PASSIVE SMOKING RESEARCH CALLED INTO QUESTION

DOUBT has been cast on scientific research which, it claimed, overestimated
the dangers of passive smoking.

The studies, published in the 'British Medical Journal' last October,
claimed that people who had never smoked had a 25 per cent greater chance
of developing lung cancer and heart disease if they lived with a smoker.
But scientists, researchers, doctors and statisticians have taken issue
with the findings, claiming that the authors had disregarded result which
did not agree with their interpretation of available data.

In letters published in today's 'BMJ', one researcher says there are better
ways to spend money than vilifing passive smoking, while another says the
evidence needs re-evaluation.

The original studies sparked a reaction from Tessa Jowell, the public
health minister, whe said they reinforced the compelllng case for reducing
smoking. The British Medical Association's science and research adviser
said the evidence showed living with a smoker was a major health hazard.

But in today's 'BMJ', Peter Lee, an independent consultant in statistics
and epidemiology, is critical of the previous studies. He says that the
authors should have included other research which would have distorted
their findings and that they based part of their conclusions on unreliable
evidence. He adds: "One might even argue that the authors have not
conclusively demonstrated that passive smoking has any effect on risk of
lung cancer."

In another letter to the 'BMJ', Dr Kenneth Denson, the director of Thames
Thrombosis and Haemostasis Research Foundation in Oxfordshire, says the
studies did not allow for other variables, such as diet. In any case, he
says: "We know the score on active smoking, but surely the money spent on
these attempts at vilifying passive smoking could be better spent in other
areas of the NHS."

The BMJ's editor, Dr Richard Smith, warns that medical studies coud be
flawed by conflicts of interest. Of 106 review articles on passive smoking,
37 per cent had concluded it was not harmful - three quarters of these
written by researchers with connections to tobacco companies.

Dr Smith says authors may not realise that they had been influenced. "Our
response is that bias works in subtle ways and that none of us is blessed
with knowledge of our own motivations and mental mechanisms." he said.