Frontiers in Public Health · Oct 28, 2026
A cross-sectional study of routine hematological and biochemical parameters with age- and sex-specific analyses in mid-to-high-altitude regions of southwestern China
By Li J, Ji Y, Zhuang S et al.
Background: Complete blood count (CBC) and biochemical parameters (liver function, renal function, Blood glucose, and lipid profile) are the most routinely used tests in clinical laboratory practice, and serve as critical evidence for disease diagnosis. This study aimed to characterize the distribution patterns of age- and sex-related differences in CBC and biochemical indicators, identify the age-related inflection points of these indicators, and analyze their correlation patterns across different sexes and age groups. Methods: A total of 83,945 individuals physical examination in mid-to-high-altitude areas of Yuxi City, southwestern China (1,500–1,800 m above sea level), were enrolled in this study. All subjects were stratified into seven age groups by sex. Age trend inflection plots, correlation analysis, and mediation models were applied to explore indicator trajectories, inter-association patterns, and the mediating role of triglyceride (TG) in the age–uric acid (UA) relationship. Results: After FDR correction, most hematological and biochemical parameters remained statistically significant in sex comparisons within each age group. For indicators with an absolute relative median difference |RMD| > 10%, total bilirubin (TBIL), direct bilirubin (DBIL), alanine aminotransferase (ALT), creatinine (CREA), and uric acid (UA) consistently exhibited clinically meaningful sex differences across all age groups. Most included CBC and biochemical indicators included in this study showed generally synchronous age trend in both male and female populations, the age inflection points were also generally concordant between sexes. However, four indicators alkaline phosphatase (ALP), globulin (GLB), triglyceride (TG), and uric acid (UA) showed pronounced sexual dimorphism in their age-dependent trajectories. The CBC indicators showed that the levels of red blood cell count (RBC), hemoglobin (Hb), and hematocrit (HCT) were higher in males from 18–25 to 56–65 years, but females surpassed males by the 66–75 years group. Sex-stratified correlation analysis revealed that in young males (18–25 years), lipid metabolism indicators had the strongest correlations with liver enzymes and liver enzyme ratios, with correlation coefficients ranging from 0.31 to 0.39; these correlations gradually attenuated with advancing age. In females, only transient moderate correlations of UA with TG and VLDL emerged during the perimenopausal period (36–45 years). After Bonferroni correction, all variable pairs with |r| > 0.3 remained statistically significant across all age groups in females, whereas some variable pairs in males failed to reach statistical significance in specific age ranges. Mediation analysis verified that TG exerted a complete mediating role in the association pathway between age and UA, which was statistically significant exclusively in females (indirect effect = 4.435, 95% CI: 4.214 to 4.679, p < 0.001), while no such mediating effect was observed in males (indirect effect = 0.101, 95% CI: −0.007 to 0.210, p > 0.05). Conclusion: Some CBC and biochemical indicators show meaningful age- and sex-specific variation in mid-to-moderate altitude physical examination populations.