Editorial

Chronic kidney disease as a cardiovascular risk factor

Associations between plasma elements and chronic kidney disease (CKD) among the elderly are poorly understood. In this cross-sectional study, we explored the associations between exposure to four plasma elements and CKD in elderly people aged ≥90 years in longevity areas in China. We measured plasma selenium, manganese, iron, and zinc levels and used logistic regression models to investigate associations between CKD and these four plasma elements after adjusting for confounding factors among 461 participants aged ≥90 years in the fifth wave of the Chinese Longitudinal Healthy Longevity Study (CLHLS) conducted in 2009. The median plasma selenium, manganese, iron, and zinc levels were 120.51 μg/L, 26.64 μg/L, 2880.52 μg/L, and 1882.42 μg/L in the CKD group and 108.76 μg/L, 31.55 μg/L, 4512.00 μg/L, and 2294.24 μg/L in the non-CKD group, respectively. Single- and multiple-element multivariable models showed that plasma manganese, iron, and zinc were negatively associated with CKD. In the multiple-element multivariable models, the adjusted odds ratios for CKD were 0.48 (95% confidence interval [CI]: 0.27–0.86) for the second highest quartile of manganese, 0.37 (95% CI: 0.21–0.68) and 0.36 (95% CI: 0.19–0.65) for the third highest and highest quartiles of iron, respectively, and 0.53 (95% CI: 0.29–0.94) for the highest quartile of zinc, compared with the lowest quartiles of these three elements. Plasma manganese, iron, and zinc levels protect against CKD in elderly people aged ≥90 years in longevity areas.

Chronic glomerulonephritis (CGN) is one of the most severe kidney diseases. Genes of vascular reactivity are thought to play an important role in development and progression of CGN. In this study, we analyzed association of genes of vascular homeostasis with hypertension and renal survival of CGN patients. The study sample included 238 patients with CGN and 304 healthy subjects of population control. Ten polymorphisms of ten genes of vascular homeostasis were genotyped through polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) analysis and TaqMan assays. Association of the genotypes with renal survival was analyzed by the Kaplan–Meier estimator. Genotypes 311SC and 311SS of the PON2 gene, (− 1166)AC and (− 1166)CC of the AGTR1 gene, (+ 46)AA of the ADRB2 gene, and 198KK and 198KN of the EDN1 gene were associated with decreased rate of renal survival of the patients. Polymorphisms S311C PON2, (− 1166)A/C AGTR1, (+ 46)G/A ADRB2, and K198N EDN1 were associated with the accelerated decline in kidney function in the CGN patients.

Chronic kidney disease (CKD) is known to be associated with the incidence and mortality of cardiovascular disease. Therefore, the prevention of CKD may improve the mortality of cardiovascular disease. The risk factors of CKD are variable and multifactorial, similar to atherosclerosis. We hypothesized that the index of atherosclerosis predicts future CKD, and investigated the association between the cardio-ankle vascular index (CAVI), the index of arterial stiffness in part of atherosclerosis, and CKD occurrence in non-CKD patients.

Of the 1000 patients undergoing CAVI in our hospital from 2006 to 2007 without CKD, we followed renal function for 1 or more years in 369 patients. CKD was defined as an estimated glomerular filtration rate of <60 ml/min/1.73 m².

We divided our study patients into 4 groups according to their CAVI: <8.0 (n = 85), 8.0–9.0 (n = 75), 9.0–10.0 (n = 112), and ≥10.0 (n = 97), respectively. The differences in serum creatinine between baseline and follow-up were 0.09 ± 0.04, 0.11 ± 0.05, 0.17 ± 0.04 and 0.23 ± 0.04, respectively (the P value for the lowest group versus the highest group was 0.04). The age- and sex-adjusted odds ratios (95% confidential interval, P value versus the lowest group) for the occurrence of CKD were 1.13 (0.58–2.20, P = 0.09), 1.58 (0.85–2.94, P = 0.09), and 2.38 (1.23–4.61, P = 0.02). Even after multivariate adjustment, the relationship remained.

CAVI was found to be associated with future renal dysfunction, thus suggesting that a CAVI ≥10 may therefore be a risk factor for CKD in Japanese patients.