New York, March 6: Exposure to third-hand smoking can cause insulin resistance, a precursor to Type-2 diabetes in non-smokers, especially kids and senior people, researchers have warned after conducting a study on mice. The findings showed that smoke accumulated on surfaces like clothing, hair, homes and cars may lead to Type-2 diabetes. "If confirmed in humans, our study could greatly impact how people view exposure to environmental tobacco toxins," said lead study author Manuela Martins-Green from the University of California-Riverside. "Children and the elderly are especially vulnerable to third-hand smoking and its impact on health. Because infants frequently crawl on carpets and touch objects exposed to exhaled smoke, they are at high risk for THS exposure," Martins-Green added in the paper published in the journal Plos One. Researchers explained that THS consists of tobacco smoke toxins that linger on surfaces and in dust after tobacco has been smoked. For the study, researchers first exposed cages (used for housing the mice) to second-hand smoke using a smoking machine. This smoke landed and accumulated on materials (commonly found in homes) in the cages and turned into THS. Mice were then introduced into the cages. A control group of mice was not exposed to any THS. THS-exposed mice were either fed a standard chow diet or a "western diet" - a modified chow diet similar to a high-fat diet people eat. The THS-exposed mice fed with the western diet showed increased oxidative stress, developed more severe insulin resistance and gained less weight than the control group of mice. While nicotine decreases appetite by affecting the brain and some hormone levels, it results also in increased oxidative stress. "Our findings have direct implications for humans because tobacco toxins are often present in human habitats," Martins-Green added. The elderly are at a high risk simply because older organs are more susceptible to disease, Martins-Green said.