A new study has found increased levels of a ‘marker’ for cardiovascular disease in workers of a company producing multi-walled carbon nanotubes (MWCNTs)[i]. Production of carbon nanotubes (CNTs) is increasing worldwide, and though there have been studies of cell cultures and animals, there are few studies of humans exposed to CNT-containing products.
CNTs are tube-shaped structures made of carbon atoms, in which the tube ‘wall’ is one atom thick. MWCNTs are tubes with multiple layers, and can take two forms: a ‘Russian doll’ model, in which several tubes are arranged with the narrowest on the inside and larger tubes forming a concentric pattern around the smaller tubes, and the ‘Parchment’ model, in which a single 2-dimensional sheet of carbon atoms is rolled up like a scroll. A characteristic feature of CNTs is that they have very large aspect ratios, whereby their length is far greater than their diameter. They are used in the manufacture of very strong, but lightweight, materials, and have applications in products such as bicycles, other sports equipment, helmets, aircraft, cars, and computer motherboards.
The study involved comparison of 22 workers of a company commercially producing MWCNTs with 42 unexposed controls. Blood samples were taken, and the researchers looked for twelve signs of inflammation and damage to the linings of blood vessels. An upward trend in the concentration of one marker of damage was observed with increasing exposure to MWCNTs. The trend was significant in different worker categories of lab personnel with low and high exposures and operators, and across different exposure concentrations. No consistent significant associations were found for the other eleven markers investigated.
The associations between MWCNT exposure and the marker suggest that there is increased inflammation and damage to blood vessel linings in workers exposed to MWCNTs.
[i] Kuijpers, E. et al. Cardiovascular effects among workers exposed to multiwalled carbon nanotubes. Occup Environ Med oemed-2017-104796 (2018). doi:10.1136/oemed-2017-104796 http://oem.bmj.com/content/early/2018/02/09/oemed-2017-104796 (Accessed 23 February 2018)