Fungal Contamination in Public Buildings: Health Effects and Investigation Methods

2. Health Effects of Indoor Molds (Continued)

2.1.1 Cross-sectional studies

Cross-sectional studies are studies in which outcomes (diseases) and exposures are assessed at one point of time. Eight cross-sectional studies, summarized in Table 3, investigated the relationship between indoor mold and respiratory, allergic or irritation symptoms, and four found significant association between mold exposure and either physician-diagnosed asthma or asthma-related symptoms (cough, wheezing or breathlessness).

Table 3. Cross-sectional studies on respiratory and allergic effects of exposure to indoor molds, 1995 to 2001

Click to enlarge table

• In the Netherlands, 470 children aged 6 to 12 were included in a survey of home environment and respiratory symptoms. Mold growth in homes in the previous two years was classified as per its frequency: “never,” “sometimes,” “often” or “always.” Odds ratios were adjusted for age, gender, parental smoking, unvented kitchen geysers and parental education. The study found that neither chronic cough, shortness of breath nor wheezing were associated with mold growth (Cuijpers et al. 1995).
  
  
• In Finland, 1,460 people aged 25 to 64 were included in a survey of home environment and respiratory symptoms. Data were collected through a mail-out questionnaire. Odds ratios were adjusted for age, gender, smoking, education and dwelling type. Living or having lived in a home with a dampness or mold problem, defined as visible mold, mold smell, moisture stains or water damage, was associated with bronchitis (OR 2.04, 95% CI 1.49 to 2.78), atopy (OR 1.63, 95% CI 1.26 to 2.10), allergic rhinitis (OR 1.66, 95% CI 1.25 to 2.19), phlegm (OR 1.36, 95% CI 1.01 to 1.85), rhinitis (OR 1.69, 95% CI 1.31 to 2.18) and eye irritation (OR 1.52, 95% CI 1.18 to 1.96), but not physician-diagnosed asthma (OR 1.02, 95% CI 0.60 to 1.72). Some non-respiratory, non-allergic diseases also showed significant associations with dampness or molds: fatigue (OR 1.81, 95% CI 1.37 to 2.39), lumbar backache (OR 1.49, 95% CI 1.15 to 1.93) and recurrent stomachache (OR 1.65, 95% CI 1.24 to 2.20). When data were re-analyzed after excluding “complainers,” defined as those who reported lumbar backache and/or recurrent stomachache, in order to control for reporting bias, only ORs of eye irritation and fatigue remained significant (Pirhonen et al. 1996).
  
  
• In Taiwan, 1,340 children aged 8 to 12 years were surveyed. Data were collected through a questionnaire to parents. Odds ratios were adjusted for age, gender, parental education, number of smokers in household, and gas stove. Mold growth in homes was significantly associated with cough (OR 1.87, 95% CI 1.00 to 3.25), bronchitis (OR 1.68, 95% CI 1.26 to 2.25) and pneumonia (OR 1.77, 95% CI 1.03 to 3.05), but not physician-diagnosed asthma (OR 1.12, 95% CI 0.72 to 1.74) (Li and Hsu 1996).
  
  
• In the United States, 2,041 people aged 20 to 22 years who had responded to a mail-out questionnaire were included in a cross-sectional study. Data collection was based entirely on the questionnaire. Odds ratios were adjusted for gender, race, education and smok ing status. Visible mold growth at home was associated with an increased risk of physician-diagnosed asthma (OR 1.5, 95% CI 1.0 to 2.4) and current asthma (OR 2.0, 95% CI 1.2 to 3.2) (Hu et al. 1997).
  
  
• In Australia, 80 households with 148 children aged 7 to 14 were surveyed. A detailed housing characterization was carried out, and air samples were collected. Also, a respiratory health questionnaire was completed and skin prick tests with extracts of common aero allergens were performed for each of the children. The odds ratio for reported physician-diagnosed asthma with a 100-CFU/m³ increase in Penicillium spores was 1.43 (95% CI 1.03 to 2.00), and the odds ratio for atopy, defined as a positive response to at least one skin prick test, with a 10-CFU/m³ increase in Aspergillus spores was 1.48 (95% CI 1.10 to 1.99) (Garrett et al. 1998).
  
  
• In Finland, 699 adults aged at least 16 years were included in a cross-sectional study. Data collection consisted of a self-administered questionnaire followed by an investigation by civil engineers of mold and dampness in participants' dwellings. Odds ratios were adjusted for smoking, age, gender, allergy, indoor pets and atopy. The presence of mold in homes reported by occupants was associated with increased risk of cough without phlegm (OR 1.60, 95% CI 1.01 to 2.53), nocturnal cough (OR 2.30, 95% CI 1.32 to 4.01), sore throat (OR 2.40, 95% CI 1.56 to 3.69) and rhinitis (OR 1.89, 95% CI 1.15 to 3.11). The presence of molds observed by the civil engineers visiting the house was associated with an increased risk of sinusitis (OR 1.92, 95% CI 1.11 to 3.30), bronchitis (OR 1.98, 95% CI 1.13 to 3.48), nocturnal cough (OR 2.11, 95% CI 1.21 to 4.98), nocturnal dyspnea (OR 2.33, 95% CI 1.09 to 4.98) and sore throat (OR 1.46, 95% CI 1.03 to 2.08) (Koskinen et al. 1999).
  
  
• In Canada, the homes of 403 school children were surveyed. Parents filled out a questionnaire about their home environment and the respiratory health of their children. Air samples were collected and analyzed for ergosterol, viable fungi and bacterial endotoxin, while dust samples were collected for dust mite antigen analysis. Odds ratios were adjusted for age, gender, parental allergies and asthma, parental education, pets in homes and household smokers. Mold or mildew growth in the home in the past year was associated with irritation of eyes, nose or skin (OR 1.80, 95% CI 1.03 to 3.16), but not cough or wheezing (OR 1.36, 95% CI 0.79 to 2.33) or physician-diagnosed asthma (OR 0.96, 95% CI 0.46 to 2.00). Additional adjustment for bacterial endotoxin and dust mites did not change the magnitude of these associations. No signifi cant association was found between ergosterol and fungal cell counts, and respiratory outcomes (Dales and Miller 1999; Dales et al. 1999).
  
  
• In Finland, 10,677 first-year university students aged 18 to 25 were included in a questionnaire-based survey. Exposure and outcome assessments were based on responses. Odds ratios were adjusted for parental education, active and passive smoking, pets, carpets, place of residence (farm, rural non-farm or urban) and type of residence. Visible mold in participants' dwelling in the past year was associated with current physician-diagnosed asthma (OR 2.21, 95% CI 1.48 to 3.28), common cold at least four times in the past year (OR 1.48, 95% CI 1.17 to 1.88) and allergic rhinitis (OR 1.29, 95% CI 1.01 to 1.66) (Kilpeläinen et al. 2001).