Inverse association between triglyceride-glucose index and Maximal Oxygen Uptake in US young and middle-aged population : a cross-sectional study

Dong Li ¹ Junxing Lai ¹ Dan Li ¹ Yongfeng Li ¹ Peng Wang ¹ Shangan Cai ¹ Qiang Ren ¹ Bin Zhang ^1,2*

• ¹ Jiangmen Central Hospital, Jiangmen, Guangdong, China
• ² The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China

Background:The triglyceride-glucose (TyG) index has been linked to impaired cardiovascular fitness (CVF). Nevertheless, the available evidence regarding the direct relationship between TyG index and Maximal oxygen uptake (VO2max) is 2 inadequate.The objective of this study is to investigate the association between TyG index and VO2max.:We conducted a retrospective cross-sectional study involving 3571 participants who completed an examination of CVF from the National Health and Nutrition Examination Survey (NHANES) 1999-2004. Triglycerides, glucose and VO2max were obtained from all participants. The TyG index was calculated by Ln[TG(mg/dL) × FPG(mg/dl)/2]. Linear regression were utilized to substantiate the research objectives.Results:Complex sampling design and mobile examination center sample weights were considered. In multivariable linear regression analyses, TyG index with per 1 unit increased was associated with decreased VO2max ( β=-1.24, 95%CI(-1.97, -0.51), p=0.002) when expressed as a continuous variable, independent of confounders.When TyG was converted into a categorical variable based on 4 quartile data.Compared to the lowest TyG quintile (Q1: 6.750~7.887), the fully β for Q4 (8.672~12.481) was -1.91 (95% CI: -3.24, -0.57, p <0.007). A significant interaction (p=0.007) between sex and the TyG index for VO2max was found in the population when subgroup analysis was performed. The results of the sensitivity analysis remained stable. Mediation analysis showed the direct effect of TyG index was -1.467(-2.019, -0.948) and total effect was -1.813 (-2.377, -1.286). The mediation effect of DBP was -0.389(-0.526, -0.268), WBC was -0.308(-0.432, -0.177) and CRP was -0.252 (-0.453, -0.135). HGB exerted a suppressing effect on the relationship between the TyG index and VO2max, with a value of 1.469(1.252, 1.702). The p values for all the above effects were less than 0.05.Conclusions:Among young and middle-aged population in the US, TyG was significantly adverse associated with levels of VO2max. Female may exert an interaction on TyG. Evidence supported DBP, WBC and CRP as intervening variables through which TyG exerts its influence on VO2max. HGB may overrule the potential inverse association between TyG index on VO2max.