This study investigated associations between plasma minerals and anemia risk in in nonagenarian and centenarian population. This cross-sectional study included 456 Chinese adults aged ≥ 90 years from the Chinese Longitudinal Healthy Longevity Survey (CLHLS, 2008). Plasma calcium (Ca), copper (Cu), iron (Fe), zinc (Zn), magnesium (Mg), manganese (Mn), and selenium (Se) levels were measured. Anemia was defined using WHO criteria and subclassified as normocytic, macrocytic, or microcytic based on the mean corpuscular volume (MCV). Analyses included generalized linear models (GLM), restricted cubic splines (RCS), parallel mediation, multinomial logistic regression, sensitivity analyses, and interaction models. Anemia prevalence was 49.78%. Participants with anemia had significantly lower Ca, Cu, Fe and Zn levels. Multivariate analysis revealed significant protective effects against anemia for plasma Ca, Cu, Fe and Zn with adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of: Ca 0.48 (0.29–0.81), Cu 0.65 (0.44–0.98), Fe 0.72 (0.57–0.89) and Zn 0.80 (0.64–0.99), though Cu, Fe, and Zn associations attenuated after renal function adjustment. Associations varied by anemia subtype. Parallel mediation analyses indicated that renal function mediated 19.61% (Cu), 43.21% (Fe) and 19.64% (Zn) of these effects, while Ca-related pathway mediated 37.25% (Cu), 17.28% (Fe) and 33.93% (Zn). Mg showed a U-shaped nonlinear association. Sensitivity analyses confirmed robustness. Interaction analyses revealed no significant combined mineral effects. No significant associations were found for Mn and Se. Plasma Ca, Cu, Fe, and Zn were inversely associated with anemia risk, with associations differed by anemia subtype. Renal function and Ca pathways mediated the associations for Cu, Fe, and Zn. Mg demonstrated a U-shaped association. These findings suggest potential considerations for these minerals in anemia management among the oldest-old.
Yang et al. (Fri,) studied this question.