An indoor air filtration study in homes of eiderly: cardiovascular and respiratory effects of exposure to particulate matter

摘要

Background Particulate air pollution increases mortality and morbidity related to respiratory and cardiovascular diseases, especially for susceptible individuals such as the elderly, possibly through oxidative stress, systemic inflammation and endothelial dysfunction. In a previous study, 48 hours air filtration in the homes of 41 healthy subjects (60 to 75 years) reduced PM2.5 concentrations from 12.6 to 4.7μg/m3 and improved the microvascular function by 8%(Brauner et al., 2008). Aims In this study we examined potential beneficial effects of two weeks air filtration in the homes of an elderly population, including people taking vasoactive drugs. Methods Re-circulating custom built particle filtration units with or without the inclusion of a high-efficiency particle air (HEPA) filters were used in a randomized, double-blind, crossover intervention study in 27 homes with 48 nonsmoking subjects (51 to 81 years), exposed to consecutive 2-week periods of either particle-filtered or non-filtered air in their living and bedrooms. At the beginning of the study (baseline) and at day 2, 7 and 14 after each exposure scenario we measured blood pressure, microvascular- and lung function and collected saliva, urine and blood samples to quantify different hematological parameters and markers of inflammation, monocyte surface markers and oxidative stress. Results The inclusion of particle air filters changed the concentration of PM2.5 from approximately 8 to 4 μg/m3 and the ultrafine particle number count from 7669 to 5352 partides/cm3. No statistically significant effects of filtration were observed on microvascular- and lung function or the biomarkers we measured among all subjects or in the subgroups taking (n=15) or not taking vasoactive drugs (n=33). Conclusion With the exposure gradient achieved no beneficial effect of air filtration for two weeks could be documented in this elderly population, irrespective of use of vasoactive drugs.