With the shortening of leukocyte telomere length (LTL) and decrease in the copy number of mitochondrial DNA, mitochondrial dysfunction and oxidative stress are considered important drivers of the aging process. Although previous experimental studies report that caloric intake is associated with age-related renal dysfunction through the changes in mitochondrial function, there are insufficient epidemiological data to establish this association.
We aimed to explore the association between caloric intake and renal function and to investigate whether mitochondrial DNA copy number (mtDNAcn) mediated this association by cross-sectional analysis.
A total of 403 individuals from a Chinese rural cohort (women = 66.50%; mean age = 53.94 ± 10.27 years) with an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 and with differences in the glucose tolerance status (diabetes, n = 106; prediabetes, n = 125; normal glucose tolerance, n = 172) were included. Dietary data were obtained by a 24-h food recall, and caloric intake was normalized by ideal body weight. The mtDNAcn and LTL were detected using real-time PCR assay. The associations between caloric intake, aging markers, and renal function were analyzed by partial correlation analysis and multiple linear regression analysis. Mediation analysis was applied to examine the role of mtDNAcn in the association between caloric intake and eGFR.
Caloric intake was higher while age-adjusted mtDNAcn was lower in individuals with eGFR <90 mL/min/1.73 m2 (n = 140) than in those with eGFR ≥90 mL/min/1.73 m2 (n = 263). After adjusting for multiple factors, linear regression analysis revealed that caloric intake was negatively associated with eGFR and mtDNAcn, while mtDNAcn was positively associated with eGFR. Moreover, mediation analysis indicated that the indirect effect of caloric intake on eGFR through mtDNAcn was significant (β = -0.0505, 95% confidence interval -0.0931 to -0.0190).
Caloric intake was negatively associated with eGFR in a Chinese population, and the association was partly mediated by decreased mtDNAcn.
© 2020 S. Karger AG, Basel.