Fasting plasma glucose and 2-h postprandial plasma glucose characteristics in a large multi-ethnic Chinese population

Objective: During an oral glucose tolerance test (OGTT), typically fasting plasma glucose is lower than 2-h postprandial plasma glucose. However, postprandial plasma glucose (PPG) levels lower than fasting plasma glucose (FPG) levels may also occur. This study aims to describe the prevalence, clinical characteristics and contributing risk factors for PPG ≤ FPG in a large diverse Chinese population. Methods: We conducted a cross-sectional analysis of baseline data from a nationwide cohort study conducted in China. In addition to sociodemographic and anthropometric data collection, individuals had OGTT and blood chemistry tests. We determined the prevalence of PPG ≤ FPG (‘Low Post Load’ group) and PPG > FPG (‘High Post Load’ group) and used logistic regression to evaluate the association of risk factors with the occurrence of Low Post Load. Results: The prevalence of Low Post Load was 26.04% (n = 3773) and High Post Load was 73.96% (n = 10,714). Low Post Load was found to be related to younger age, male, lower BMI, lower blood pressure, higher HDL cholesterol levels and lower triglycerides levels. Compared with participants in the High Post Load group, participants in Low Post Load group had lower PPG (4.59 ± 0.83 mmol/L vs 7.15 ± 1.41 mmol/L) and HbA1c (5.30 ± 0.43% vs 5.39 ± 0.45%). People in Low Post Load group were more likely to have hypoglycaemic episodes (2.12% vs 0.01%) and impaired fasting glucose (12.30% vs 4.81%) compared with people with High Post Load, all p < 0.001. Conclusions: We found a high prevalence of people with Low Post Load glucose (26.04%) in a Chinese population cohort. The relationship between Low Post Load and the progression to or protection from diabetes and related complications and future incidence of cardiovascular disease needs further exploration in longitudinal analyses.