UNIV Angers, CHU Angers, Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-49000 Angers, France; AP-HP (Paris Hospital), Occupational Health Unit, Poincaré University Hospital, Garches, France; Versailles St-Quentin Univ-Paris Saclay Univ (UVSQ), UMS 011, UMR-S 1168, France; Inserm, U1168 UMS 011, Villejuif, France.
Department of Occupational Medicine Epidemiology and Prevention, Zucker School of Medicine at Hofstra University, Feinstein Institutes for Medical Research, Northwell Health, NY, USA.
Environ Int. 2020 Sep;142:105746. doi: 10.1016/j.envint.2020.105746. Epub 2020 Jun 3.
The World Health Organization (WHO) and the International Labour Organization (ILO) are developing joint estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large network of individual experts. Evidence from mechanistic data and prior studies suggests that exposure to long working hours may cause stroke. In this paper, we present a systematic review and meta-analysis of parameters for estimating the number of deaths and disability-adjusted life years from stroke that are attributable to exposure to long working hours, for the development of the WHO/ILO Joint Estimates.
We aimed to systematically review and meta-analyse estimates of the effect of exposure to long working hours (three categories: 41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on stroke (three outcomes: prevalence, incidence, and mortality).
A protocol was developed and published, applying the Navigation Guide to systematic reviews as an organizing framework where feasible. We searched electronic databases for potentially relevant records from published and unpublished studies, including Ovid MEDLINE, PubMed, EMBASE, Scopus, Web of Science, CISDOC, PsycINFO, and WHO ICTRP. We also searched grey literature databases, Internet search engines, and organizational websites; hand-searched reference lists of previous systematic reviews; and consulted additional experts.
We included working-age (≥15 years) individuals in the formal and informal economy in any WHO and/or ILO Member State but excluded children (aged < 15 years) and unpaid domestic workers. We included randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the effect of exposure to long working hours (41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on stroke (prevalence, incidence or mortality).
At least two review authors independently screened titles and abstracts against the eligibility criteria at a first review stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. Missing data were requested from principal study authors. We combined relative risks using random-effects meta-analysis. Two or more review authors assessed the risk of bias, quality of evidence and strength of evidence, using the Navigation Guide and GRADE tools and approaches adapted to this project.
Twenty-two studies (20 cohort studies, 2 case-control studies) met the inclusion criteria, comprising a total of 839,680 participants (364,616 females) in eight countries from three WHO regions (Americas, Europe, and Western Pacific). The exposure was measured using self-reports in all studies, and the outcome was assessed with administrative health records (13 studies), self-reported physician diagnosis (7 studies), direct diagnosis by a physician (1 study) or during a medical interview (1 study). The outcome was defined as an incident non-fatal stroke event in nine studies (7 cohort studies, 2 case-control studies), incident fatal stroke event in one cohort study and incident non-fatal or fatal ("mixed") event in 12 studies (all cohort studies). Cohort studies were judged to have a relatively low risk of bias; therefore, we prioritized evidence from these studies, but synthesised evidence from case-control studies as supporting evidence. For the bodies of evidence for both outcomes with any eligible studies (i.e. stroke incidence and mortality), we did not have serious concerns for risk of bias (at least for the cohort studies). Eligible studies were found on the effects of long working hours on stroke incidence and mortality, but not prevalence. Compared with working 35-40 h/week, we were uncertain about the effect on incidence of stroke due to working 41-48 h/week (relative risk (RR) 1.04, 95% confidence interval (CI) 0.94-1.14, 18 studies, 277,202 participants, I 0%, low quality of evidence). There may have been an increased risk for acquiring stroke when working 49-54 h/week compared with 35-40 h/week (RR 1.13, 95% CI 1.00-1.28, 17 studies, 275,181participants, I 0%, p 0.04, moderate quality of evidence). Compared with working 35-40 h/week, working ≥55 h/week may have led to a moderate, clinically meaningful increase in the risk of acquiring stroke, when followed up between one year and 20 years (RR 1.35, 95% CI 1.13 to 1.61, 7 studies, 162,644 participants, I 3%, moderate quality of evidence). Compared with working 35-40 h/week, we were very uncertain about the effect on dying (mortality) of stroke due to working 41-48 h/week (RR 1.01, 95% CI 0.91-1.12, 12 studies, 265,937 participants, I 0%, low quality of evidence), 49-54 h/week (RR 1.13, 95% CI 0.99-1.29, 11 studies, 256,129 participants, I 0%, low quality of evidence) and 55 h/week (RR 1.08, 95% CI 0.89-1.31, 10 studies, 664,647 participants, I 20%, low quality of evidence). Subgroup analyses found no evidence for differences by WHO region, age, sex, socioeconomic status and type of stroke. Sensitivity analyses found no differences by outcome definition (exclusively non-fatal or fatal versus "mixed") except for the comparison working ≥55 h/week versus 35-40 h/week for stroke incidence (p for subgroup differences: 0.05), risk of bias ("high"/"probably high" ratings in any domain versus "low"/"probably low" in all domains), effect estimate measures (risk versus hazard versus odds ratios) and comparator (exact versus approximate definition).
We judged the existing bodies of evidence for human evidence as "inadequate evidence for harmfulness" for all exposure categories for stroke prevalence and mortality and for exposure to 41-48 h/week for stroke incidence. Evidence on exposure to 48-54 h/week and ≥55 h/week was judged as "limited evidence for harmfulness" and "sufficient evidence for harmfulness" for stroke incidence, respectively. Producing estimates for the burden of stroke attributable to exposures to working 48-54 and ≥55 h/week appears evidence-based, and the pooled effect estimates presented in this systematic review could be used as input data for the WHO/ILO Joint Estimates. PROTOCOL IDENTIFIER: https://doi.org/10.1016/j.envint.2018.06.016.
CRD42017060124.
世界卫生组织（世卫组织）和国际劳工组织（劳工组织）正在制定与工作相关的疾病和伤害负担的联合估计数，这得益于一个由众多个体专家组成的网络提供的贡献。来自机制数据和先前研究的证据表明，暴露于长工作时间可能会导致中风。在本文中，我们对暴露于长工作时间（41-48 小时、49-54 小时和≥55 小时/周）与暴露于标准工作时间（35-40 小时/周）相比，与中风相关的死亡和残疾调整生命年的数量的估计参数进行了系统评价和荟萃分析，作为世卫组织/劳工组织联合估计数的发展。
我们旨在系统回顾和荟萃分析暴露于长工作时间（41-48 小时、49-54 小时和≥55 小时/周）与暴露于标准工作时间（35-40 小时/周）相比对中风（三个结局：患病率、发病率和死亡率）的影响的估计值。
制定了一项方案，并根据可行性使用导航指南组织框架进行了公布。我们从已发表和未发表的研究中搜索了可能相关的记录的电子数据库，包括 Ovid MEDLINE、PubMed、EMBASE、Scopus、Web of Science、CISDOC、PsycINFO 和世卫组织信息交流中心。我们还搜索了灰色文献数据库、互联网搜索引擎和组织网站；手动检索了以前系统评价的参考文献列表；并咨询了其他专家。
我们纳入了在任何世卫组织和/或劳工组织成员国的正规和非正规经济部门工作的 15 岁及以上的个体，但排除了儿童（<15 岁）和无薪家庭工人。我们纳入了随机对照试验、队列研究、病例对照研究和其他非随机干预研究，这些研究估计了暴露于长工作时间（41-48 小时、49-54 小时和≥55 小时/周）与暴露于标准工作时间（35-40 小时/周）相比对中风（患病率、发病率或死亡率）的影响。
在第一阶段，至少两名综述作者根据资格标准筛选标题和摘要，在第二阶段根据合格记录的全文筛选标题和摘要，然后从合格研究中提取数据。向主要研究作者请求缺失的数据。我们使用随机效应荟萃分析合并相对风险。两名或多名综述作者使用导航指南和 GRADE 工具和方法（适用于该项目）评估偏倚风险、证据质量和证据强度。
22 项研究（20 项队列研究，2 项病例对照研究）符合纳入标准，共纳入了来自世卫组织三个区域（美洲、欧洲和西太平洋）的 839680 名参与者（364616 名女性），他们在八个国家工作。所有研究均使用自我报告来衡量暴露情况，使用行政健康记录（13 项研究）、自我报告的医生诊断（7 项研究）、医生直接诊断（1 项研究）或医疗访谈期间的诊断（1 项研究）来评估结果。该结果定义为 9 项研究（7 项队列研究，2 项病例对照研究）中的非致命性中风事件的发生率，1 项队列研究中的致命性中风事件和 12 项研究（所有队列研究）中的非致命性或致命性（“混合”）事件的发生率。队列研究被认为具有相对较低的偏倚风险；因此，我们优先考虑这些研究的证据，但也将病例对照研究的证据作为支持证据进行综合。对于任何符合条件的研究（即中风发病率和死亡率）的证据，我们对偏倚风险没有严重的担忧（至少对于队列研究）。我们发现了与长工作时间对中风发病率和死亡率影响的研究，但没有发现对中风患病率影响的研究。与每周工作 35-40 小时相比，我们不确定每周工作 41-48 小时对中风发病率的影响（相对风险（RR）1.04，95%置信区间（CI）0.94-1.14，18 项研究，277202 名参与者，I 0%，低质量证据）。与每周工作 35-40 小时相比，每周工作 49-54 小时可能会增加中风的发病风险（RR 1.13，95%置信区间（CI）1.00-1.28，17 项研究，275181 名参与者，I 0%，p 0.04，中等质量证据）。与每周工作 35-40 小时相比，每周工作≥55 小时可能会导致在 1 年至 20 年期间中风的发病风险出现中度、临床相关增加（RR 1.35，95%置信区间（CI）1.13-1.61，7 项研究，162644 名参与者，I 3%，中等质量证据）。与每周工作 35-40 小时相比，我们对每周工作 41-48 小时（RR 1.01，95%置信区间（CI）0.91-1.12，12 项研究，265937 名参与者，I 0%，低质量证据）、每周工作 49-54 小时（RR 1.13，95%置信区间（CI）0.99-1.29，11 项研究，256129 名参与者，I 0%，低质量证据）和每周工作 55 小时（RR 1.08，95%置信区间（CI）0.89-1.31，10 项研究，664647 名参与者，I 20%，低质量证据）导致中风死亡（死亡率）的影响存在很大的不确定性。亚组分析发现，按世卫组织区域、年龄、性别、社会经济地位和中风类型没有证据表明存在差异。敏感性分析发现，除了每周工作≥55 小时与每周工作 35-40 小时相比中风发病率（p 为亚组差异：0.05）的结果定义（仅非致命或致命与“混合”）外，没有证据表明按结局定义（风险与危险比与比值比）和比较（精确与近似定义）存在差异。
我们认为，现有的人类证据有害性证据不足，适用于所有暴露类别（患病率和死亡率）和每周工作 41-48 小时的中风发病率。每周工作 48-54 小时和每周工作≥55 小时的暴露证据被认为是中风发病率的“有限有害性证据”和“充分有害性证据”。基于此，每周 48-54 小时和每周≥55 小时的工作暴露估计数产生的证据具有基于证据的依据，本系统评价中提出的汇总效应估计值可作为世卫组织/劳工组织联合估计数的输入数据。
https://doi.org/10.1016/j.envint.2018.06.016.
PROSPERO 注册号：CRD42017060124.
