Een congres over de wetenschappelijke bewijsvoering rond de gevaren van meeroken werd, ondanks dat deze daar voor uitgenodigd waren, geboycot door vertegenwoordigers van anti-roken organisaties.
Tijdens het congres gaven epidemiologen en andere wetenschappers hun visie over meeroken weer.
General conclusions from Science and ETS seminar
- The findings of individual studies on the health effects of ETS are inconsistent and inconclusive. Few of the studies have produced results that fulfil conventional statistical tests for significance. Where a positive effect has been found, the relative risk has been so low that it is beyond the limits of reliable epidemiological inference.
- The concepts of relative and absolute risk have frequently been confused in the ETS debate. Associations between exposure and consequences have been overstated and causal relationships have been claimed where none have been shown to exist.
· Reviews of the ETS literature using meta-analysis of the published data are unreliable because of the wide disparity of experimental designs and methodologies used in the studies brought together using this technique.
- A number of studies have projected the number of deaths claimed to be “caused by ETS” or that “would be saved” by banning smoking in public places. These are simply arithmetical exercises and have no real-world relevance. This is because they are founded on a disregard for fundamental epidemiological and statistical methods.
- Small increases in relative risk are sometimes reported in percentage terms. For example, a relative risk of 1.2 is often popularised as a 20% increase in risk, giving an impression that if 100 people were exposed to the risk, 20 of them would contract the disease. This is highly misleading.
- A relative risk of 1.2 for a disease for which the incidence is 10 per 100,000 per year in a non-exposed population implies that the incidence is 12 per 100,000 per year in an exposed population. Thus, among 100,000 exposed individuals, two additional cases could occur each year.