Dietary acid load and chronic kidney disease among adults in the United States
1 Department of Medicine, University of California, San Francisco, CA, USA
2 Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
3 Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD, USA
4 Texas A&M College of Medicine and Scott and White Healthcare, Texas, USA
5 Kidney Epidemiology & Cost Center, University of Michigan, Ann Arbor, MI, USA
6 Division of Nephrology, Department of Medicine and Kidney Epidemiology & Cost Center, University of Michigan, Ann Arbor, MI, USA
7 Centers of Disease and Control and Prevention, Atlanta, GA, USA
8 Department of Medicine, San Francisco General Hospital, San Francisco, CA, USA
BMC Nephrology 2014, 15:137 doi:10.1186/1471-2369-15-137Published: 24 August 2014
Diet can markedly affect acid-base status and it significantly influences chronic kidney disease (CKD) and its progression. The relationship of dietary acid load (DAL) and CKD has not been assessed on a population level. We examined the association of estimated net acid excretion (NAEes) with CKD; and socio-demographic and clinical correlates of NAEes.
Among 12,293 U.S. adult participants aged >20 years in the National Health and Nutrition Examination Survey 1999–2004, we assessed dietary acid by estimating NAEes from nutrient intake and body surface area; kidney damage by albuminuria; and kidney dysfunction by eGFR < 60 ml/min/1.73m2 using the MDRD equation. We tested the association of NAEes with participant characteristics using median regression; while for albuminuria, eGFR, and stages of CKD we used logistic regression.
Median regression results (β per quintile) indicated that adults aged 40–60 years (β [95% CI] = 3.1 [0.3–5.8]), poverty (β [95% CI] = 7.1 [4.01–10.22]), black race (β [95% CI] = 13.8 [10.8–16.8]), and male sex (β [95% CI] = 3.0 [0.7- 5.2]) were significantly associated with an increasing level of NAEes. Higher levels of NAEes compared with lower levels were associated with greater odds of albuminuria (OR [95% CI] = 1.57 [1.20–2.05]). We observed a trend toward greater NAEes being associated with higher risk of low eGFR, which persisted after adjustment for confounders.
Higher NAEes is associated with albuminuria and low eGFR, and socio-demographic risk factors for CKD are associated with higher levels of NAEes. DAL may be an important target for future interventions in populations at high risk for CKD.