Abstract：
BACKGROUND: Although growing evidence has shown independent links of long-term exposure to fine particulate matter (PM2.5) with cognitive impairment, the effects of its constituents remain unclear. This study aims to explore the associations of long-term exposure to ambient PM2.5 constituents\' mixture with cognitive impairment in Chinese older adults, and to further identify the main contributor.
METHODS: 15,274 adults ≥ 65 years old were recruited by the Chinese Longitudinal Healthy Longevity Study (CLHLS) and followed up through 7 waves during 2000-2018. Concentrations of ambient PM2.5 and its constituents (i.e., black carbon [BC], organic matter [OM], ammonium [NH4+], sulfate [SO42-], and nitrate [NO3-]) were estimated by satellite retrievals and machine learning models. Quantile-based g-computation model was employed to assess the joint effects of a mixture of 5 PM2.5 constituents and their relative contributions to cognitive impairment. Analyses stratified by age group, sex, residence (urban vs. rural), and region (north vs. south) were performed to identify vulnerable populations.
RESULTS: During the average 3.03 follow-up visits (89,296.9 person-years), 4294 (28.1%) participants had developed cognitive impairment. The adjusted hazard ratio [HR] (95% confidence interval [CI]) for cognitive impairment for every quartile increase in mixture exposure to 5 PM2.5 constituents was 1.08 (1.05-1.11). BC held the largest index weight (0.69) in the positive direction in the qg-computation model, followed by OM (0.31). Subgroup analyses suggested stronger associations in younger old adults and rural residents.
CONCLUSIONS: Long-term exposure to ambient PM2.5, particularly its constituents BC and OM, is associated with an elevated risk of cognitive impairment onset among Chinese older adults.
METHODS: 15,274 adults ≥ 65 years old were recruited by the Chinese Longitudinal Healthy Longevity Study (CLHLS) and followed up through 7 waves during 2000-2018. Concentrations of ambient PM2.5 and its constituents (i.e., black carbon [BC], organic matter [OM], ammonium [NH4+], sulfate [SO42-], and nitrate [NO3-]) were estimated by satellite retrievals and machine learning models. Quantile-based g-computation model was employed to assess the joint effects of a mixture of 5 PM2.5 constituents and their relative contributions to cognitive impairment. Analyses stratified by age group, sex, residence (urban vs. rural), and region (north vs. south) were performed to identify vulnerable populations.
RESULTS: During the average 3.03 follow-up visits (89,296.9 person-years), 4294 (28.1%) participants had developed cognitive impairment. The adjusted hazard ratio [HR] (95% confidence interval [CI]) for cognitive impairment for every quartile increase in mixture exposure to 5 PM2.5 constituents was 1.08 (1.05-1.11). BC held the largest index weight (0.69) in the positive direction in the qg-computation model, followed by OM (0.31). Subgroup analyses suggested stronger associations in younger old adults and rural residents.
CONCLUSIONS: Long-term exposure to ambient PM2.5, particularly its constituents BC and OM, is associated with an elevated risk of cognitive impairment onset among Chinese older adults.
摘要：
背景：尽管越来越多的证据表明，长期接触细颗粒物（PM2.5）与认知障碍有独立的联系，其成分的影响仍不清楚。本研究旨在探讨长期暴露于环境PM2.5成分混合物与中国老年人认知障碍的关系。并进一步确定主要贡献者。
方法：中国纵向健康长寿研究（CLHLS）招募了15,274名≥65岁的成年人，并在2000-2018年期间进行了7次随访。环境PM2.5及其成分的浓度(即，黑碳[BC]，有机质[OM]，铵[NH4+]，硫酸盐[SO42-]，和硝酸盐[NO3-])是通过卫星检索和机器学习模型估计的。基于分位数的g计算模型用于评估5种PM2.5成分混合物的联合作用及其对认知障碍的相对贡献。按年龄组分层分析，性别,住宅(城市与农村)，和地区(北部与南部)是为了识别弱势群体。
结果：在平均3.03次随访（89,296.9人年）中，4294名（28.1%）参与者出现认知障碍。混合物暴露于5种PM2.5成分的每四分位数增加，认知障碍的校正风险比[HR]（95％置信区间[CI]）为1.08（1.05-1.11）。在qg计算模型中，BC在正方向上保持最大的指标权重(0.69)，其次是OM(0.31)。亚组分析表明，年轻的老年人和农村居民之间的关联更强。
结论：长期暴露于环境PM2.5，特别是其成分BC和OM，与中国老年人认知障碍发病风险升高相关。
方法：中国纵向健康长寿研究（CLHLS）招募了15,274名≥65岁的成年人，并在2000-2018年期间进行了7次随访。环境PM2.5及其成分的浓度(即，黑碳[BC]，有机质[OM]，铵[NH4+]，硫酸盐[SO42-]，和硝酸盐[NO3-])是通过卫星检索和机器学习模型估计的。基于分位数的g计算模型用于评估5种PM2.5成分混合物的联合作用及其对认知障碍的相对贡献。按年龄组分层分析，性别,住宅(城市与农村)，和地区(北部与南部)是为了识别弱势群体。
结果：在平均3.03次随访（89,296.9人年）中，4294名（28.1%）参与者出现认知障碍。混合物暴露于5种PM2.5成分的每四分位数增加，认知障碍的校正风险比[HR]（95％置信区间[CI]）为1.08（1.05-1.11）。在qg计算模型中，BC在正方向上保持最大的指标权重(0.69)，其次是OM(0.31)。亚组分析表明，年轻的老年人和农村居民之间的关联更强。
结论：长期暴露于环境PM2.5，特别是其成分BC和OM，与中国老年人认知障碍发病风险升高相关。
