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BACKGROUND: High glycemic index (GI) diets have been linked to elevated risk of cardiometabolic diseases. One possible underlying mechanism comes from high GI diet's potential to promote lipid peroxidation. OBJECTIVES: We aim to evaluate whether and to what extent dietary carbohydrate quality and quantity are associated with systemic levels of lipid peroxidation in females. METHODS: In this cross-sectional analysis of 2163 middle-aged women, a subset of the Shanghai Women's Health Study, we measured lipid peroxidation biomarkers F(2)-isoprostanes (F(2)-IsoPs) and its metabolite, 2,3-dinor-5,6-dihydro-15-F(2t)-IsoP (F(2)-IsoP-M), in urine. The quality of carbohydrate was defined by dietary GI, assessed using a validated FFQ via in-person interviews. A multivariable linear regression model with restricted cubic spline functions was used to evaluate the association of measured biomarkers with carbohydrate intake and dietary GI. RESULTS: After adjustment for potential confounding factors such as cigarette smoking, BMI, and comorbidities, among others, we found that F(2)-IsoP-M concentrations were positively associated with both carbohydrate intake and dietary GI. Carbohydrate intake and dietary GI were weakly correlated (r = 0.12). When further mutually adjusted for the 2 factors, the positive association with F(2)-IsoP-M remained statistically significant for GI (P = 0.004) but not for carbohydrate intake (P = 0.50). Compared with those in the 10th percentile of dietary GI, fold increases (95% CI) in F(2)-IsoP-M concentrations for those in the 30th, 50th, 70th, and 90th percentiles were 1.03 (1.00, 1.07), 1.06 (1.01, 1.10), 1.09 (1.03, 1.14), and 1.13 (1.05, 1.21), respectively. Moreover, there appeared a threshold regarding the association between dietary GI and F(2)-IsoP-M concentrations, with the dose-effect slope of GI being 2.3 times greater when GI was ≥75 relative to GI

OBJECTIVE: We aim to investigate whether and how lipid peroxidation markers are associated with height and obesity measures. METHODS: In two independent samples of women (Study-1, n=1005; Study-2, n=1158), systemic levels of lipid peroxidation were assessed by urinary markers F(2)-isoprostanes (F(2)-IsoPs) and its major metabolite (F(2)-IsoP-M), with GC/NICI MS assays. Anthropometric parameters were directly measured and were genetically estimated, used in the primary analysis and in a Mendelian randomization analysis in relation to lipid peroxidation, respectively, with general linear models. RESULTS: After adjusted for potential confounders, we found that measured adult height was inversely associated with levels of F(2)-IsoPs (β=−0.89, P

Total knee arthroplasty (TKA) is effective for pain reduction in most patients, but 15% or more report unsatisfactory long-term pain outcomes. We tested whether oxidative stress (OS) related to extended tourniquet application during TKA and subsequent ischemic reperfusion (IR) contributed to adverse post-TKA pain outcomes. Blood samples were obtained in 91 patients with osteoarthritis (63% female) undergoing TKA before tourniquet placement (T1), 45 minutes after tourniquet inflation (T2), and 15 minutes after tourniquet removal (T3). Plasma levels of F 2 -isoprostanes and isofurans, the most specific measures of in vivo OS, were quantified. Pain intensity and function were assessed at baseline and again at 6 weeks and 6 months after TKA. Results indicated that higher Combined OS (F 2 -isoprostanes + isofurans/2) at T1 baseline and larger increases in Combined OS from T1 to T2 were associated with higher baseline-corrected past 24-hour worst and average pain intensity (numeric rating scale) and higher past week McGill Pain Questionnaire-2 total scores at 6-month follow-up ( P 's0.05). Increases in Combined OS from T1 to T3, which should most directly capture OS and IR injury related to tourniquet use, were not associated with short-term or long-term post-TKA pain outcomes. Longer ischemia duration was unexpectedly associated with lower baseline-corrected pain intensity at 6-month follow-up. Combined OS was not linked to functional outcomes at either follow-up. Elevated perioperative OS seems to exert small but significant adverse effects on long-term post-TKA pain outcomes, although this OS seems unrelated to IR injury associated with extended tourniquet use.