Effect of an educational indoor air quality intervention on cognitive status, sleep quality, balance, and sick building syndrome in older adults: a randomized controlled trial

Indoor air pollution threatens healthy aging. This randomized controlled trial (RCT) evaluated a multicomponent educational/behavioral intervention targeting indoor air quality (IAQ) among older adults. To assess the efficacy of an educational/behavioral IAQ intervention on cognitive function, sleep quality, balance, and sick building syndrome (SBS) symptoms. In this assessor- and analyst-blinded RCT, 112 older participants (mean age 67.1 ± 5.7 years) in Shiraz, south Iran, were randomly assigned to an intervention (n = 56) or control (n = 56) group. The intervention group received a three-month program of educational sessions on pollution reduction and ventilation, plus daily reminders. The control group received no active intervention. Outcomes were assessed pre- and post-intervention. Analysis of covariance, adjusting for baseline scores, showed that the intervention group achieved significantly greater improvements in cognitive scores (adjusted MD = 1.62, p < 0.001), sleep quality (adjusted MD = − 0.56, p < 0.001), balance (adjusted MD = 2.96, p < 0.001), and a greater reduction in SBS symptoms (adjusted MD = − 1.22, p < 0.001) versus controls. Effect sizes (Cohen’s d) ranged from small to large (0.13–1.60). The Number Needed to Treat (NNT) for clinically meaningful improvement was 3 for cognition and SBS symptoms. This RCT indicates that a practical educational/behavioral intervention targeting IAQ is associated with significant improvements across multiple health domains in older adults. These findings support further evaluation of such interventions as a potential public health strategy for healthy aging, though the present study did not include objective measurements of indoor pollutant concentrations, and the observed benefits should therefore be attributed to the intervention as delivered rather than to verified changes in air quality. Iranian Registry of Clinical Trials (IRCT) IRCT20180514039648N7. Registered on 18 May 2024