Research commissioned by the tobacco conglomerate Philip Morris found that cot death was linked to passive smoking, fuelling the debate on banning smoking in public places as the dangers of "second-hand smoke" become increasingly irrefutable.
The draft report was later modified to say that the links were "difficult to quantify," raising concerns that the tobacco firm sought to influence the findings of the study.
The link between cot death and babies who live in homes where adults smoke has been strengthening over the past decade. This year, a report by the government's scientific committee on tobacco and health said children exposed to cigarette smoke are at "greater risk" of cot death.
The disclosure that the world's largest tobacco firm commissioned research that originally came to this same conclusion will fuel the debate on banning smoking in public places.
The original drafts of the study emerged after researchers from the University of California trawled through thousands of confidential company documents released as a result of lawsuits in the US. Their findings have just been published in the journal Pediatrics.
The report was written by the British toxicology consultant Dr. Frank Sullivan. When his first draft concluded that passive smoking was a possible cause of cot death, or sudden infant death syndrome, company scientists persuaded him to change his mind, supplying him with evidence to suggest that the links were "unproven."
As a result of interventions by Philip Morris -- which makes Marlboro cigarettes -- Sullivan agreed to modify his findings. His final study was published in 2001 in an influential scientific journal without revealing the full role played by the tobacco giant in his report.
The authors claim that the once-secret company documents reveal how the Sullivan study was part of an elaborate attempt by the firm to sway public policy about smoking around children.
In the early 1990s, Philip Morris was trying to counter the view that tobacco smoke could cause cot death. Tobacco bosses feared that such evidence would create a powerful argument for smoke-free areas in the home and public places.
Stan Glantz, professor of medicine at the University of California, claims their investigation reveals the extreme efforts adopted by the tobacco industry to influence public policy. He said: "Their aim was to use this study to subtly manipulate public opinion. By [using] the scientific literature, they can create doubt and confusion among doctors and health officials over the debate about smoking around children."
In 1997, Philip Morris commissioned Sullivan to write a review of all the known risk factors of sudden infant death syndrome. Sullivan was an expert on birth deformities and had advised the British government on the impact of chemicals on human reproduction. There is no suggestion that he was knowingly part of any plan improperly to shift public policy.
For Philip Morris, he was an ideal candidate because he had also been a consultant to the cigarette firm Rothmans and had taken part in tobacco-funded research that had questioned the role played by second-hand smoke in damaging health. A company memo describes him as having "excellent credentials."
Sullivan's consulting fees from Philip Morris were ?800 (US$1500) a day and the company budgeted between US$47,000 and US$94,000 for his study. The contract stated that Sullivan would remain free to publish the final version without restriction by Philip Morris.