Gender-specific age inflection points for hypertension, elevated fasting blood glucose, and dyslipidemia in a Northern Chinese cohort: a comorbidity-based analysis

This study aims to characterize age inflection points for hypertension, elevated fasting blood glucose, and dyslipidemia in a Chinese physical examination population, analyze gender differences and the impact of comorbid conditions on these inflection points, and inform the development of gender-specific precision screening strategies. Data from 263,824 health examination records collected at the General Hospital of the Northern Theater Command between January 2020 and May 2025 were included. The maximum Youden index was used to determine age inflection points for single diseases and comorbid conditions. Chi-square tests were employed to compare disease prevalence before and after the inflection points, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Significant gender differences were observed in inflection points for single diseases. The overall inflection point for hypertension was 40.5 years (38.5 years in males, 43.5 years in females). After the inflection point, prevalence increased from 7.7% to 23.1% in males (OR = 3.59, 95%CI: 3.46–3.72) and from 2.9% to 11.2% in females (OR = 4.24, 95%CI: 4.00-4.50). The overall inflection point for elevated fasting blood glucose was 44.5 years (43.5 years in males, 50.5 years in females). After the inflection point, prevalence increased from 4.6% to 23.6% in males (OR = 6.39, 95%CI: 6.13–6.66) and from 3.1% to 14.5% in females (OR = 5.36, 95%CI: 5.08–5.66). The overall inflection point for dyslipidemia was 40.5 years (31.5 years in males, 45.5 years in females). After the inflection point, prevalence increased from 36.7% to 46.6% in males (OR = 1.50, 95%CI: 1.45–1.56) and from 14.4% to 36.9% in females (OR = 3.48, 95%CI: 3.37–3.60). All differences were statistically significant (P < 0.001). Compared to single-disease models, comorbid conditions showed an average increase of 0.12 in area under the curve (AUC). The combination of elevated fasting blood glucose and hypertension in females had the highest AUC (0.75, 95%CI: 0.74–0.76), with sensitivity of 69.1%, specificity of 69.5%, and Youden index of 0.39. The combination of dyslipidemia and elevated fasting blood glucose achieved the highest Youden index (0.41), with significantly higher AUC in females (0.76, 95%CI: 0.75–0.77) than in males (0.72, 95%CI: 0.71–0.72). For triple comorbidity, AUC was 0.75 (95%CI: 0.73–0.76) in females versus 0.70 (95%CI: 0.69–0.71) in males. Female inflection points for comorbidities were consistently later than those in males, and AUC values were uniformly higher in females, with the most pronounced gender difference observed for the combination of dyslipidemia and hypertension (AUC = 0.73 in females vs. 0.64 in males). This study identified gender-specific age inflection points for hypertension, elevated fasting blood glucose, and dyslipidemia, and further characterized these thresholds for comorbid conditions. Comorbidity models showed improved predictive performance over single-disease models. A consistent gender pattern was observed: female inflection points occurred later than those in males but converged around age 50 for all comorbid conditions, while the discriminative power of age for male dyslipidemia was limited. These findings may inform the development of gender-specific, comorbidity-focused screening strategies.