Table 1 Participants characteristics of eligible studies included in the meta-analysis

Gent et al.,

2002

USA

Indoor Air

Burkard portable air sampler

Fungi

Plate count;

Undetectable® Vs ≥ 1000 cfu/m³

Reported wheeze and persistent cough measured as number of days of symptoms (0, < 30 and ≥ 30 days)

119

880

RPW: 2.15 (1.34 – 3.46)^a

PC: 2.06 (1.31 – 3.24)^a

Rosenbaum et al.,

2010

USA

Indoor Air; Dust sample

Single-stage Andersen air sampler; High volume vacuum cleaner

Bacteria; Fungi; Endotoxin

Plate count; KLARE

Not detectable® Vs > 75^th percentile

Primary care provider documented wheeze; Wheeze heard on physical examination by a clinician

39

103

6.18 (1.34—28.46)^a

Horick et al.,

2006

USA

Dust sample

High volume vacuum cleaner

Endotoxin

KLARE

TEC < 100 EU/mg® Vs ≥ 100EU/mg

Primary care provider reported “any wheeze” ≥ 1 episode

42

360

5.56 (1.19 – 26.03)^a

Park et al.,

2001

USA

Dust sample

Eureka Mighty-Mite vacuum cleaner

Endotoxin

KLARE

TEC < 100 EU/mg® Vs ≥ 100EU/mg

Primary care provider reported “any wheeze” ≥ 1 episode or repeated episode of wheeze

211

499

AW: 1.33 (0.99–1.79)^a

RW: 1.55 (1.00 – 2.42)^a

Harley et al.,

2009

USA

Indoor Air

Hirst-type sampler

Fungi spores

Spore count

Not detectable® Vs ≥ 1000 cfu/m³

A child was considered to have early wheezing if medical records indicated a clinician’s diagnosis of asthma at any time between birth and 24 months of age

35

514

1.2 (0.7 – 2.7)^a

Litonjua et al.,

2002

USA

Dust sample

High volume vacuum cleaner

Endotoxin

KLARE

TEC < 81.3 EU/mg® Vs ≥ 81.3EU/mg

Wheezing in the past 12 month or repeated wheezing twice in the 4 years of follow-up

57

226

W: 1.52 (1.07—2.14)^a

RW: 2.57 (1.00 – 6.62)^a

Campo et al.,

2006

USA

Dust sample

Filter Queen Majestic vacuum cleaner

Endotoxin

Kinetic Chromogenic -LAL

TEC < 100 EU/mg® Vs ≥ 100EU/mg

Recurrent wheeze; ≥ 2 wheezing episodes in the past 12 months or any wheezing: ≥ 1 wheezing episode in the past 12 months

137

532

RCW: 0.4 (0.1–0.9)^a

AW: 0.3 (0.1–0.8)^a

Gillespie et al.,

2006

New Zealand

Dust sample

High volume vacuum cleaner

Endotoxin

Kinetic Chromogenic -LAL

TEC < 100 EU/mg® Vs ≥ 100EU/mg

Reported wheeze for at least 6 months. Rhinitis defined as blocked or runny nose when the child do not have a cold or flu

342

881

1.54 (1.03 – 2.30)^a

Perzanowski et al.,

2006

USA

Dust sample

Eureka Mighty-Mite vacuum cleaner

Endotoxin

Kinetic Chromogenic -LAL

TEC < 100 EU/mg® Vs ≥ 100EU/mg

Wheezing defined as presence of runny nose, sneezing, itchy eyes without cold at age 12, 24 and 36 months

163

301

1.04 (0.71 – 1.5)^a

Karvonen et al.,

2012

EU

Dust sample

High volume vacuum cleaner

Endotoxin

Kinetic Chromogenic -LAL

TEC < 100 EU/mg® Vs ≥ 100EU/mg

Primary care provider reported “any wheeze” ≥ 1 episode

984

1133

0.71 (0.51 – 0.99)^a

Stark et al.,

2005

USA

Indoor Air

Dust sample

Burkard portable air sampler; Eureka Mighty Mite canister vacuum cleaner

Fungi

Plate count

Low® Vs High

TEC < 100 EU/mg® Vs ≥ 100EU/mg

Doctor diagnosed allergic rhinitis or hay fever

52

405

3.13 (1.51 – 6.47)^a

Biagini et al.,

2006

USA

Home inspection

Walkthrough Checklist

Mold

Observation

Low® Vs High

Rhinitis defined as parents’ report of sneezing or a runny or blocked nose not associated with a cold or chest infection’ in the past 30 days

242

495

1.7 (0.7 – 3.8)^a

Bolte et al.,

2003

Germany

Dust sample

High volume vacuum cleaner

Endotoxin

Kinetic Chromogenic -LAL

Highest quartile Vs Lowest quartile®

Repeated wheeze defined as having had at least 2 episode of wheezing

378

1,942

1.77 (1.14 – 2.73)^a

Douwes et al.,

2006

The Netherlands

Dust sample

Rowenta Dymbo vacuum cleaner

Endotoxin

Kinetic Chromogenic -LAL

Highest quartile Vs Medium quartile®

Doctor-diagnosed asthma was defined as a reported diagnosis confirmed by a doctor at any time in the past 4 years

547

696

0.40 (0.21 – 0.77)^a

Phipatanakul et al.,

2005

USA

Dust sample

High volume vacuum cleaner

Endotoxin

Kinetic Chromogenic -LAL

4^th quartile Vs 1^st quartile®

Any report of wheeze (any wheeze) in the first year of life

197

498

2.39 (1.22 – 4.68)^a