Abstract
Objectives
Cystatin C (Cys C) is a promising biomarker for early-stage chronic kidney disease. Dietary intake plays an essential role in the prevention of kidney function decline, which has yet to be examined in relation to changes in Cys C among older adults. Our objective was to test whether scores on the Alternative Healthy Eating Index-2010 (AHEI-2010) were associated with change in Cys C from 2012–2016 and if this varied by race/ethnicity.
Methods
Observations were drawn from the Health and Retirement Study. Blood spot collection and examination occurred in 2012 and 2016, participant attributes were measured in 2012, and dietary assessment was conducted by a validated dietary frequency questionnaire in 2013. The sample was restricted to respondents aged ≥65 years who were White (n = 789), Black (n = 108), or Hispanic (n = 61) and had biomarkers measured in 2012 and 2016 (n = 958). Serum Cys C (mg/L) was constructed to be equivalent to the 1999–2002 NHANES scale. Dietary quality was measured using AHEI-2010. Autoregressive linear modeling adjusting for covariates and sampling design was used to examine the associations of interest.
Results
Mean serum Cys C was 1.20 ± 0.44 mg/L (SD) in 2012 and 1.25 ± 0.45 mg/L in 2016, and mean AHEI-2010 score was 58.11 ± 11.0. Greater AHEI-2010 was associated with lower serum Cys C level at baseline (b = −.004, SE = .013, P = .002) and less rapid increase in the Cys C level from 2012–2016 (b = −.003, SE = .012, P = .024). The association between AHEI-2010 and change in serum Cys C was significantly different for Whites and Hispanics (b = .128, SE = .031, P < .001), but null when comparing Whites and Blacks. AHEI-2010 was negatively associated with change in Cys C for Whites, and positively associated with change in Cys C among Hispanics. Stratified analyses suggested that AHEI-2010 was not significantly different for Whites and Hispanics. Hispanics had significantly lower household income, assets, and educational attainment than Whites, and greater levels of food insecurity.
Conclusions
Our results indicate that dietary quality has a divergent association with change in serum Cys C for White and Hispanic older adults. These results suggest the need for examination of how disparities in socioeconomic status may influence the effect of dietary intake on kidney function for older adults from different racial/ethnic backgrounds.
Funding Sources
No funding.
Racial/Ethnic Disparities in Access to Care and Survival for Patients With Early-Stage Hepatocellular Carcinoma
