Table 2

Odds ratios of bronchial hyperreactivity in school aged children by exposure to environmental tobacco smoke

Reference no.Provoking agentPrevalence (%)Exposure comparisonOdds ratio95% CIConfounding/exclusions2-151
 3 Cold dry air23Mother smokes v not 0.815 0.38 to 1.72Adjusted for sex. Current respiratory illness excluded. Only two children actively smoked
11 Exercise + cold air40Smoking families v not 2.60 1.02 to 6.65Asthmatics and active smokers excluded
12 Exercise12Salivary cotinine >3.6 ng/ml v ND 1.01 0.47 to 2.15Asthmatics, those with recent symptoms and active smokers excluded
13 Exercise7Mother smokes v not 1.07 0.68 to 1.68Unadjusted
Mother smoked at 1 year1.530.98 to 2.40
Mother smoked while pregnant1.160.65 to 2.05
18 Exercise7Mother smokes at home v not 1.86 1.07 to 3.26Matched for sex, age and classroom. Active smoking not mentioned
Father smokes at home v not1.050.63 to 1.76
Mother smokes at home v neither2.231.06 to 4.69
9 2-150 Carbachol45Mother smokes v neither 1.89 0.85 to 4.21Adjusted for sex
Father smokes v neither2.211.06 to 4.59
Both smoke v neither2.311.13 to 4.75
Father only smokes2.881.29 to 6.45
10 Methacholine16Smoking mothers v not 0.77 0.36 to 1.63Asthmatics excluded. Active smoking ignored
19 2-150 Methacholine51Mother smokes v neither 1.34 1.01 to 1.78Adjusted for sex. Adjustment for a wide range of confounders reduced odds to 1.30
Both smoke v neither1.310.94 to 1.84
Father only v neither1.130.82 to 1.55
20 Methacholine43Mother smokes daily v not 1.23 0.76 to 1.99Unadjusted. Active smoking not mentioned
Mother smoked first year v not0.8150.5 to 1.33
Mother smoked when pregnant0.800.48 to 1.33
Father smokes daily v not0.940.58 to 1.54
15 Histamine24Any smoker in home v none1.300.92 to 1.84Adjusted for age, sex, area, house dust mite atopy
  • 2-150 Results presented for girls and boys combined, but adjusted for sex.

  • 2-151 Comment is made on active smoking for all studies including children >11 years.