Table 1

Summary of studies reviewed

Reference no.YearCountryAgeSample sizeSample selectionProvoking agentOutcomes
Studies of bronchial reactivity in neonates
7 91Australia4 weeks63Random recruitment at prenatal clinicHistaminePC40 (g/l) for VmaxFRC
Studies of bronchial reactivity in schoolchildren: odds ratios available
3,4,8 85US11–16173Population sample from East BostonCold dry airDecline in FEV1/VC ⩾9%
9 88Italy9166Population sample from three townsCarbacholFall in FEV1 ⩾20%
10 88Italy11–14276Random sample of childrenMethacholineFall in FEV1 ⩾20%
11 89Germany10–1480Healthy children from three schoolsExercise + cold air50% Raw increase
12 90UK777030 primary schools in EdinburghRunning for 6 minFall in FEV1 >10% (other cutoffs available)
13,14 92Germany81461Children entering primary schools in three townsRunning for 3 minDecrease in PEF ⩾15%
1517 91Australia5–12783Children living near power stationsHistamineFall in FEV1 ⩾20%
18 94Spain9–14338C-C study based on prevalence surveyRunning for 5 minFall in PEF >15%
19 94Italy7–111183Random sample of schools in two areasMethacholinePC20 >64 mg/ml
20 95Norway7–13529Children from two valleys in Western NorwayMethacholinePC20 ⩽8 mg/ml (or 20% increase in FEV1 after bronchodilator)
Studies of bronchial reactivity in schoolchildren: odds ratios not available
21,22 89Denmark7–16495Population sample around Copenhagen UniversityHistaminePC20 <8.0 mg/ml
23 91Hungary9–13206Children with “obstructive bronchitis”AceticholineFall in PEF (or FEV1⩾20%
24 92Australia7–121217Schoolchildren from Sydney suburbHistaminePC20 ⩽3.9 μmol)
25 94Hong Kong9–12412Four schools in two districtsFall in FEV1 ⩾20%
26 94Croatia7–141201?Cold dry air
Studies of bronchial reactivity in schoolchildren: data not published
27 90Germany7–16623Mail invitation to 7500 childrenCarbachol
28 94Australia8–112765All schools in three areasHistamineFall in FEV1 ⩾20% or ⩾15% bronchodilation if FEV1 <60% predicted
29 96Australia8–11808Children living near GPO in SydneyRunning for 6 minFall in FEV1 ⩾15%
30 96New Zealand9–151037Dunedin birth cohortMethacholinePC20 FEV1 ⩽8 mg/ml (or bronchodilation ⩾10% after salbutamol)
Study of bronchial reactivity amongst referrals to an allergy clinic
2,3134 86Canada7–1741Allergy referrals with history of asthma/wheezeHistaminePC20
Observational studies of PEF variability
35 90USA5–14108Community study in TucsonObservational“Diurnal variation” in PEF
36 92Italy10–1140UnclearObservationalCircadian rythm of PEF
37 93Germany81237All children entering primary school in three townsObservationalAverage over 5 days of PEFhigh–PEFlow/PEF mean
38 96Holland9.355Unclear - “Children with allergic asthma at primary school”Observational(PEFhigh–PEFlow)/PEFmean
Study of bronchodilation in school aged children
39 83US6–12183Children attending school in Iowa cityIsoproterenolChange in FVC, FEV1, PEF, FEF25, FEF50, FEF75
Studies of the acute effects of ETS exposure
40 91Germany8–1311Asthmatic childrenHistamineConcentration leading to 20% fall in FEV1
41 93Germany8–1313Asthmatic childrenCycling for 6 min% fall in FEV1 after exercise
42 89Mexico6–1662Asthmatic childrenNoneFVC, FEV, MMEF measured before and after ETS exposure
  • C-C = case-control; FEV1 = forced expiratory volume in one second; VC = vital capacity; PC20 = concentration required to reduce FEV1 by 20%; PEF = peak expiratory flow; ETS = environmental tobacco smoke.