Plasma copper/zinc ratio: an inflammatory/nutritional biomarker as predictor of all-cause mortality in elderly population

Abstract

Associations have been reported between plasma Cu and Zn levels and the incidence of the most important age-related diseases. Previously proposed methods of using plasma Cu/Zn as a predictor of all-cause mortality have been derived from populations in which old and very old subjects were underrepresented. The purpose of this paper is to estimate the usefulness of plasma Cu/Zn as a sensitive biomarker of harmful inflammatory or nutritional changes in the elderly and its incremental prognostic utility as a predictor of all-cause mortality in a functionally independent elderly Italian cohort. The association between plasma Cu/Zn and inflammatory (CRP, ESR, IL-6) or nutritional (albumin, BMI) markers was studied in 498 elderly subjects. Blood samples were taken from 164 healthy 20- to 60-year-old volunteer controls. A 3.5 years prospective follow-up study of mortality by age-related diseases was performed in n = 218 over 70-year-olds. Plasma Cu/Zn ratio was associated with all the inflammatory markers studied, as well as with serum albumin, and predicted 3.5 years mortality in subjects over 70. Plasma Cu/Zn was higher in women than men and increased with advancing age. Subjects with stable cardiovascular disease (CVD) displayed higher plasma Cu/Zn than those without, due mainly to increased plasma Cu. However, most of the age-related changes of Cu/Zn resulted from a progressive decline of plasma Zn. Cu/Zn ratio may be considered an important clinical inflammatory-nutritional biomarker as well as a significant predictor of all-cause mortality in over 70-year-olds.

Cu to Zn ratio, physical function, disability, and mortality risk in older elderly (ilSIRENTE study)

“…Moreover, the results presented in this manuscript highlight also the higher sensibility of CZr than Cu or Zn alone to general clinical risk conditions in the elderly because these circumstances are generally reflected by a decrease in Zn or by an increase in Cu or both (Belbraouet et al 2007;Ghaemian et al 2011;Malavolta et al 2010).…”

“…Our previous findings , in a functional independent population over 81 years, observed a significant risk for mortality in men with levels above 1.78 and women with levels above 2.04 that are substantially lower than the mean values reported in the current sample (1.93 in men and 2.06 in women). However, it is important to consider that the thresholds in Malavolta et al (2010) were calculated from tertiles of a functional independent population where death events were relatively rare (32 deaths after 3.5 years) compared to those reported in this study (145 deaths after 4 years) performed in older people affected by various grade of disease and disability. Therefore, the thresholds identified in this study could potentially display higher clinical relevance than those reported in functionally independent population, taking also into account that clinicians are rarely in contact with healthy and functionally independent elderly, while being usually involved in the clinical management of elderly people with comorbidity and disability.…”

Prevalencia de las deficiencias de zinc y cobre en adultos mayores de la Región Metropolitana de Santiago

“…Si bien no hay consenso, existen estudios que encuentran que los adultos mayores tienen valores de zinc sérico más bajos y de cobre sérico más elevados que los encontrados en adultos jóvenes 3,[20][21][22][23] . Se ha descrito también un aumento de la proporción Cu/Zn séricos en adultos mayores a medida que progresa la edad 24 . La pregunta aún sin resolver es en qué medida esta reducción de los valores séricos de zinc sería consecuencia de los cambios fi siológicos que ocurren durante el envejecimiento, como por ejemplo, la reducción de las masas muscular y ósea, que contienen parte importante del zinc tisular y cuánto se debería a que este grupo etario presenta una mayor frecuencia de procesos infl amatorios y una mayor prevalencia de defi ciencia de zinc.…”

Copper-Zinc ratio and nutritional status in colorectal cancer patients during the perioperative period

“…In the elderly, increased Cu/Zn ratio was a predictive factor of mortality and it was associated with reduced serum albumin and increased inflammatory markers, like C-reactive protein and erythrocytes sedimentation rate 12 .…”