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Keywords:

  • Asthma;
  • Dampness;
  • Health;
  • Meta-analysis;
  • Mold

Abstract

  1. Top of page
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Conclusions
  7. Acknowledgements
  8. References
  9. Appendix

Abstract 

Abstract  The Institute of Medicine (IOM) of the National Academy of Sciences recently completed a critical review of the scientific literature pertaining to the association of indoor dampness and mold contamination with adverse health effects. In this paper, we report the results of quantitative meta-analyses of the studies reviewed in the IOM report plus other related studies. We developed point estimates and confidence intervals (CIs) of odds ratios (ORs) that summarize the association of several respiratory and asthma-related health outcomes with the presence of dampness and mold in homes. The ORs and CIs from the original studies were transformed to the log scale and random effect models were applied to the log ORs and their variance. Models accounted for the correlation between multiple results within the studies analyzed. Central estimates of ORs for the health outcomes ranged from 1.34 to 1.75. CIs (95%) excluded unity in nine of 10 instances, and in most cases the lower bound of the CI exceeded 1.2. Based on the results of the meta-analyses, building dampness and mold are associated with approximately 30–50% increases in a variety of respiratory and asthma-related health outcomes.


Introduction

  1. Top of page
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Conclusions
  7. Acknowledgements
  8. References
  9. Appendix

The association of adverse health effects with dampness and mold in buildings has been the subject of much research. Most studies on this topic have found an increased risk of one or more adverse health effects in buildings with signs of dampness or visible mold. The Institute of Medicine (IOM) of the National Academy of Sciences recently completed a critical review (IOM, 2004) of this scientific literature. The IOM concluded that excessive indoor dampness is a public health problem, noted that dampness problems are common, and recommended corrective measures. While the IOM report summarized the main features and results of the reviewed studies, which included a broad range of health outcomes, it provided no quantitative summaries of the findings of these studies.

In this paper, we report the results of quantitative meta-analyses of the studies reviewed in the IOM report and other similar studies that met specified study inclusion criteria. A meta-analysis uses statistical methods to combine data from different but comparable research studies, in order to provide a quantitative summary estimate on the size and variability of an association. Studies are generally selected for relevance, quality, and similarity. The contribution of larger, more precise studies to the summary estimate is generally more heavily weighted. Results of meta-analyses presented here are central point estimates and confidence intervals (CIs) of odds ratios (ORs) that summarize the magnitude of increased risk of several health outcomes in buildings with dampness and mold. The central estimates and CIs of ORs, if assumed to reflect causal relationships, can be used to communicate the importance of dampness and mold as health risks, to estimate the economic significance of dampness- and mold-related health effects to society, and to estimate the magnitude of health and economic benefits from programs that reduce dampness and mold.

Methods

  1. Top of page
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Conclusions
  7. Acknowledgements
  8. References
  9. Appendix

We began with the full list of studies included in Tables 5-1, 5-2, 5-3, 5-6, 5-7, and 5-8 of the recent IOM review (IOM, 2004) and added studies identified in a search using PubMed. Search terms included combinations of dampness, building, home, health, asthma, respiratory, symptoms, and similar terms. Additional studies were identified via the reference lists of the original set of papers. Papers meeting the following criteria were selected for use in the meta-analyses:

  • • 
    Article was published in a refereed archival journal.
  • • 
    Article was based on original data; i.e. not a review article or meta-analysis.
  • • 
    Data were analyzed statistically to produce an odds ratio or relative risk (RR) and confidence interval (CI).
  • • 
    Risk factors included one or more measures of dampness, mold, or dampness and mold in housing located in a developed country setting.
  • • 
    Health outcomes were one or more of the outcomes included in this analysis (see below).
  • • 
    Study controlled for potential confounding by the following factors via study design or analysis method: age, gender, smoking in home or prenatal smoking; and some measure of socioeconomic status (SES). No control for SES was required if the study subjects were from Sweden which has limited SES variation and where control for SES in studies is not common.
  • • 
    For analyses with asthma development as the outcome, a subject age 3 years or greater was required.
  • • 
    Study included more than two damp and two non-damp buildings or assessed spatial variability of dampness within buildings.

Ideally, each meta-analysis would combine estimates only from studies with the same precisely defined health outcome, risk factor, and population/subjects. Because the original studies included many differently defined respiratory health outcomes, risk factors, and populations, this was not possible, and we analyzed groups of studies that were as similar as practicable with respect to these. Table 1 shows the categories of health outcome used in meta-analyses here, with the specific outcomes from reviewed studies included in each category.

Table 1.   Health outcomes from reviewed studies, grouped into outcome categories used in meta-analyses
Category in meta-analysisOutcomes from individual studies included in each category
  1. aThe question's wording reflects the fact that the study assessed the risk of asthma in mothers and fathers of school children as a function of dampness in the home as part of a broader study focusing on children's asthma symptoms.

Upper respiratory tract symptomsIrritated, stuffy, or runny nose; nasal symptoms; nasal congestion; nasal congestion or runny nose; nasal excretion; nose irritation; rhinitis; sinusitis; allergic rhinitis; allergy; hay fever
CoughCough; cough with phlegm; cough without phlegm; day or night cough; dry cough; morning cough; long-term cough; chronic cough; cough on most days for 3 months; night cough with wheeze; persistent cough; nocturnal cough; cough 3 months of year apart from colds
WheezeWheeze; persistent wheeze; wheeze apart from cold; wheeze including shortness of breath and asthma; wheeze/breathlessness; wheezing or whistling in the chest; wheeze in last year; wheeze apart from colds on most days; wheeze after exercise
Ever diagnosed with asthmaPositive response to – has a doctor ever diagnosed mother (father) to have attacks of shortness of breath (asthma)a; Positive response to– did a doctor ever diagnose your having attacks of shortness of breath or asthma?; Physician-diagnosed asthma; Physician-diagnosed asthma, ever (atopic and non-atopic); Physician diagnosis of asthma since age >16; Self-reported physician-diagnosed or nurse-diagnosed asthma
Current asthmaCurrent physician-diagnosed asthma, defined as diagnosis plus symptoms in last 12 months; Ever doctor-diagnosed asthma, plus asthma symptoms or medication in past 12 months; Current asthma defined as combination of bronchial hyper-responsiveness and at least one of wheeze or breathlessness in last 12 months; Subjective symptoms of asthma plus one or more of the following: doctor-diagnosed asthma attack and the disappearance of wheezing; doctor diagnosed asthma attack and >15% decrease in PEF or FEV1; >15% decrease in PEF or FEV1 in exercise test; >20% daily variation in PEF at least 2 days per week in 4 weeks of tracking; >15% rise in PEF or FEV1 in a bronchodilating test; Asthma – current and diagnosed by physician; Current asthma diagnosed by a doctor – text implies that current refers to last 12 months; Asthma currently present and reported to be confirmed by a physician; Occurrence of doctor-diagnosed asthma in past year; Positive response to following two questions – has your doctor ever said your child has asthma? does he or she still have asthma? Doctor-diagnosed asthma and attendance of asthma clinic in 4-month period prior to study
Asthma developmentNewly doctor-diagnosed cases of asthma in past 2.5 years; Physician diagnosis of asthma at age >16; First-time diagnosis of asthma New doctor-diagnosed asthma between baseline study and follow-up study after 6 years

Subject types

The reviewed studies included diverse populations: adults, male adults, female adults, children (age < 18), and children (infants). For wheeze and cough outcomes, the largest numbers of studies were available and we performed separate analyses for adults (including studies of mixed or single gender), children (including studies of age <18 or infants), and all ages combined. However, for other outcomes, too few studies were available to support separate meta-analyses for children and adults.

Risk factors

In general, the risk factors in the reviewed studies included visible signs of dampness, visible mold, dampness or mold, dampness and mold, and measured concentrations of airborne mold spores or related agents of microbial origin. We included in meta-analyses only studies with reports of visible dampness and/or mold or mold odor as risk factors. A large majority of studies used these risk factors. We did not distinguish among dampness, mold, dampness or mold, and dampness and mold as risk factors. Our rationale – visible mold is always considered the result of excess dampness whether or not the dampness is reported, and excess dampness is very often accompanied by mold, although the mold may not be visible. Thus, it was not possible to make a clear distinction among these risk factors. We excluded from the meta-analyses ORs for associations of health effects with measured concentrations of microbial agents or measured or reported air humidity.

Presence of dampness and/or mold was determined in each study by either the occupants or the researchers. We did not distinguish between occupant-reported dampness and/or mold and researcher-reported dampness and/or mold. The discussion section of this paper provides further related information.

Health outcome categories

We categorized the health outcomes as upper respiratory tract (URT) symptoms, cough, wheeze, asthma diagnosis, current asthma, and asthma development. The specific outcome definitions varied among papers and are listed in Table 1. The URT symptom category included the broadest set of health outcomes, but nasal symptoms predominated. For asthma outcomes, based on review of the original papers, we developed different outcome categories than were used in the IOM report (IOM, 2004). Our asthma development category included ORs from studies that assessed whether the development of asthma, as opposed to presence of asthma symptoms, was associated with prior dampness and mold; however, the associated time period for the asthma development and exposure assessment ranged widely and there were few studies in this category.

Statistical methods

These analyses used random effect models (DerSimonian and Laird, 1986) to summarize effect estimates across studies with substantial differences in risk assessment, symptom definition, subjects, and location. While fixed effect models account only for variability within each study from sampling error, random effect models are more appropriate here because they also account for variability between different studies. Some of the studies reported more than one estimated odds ratio, for different but related risk factors (e.g. visible mold; visible mold and dampness), or health outcome metrics (e.g. cough; night cough). Because these findings within the same study may not be statistically independent, a meta-analysis that ignored this possible dependence between multiple estimates within a study might overestimate the precision of the summary estimates. Therefore, random effect models adjusting for this type of within-study correlation were used in primary analyses. Results from analyses ignoring such correlation (not provided) differed only slightly to moderately from results of the primary analyses. We used the SAS procedure PROC MIXED, which allows fixing the within-study variances (matrix R in SAS) while estimating between-study variance (matrix G in SAS).

Odds ratios and 95% CIs reported in each reviewed study were first transformed to the log scale. The transformed results for each outcome category were then combined using a random effect model. The model accounting for the correlation between multiple results within studies (‘dependent sub-studies’) was

  • image(1)

where: yij is the ln OR in the jth sub-study of the ith study; β0 is the fixed effect across all studies; β0i is the random effect in the ith study. β0iN(0, σ*2), where: σ*2 is the between-study variance; and inline image is the within-study variance, calculated from the log CI.

Estimation of percentage increases in health outcomes

To communicate the results of the meta-analyses in familiar terms, percentage increases in health outcomes were estimated from the central estimates of ORs and assumed typical outcome prevalence rates. The protocol follows.

The definition of OR is

  • image(2)

where P1 and P2 are the prevalence rates of the health outcomes in the populations with and without the risk factor, e.g. mold, respectively. When P1 and P2 are much smaller than unity, which is the typical case for this paper, the OR is approximately equal to P1 divided by P2 and the percentage increase in the outcome in the population with the risk factor, denoted by I, is then approximated as follows

  • image(3)

In the more general case

  • image(4)

Initial estimates of I were developed using equation 3. To derive more accurate (slightly smaller) estimates of I, values of P2 were calculated from equation 2 with assumed typical values of P1 and our central estimates of OR.I was then calculated with equation 4. We assumed a 12% prevalence rate for asthma outcomes and a 25% prevalence rate for URT and cough symptoms.

Results

  1. Top of page
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Conclusions
  7. Acknowledgements
  8. References
  9. Appendix

Overall, 33 studies were selected for inclusion in these meta-analyses. Details on the included studies are provided in Appendix. Major results for the specific meta-analyses, along with the number of studies included in each, are summarized in Table 2.

Table 2.   Key results of the meta-analyses
OutcomeSubjectsNo. studiesOdds ratio central estimate (CI)Estimated % increase in damp homes
Upper respiratory tract symptomsAll131.70 (1.44–2.00)52
CoughAll181.67 (1.49–1.86)50
Adults61.52 (1.18–1.96)
Children121.75 (1.56–1.96)
WheezeAll221.50 (1.38–1.64)44
Adults51.39 (1.04–1.85)
Children171.53 (1.39–1.68)
Current asthmaAll101.56 (1.30–1.86)50
Ever-diagnosed asthmaAll81.37 (1.23–1.53)33
Asthma developmentAll41.34 (0.86–2.10)30

Central estimates of ORs ranged from 1.34 to 1.75. Confidence intervals (95%) excluded unity for 10 of 11 analyses, and in most cases the lower bound of the CI exceeded 1.2. For wheeze and cough, the ORs for health effects in children were slightly higher than corresponding ORs for adults. The CI for asthma development was broad, with a lower bound below unity, presumably because the analyses included data from only four studies. The estimated associated percent increases in health outcomes for all subjects in damp houses ranged from 30% to 52%.

Figure 1 shows, as an example, ORs and CIs for the association of wheeze with dampness and mold in the original studies, and also from the summary estimate produced in the meta-analysis.

image

Figure 1.  Odds ratios and confidence intervals for wheeze from original studies and from a meta-analysis performed using the random effects model and assuming dependent sub-studies. The width of the boxes (some so small they appear as points) is proportional to the precision (inverse of variance) of the study and the ends of the horizontal lines represent lower and upper 95% confidence limits. The left vertical line is located at an odds ratio of unity which corresponds to no increased risk of wheeze, while nearly all the reported odds ratios are greater than unity indicating an increase in risk with dampness and mold. The central estimate from the meta-analysis is indicated by the right vertical line and the left- and right-side points of the diamond (labeled ‘Combined’) at the bottom of the figure indicate the lower and upper 95% confidence limits from the meta-analysis.

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Discussion

  1. Top of page
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Conclusions
  7. Acknowledgements
  8. References
  9. Appendix

Importance of building dampness

The meta-analyses described in this report suggest that building dampness and mold are associated with increases of 30–50% in a variety of health outcomes in a variety of populations. These associations are statistically significant – with 95% CIs excluding unity – in almost all cases.

While statistical associations do not prove that dampness and mold are causally related to the health outcomes, and building dampness itself is very unlikely to directly cause adverse health effects, the consistent and relatively strong associations of dampness with adverse health effects strongly suggest causation by dampness-related exposures. Building dampness may cause the building to become contaminated with microorganisms such as mold or bacteria, which might in-turn cause adverse health effects (IOM, 2004). Building dampness could also cause increased emissions of some chemical pollutants from materials and surfaces (IOM, 2004). Research has not yet determined the exact causal agent(s) (IOM, 2004).

The increased risk associated with building dampness suggests a potentially large public health problem. Most available data indicate that at least 20% of homes have dampness problems or visible mold (IOM, 2004). In addition, the adverse consequences of building dampness go beyond health effects and the related personal and economic costs. Dampness causes structural damage to buildings that is expensive to repair. Also, mold contamination resulting from building dampness often precipitates very expensive remediation efforts (Levin, 2005).

While this analysis does not specifically prove causation between dampness or mold and these health effects, it strongly supports the need to prevent building dampness and mold and to take corrective actions where such conditions occur, as suggested in the IOM report (IOM, 2004). Many of the preventive and corrective actions are straightforward. Examples include better moisture control in design, moisture control practices during construction, and improved ongoing preventive maintenance programs to identify and quickly remedy roof and plumbing leaks or other causes of moisture accumulation or mold growth.

Limitations in this analysis

One potential source of bias pertains to the methods used to determine whether a building had dampness or mold. Most studies have relied on the occupants to report whether dampness or mold is present in their home. It is possible that homeowners with respiratory problems would be more aware of or concerned about, and thus, more likely to report, dampness and mold than homeowners without such health problems. If true, this reporting bias would lead to overestimated ORs in the original studies and corresponding overestimated ORs from our meta-analyses. On the other hand, as homeowners within each study would report dampness or mold in a relatively unstandardized and inaccurate way, the resulting random error in assessment could result in what is called ‘non-differential exposure misclassification,’ leading to underestimated ORs in those studies. In the course of this review, we identified six papers that provide some information about the potential bias from self-reporting of mold and dampness. Brief summaries of the relevant information are provided below:

  • • 
    To validate a questionnaire that asked occupants to self-report dampness, Andrae et al. (1988) had inspectors visit 34 houses and inspect for dampness signs. In 23 of the 34 inspected houses, occupants had reported dampness. Inspectors noted visible mold in 14 of 23 houses and signs of dampness in the remaining nine of 23. Inspectors found dampness in only three of 11 houses that did not have self-reported dampness. The authors concluded ‘when parents claimed dampness …, experienced health inspectors agreed.’
  • • 
    Emenius et al. (2004) conducted a case–control study of wheeze that included both parental reports and inspector-confirmed signs of dampness; however, the two dampness assessments were for different time periods. Inspectors reported mold and window pane condensation more often than parents but found any moisture or mold less often than parents. Although direct quantitative comparisons are not possible, wheeze was associated with both self-reported and inspector-reported signs of dampness.
  • • 
    Nafstad et al. (1998) found a substantially stronger association of bronchial obstruction with parent-reported plus inspector-confirmed dampness [OR 3.8 CI (2.0–7.2)] than with parent-reported but not confirmed dampness [OR 2.5 CI (1.1–5.5)].
  • • 
    Norbäck et al. (1999) had industrial hygienists visit 62 houses and check for four signs of dampness. Previously, occupants had responded to questions about the same four signs of dampness. The authors concluded that ‘questions on building dampness, water damage, and mold were reliable.’ Detailed results are provided in the paper.
  • • 
    Verhoeff et al. (1995) assessed dampness via a parent-completed questionnaire and via trained investigators in a case–control study of respiratory symptoms with 259 cases and 257 controls. Based on the data provided, in homes of respiratory cases the inspectors’ and parents’ reports were mutually consistent 78% of the time for dampness and 85% of the time for mold. In homes of control subjects, the corresponding numbers were 71% and 85%. The authors concluded there was ‘no indication of over reporting of dampness and mold by parents of cases relative to the parents of controls.’ ORs for self-reported dampness in homes of respiratory cases were larger than corresponding ORs for inspector-observed dampness; however, ORs for self-reported mold in homes of respiratory cases were smaller than ORs for inspector-observed mold.
  • • 
    In another case–control study, Williamson et al. (1997) obtained data on self-reported dampness and mold and also had a surveyor visit homes and assess dampness and mold. If the surveyors’ responses were treated as the ‘gold standard,’ both asthmatic and control subjects underreported dampness. The OR for the association of case status with self-reported dampness was 1.93 (1.14–3.28), while the OR for the association of case status with inspector-reported dampness was 3.03 (1.65–5.57).

Based on these six studies, it seems very unlikely that the observed association of respiratory health effects with dampness and mold is a consequence of over-reporting of dampness and mold by occupants with respiratory symptoms.

Reviews and meta-analyses are also subject to publication bias – the overestimation of summary estimates of association that can occur because studies with positive findings are published more often (IOM, 2004, p. 20) and more quickly than studies that failed to find significant associations. Publication bias would bias the results of our meta-analyses upward; i.e. estimated ORs based only on all published studies would exceed true central estimates based on all performed studies. While there are statistical tools available that enable one to check for evidence of publication bias, it remains difficult to quantify the extent of publication bias or to make corrections in the resulting central estimates of ORs. We created and examined funnel plots1 for the asymmetries indicative of publication bias; i.e. for the smaller studies most often having ORs above the central estimate, suggesting non-publication of those smaller studies with ORs below the overall central estimate. The funnel plots provided no consistent evidence of publication bias. However, in the course of reviewing papers, we identified one that specifically stated that results for the association of a respiratory effect with dampness were not presented because the association was not statistically significant – a clear example of publication bias.

It is important to note that the confidence intervals associated with our central estimates of ORs reflect only the probabilistic or chance uncertainties. The full uncertainties in the magnitudes of increased health risks are likely to be larger because they would also include potential uncontrolled confounding and bias such as noted above.

Asthma development – comparison to findings of IOM

The IOM Committee found limited or suggestive evidence of an association between building dampness and asthma development, and inadequate or insufficient evidence to determine whether an association exists between mold and asthma development. These statements are consistent with the results of our meta-analysis. We calculated an OR of 1.34 for asthma development if the home had dampness or mold; however, the 95% CI (0.86–2.10) included unity. Also, our meta-analysis for asthma development was based on only four studies and the definitions for asthma development used in these studies were variable.

Conclusions

  1. Top of page
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Conclusions
  7. Acknowledgements
  8. References
  9. Appendix

This meta-analysis suggests that building dampness and mold are associated with increases of 30–50% in a variety of respiratory and asthma-related health outcomes, and the associations are statistically significant in nearly all cases. These results support a recommendation to prevent building dampness and mold problems in buildings, and to take corrective actions where such problems occur.

Footnotes
  • 1

    The heterogeneity of sets of observational studies makes it difficult to draw firm conclusions about publication bias based on funnel plots (Egger et al., 1998).

Acknowledgements

  1. Top of page
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Conclusions
  7. Acknowledgements
  8. References
  9. Appendix

This study was funded through interagency agreement DW89922244-01-0 between the Indoor Environments Division, Office of Radiation and Indoor Air of the U.S. Environmental Protection Agency (EPA) and the US Department of Energy under contract DE-AC02-05CH11231, to support EPA's IAQ Scientific Findings Resource Bank. Conclusions in this paper are those of the authors and not necessarily those of the U.S. EPA. The authors would like to thank Phil Price, and David Mudarri and his colleagues at EPA, for their valuable comments on a draft document.

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  1. Top of page
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Conclusions
  7. Acknowledgements
  8. References
  9. Appendix
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Appendix

  1. Top of page
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Conclusions
  7. Acknowledgements
  8. References
  9. Appendix

Appendix Description of studies included in the meta-analyses

Table A1.   Studies with upper respiratory tract symptoms
SubjectsAuthor (Year)Risk factorSymptomx
AdultsEngvall et al. (2001b)CondensationNasal
Mold odor
Water leakage
Koskinen et al. (1999b))Surveyor-assessed moistureRhinitis
Pirhonen et al. (1996)Dampness or moldAllergic rhinitis
  Rhinitis
ChildrenBornehag et al. (2005)Water leakageRhinitis
Floor moisture
Visible dampness
Condensation
Brunekreef et al. (1989)Damp everHay fever
Mold ever
Jaakkola et al. (1993)Any dampness indicator everNasal congestion
Nasal excretion
Mold odor last yearNasal congestion
Nasal excretion
Visible mold last yearNasal congestion
Nasal excretion
Moisture past yearNasal congestion
Nasal excretion
Water damage past yrNasal congestion
Nasal excretion
Jędrychowski and Flak (1998)Molds or dampnessHay fever
Li and Hsu (1997)DampnessAllergic rhinitis
Mold
Water damage
Stuffy odor
Flooding
Any dampness or mold indicator
Koskinen et al. (1999b)Surveyor-assessed moistureRhinitis
Sinusitis
Simoni et al. (2005)Mold or dampness in first year of lifenasal symptoms apart from colds
Mold or dampness current but not in 1st year
Mold or dampness 1st year and current
Stark et al. (2005)Water damage or mold or mildewallergic rhinitis
Waegemaekers et al. (1989)DampnessRunny nose
Yang et al. (1997b)Mold or mildew or standing water, or water damage, or water leaksAllergic rhinitis
Table A2.   Studies with cough as an outcome
SubjectsAuthor (year)RiskHealth outcome
AdultsEngvall et al. (2001b))CondensationCough
Mold odor
Water leakage
Gunnbjörnsdottir et al. (2003)Water damageLong-term cough
Nocturnal cough
MoldLong-term cough
Nocturnal cough
Gunnbjörnsdottir et al. (2003)Water damage or moldLong-term cough
Nocturnal cough
Gunnbjörnsdottir et al. (2006)Water damageNew nocturnal cough in last 12 months
Haverinen et al. (2001)Moisture problem based on inspectorCough without phlegm
Cough with phlegm
Nocturnal cough
Koskinen et al. (1999b))Surveyor assessed moistureCough w/o phlegm
Night cough
Cough w/ phlegm
Owner reported moldCough w/o phlegm
Night cough
Cough w/phlegm
Pirhonen et al. (1996)Mold or dampCough
Skorge et al. (2005)Mold before last yearCough with phlegm
Chronic cough
Mold last year and earlierCough with phlegm
Chronic cough
Water damage before last yearCough with phlegm
Chronic cough
Water damage last year and earlierCough with phlegm
Chronic cough
ChildrenBornehag et al. (2005)Water leakageCough at night
Floor moisture
Visible dampness
Condensation
Brunekreef et al. (1989)Damp everCough
Mold ever
Brunekreef (1992b)Damp stainsCough on most days
Mold
Cuijpers et al. (1995)Mold always vs. neverChronic cough
Mold often vs. never
Mold sometimes vs. never
Jaakkola et al. (1993)Any dampness indicator everPersistent cough
Mold odor last year
Visible mold last year
Moisture past year
Water damage past yr
Jędrychowski and Flak (1998)Mold or dampChronic cough
Koskinen et al. (1999b))MoistureCough w/ phlegm
Cough w/o phlegm
Night cough
Mommers et al. (2005)Mold or dampness short period vs. neverCoughing
Mold or dampness long period vs. never
Mold or dampness always vs. never
Simoni et al. (2005)Mold or dampness in first year of lifePersistent cough and/or phlegm (two age groups)
Mold or dampness current but not in 1st year
Mold or dampness 1st year and current
Waegemaekers et al. (1989)DampnessDay or night cough
Morning cough
Yang et al. (1997a)Dampness, mold, or floodingCough 3 months of year apart from colds
Yang et al. (1997b)Mold or mildew or standing water, or water damage, or water leaksCough 3 months of year apart from colds
Infants w/ asthmatic siblingGent et al. (2002)Water leaksCough
Table A3.   Studies with wheeze as an outcome
SubjectsAuthor (year)RiskOutcome
AdultsGunnbjörnsdottir et al. (2003)Water damageWheeze or whistling in chest
MoldWheeze or whistling in chest
Water damage or moldWheeze or whistling in chest
Gunnbjörnsdottir et al. (2006)Water damageNew whistling or wheezing in chest in last 12 months
Haverinen et al. (2001)Moisture problem based on inspectorWheeze
Norbäck (1999)>1 signs of dampnessWheeze
Damp floor
Visible mold on indoor surfaces
Moldy odor
Water damage or flood
Skorge et al. (2005)Mold before last yearwheeze in last 12 months
Mold last year and earlier
Water damage before last year
Water damage last year and earlier
ChildrenBornehag et al. (2005)Water leakagewheeze
Floor moisture
Visible dampness
Condensation
Brunekreef et al. (1989)Damp everWheeze
Molds everWheeze
Cuijpers et al. (1995)Mold always vs. neverWheeze
Mold often vs. never
Mold sometimes vs. never
Emenius et al. (2004)Dampness, any self-reported (case–control)Recurrent wheeze
Mold odor self-reported (case–control)
Mold at shower bath tile joints via inspector (case–control)
Dampness, any sign via inspector (case–control)
Dampness self-reported or noted by inspector (case–control)
Dampness both self-reported and by inspector (case–control)
Condensation on windows self-reported and via inspection (case–control)
Damage by dampness, self-reported (cohort)
Mold odor self-reported (cohort)
Visible mold last year, self-reported (cohort)
Any sign of dampness, self reported (cohort)
Jaakkola et al. (1993)Any dampness indicator everPersistent wheeze
Mold odor last year
Visible mold last year
Moisture past year
Water damage past yr
Jędrychowski and Flak (1998)Mold or dampWheeze
Maier et al. (1997)Water damageWheeze in last 12 months
Any dampness except water damage
Mommers et al. (2005)Mold or dampness short period vs. neverwheeze
Mold or dampness long period vs. never
Mold or dampness always vs. never
Ronmark et al. (2002)DampnessWheeze
Simoni et al. (2005)Mold or dampness in first year of lifeCurrent wheeze (two age groups)
Mold or dampness current but not in 1st year
Mold or dampness 1st year and current
Slezak et al. (1998)Mold or dampWheeze in past 12 months
Venn et al. (2003)Visible moldWheeze in last year
Meas living room damp low vs. very low
Meas living room damp moderate vs. very low
Meas living room damp high vs. very low
Meas kitchen damp low vs. very low
Meas kitchen damp moderate vs. very low
Meas kitchen damp high vs. very low
Meas bedroom damp low vs. very low
Meas bedroom damp medium vs. very low
Waegemaekers et al. (1989)DampnessWheeze
Yang et al. (1997a)Dampness, mold, or floodingWheeze apart from colds on most days or wheeze after exercise
Yang et al. (1997b)Mold or mildew or standing water, or water damage, or water leaksWheeze apart from colds on most days or wheeze after exercise
Infants w/asthmatic siblingGent et al. (2002)Water leaksWheeze
Table A4.   Studies with asthma diagnosis as an outcome
SubjectsAuthor (year)RiskOutcome description
  1. sx, symptom; dx, diagnosis; Dr, doctor.

AdultsPirhonen et al. (1996)Dampness or moldDr dx asthma
Skorge et al. (2005)Mold before last yearDr dx asthma
Mold last year and earlier
Water damage before last year
Water damage last year and earlier
ChildrenBornehag et al. (2005)Water leakageDr dx. asthma
Floor moisture
Visible dampness
Condensation
Jędrychowski and Flak (1998)Mold or dampDr dx. asthma
Lee et al. (2003)Water damageDr dx. asthma
Visible mold
Maier et al. (1997)Water damageDr dx. asthma
Any dampness except water damage
Slezak et al. (1998)Damp or moldDr or nurse dx asthma
Yang et al. (1998)Mold or mildew or standing water, or water damage, or water leaksDr dx. asthma
Children & adultsWilliamson et al. (1997)DampDr dx asthma
Damp or condensation current home
Damp previous home
Mold
Severe damp
Significant mold
Table A5.   Studies with current asthma as an outcome
SubjectsAuthor (year)RiskOutcome description
  1. sx, symptom; dx, diagnosis; Dr, doctor.

AdultsNorbäck (1999)>1 dampness factorCurrent asthma defined as combination of bronchial hyper-responsiveness and at least one asthma sx in last year
Damp floor
Moldy odor
Visible mold
Water damage or flood
ChildrenBrunekreef et al. (1989)Damp everDr dx asthma in past year
Mold
Dales and Miller (1999)Mold or mildew in last 12 monthsDr dx. asthma and current asthma or regular asthma medications
Dekker et al. (1991)Dampness or visible mold or water damageDr dx asthma + current sx
Jaakkola et al. (1993)Any damp indicator everCurrent Dr dx asthma
Moisture past yr
Mold odor past yr
Visible mold past yr
Li and Hsu (1997)DampnessCurrent Dr dx asthma
Mold
Water damage
Stuffy odor
Flooding
Any dampness or mold indicator
Simoni et al. (2005)Mold or dampness current but not in 1st yearCurrent Dr dx asthma (two age groups)
Mold or dampness 1st year and current
Yang et al. (1997a)Damp homeCurrent Dr diagnosed asthma
Adults and childrenWilliamson et al. (1997)Self-reported serious dampness and condensationDoctor diagnosed asthma and attendance of asthma clinic in 4-month period prior to study
Self-reported previous home damp
Inspector-determined any dampness
Inspector-determined severe dampness
Inspector-determined any mold
Inspector-determined significant mold
Table A6.   Studies with asthma development as an outcome
SubjectsAuthor (year)RiskOutcome description
  1. dx, diagnosis; Dr, doctor.

AdultsJaakkola et al. (2002)Damp stains or paint peelingNew Dr dx asthma in past year
Visible mold or odor
Water damage
Jaakkola et al. (2005)Any dampness or mold indicatorNew doctor-diagnosed asthma between baseline study and follow-up study after 6 years
Mold odor
Visible mold
Moisture on surfaces
Water damage
Simoni et al. (2005)Mold or dampness in first year of lifeAsthma diagnosis in last 12 months plus sx (two age groups)
Thorn et al. (2001)DampDr. dx asthma since age >16
Damp or visible mold
Visible mold
Yang et al. (1998)Damp or mold or water damageFirst-time Dr dx asthma
MenThorn et al. (2001)DampDr dx asthma since age >16
Damp or visible mold
Visible mold
WomenThorn et al. (2001)DampDr dx asthma since age >16
Damp or visible mold
Damp