Exposure to moulds and exacerbation of asthma in children (panel studies)

First author, location [ref.]Study designMould exposureMain outcomesResults
Hagmolen of Ten Have, the Netherlands [104]526 children with asthma (mean age 11 years)
Follow-up: 2 weeks (2 visits)
At baseline: positive response to a question on visible mould in the past 2 yearsDaily variability of peak flow
Daily symptoms: wheezing, cough, BHR at follow-up
No association between mould exposure and symptoms
In exposed children: increased peak flow variability: +2.70% (95% CI 0.92–4.47, p=0.003), and higher BHR: aOR: 3.95 (1.82–8.57)
Inal, Turkey [105]19 children with asthma or rhinitis, and monosensitised to mould (aged 4–13 years)
Follow-up: 1 year
Every month: indoor air:
MAS-100 Eco 100 L·min−1
Culture CFU·m−3: Cladosporium, Penicillium, Aspergillus, Alternaria and others (undefined or >1%)
Daily variability of peak flow: morning and evening
Daily symptoms (rhinitis and asthma scores)
No association between mean exposure to mould (37.5 CFU·m−3) and daily variability of peak flow or symptoms
Bundy, Western Massachusetts and Connecticut, USA [106]225 children with asthma (6–12 years old)
Follow-up: 2 weeks
At baseline: indoor air:
Burkard 1 min 20 L·min−1
Culture and classification:
0 CFU·m−3, 1–499 CFU·m−3, 500–999 CFU·m−3, >1000 CFU·m−3, Cladosporium, Alternaria, Penicillium or Aspergillus
Daily variability of peak flow: three series of measurements morning and evening performed by children
Daily symptoms (wheezing, cough and nocturnal symptoms), drugs reported by the mother
No association between mould exposure and symptoms
Associations between Penicillium (0 versus detectable) and peak flow variability of >18.5% (75th percentile) aOR 2.39 (95% CI 1.19–4.81)
Pongracic, the Inner-City Asthma Study: USA
469 children with mild to severe asthma and at least one positive SPT to mould (aged 5–11 years)
Follow-up: 2 years
At baseline and every 6 months: indoor air
2 measurements Burkard 1 min 30.5 L·min−1, 1 m from floor, children's room
Outdoor air
Culture CFU·m−3: Cladosporium, Alternaria, Penicillium and Aspergillus
Dust measurements on floor and bed
Call report every 2 months:
max number of days (in 2 weeks) with symptoms (wheezing, cough, chest tightness, awakening due to asthma or play activities stopped because of asthma)
Number of unplanned visits to hospital or EV in the past 2 months
Association between 10-fold increase in Penicillium level and increased number of days with symptoms: 1.19 days per 2 weeks, p<0.03
Association between indoor mould and exacerbations and EV:
aOR 1.22 (95% CI 1.05–1.43) and 1.13 (1.01–1.26)
Association between Penicillium and EV:
OR 1.15 (1.05–1.27) (all children), and 1.11 (1.03–1.20) in those SPT− for Penicillium
Wu, USA [32]395 children with mild-to-moderate persistent asthma
CAMP study
(aged 5–12 years)
Follow-up: 6 months and 3 years or before in case of moving
At baseline and at the first follow-up (6 months):
dust measurements on floor (main living room, bedrooms and kitchen) and on child's bed
Vacuum cleaner equipped with a filter (Douglas ReadiVac model): 2 min for each zone of different surfaces
Culture and classification: high mould dust exposure: >25 000 CFU·g−1 of house dust
Severe asthma exacerbations
Hospitalisations or urgent care visits during the 4 years of follow-up (report every 4 months)
Polymorphisms (SNPs) in chitinase genes
24% (n=95) had high mould dust exposure
Number of urgent care visits increased with high mould dust exposure in children with genetic polymorphisms (rs2486953, rs4950936 and rs1417149) in the CHIT1 gene
Gent, Western Massachusetts and Connecticut, USA [108]1233 school-aged children with asthma (aged 5–10 years)
Follow-up: 1 month
At baseline: indoor air:
Burkard 1 min 20 L·min−1, culture: CFU·m−3
Dust measurements on floor and furniture in the main living room
Blood allergens: mould, mites, cat, dog (µg·g−1) and cockroaches (U·g−1)
Daily symptoms (wheezing, cough), drugs and severity (five levels)
Allergic sensitisation: allergens and IgE
In sensitised children: associations between Penicillium and risk of wheezing: aOR 2.12 (95% CI 1.12–4.04), cough: 2.01 (1.05–3.85) and asthma severity score: 1.99 (1.06–3.72)
Vicendese, Melbourne, Australia [33]Nested incident case–control study within the MAPCAH study: 44 children (aged 2–17 years)
Follow-up: September 2009 to December 2011
Air fungi in the child's bedroom: two-stage Andersen Sampler for 1 min, flow rate: 28 L·min−1
Total fungi, Cladosporium, Penicillium/Aspergillus and Alternaria, CFU per 28 L of air
Standardised questionnaires from the ISAAC and NZ Otago studies
Incident asthma readmissions
Association between every doubling concentration of CFU of airborne Cladosporium (per 28 L of air) in the bedroom and asthma readmission:
aOR 1.68 (95% CI 1.04–2.72)
Dannemiller, Western Massachusetts and Connecticut, USA [34]n=196, subgroup of the 1233 school-aged children with asthma (aged 5–10 years)
Follow-up: 1 month
At baseline: indoor air: Burkard 1 min 20 L·min−1, culture: CFU·m−3
Dust measurements on floor and furniture in the main living room
Total fungi concentration dichotomised at the median (high and low exposure)
Daily symptoms (wheezing, cough), and medication use
Asthma severity (five levels) expressed as mild (reference, 0 or 1) or severe (3 or 4), level 2 not included in the analyses
Total and specific IgE
Association between high fungal concentration and asthma severity in all children:
aOR 2.02 (95% CI 1.14–3.56) and in nonatopic children:
aOR 2.40 (95% CI 1.06–5.44), but not in atopic children:
1.69 (0.77–3.75)
Casas, HITEA project: Spain, the Netherlands, Finland
419 children (aged 6–12 years) from 25 schools: 106 children from 8 schools in Spain, 150 children from 11 schools in the Netherlands, 163 children from 6 schools in Finland
Follow-up: 1 year
School with or without (reference) moisture damage: number, extent, severity and location of dampness, and moisture damage observations recorded during inspectionsThree symptom diaries: a 2-week diary starting before the summer school holiday (May–July 2009), a 3-week diary starting at the end of the summer holiday (August–October 2009) and a 2-week diary during winter and spring (January–May 2010)
16 symptoms in the past 24 h: wheeze, shortness of breath, dry cough during day or at night, phlegm, woken up… and severity (no symptom, slight, moderate or severe)
Holiday and weekends were associated with lower scores
Results were heterogeneous across the three countries
In Spain, all adjusted IRRs <1 for summer holiday (ref. school day) in schools with moisture damage: lower respiratory symptoms IRR 0.61 (95% CI 0.46–0.81), upper respiratory or allergy symptoms 0.78 (95% CI 0.63–0.93), other symptoms 0.64 (95% CI 0.49–0.83)
Similar results in Finland for summer holiday and weekend
All random-effect combined IRRs <1

HITEA: Health Effects of Indoor Pollutants: Integrating Microbial, Toxicological and Epidemiological Approaches; BHR: bronchial hyperresponsiveness; aOR: adjusted odds ratio; EV: emergency visit; SPT: skin prick test; SNP: single nucleotide polymorphism; Ig: immunoglobulin; MAPCAH: Melbourne Air Pollen Children and Adolescent Health; ISAAC: International Study of Asthma and Allergies in Childhood; IRR: incidence rate ratio.