Effect of sauna bathing and beer ingestion on plasma concentrations of purine bases

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.

Review Article: URIC ACID HOMEOSTASIS AND DISTURBANCES

This review examined the homeostasis of uric acid in human body and analyzed recent studies of the affecting major variables. Normal uric acid concentration in male is 3.5-7.2 mg/dL and in female is 2.6-6 mg/dL. Daily turnover of normal uric acid ranges from 498-1392 mg/day, miscible pool is 767-1650 mg, reabsorption is 8064 mg/day, renal excretion is 262-620 mg/day and intestine 186-313 mg/day. The dynamics of uric acid is influenced by factors of food, drink, age, history of disease, and genetic. High purine dietary consumption increases blood uric acid by 1-2 mg/dL, 213-290 g/day fructose drinks increases 0.52-1.7 mg/dL, 1.5 g/kgBW sucrose increases 0.61 mg/dL, and 10-20 ml/kgBW beer increases 0.50-0.92 mg/dL. The ABCG2 gene plays a role in bringing uric acid out of the body by 114.31-162.73 mg/dL, SLC2A9 of 5.43-20.17 mg/dL, and SLC22A12 of 5.77-6.71 mg/dL. The data described the homeostasis of uric acid and the magnitude of the impact of environmental (consumption of food, beverages, and lifestyle) and genetic factors. Understanding uric acid homeostasis and its disturbances is important in managing diseases as a consequence of hyperuricemia and hypouryscemia

Nonpharmacological Management of Gout and Hyperuricemia: Hints for Better Lifestyle

We reviewed lifestyle factors that influence serum uric acid levels and risk of gout flare, and how to improve their deleterious effects. Since obesity increases uric acid and weight gain increases gout risk, weight reduction by daily exercise and limiting intake of excess calories is recommended. However, strenuous exercise, which causes adenine nucleotide degradation; starvation, which decreases uric acid excretion; and dehydration may raise the level of uric acid in serum and trigger gout. Increased intake of purine-rich foods, such as meat and seafood, raise the level of uric acid in serum and is associated with increased risk of gout, whereas dairy products, especially low-fat types, are associated with a lower risk of gout. Also, heavy alcohol drinking raises the uric acid level and increases the risk of gout through adenine nucleotide degradation and lactate production. Sweet fruits and soft drinks containing fructose should be moderated, since fructose may raise uric acid and increase gout risk through uric acid production and/or decreased excretion. On the other hand, the Mediterranean diet is recommended for gout patients, since it may also help prevent hyperuricemia. Furthermore, coffee and vitamin C supplementation could be considered as preventive measures, as those can lower serum uric acid levels as well as the risk of gout.

Serum markers of chronic dehydration are associated with saliva spinability

Findings of a relationship between saliva and dehydration have been observed, but the precise nature of these relationships is unclear and no evidence of a direct link has been found. In particular, no study reports a relationship between chronic dehydration and saliva conditions in community-dwelling older adults. This study aimed to identify whether salivary conditions are sensitive to body hydration markers in an elderly population. A total of 403 subjects aged 76 years participated in the study. Stimulated saliva flow rate and spinability of saliva were measured. In addition, determinations of serum levels of uric acid, blood urea nitrogen (BUN), creatinine, sodium and potassium were made. Dehydration was defined as uric acid >/= 7 mg dL(-1) according to the standard value. The salivary spinability were significantly associated with the concentration of uric acid (OR=2.06, P=0.044) according to multiple logistic regression analysis. In addition, after adjusting for gender, the uric acid concentration and the salivary spinability was significantly associated with BUN, potassium and creatinine levels. The subjects with high uric acid levels (>/= 7 mg dL(-1)) had the most elastic saliva. Both BUN and serum creatinine are the most commonly used indicators of renal function. Therefore, our findings might demonstrate that older adults who are dehydrated showed highly elastic saliva, which was associated with renal function. In conclusion, this study suggests that there is a significant relationship between chronic dehydration status and salivary spinability level.

Effect of ethanol on metabolism of purine bases (hypoxanthine, xanthine, and uric acid)

There are many factors that contribute to hyperuricemia, including obesity, insulin resistance, alcohol consumption, diuretic use, hypertension, renal insufficiency, genetic makeup, etc. Of these, alcohol (ethanol) is the most important. Ethanol enhances adenine nucleotide degradation and increases lactic acid level in blood, leading to hyperuricemia. In beer, purines also contribute to an increase in plasma uric acid. Although rare, dehydration and ketoacidosis (due to ethanol ingestion) are associated with the ethanol-induced increase in serum uric acid levels. Ethanol also increases the plasma concentrations and urinary excretion of hypoxanthine and xanthine via the acceleration of adenine nucleotide degradation and a possible weak inhibition of xanthine dehydrogenase activity. Since many factors such as the ALDH2*1 gene and ADH2*2 gene, daily drinking habits, exercise, and dehydration enhance the increase in plasma concentration of uric acid induced by ethanol, it is important to pay attention to these factors, as well as ingested ethanol volume, type of alcoholic beverage, and the administration of anti-hyperuricemic agents, to prevent and treat ethanol-induced hyperuricemia.