47.5 years; 48.7% men). DUS consists of 14 contributors (eight positive, six negative), whereas DAS consists of 23 contributors (six positive, 17 negative). An increasing risk of cause-specific mortality was found across the quartiles (Q) of DUS, i.e., participants with the highest score of DUS (Q4) had a greater risk of all-cause (hazard ratio (HR): 1.17, 95% confidence interval (CI): 1.07-1.30), cardiovascular disease (CVD) (HR: 1.36, 95%CI: 1.21-1.59) and cancer (HR: 1.06, 95%CI: 1.01-1.14) mortality compared with Q1. Similarly, participants at the highest DAS quartile had 25, 40 and 11% greater risk of all-cause, CVD and cancer mortality, respectively, compared with Q1. For the first time, we reported an underlying shared link between two atherosclerosis factors (SUA and apoB) and nutrients, as well as their joint adverse impact on all-cause and cause-specific mortality.

Metoprolol Increases Uric Acid and Risk of Gout in African Americans With Chronic Kidney Disease Attributed to Hypertension

BACKGROUND

There is little evidence guiding selection of nondiuretic, antihypertensive agents with a goal of lowering uric acid (SUA) and minimizing gout risk.

METHODS

In the African American Study of Kidney Disease and Hypertension (AASK) trial, African Americans with chronic kidney disease were randomly assigned to metoprolol (a beta-blocker), ramipril (an angiotensin-converting enzyme inhibitors [ACEi]), or amlodipine (a dihydropyridine calcium-channel blocker). SUA was measured at baseline and 12 months. Gout-related hospitalizations were based on ICD9 codes. Gout-related medication use (GRMs) was based on active prescriptions of allopurinol, colchicine, or probenecid during the baseline visit of the AASK cohort phase. We examined the effect of drug assignment on 12-month SUA (linear regression), gout-related hospitalization (Cox regression), and GRM (logistic regression).

RESULTS

Of the 630 participants, 40% were female with a mean age of 55 years (SD, 10), mean SUA of 8.2 mg/dl (2.0), and mean serum creatinine of 1.8 mg/dl (0.6). After 12 months, metoprolol increased SUA by 0.3 mg/dl, while ramipril or amlodipine had no effect on SUA. Compared to ramipril, metoprolol significantly increased 12-month SUA (0.40; 0.10, 0.70 mg/dl; P = 0.009), nonsignificantly increased risk of gout-related hospitalization (hazard ratio: 3.87; 0.82, 18.26; P = 0.09), and significantly increased the odds of GRM (odds ratio: 1.62; 1.03, 2.54; P = 0.04). While metoprolol was associated with a higher 12-month SUA compared with amlodipine (0.57; 0.18, 0.95; P = 0.004), there was no difference in gout-related hospitalizations or GRM.

CONCLUSIONS

Metoprolol increased SUA and GRM in African American adults. Health professionals treating patients with kidney disease at risk for gout should avoid metoprolol and possibly consider an ACEi.

CLINICAL TRIALS REGISTRATION

Trial Number NCT00582777.

The effects of urate lowering therapy on inflammation, endothelial function, and blood pressure (SURPHER) study design and rationale

BACKGROUND

The association between hyperuricemia and hypertension is controversial. Animal models, epidemiological data, and small clinical trials have favored a causative role for hyperuricemia in hypertension but more studies are necessary to elucidate putative mechanisms, population susceptibility, and potential for urate-lowering therapies (ULT) to decrease blood pressure (BP).

PURPOSE

To describe the background and design of the Serum Urate Reduction to Prevent Hypertension (SURPHER) study.

METHODS

SURPHER is a single center, double-blinded, crossover trial in which participants are randomly assigned to allopurinol (300mg) or placebo. Enrollment focused on adults 18-40years old with baseline systolic blood pressure≥120 and <160mmHg or diastolic blood pressure≥80 and <100mmHg, and serum urate ≥5.0mg/dL or ≥4.0mg/dL for men or women, respectively. SURPHER recruitment targets participants without chronic kidney disease (estimated glomerular filtration rate>60mL/min/1.73m2), and without prior diagnosis of gout or use of ULT to treat gout. The primary outcome is change from baseline in blood pressure assessed by 24hour ambulatory blood pressure monitoring and mechanistic outcomes include changes in endothelial function as measured by flow-mediated dilation, as well as C-reactive protein levels.

RESULTS

Since June 16, 2014 until present, SURPHER is recruiting participants in the city of Birmingham, Alabama.

LIMITATIONS

The study aims to enroll otherwise healthy young adults for a pharmacological intervention study with multiple study-related procedures. Challenges related to recruitment are anticipated and multiple strategies for increasing recruitment and retention are planned if necessary.

Prevalence of hyperuricemia among Beijing post-menopausal women in 10 years

OBJECTIVES

The objective of this study was to explore the trend and risk factors of the prevalence of hyperuricemia among post-menopausal women in Beijing over a ten years period.

METHOD

This research was based on two cross-sectional surveys in post-menopausal women in Beijing. A total of 1881 post-menopausal women were included. Subjects answered a questionnaire and underwent a physical examination and blood test. Serum uric acid >357 μmol/L was diagnosed as hyperuricemia, and another diagnosis criterion (serum uric acid >416 μmol/L) was applied in these women.

RESULTS

Serum uric acid levels and hyperuricemia prevalence increased remarkably in the 10-year period. The prevalence of hyperuricemia increased more than 2-fold after being adjusted by age. Multivariate logistic regression models revealed hyperuricemia associated with age, education level, urban residents, alcohol consumption, hypertension, obesity, and dyslipidemia. With the increasing number of traditional cardiovascular risk factors (including hypertension, obesity, diabetes, and dyslipidemia), the risk of hyperuricemia increased significantly, and the accumulative effect of the factors on the risk of hyperuricemia was determined.

CONCLUSION

The prevalence of hyperuricemia was high and exhibited a remarkable, increasing trend in Beijing community-based, post-menopausal women. Better management of relative factors could help to prevent further increases in the burden of hyperuricemia in post-menopausal women in this region.

[The prevalence of hyperuricemia in Xinjiang Kazaks in Fuhaii]

OBJECTIVE

to investigate the prevalence of hyperuricemia (HUA) in Kazak population in Fuhai county, Xinjiang Aletai area.

METHODS

A randomized cross-sectional cluster sampling was performed in Kazaks in Fuhai. A total of 2 006 inhabitants were investigated by household survey. The questionnaires were completed for general performance, past illness history and family history. Height, weight, body mass index (BMI) and blood pressure were measured and recorded. Fasting blood samples were collected for serum uric acid and other biochemical tests.

RESULTS

(1) Finally a total of 1 921 Kazaks were enrolled.The serum uric acid level in Kazaks in Fuhai was (234.11 ± 82.56) μmol/L, which was higher in males (287.48 ± 80.27) μmol/L than that in females (201.03 ± 64.74) μmol/L (P<0.001). In HUA group, serum uric acid level also had significant difference between men and women [(498.93 ± 130.24) μmol/L vs (471.20 ± 167.71) μmol/L; P = 0.044]. (2) the prevalence of HUA in Kazak general population was 2.97% (57/1 921). After standardization according to the natural population survey in 2000, the standardized rate in general group was 3.34%, in which the prevalence in males (4.76%, standardized rate was 4.64%) was higher than that in females (1.85%, standardized rate was 1.88%) (P<0.001). There was no gout found in 1 921 Kazaks in Fuhan when the study was taken. (3) Cohorts of different dietary habit ( who preferred vegetable or meat or both of them) who had drunk alcohol had higher prevalence of HUA than those with vegetarian diet without alcohol group (7.69%, 5.66% and 5.62% vs 0.78%; all P<0.05). The cohort who preferred animal food with alcohol had higher prevalence of HUA than those who preferred both vegetable and meat without alcohol (5.66% vs 5.62%; P = 0.009). (4) In men, those who had stable career, higher degree of education, regular income, had higher HUA prevalence than other cohorts. (5) people with HUA had higher plasma TC, TG, LDL, urea nitrogen and creatinine levels, higher blood pressure and higher BMI.

CONCLUSION

The prevalence of HUA was lower in Kazaks in Fuhai than that in other areas in China. Males were more susceptible to HUA. diet, occupation, educational background and economic status may partly affect the prevalence of HUA in Kazaks in Fuhai.

Association of Uric Acid With Vascular Stiffness in the Framingham Heart Study

BACKGROUND

Uric acid is associated with increased risk of cardiovascular disease and arterial stiffness in patients with hypertension or stroke. It remains unknown if uric acid is associated with arterial stiffness in the general population.

METHODS

We analyzed the association between serum uric acid levels and measures of arterial stiffness such as carotid-femoral pulse wave velocity (CF PWV), carotid-radial pulse wave velocity (CR PWV) and augmentation index (AI) in 4,140 participants from the Generation 3 Framingham cohort using linear regression.

RESULTS

Mean (SD) age was 40.0 (8.8) years and mean (SD) serum uric acid levels were 5.3 (1.5) mg/dl. Mean (SD) CF PWV was 7.0 (1.4) m/s. Individuals in the highest quartile of uric acid were more likely to be male, have a higher prevalence of hypertension, higher BMI, fasting glucose and insulin, and lower estimated glomerular filtration rate (eGFR). Multivariate adjusted means of CF PWV were 6.90, 6.94, 7.06, and 7.15 m/s for uric acid quartile 1, 2, 3, and 4 respectively. In unadjusted analysis each 1mg/dl increase in uric acid was associated with higher CF-PWV (β = 0.27; 95% CI = 0.25, 0.29; P < 0.0001). This was attenuated but remained significant after adjusting for age, sex, smoking, hypertension, BMI, fasting glucose, insulin, animal protein intake, and eGFR (β= 0.06; 95% CI = 0.02, 0.09; P < 0.0007). There was no association between serum uric acid levels and AI upon adjustment for cardiovascular risk factors.

CONCLUSIONS

Serum uric acid levels are significantly associated with CF PWV and CR PWV in a younger Caucasian population.

Association between serum uric acid levels and cardiovascular disease in middle-aged and elderly Chinese individuals

BACKGROUND

A link between uric acid (UA) levels and cardiovascular diseases has been previously reported. However, its importance as a risk factor is still controversial. This study sought to determine whether elevated serum uric acid levels are associated with cardiovascular disease (CVD) in middle-aged and elderly Chinese individuals.

METHODS

We conducted a population-based cross-sectional study in Shanghai, with a total of 8510 participants aged ≥40 years. The CVD included diagnosed coronary heart disease (CHD) and stroke. MetS was defined according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans.

RESULTS

Uric acid levels were positively associated with BMI, waist circumference, triglycerides, systolic blood pressure, diastolic blood pressure, glycohemoglobin, fasting plasma glucose, postprandial 2-hour plasma glucose (all P < 0.05), and negatively associated with HDL-cholesterol (P < 0.001). The prevalence of CVD significantly increased with increasing quartiles of UA in those without MetS group (p trend < 0.001), but not necessarily increased in those with MetS. After adjustment for metabolic syndrome and other cardiovascular risk factors, multivariate logistic regression analysis showed that odds ratios (OR) for CHD, stroke, and CVD in those in the fourth quartiles were 2.34 (95% confidence interval [CI] 1.73 to 3.45), 2.18 (95% CI 1.86 to 3.28), and 2.16 (95% CI 1.80 to 3.29), respectively, compared with those in the first quartile of UA.

CONCLUSIONS

Elevated serum uric acid level was associated with CVD, independent of conventional cardiovascular disease risk factors and metabolic syndrome.

Association between vitamin D insufficiency and elevated serum uric acid among middle-aged and elderly Chinese Han women

BACKGROUND

Association between vitamin D insufficiency and hyperuricemia has not been reported so far. We aimed to study the association of vitamin D insufficiency with elevated serum uric acid among middle-aged and elderly Chinese Han women.

METHODS

We collected data from participants residing in Jinchang district of Suzhou from January to May, 2010. Serum uric acid, 25-hydroxy vitamin D and other traditional biomarkers including fasting plasma glucose and blood lipids were determined in 1726 women aged above 30 years. Association between vitamin D insufficiency and elevated uric acid was analyzed in premenopausal and postmenopausal women, respectively.

RESULTS

Among postmenopausal women, 25-hydroxy vitamin D level of participants with elevated uric acid was lower than that of those with normal uric acid (median [interquartile range]: 35[28-57] vs 40[32-58], µg/L; P = 0.006). Elevated uric acid was more prevalent in participants with vitamin D insufficiency compared to those without vitamin D insufficiency (16.50% vs 8.08%; P<0.001). Association between vitamin D insufficiency and elevated uric acid was not significant among premenopausal women. However, participants with vitamin D insufficiency were more likely to have elevated uric acid compared with those without vitamin D insufficiency among postmenopausal women (OR, 95% CI: 2.38, 1.47-3.87). Moreover, after excluding individuals with diabetes and/or hypertension, the association of vitamin D insufficiency with elevated uric acid was still significant (OR, 95% CI: 2.48, 1.17-5.44).

CONCLUSIONS

Vitamin D insufficiency was significantly associated with elevated uric acid among postmenopausal Chinese Han women. This study suggested that a clinical trial should be conducted to confirm the association of vitamin D insufficiency with hyperuricemia.

Purine-rich foods, protein intake, and the prevalence of hyperuricemia: the Shanghai Men's Health Study

BACKGROUND AND AIMS

Diet may play an important role in the development of hyperuricemia and gout. However, the association between dietary factors and hyperuricemia remains unclear, and few studies have investigated direct links between food intake and hyperuricemia. The aim of this study was to investigate associations between high purine-content foods and protein intake with the prevalence of hyperuricemia by using data from a cross-sectional study of 3978 men aged 40-74 yrs living in Shanghai, China.

METHODS AND RESULTS

Hyperuricemia was defined as blood uric acid level >7.0 mg/dl. One quarter of this population had hyperuricemia. Dietary information was collected by using a food frequency questionnaire. We collected information on anthropometric measurements and lifestyle factors and other potential confounding factors and disease history via interviews. Total protein consumption was not associated with hyperuricemia. We found a positive association between protein from animal sources and prevalence of hyperuricemia and an inverse association between protein from plant sources and hyperuricemia. However, these associations failed to reach significance in mutually adjusted analysis. Seafood intake was associated with higher prevalence of hyperuricemia. The ORs for quintiles of seafood intake (including fish and shellfish) were 1.00, 1.49, 1.35, 1.34, and 1.56 (p for trend: 0.01). An inverse association approaching significance between soy food consumption and hyperuricemia was observed (ORs: 1.00, 0.90, 0.70, 0.89, and 0.77 for quintiles of intake; p for trend: 0.07). No associations between consumption of purine-rich vegetables or meat and prevalence of hyperuricemia were observed.

CONCLUSIONS

Our data suggest a direct association between seafood consumption and hyperuricemia and an inverse association between consumption of soy food and hyperuricemia among middle-aged, Chinese men.

[Epidemiological study on hyperuricemia and gout in Uygur population in Turpan area of Xinjiang]

OBJECTIVE

To study the prevalence of hyperuricemia (HUA) and gout in Uygur inhabitants in Turfan of Xinjiang.

METHODS

A random cluster sampling was conducted, and 3 982 Uygur inhabitants(1 745 males and 2 237 females) aged over 14 years were investigated for prevalence of HUA and gout in Turfan.

RESULTS

(1) The mean level of serum uric acid (SUA) was (284.33±88.81)μmol/L in normal Uygur males and (201.04±66.30)μmol/L in normal Uygur females in Turfan. (2) The prevalence of HUA was 3.97%(158/3 982),in which 6.36% (111/1 745) was with males and 2.10%(47/2 237) with females. The prevalence of gout was 0.025% (1/3 982),one gout patient was male, and the prevalence of gout in males was 0.06% (1/1 745).

CONCLUSION

The prevalence rates of HUA and gout among the Uygur population in Turfan of Xinjiang were lower than those in other districts in China.

Association among serum uric acid, cardiovascular risk, and arterial stiffness: a cross-sectional study in She ethnic minority group of Fujian Province in China

OBJECTIVES

To investigate the association between serum uric acid levels, cardiovascular risk, and arterial stiffness in She ethnic minority in South China's Fujian Province.

METHODS

5109 participants aged 20-79 yr were enrolled in analysis. Tpeak-Tend interval (Tp-e), QT interval, and height of the R wave in lead aVL (aVLR) were measured on 12-lead electrocardiogram (ECG), and Minnesota code-indicated major abnormal ECG MA-ECG was used as a risk indicator of cardiovascular disease. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV).

RESULTS

Longer Tp-e interval, greater Tp-e/QT ratio, and higher aVLR were observed in the highest quartile of uric acid level. The incidence of MA-ECG was gradually increased from lowest to highest quartile of serum uric acid in males (p for trend <0.01). After adjusting traditional cardiovascular risk factors, multivariate analysis revealed that the fourth quartile of serum uric acid level was independently associated with MA-ECG in males [odds ratios (OR) (95% confidence interval): 2.129 (1.376-3.295)] but not in females. Serum uric acid was also associated with abnormal baPWV, when adjusted for atherogenic confounders. Compared with the lowest serum uric acid quartile, the OR (95% confidence interval) of the second, third, and fourth quartile were 1.920 (1.246-2.957), 1.650 (1.064-2.558), and 2.501 (1.600-3.908) in males.

CONCLUSION

Among China's She ethnic minority, uric acid level was independently related to arterial stiffness assessed by baPWV in both genders. The evaluation of uric acid level was related to higher cardiovascular risk in males but not in females.

Relationship between dietary patterns and serum uric acid concentrations among ethnic Chinese adults in Taiwan

The evidence for a relationship between dietary patterns and uric acid concentrations is scanty. Here, we used a validated food frequency questionnaire for an ethnic Chinese population in Taiwan to investigate the relationship between dietary patterns and uric acid concentrations. A cross-sectional study on 266 adults, who were interviewed with a 38-item food frequency questionnaire, was conducted and serum uric acid levels were measured. Three dietary patterns were derived from the questionnaire by exploratory factor analysis. Participants in the higher vegetable and fruit pattern quartiles were more likely to have a lower uric acid concentration (6.5 for the first, 5.7 for the second, 6.0 for the third, and 6.0 mg/dL for the fourth quartile, p = 0.030). For uric acid-prone patterns, as the quartiles increased, the adjusted mean uric acid concentrations increased significantly (5.88, 5.93, 5.99 and 6.38 mg/dL for each quartile, respectively, p = 0.04). However, the significance level was attenuated after adjusting for additional confounding factors. In conclusion, three dietary patterns were identified for ethnic Chinese in Taiwan, and the relationship between these dietary patterns and uric acid was not significant after adjustment.

Factor analysis of diabetic nephropathy in Chinese patients

OBJECTIVE

To investigate factors related to albuminuria in diabetic nephropathy (DN).

METHODS

Clinical data of 873 Chinese patients with type 2 diabetes were gathered retrospectively. Urinary albumin-creatinine-ratio was tested thrice for each patient before calculating its mean value for DN diagnosing and staging. Inter-relationship among variables was studied using factor analysis, and factor scores were compared and used as independent variables in regression models to identify the parameter clusters that predict the development and/or progression of DN.

RESULTS

Factor analysis reduced 21 original variables to eight unique factors, representing obesity, glycemic, C peptide, lipids, time, renal, blood pressure and metabolism status. Logistic regression revealed that presence of hyperuricemia/gout (OR=1.821, 95%CI 1.224-2.707), time factor (OR=1.404, 95%CI 1.194-1.651) and blood pressure factor (OR=1.424, 95%CI 1.216-1.668) were positively associated with DN, while C peptide factor (OR=0.816, 95%CI 0.691-0.963) was negatively associated with DN. Ordinal regression revealed another positively related lipid factor (OR=1.237, 95%CI 1.060-1.445) besides those determined in Logistic regression.

CONCLUSION

Hyperuricemia/gout, time, blood pressure and lipid factors are predictors of DN, while C peptide factor is negatively associated with the development and/or progression of DN.

Serum uric acid and ambulatory blood pressure in children with primary hypertension

Hyperuricemia is associated with primary hypertension (HTN) in adults and children. Furthermore, uric acid levels during childhood are associated with blood pressure (BP) levels in adulthood. We measured 24-h ambulatory BP and serum uric acid (SUA) in 104 children referred for possible hypertension. Mean age was 13.7 +/- 2.6 y (range, 7-18 y) with 67 males and 37 females; 74 were African-American, 29 Caucasian and one Asian. SUA was associated with age (r = 0.38, p = 0.0001) and BMI Z-score (r = 0.23, p = 0.021). SUA was significantly associated with mean ambulatory systolic (S) and diastolic (D) BP. Mean ambulatory BP was normalized to gender- and height-specific reference standards using BP index. SUA was significantly associated with 24-h DBP index and nocturnal DBP index after adjusting for age, gender, race, BMI Z-score and urinary sodium excretion. SUA was also significantly associated with 24-h DBP load and nocturnal DBP load. Uric acid was significantly associated with increased likelihood for diastolic HTN (OR = 2.1, CI = 1.2, 3.7; p = 0.0063) after adjusting for other co-variables. Among children at risk for HTN, the likelihood for diastolic HTN (as defined by ambulatory blood pressure monitoring) increases significantly as SUA increases. SUA may be associated with increased severity of HTN during youth.

Biological risk factors relevant to chronic disease in three ethnic groups in Taiwan: results from Li-Shin Outreaching Neighborhood Screening (LIONS A1)

OBJECTIVES

Few population-based studies have compared risk factors related to chronic diseases across multiethnic groups of Chinese people. Consequently, we report the prevalence of common chronic disorders that make up the metabolic syndrome and compare their distribution in three ethnic subgroups: the offspring of Hakka, Minnan, and mainlander women.

METHODS

We included 6854 participants in the Li-Shin Outreaching Neighborhood Screening (LIONS) project: 3088 (45.1%) Hakkas, 2461 (35.9%) Minnans, and 1305 (19.0%) mainlanders. Information on demographic features and recognized lifestyle factors was collected by using questionnaires; data on biological markers of metabolic syndrome were collected from serum samples by using standard biochemical analyses.

RESULTS

Miscegenation averaged 22%. Smoking, alcohol consumption, and betel chewing varied across the three subpopulations. After controlling for demographic features and these three risk factors, men with mainlander mothers had more body fat. Compared with offspring with Hakka mothers, attendees whose mothers were from Minnan had higher uric acid concentrations.

CONCLUSIONS

Despite the rarity of racial miscegenation in the three ethnic groups, most biological markers of metabolic syndrome were identical across the groups. Disparities were found for hyperuricemia in attendees whose mothers were from Minnan and for obesity in men whose mothers were mainlanders. These findings can help design health policy for the early detection of chronic disease in different ethnic Chinese groups.

Childhood uric acid predicts adult blood pressure: the Bogalusa Heart Study

Uric acid has been proposed as an important risk factor in the development of primary hypertension in humans. However, limited information is available linking childhood uric acid levels and blood pressure levels in adulthood. This study examined 334 whites and 243 blacks enrolled in the Bogalusa Heart Study as children aged 5 to 17 years and as adults aged 18 to 35 years. The average follow-up period was 12 years. Childhood uric acid was significantly correlated with childhood and adult blood pressure, both systolic and diastolic. In a multivariate regression analysis, adjusting for age, sex, race, childhood body mass index, childhood uric acid levels, and change in levels of uric acid were significant predictors of adult diastolic blood pressure, whereas change in uric acid was a significant predictor of adult systolic blood pressures. In conclusion, elevated childhood serum uric acid levels are associated with increased blood pressure beginning in childhood and higher blood pressure levels that persist into adulthood, in males and females, whites and blacks, suggesting that early elevations in serum uric acid levels may play a key role in the development of human hypertension.

Independent association of uric acid levels with peripheral arterial disease in Taiwanese patients with Type 2 diabetes

AIMS

Hyperuricaemia may be a risk factor for atherosclerotic disease. Its association with peripheral arterial disease (PAD) has not been studied in Taiwanese patients with Type 2 diabetes.

METHODS

Uric acid (UA) levels and PAD were evaluated in 508 Taiwanese outpatients with Type 2 diabetes (210 men, 298 women; mean age +/- sd, 63.8 +/- 10.6 years). PAD was diagnosed when the ankle-brachial index was < 0.9. Patients with an ankle-brachial index of > or = 1.3 were excluded because of possible medial arterial calcification. Potential confounding variables with P < 0.10 were adjusted for in multivariate analyses.

RESULTS

In univariate analyses, UA levels were higher in patients with PAD than in those without PAD (345.0 +/- 95.2 vs. 309.3 +/- 89.2 micromol/l; P < 0.0005). Prevalences of PAD for quintiles of UA levels were 6.8, 8.9, 10.2, 13.1 and 16.5%, respectively (P-trend < 0.05). With UA level as a continuous variable, the multivariate-adjusted odds ratio (95% confidence interval) for PAD was 1.005 (1.001-1.008) (P < 0.01). The optimal cut-off point for UA as determined by the receiver operating characteristic curve was 264.7 micromol/l. The sensitivity and specificity at this cut-off point was 82.6 and 33.3%, respectively. The area under curve was 0.60 (95% confidence interval: 0.53-0.68). The multivariate-adjusted odds ratio for PAD for UA above this level was 2.736 (1.239-6.043) (P < 0.05). The results after excluding 56 cases using diuretics were similar.

CONCLUSIONS

Elevated uric acid level is a significant and independent risk factor for PAD in Taiwanese patients with Type 2 diabetes.

Complex segregation and linkage analysis of familial gout in Taiwanese aborigines

OBJECTIVE

The prevalence of gout and hyperuricemia in Taiwanese aborigines is remarkably high. Although previous studies have failed to find evidence of a major gene responsible for gout, the disease is thought to involve genetic predisposition. We sought to determine whether genetic factors for familial gout exist among Taiwanese aborigines, and, if so, their chromosomal location.

METHODS

We first performed complex segregation analysis. The study sample comprised 945 relatives distributed in 64 pedigrees; among them, 261 affected members (including probands) were found. In all of the aboriginal probands with gout, the disease was diagnosed and confirmed by rheumatologists. Blood specimens were then collected from 127 individuals living in one community that was used in the segregation analysis (from 25 pedigrees, 36 nuclear families, and 112 full sibpairs), and sibpair linkage analysis and a combined transmission disequilibrium test (TDT) method were used to test the genetic components.

RESULTS

In segregation analysis, after adjusting for sex and age, an autosomal-arbitrary major gene model was found to fit the data best, with disease allelic frequency of 0.31 and susceptibility of 0.92. In sibpair analysis, there was a clustering of many flanking markers showing significant linkage, including D1S498 (regression coefficient -0.52), D1S2635 (regression coefficient -0.47), and D1S196 (regression coefficient -0.51), in the 1q21 region of chromosome 1 (all P < 0.005). Results of the combined TDT showed that the marker D1S484 was significantly associated (had linkage) with allele 1 and was transmitted more frequently than other markers to the affected offspring (P < 0.005).

CONCLUSION

Results of this study provide evidence of a genetic basis for familial gout in the aboriginal Taiwanese population and suggest that a susceptibility locus may be located in the 1q21 region of chromosome 1.

The epidemiology of hyperuricemia in children of Taiwan aborigines

OBJECTIVE

To explore the factors influencing serum uric acid concentrations and the prevalence of hyperuricemia in aboriginal children from an area in Taiwan with a high prevalence of gouty arthritis.

METHODS

A cross sectional study of the Bunun tribe was conducted in central Taiwan from March to May 2001. Children aged 4-13 were requested to fill out a structured questionnaire with the assistance of their parents. A total of 414 children (mean age, 8.9 +/- 2.1 yrs) were recruited. Uric acid was determined by colorimetry using the uricase method. Since no previous study has investigated serum uric acid concentrations in these aboriginal children, hyperuricemia was defined as uric acid > 416.5 micromol/l (7 mg/dl) in boys and > 357 micromol/l (6 mg/dl) in girls.

RESULTS

The mean concentration of serum uric acid was 368.9 +/- 83.3 micro mol/l. Ninety of 224 girls (40.2%) and 56 of 190 boys (29.5%) were hyperuricemic. Children with hyperuricemia had significantly higher body mass index (BMI), blood pressure, and triglyceride and creatinine concentrations than those with normal uric acid concentrations. After adjustment for age, sex, lipid profile, and blood pressure, hyperuricemia was found to be significantly associated with serum creatinine (OR 2.40, 95% CI 1.91-3.04), BMI (OR 1.24, 95% CI 1.11-1.40), and a family history of gouty arthritis in parents (OR 2.01, 95% CI 1.02-3.96).

CONCLUSION

BMI, a positive family history of gouty arthritis in parents, and creatinine level correlated with hyperuricemia in aboriginal children in Taiwan.