Table 3

 Symptom reporting by ventilation system

Ventilation systemNumber of buildingsMean (SE) symptom score in the building*
*Estimates are adjusted for age, sex, and employment grade using a regression model.
Mechanical ventilation21.74 (0.26)
Natural ventilation232.12 (0.09)
All air system102.07 (0.11)
Central induction62.21 (0.09)
Local induction32.20 (0.24)
p = 0.8