Macronutrient composition and incident hypertension during China's nutrition transition: a longitudinal cohort analysis of the China Health and Nutrition Survey

Background China's nutrition transition has shifted dietary macronutrient composition while hypertension prevalence has risen. Whether the routinely available macronutrient composition adequately captures the risk of incident hypertension remains unclear. Methods We followed 14,384 baseline normotensive adults in the China Health and Nutrition Survey (baseline 1991–2011; blood pressure follow-up through 2015). Baseline diet was assessed using three consecutive 24-h recalls combined with household food inventories. Primary composition analyses retained records whose calculated protein, fat, and carbohydrate shares summed to 95%–105%. These shares were closed to 100% for substitution models; acceptable macronutrient distribution ranges (AMDR) from the Chinese Dietary Reference Intakes (DRI) were instead applied to the original percentages of total reported energy. Cox models used Efron handling of tied event times and community-clustered robust standard errors. Sensitivities included alternative composition-sum windows, event-time models, categorical and nonlinear exposure forms, cumulative-average repeated diet, measured-blood-pressure-only outcomes, and censoring-weighted 6-year temporal prediction. Results Hypertension was detected in 5,234 adults (36.4%). In primary Model 3 ( n = 13, 276; 4,745 events), closed protein replacing carbohydrate [hazard ratio (HR) per five composition points 0.986, 95% confidence interval (CI) 0.920–1.056; p = 0.679], closed fat replacing carbohydrate (HR 0.986, 95% CI 0.968–1.004; p = 0.120), and AMDR count (HR per component 1.007, 95% CI 0.974–1.041; p = 0.679) crossed the null. Categorical AMDR and alternative event-time models were concordant. From 1991 to 2011, the standardized AMDR count increased from 1.37 to 1.53 and standardized hypertension prevalence from 17.4% to 22.6%. Among 9,284 verified 6-year endpoints, dietary features did not materially improve temporal prediction. Conclusion A single baseline measure of gross macronutrient composition had limited association and predictive value for incident hypertension. Hypertension-related surveillance still requires sodium, potassium, dietary fiber, fat quality, and food-group information. Repeated-diet findings were exploratory and require dedicated longitudinal confirmation.