Secondly, the devastating effects of tobacco are not known to the general public in detail, and it has taken over 40 years even in a country like the USA to convincingly establish a link between lung cancer and tobacco. The third important reason for this is that the effect of smoking on environment and the passive smokers, is not being well appreciated,although the Japanese epidemiologist, Dr T. Hirayama convincingly showed 20 years back the relation between the lung cancer among the non-smoking wives of heavy smokers. Happily, the awareness on this front is increasing all over the world and many countries are taking steps to combat the menace. Oral cancer and cancer of the throat are associated with tobacco chewing of all kinds. Smoking during pregnancy can lead to foetus death, abortion, growth retadation of the foetus, and low birth-weight babies.
Smoking also increases the risk of other carcinogens even among passive smokers.
On the other hand, it is heartening to know that giving up of smoking at any stage leads to a reversal of many of these ailments including the risk of heart disease, cancer of the lung, improvement in general health besides the economic benefits. One thing which does not reverse very easily is the air-way obstructive disease. But even there the deterioration stops. The epidemiology of smoking does not paint a very good picture for the poor developing countries. In 1997, the World Bank and World Health Organisation did a global study on the economics of tobacco control covering 70 countries.