Associations between difference in anemia-related blood cell parameters and short-term exposure to ambient fine particles in Beijing elderly residents

Abstract

BACKGROUND AND AIM: Anemia is a highly prevalent disease among elderly population with multiple adverse health outcomes. Particle exposure was a potentially risk factor of anemia. However, few studies have investigated the associations of particle exposure with anemia-related outcomes in the elderly, and the underlying mechanism is unclear. METHODS: Based on a panel study conducted between July 2016 and September 2017, anemia-related blood cell parameters, including red blood cell count (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and tumor necrosis factor α (TNF α), a marker of systemic inflammation, in serum samples were measured from 135 elderly participants at up to four clinical visits. Particulate pollutants—including particulate matter with an aerodynamic diameter of ≤ 2.5μm (PM2.5), black carbon (BC), ultrafine particles (UFPs), and accumulated-mode particles (Acc)—were continuously monitored at a fixed-site monitoring station. Linear mixed-effects models were used to examine the associations between particle exposure and anemia-related blood cell parameters, and mediation models were used to evaluate the mediation effect of TNFα on the associations. RESULTS:In the elderly participants, exposure to all measured pollutants were significantly associated with differences in anemia-related blood cell parameters, such as the association between HGB difference and per interquartile range (IQR) increase in average Acc concentration 14 d before clinical visits was -2.2% (95% CI: -3.8%, -0.6%). The significant associations of UFPs and Acc exposure with difference in anemia-related blood cells kept robust after adjustment for other pollutants. In advanced analysis, 25.2 % (95% CI: 7.4 %, 64.8 %) of difference in MCHC associated with average UFPs concentration 14 d before clinical visits were mediated by the level of TNFα. CONCLUSIONS:Short-term exposure to fine particles, especially UFPs and Acc, contributed to damage of anemia-related blood cell in the elderly, and systemic inflammation is a potential internal mediator. KEYWORDS: anemia-related blood cell parameters, ambient fine particles, mean corpuscular hemoglobin concentration (MCHC), tumor necrosis factor α (TNF α), ultrafine particles (UFPs), accumulated-mode particles (Acc)