Christopher Booker :
In 1998 and 2003 came the results of by far the biggest studies of passive smoking ever carried out. One was conducted by the International Agency for Research on Cancer, part of the World Health Organisation. The other, run by Prof James Enstrom and Geoffrey Kabat for the American Cancer Society, was a mammoth 40-year-long study of 35,000 non-smokers living with smokers. In each case, when the sponsors saw the results they were horrified. The evidence inescapably showed that passive smoking posed no significant risk. This confirmed Sir Richard Doll's own comment in 2001: "The effects of other people's smoking in my presence is so small it doesn't worry me".
In each case, the sponsors tried to suppress the results, which were only with difficulty made public (the fact that Enstrom and Kabat, both non-smokers, could only get their results published with help from the tobacco industry was inevitably used to discredit them, even though all their research had been financed by the anti-tobacco cancer charity).