Health effects of WiFi radiation: a review based on systematic quality evaluation

Although WiFi contributes little to total radiofrequency electromagnetic field (RF-EMF) exposure in our everyday environment, concern has raised whether this specific type of modulated RF-EMF causes health problems. The aim of this review is to evaluate all types of studies that investigated biological and health effects of WiFi exposure and fulfilled basic quality criteria. Eligible for inclusion were epidemiological, human experimental, <i>in vivo</i> and <i>in vitro</i> studies using realistic WiFi exposure settings. We conducted a systematic literature search for all papers published between January 1997 and August 2020 followed by a quality review addressing blinding and dosimetry in experimental studies and various types of biases in epidemiological studies. All studies fulfilling the quality criteria were descriptively summarized in terms of observation or absence of associations. From 1385 articles identified by the literature search, 23 fulfilled basic quality criteria: 6 epidemiological papers, 6 human experimental articles, 9 <i>in vivo</i> articles, and 2 <i>in vitro</i> articles. Whereas <i>in vivo</i> and <i>in vitro</i> studies applied exposure levels up to 4 W/kg, human studies dealt with exposure levels several orders of magnitude below the ICNIRP guidelines, which are typical for WiFi exposure situations in the everyday environment. Numerous outcomes ranging from biological markers to symptoms were mostly found not to be associated with WiFi exposure. Sporadic findings were not consistent in terms of outcomes or exposure-response associations. This review based on a systematic literature search and quality evaluation does not suggest detrimental health effects from WiFi exposure below regulatory limits.

尽管在日常环境中，WiFi对射频电磁场（radiofrequency electromagnetic field, RF-EMF）总暴露量的贡献微乎其微，但人们仍对这种特定调制类型的射频电磁场是否会引发健康问题存有疑虑。本综述旨在评估所有探究WiFi暴露的生物学与健康效应、且符合基本质量标准的各类研究。纳入本次综述的研究需采用真实WiFi暴露场景，类型涵盖流行病学研究、人体实验研究、体内实验（in vivo）与体外实验（in vitro）研究。我们对1997年1月至2020年8月期间发表的所有相关文献开展系统性检索，随后针对实验研究中的盲法设计与剂量学分析、以及流行病学研究中的各类偏倚开展质量评估。所有符合质量标准的研究均从关联的存在与否两方面进行描述性总结。本次文献检索共识别出1385篇论文，其中23篇符合基本质量标准：包括6篇流行病学研究论文、6篇人体实验研究论文、9篇体内实验研究论文与2篇体外实验研究论文。体内实验与体外实验的暴露水平最高可达4 W/kg，而人体研究的暴露水平则比日常环境中典型WiFi暴露场景对应的国际非电离辐射防护委员会（International Commission on Non-Ionizing Radiation Protection, ICNIRP）指南限值低数个数量级。从生物学标志物到各类症状在内的诸多观测结局，大多未发现与WiFi暴露存在关联。零散出现的研究结果在观测结局或暴露-效应关联方面均未表现出一致性。本项基于系统性文献检索与质量评估的综述未表明，低于监管限值的WiFi暴露会引发有害健康效应。