Table 2

Subgroup analysis of the effect of active tobacco use during pregnancy on wheezing occurrence in infants

VariableGroupsOR (95% CI)I2 (%)X2 p value
Sample size<10001.92 (1.31 to 2.85)0.00.72
≥10001.43 (1.19 to 1.73)70.40.01
Study designProspective cohort1.72 (1.25 to 2.37)740.00
Retrospective cohort1.36 (1.20 to 1.55)0.00.58
Methodological qualityModerate1.29 (1.10 to 1.51)29.30.23
High1.77 (1.35 to 2.31)52.90.08