Association between glucose fluctuation during 2-hour oral glucose tolerance test, inflammation and oxidative stress markers, and β-cell function in a Chinese population with normal glucose tolerance.

Backgrounds Glucose fluctuation (GF) may have detrimental effects in individuals with diabetes; however, clinical data on the association between short-term GF, inflammation/oxidative stress markers, and islet β-cell function based on a population with normal glucose tolerance (NGT) are insufficient. Therefore, we aimed to explore these associations in a Chinese population of 209 individuals with NGT in a cross-sectional analysis. Methods Individuals were categorized based on GF tertiles, calculated as the maximum-minimum glucose levels among four time points (0, 30, 60, 120 min) during 2-hour oral glucose tolerance test (OGTT). Plasma inflammation markers tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and oxidative stress markers superoxide dismutase (SOD), and 8-oxo-2'-deoxyguanosine (8-oxo-dG) were measured. Islet β-cell function was estimated according to the disposition index (DI) at the early (30 min) and total (120 min) phase of the OGTT, adjusted for insulin sensitivity. Results Individuals in the middle and highest tertile of GF had reduced β-cell function, and increased plasma SOD and TNF-α levels compared with those in the lowest tertile of GF (P<0.05). Multiple linear regression analysis indicated that GF was positively associated with TNF-α, 8-oxo-dG and SOD levels, but negatively associated with β-cell function, whereas IL-6, TNF-α, 8-oxo-dG and SOD levels were negatively associated with β-cell function (P<0.05). Conclusions GF may increase inflammation and oxidative stress markers in individuals with NGT, which could contribute to reduced β-cell function. Thus, maintaining glucose stability after a meal may have beneficial effects on delaying β-cell dysfunction, suggesting that diet and exercise strategies to decrease diet related GF are warranted.