According to a new study, smokers increased their health risks by inhaling their own secondhand smoke. The effect increased in enclosed spaces.

It was stated that the findings contradicted present belief that secondhand smoke was not dangerous when compared to smoking directly.

Researcher Maria Teresa Piccardo of the National Cancer Research Institute in Genoa, Italy, said, "Both active and passive smoking contributions should always be considered in studies about health of active smokers."

About 15 smokers in Italy were analyzed for a study that was published in Environmental Health. The total carcinogen exposure of these smokers was measured for the study.

An average smoker consumed about 14 cigarettes a day during the study and it was found that secondhand smoke meant 15 per cent and 23 per cent of regular cigarettes and 21 per cent to 34 per cent of light cigarettes.

Apart from this inhaling secondhand smoke from other smokers meant about 1.3 regular cigarettes.