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Large-scale production and use of amorphous silica nanoparticles (SiNPs) have increased the risk of human exposure to SiNPs, while their health effects remain unclear. In this review, scientific papers from 2010 to 2016 were systematically selected and sorted based on in vitro and in vivo studies: to provide an update on SiNPs toxicity and to address the knowledge gaps indicated in the review of Napierska (Part Fibre Toxicol 7:39, 2010). Toxicity of SiNPs in vitro is size, dose, and cell type dependent. SiNPs synthesized by wet route exhibited noticeably different biological effects compared to thermal route-based SiNPs. Amorphous SiNPs (particularly colloidal and stöber) induced toxicity via mechanisms similar to crystalline silica. In vivo, route of administration and physico-chemical properties of SiNPs influences the toxicokinetics. Adverse effects were mainly observed in acutely exposed animals, while no significant signs of toxicity were noted in chronically dosed animals. The correlation between in vitro and in vivo toxicity remains less well established mainly due to improper—unrealistic—dosing both in vitro and in vivo. In conclusion, notwithstanding the multiple studies published in recent years, unambiguous linking of physico-chemical properties of SiNPs types to toxicity, bioavailability, or human health effects is not yet possible.

Employers should invest in creating good work environments in general, among both telecommuters and nontelecommuters.

Highlights We present the first WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury. Globally in 2016, 488 million people were exposed to long working hours (≥55 hours/week). This exposure had 745,194 attributable deaths and 23.3 million DALYs from ischemic heart disease and stroke. These are 4.9% of all deaths and 6.9% of all DALYs from these causes. The Western Pacific, South-East Asia, men, and older people carried higher burdens.