Resolving the questions on which this study fails to be statistically clear (ie, on the questions of the mechanism) will require further controlled trials in which objective data are concurrently gathered on family asthma-management behaviors (eg, medication adherence and other environmental control practices), as well as on ETS exposure and asthma outcomes (eg, symptoms, lung function, activity limitations, and health-care utilization). We suggest that it also would be important to measure the stage of change of the caregiver with regard to smoking cessation and the prohibition of smoking in the home at the outset and at the conclusion of the study. With permission, stage data might also be gathered from those caregivers who decline to participate. This information could help to identify the segment of the ETS-exposed population that is reached by such an intervention and could reveal whether certain types of caregivers are more responsive to the intervention than others and whether the intervention is able to move participants from a precontemplation stage to contemplation and action. The measurement of all the key links in the presumed causal chain initiated by any environmental exposure reduction intervention is clearly critical to improving such interventions and to understanding the mechanisms involved in any associated clinical benefits. canadian family pharmacy
Methodologic Issues in Evaluation of Exposure Reduction Interventions
Observing very marked differential improvement in asthma health-care utilization, coupled with failing to demonstrate a statistically significant difference in ETS exposure reduction or asthma symptoms, raises yet other important methodological issues for exposure mitigation research, regardless of whether the exposure is to ETS or some other agent in indoor air that exacerbates asthma. The effectiveness of previous attempts to reduce ETS exposure has been mixed, as noted earlier. Convincing reductions in ETS exposure have not been reported. Where a reduction has been noted, the reduction was in home air concentration rather than in personal exposure, and there was only a very limited concurrent assessment of asthma symptoms and no assessment of asthma health-care utilization. Consequently, the clinical significance of any ETS exposure reduction that might have been achieved is unknown.