Prevalence of High-Altitude Polycythemia and Hyperuricemia and Risk Factors for Hyperuricemia in High-Altitude Immigrants

Association between high-altitude polycythemia and hypertension: a cross-sectional study in adults at Tibetan ultrahigh altitudes

The study aimed to evaluate the association between high-altitude polycythemia and hypertension in adults residing on Anduo County's plateau, which is located 4700 meters above sea level. A total of 387 individuals participated in the cross-sectional survey conducted between April and May of 2021. Interviews, physical inspections, and laboratory tests were employed to gather information about all of the subjects. The association between high-altitude polycythemia and hypertension was assessed using multivariable logistic regression models. The average age of the 387 participants was 32.6 ± 6.3 years. Of these participants, 260 (67%) were male. The overall prevalence of hypertension was 27.1% (57/380). When stratified by gender, the prevalence was 12.6% (16/127) in females and 34.2% (89/260) in males. The overall prevalence of high-altitude polycythemia was 19.6% (76/387). When stratified by gender, the prevalence was 26.2% (68/260) in males and 6.3% (8/127) in females. During logistic regression analysis, we found that participants with elevated hemoglobin per 10 g/L had a 26% greater risk of hypertension (adjusting for odds ratio [OR], 1.26; 95% confidence interval [CI], 1.11-1.44). Additionally, high-altitude polycythemia greatly increased the risk of hypertension in comparison to non-high-altitude polycythemia (OR, 3.01; 95% CI, 1.66-5.44, P < 0.001). The consistency of the results was further demonstrated by stratified and interaction analyses, showing that Hans individuals had a higher risk of hypertension. High-altitude polycythemia is positively associated with hypertension in adults residing at Tibetan ultrahigh altitudes. The results of the investigation may aid in the planning of future research and guide the development of targeted healthcare practices for high-altitude populations, particularly among Han Chinese residents of the Tibetan Plateau.

Gender-specific association between blood cell parameters and hyperuricemia in high-altitude areas

Background

Hyperuricemia is a common metabolic disorder linked to various health conditions. Its prevalence varies among populations and genders, and high-altitude environments may contribute to its development. Understanding the connection between blood cell parameters and hyperuricemia in high-altitude areas can shed light on the underlying mechanisms. This study aimed to investigate the relationship between blood cell parameters and hyperuricemia in high-altitude areas, with a particular focus on gender differences.

Methods

We consecutively enrolled all eligible Tibetan participants aged 18-60 who were undergoing routine medical examinations at the People's Hospital of Chaya County between January and December 2022. During this period, demographic and laboratory data were collected to investigate the risk factors associated with hyperuricemia.

Results

Among the participants, 46.09% were diagnosed with hyperuricemia. In the male cohort, significant correlations were found between serum uric acid (SUA) levels and red blood cell (RBC) count, creatinine (Cr). Urea, alanine transaminase (ALT), and albumin (ALB). Notably, RBC exhibited the strongest association. Conversely, in the female cohort, elevated SUA levels were associated with factors such as white blood cell (WBC) count. Urea, ALT, and ALB, with WBC demonstrating the most significant association. Further analysis within the female group revealed a compelling relationship between SUA levels and specific white blood cell subtypes, particularly neutrophils (Neu).

Conclusion

This study revealed gender-specific associations between SUA levels and blood cell parameters in high-altitude areas. In males, RBC count may play a role in hyperuricemia, while in females, WBC count appears to be a significant factor. These findings contribute to our understanding of metabolic dynamics in high-altitude regions but require further research for comprehensive mechanistic insights.

Distinctive biochemistry profiles associated with hyperuricemia between Tibetans and Hans in China

Purpose

We sought to identify distinct risk factors for hyperuricemia in native Tibetan and immigrant Han populations in Tibet, China.

Methods

Three cohorts of male participants aged between 20 and 40 years were enrolled in this study. Biochemical parameters including serum uric acid (UA), fasting plasma glucose, insulin, lactate dehydrogenase (LDH), thyroxin, blood cell count, aminotransferase, and lipid profiles were analyzed. The association of risk factors with UA levels was evaluated using a multivariable line regression model. The effect of UA level on the biochemical parameters between the Hans and Tibetans was evaluated by two-way ANOVA.

Results

The prevalence of hyperuricemia (≥420 μmol/L) was 24.8% (62/250) in the Hans, similar to 23.8% (29/136) in the Tibetans. In the regression analysis, the risk factors that were significantly associated with UA in Hans did not apply to Tibetans. Tibetans had higher fasting insulin (P<0.05) and LDH (P<0.01) levels, in contrast with lower levels of triglycerides (P<0.05), total cholesterol (P<0.01), and low-density lipoprotein-cholesterol (P<0.01) than Hans in normal UA populations. Biochemistry analysis revealed lower albumin levels (P<0.001) and higher levels of all aminotransaminase and especially alkaline phosphatase (P<0.01) in Tibetans than in Hans in both populations. Compared with Hans, Tibetans had lower serum levels of urea, creatinine, and electrolytes in the normal UA population, which were further exacerbated in the high UA population. Tibetans had comparable white blood cell counts as Hans in both normal and high UA populations. In contrast, the red blood cell count and hemoglobin concentration were much lower in Tibetans than in Hans under high UA conditions.

Conclusions

The distinctive biochemistry between Tibetans and Hans may underlie the different etiologies of hyperuricemia in Tibet, China.