Fu Zhen, Jiang Hongwei, Xu Zhongyu, Li Hongyu, Wu Nanjin, Yin Ping
Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Ann Transl Med. 2020 Apr;8(7):445. doi: 10.21037/atm.2020.03.145.
Secondhand smoke (SHS) may be related to worse outcomes in chronic obstructive pulmonary disease (COPD), but the reported SHS prevalence in different studies varied from 27% to 65% and the effects of SHS are still questionable among these patients. The study aims were to estimate the objective SHS prevalence and explore the SHS impact on outcomes among COPD patients without active smoking.
A cross-sectional design combined with longitudinal death outcome. We selected COPD patients over 40 years old based on the spirometry from National Health and Nutrition Examination Survey (2007-2012), and used the tobacco-specific biomarkers [cotinine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanonol] to determine exposure statuses (active smoking, SHS exposure, or no smoke exposure). Then we estimated the short-term (past 2-4 days) and medium-term (past 6-12 weeks) SHS prevalence among 334 patients without active smoking. Weighted multiple regressions were performed to assess the associations between medium-term SHS exposure and outcomes (symptoms, health status, medical institution visits, and death).
Among the patients without active smoking, the objective prevalence rates of short-term and medium-term SHS were 66.65% [95% confidence interval (CI), 59.63-73.67%] and 34.91% (95% CI, 28.86%-40.96%), respectively. Medium-term SHS exposure showed a significant effect (odds ratio, 3.57; 95% CI, 1.22-10.40) on more chronic coughing after adjusting for the covariates and indicated a trend of unadjusted increasing death risk (log-rank test, P=0.01).
Among COPD patients without active smoking, both short-term and medium-term SHS exposure are prevalent. Chronic cough may be the most susceptible patient-centred outcome related to medium-term SHS exposure. The crude longitudinal trend of elevated death risk associated with medium-term SHS exposure deserves further study.
二手烟（SHS）可能与慢性阻塞性肺疾病（COPD）的更差预后相关，但不同研究报道的二手烟患病率从27%到65%不等，且二手烟对这些患者的影响仍存在疑问。本研究的目的是估计客观的二手烟患病率，并探讨二手烟对无主动吸烟的COPD患者预后的影响。
采用横断面设计并结合纵向死亡结局。我们根据2007 - 2012年国家健康与营养检查调查的肺活量测定结果，选取40岁以上的COPD患者，并使用烟草特异性生物标志物[可替宁和4-(甲基亚硝胺基)-1-(3-吡啶基)-1-丁醇]来确定暴露状态（主动吸烟、二手烟暴露或无烟雾暴露）。然后我们估计了334例无主动吸烟患者的短期（过去2 - 4天）和中期（过去6 - 12周）二手烟患病率。进行加权多元回归以评估中期二手烟暴露与预后（症状、健康状况、医疗机构就诊和死亡）之间的关联。
在无主动吸烟的患者中，短期和中期二手烟的客观患病率分别为66.65%[95%置信区间（CI），59.63 - 73.67%]和34.91%（95% CI，28.86% - 40.96%）。在调整协变量后，中期二手烟暴露对更多慢性咳嗽有显著影响（优势比，3.57；95% CI，1.22 - 10.40），并且显示出未调整的死亡风险增加趋势（对数秩检验，P = 0.01）。
在无主动吸烟的COPD患者中，短期和中期二手烟暴露都很普遍。慢性咳嗽可能是与中期二手烟暴露相关的最易受影响的以患者为中心的结局。与中期二手烟暴露相关的死亡风险升高的粗略纵向趋势值得进一步研究。
