Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA.
Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, CA, USA.
Nicotine Tob Res. 2023 Jan 5;25(2):211-220. doi: 10.1093/ntr/ntac090.
The relationship between tobacco smoking status and SARS-CoV-2 infection and coronavirus disease 2019 (COVID-19) severity is highly debated. We conducted a retrospective cohort study of >2.4 million adults in a large healthcare system to evaluate whether smoking is associated with SARS-CoV-2 infection and disease severity.
This retrospective cohort study of 2,427,293 adults in KPNC from March 5, 2020 (baseline) to December 31, 2020 (pre-vaccine) included smoking status (current, former, never), socio-demographics, and comorbidities from the electronic health record. SARS-CoV-2 infection (identified by a positive PCR test) and COVID-19 severity (hospitalization, ICU admission or death ≤ 30 days of COVID-19 diagnosis) were estimated in time-to-event analyses using Cox proportional hazard regression models adjusting for covariates. Secondary analyses examined COVID-19 severity among patients with COVID-19 using logistic regression.
During the study, 44,270 patients had SARS-CoV-2 infection. Current smoking was associated with lower adjusted rates of SARS-CoV-2 infection (aHR = 0.64 95% CI: 0.61-0.67), COVID-19-related hospitalization (aHR = 0.48 95% CI: 0.40-0.58), ICU admission (aHR = 0.62 95% CI: 0.42-0.87), and death (aHR = 0.52 95% CI: 0.27-0.89) than never-smoking. Former smoking was associated with a lower adjusted rate of SARS-CoV-2 infection (aHR = 0.96 95% CI: 0.94-0.99) and higher adjusted rates of hospitalization (aHR = 1.10 95% CI: 1.03-1.08) and death (aHR = 1.32 95% CI: 1.11-1.56) than never-smoking. Logistic regression analyses among patients with COVID-19 found lower odds of hospitalization for current versus never-smoking and higher odds of hospitalization and death for former versus never-smoking.
In the largest US study to date on smoking and COVID-19, current and former smoking showed lower risk of SARS-CoV-2 infection than never-smoking, while a history of smoking was associated with higher risk of severe COVID-19.
In this cohort study of 2.4 million adults, adjusting for socio-demographics and medical comorbidities, current tobacco smoking was associated with a lower risk of both SARS-CoV-2 infection and severe COVID-19 illness compared to never-smoking. A history of smoking was associated with a slightly lower risk of SARS-CoV-2 infection and a modestly higher risk of severe COVID-19 illness compared to never-smoking. The lower observed COVID-19 risk for current versus never-smoking deserves further investigation. Results support prioritizing individuals with smoking-related comorbidities for vaccine outreach and treatments as they become available.
吸烟状况与 SARS-CoV-2 感染和 2019 年冠状病毒病（COVID-19）严重程度之间的关系存在很大争议。我们对大型医疗保健系统中的超过 240 万名成年人进行了回顾性队列研究，以评估吸烟是否与 SARS-CoV-2 感染和疾病严重程度有关。
这项对 KPNC 2427293 名成年人的回顾性队列研究于 2020 年 3 月 5 日（基线）至 2020 年 12 月 31 日（疫苗前）进行，包括吸烟状况（当前、既往、从不）、来自电子健康记录的社会人口统计学和合并症。使用 Cox 比例风险回归模型，根据协变量调整，通过时间事件分析估计 SARS-CoV-2 感染（通过阳性 PCR 检测确定）和 COVID-19 严重程度（COVID-19 诊断后 30 天内住院、入住 ICU 或死亡）。二次分析使用逻辑回归检查 COVID-19 患者的 COVID-19 严重程度。
在研究期间，有 44270 名患者感染了 SARS-CoV-2。与从不吸烟相比，当前吸烟与 SARS-CoV-2 感染率（调整后的 HR=0.64，95%CI：0.61-0.67）、COVID-19 相关住院率（调整后的 HR=0.48，95%CI：0.40-0.58）、入住 ICU 率（调整后的 HR=0.62，95%CI：0.42-0.87）和死亡率（调整后的 HR=0.52，95%CI：0.27-0.89）较低有关。与从不吸烟相比，既往吸烟与 SARS-CoV-2 感染率（调整后的 HR=0.96，95%CI：0.94-0.99）较低，与住院率（调整后的 HR=1.10，95%CI：1.03-1.08）和死亡率（调整后的 HR=1.32，95%CI：1.11-1.56）较高有关。在 COVID-19 患者中进行的逻辑回归分析发现，与从不吸烟相比，当前吸烟与住院的可能性较低，而与从不吸烟相比，既往吸烟与住院和死亡的可能性较高。
在迄今为止美国关于吸烟和 COVID-19 的最大研究中，目前和既往吸烟与从未吸烟相比，SARS-CoV-2 感染风险较低，而吸烟史与严重 COVID-19 风险较高有关。
在这项对 240 万成年人的队列研究中，调整了社会人口统计学和医疗合并症因素后，与从不吸烟相比，当前吸烟与 SARS-CoV-2 感染和严重 COVID-19 疾病的风险较低。与从不吸烟相比，吸烟史与 SARS-CoV-2 感染的风险略低，与严重 COVID-19 疾病的风险略高有关。与从不吸烟相比，当前吸烟的 COVID-19 风险较低值得进一步研究。结果支持优先考虑有吸烟相关合并症的人进行疫苗推广和治疗，因为这些治疗方法正在不断推出。
