Send letter to journal:
Re: Reply to Dr Helen C Francis

Dear Editor

We thank Helen C Francis for the interest in our article “Mould/dampness exposure at home is associated with respiratory disorders in Italian children and adolescents: the SIDRIA-2 Study” [1] and we appreciate her comments reported in the letter “The validity of self- reported measures of mould/dampness”, 21 September, 2005. We think it is difficult to compare our findings with those of Tavernier and colleagues [2] for the following reasons:

1. that study regards a relatively little (n=200) sample of subjects, aged 4 to 17 years, whereas we studied thousands of children and adolescents, separately;

2. that study regards current exposure, whereas we compared the effects of current and early exposure.

In addition, as regard the current exposure, the findings by Tavernier and colleagues do not seem to disagree with our results. We also did not find a significant association between asthma and current exposure, among the adolescents, and the association was not so strong, as indicated by 95%CI (1.00-1.93), among the children.

It is not surprising to find controversial results in the literature. Although some studies showed a poor concordance between self-reported dampness and objective measures [2, 3], other authors confirmed the validity of questionnaires. For instance, Belanger et al report that “the association of reported mold and wheeze was confirmed by measured levels of fungi and wheeze, suggesting that reports of mold were not biased”[4]. The fact that some studies suggest “an almost complete disagreement between self-reported dampness, visual inspection by a trained investigator and measurement using an industrial dampmeter” might even suggest that objective measurements are not completely reliable. As we reported in our article, although studies that objectively assess exposure would be desirable, there are problems with accurate air sampling [5]. The measurements currently used might not accurately represent the variability of concentration over time, because the measurement periods are too short and the variability in repeated measures is elevated over a very short period of time. Thus, both self-report and direct measurement would be desirable. However, our study focused on the comparison between possible effects by current or by early exposure and, obviously, early exposure assessment could only be assessed through the questionnaire.

References

1. Simoni M, Lombardi E, Berti G et al. Mould/dampness exposure at home is associated with respiratory disorders in Italian children and adolescents: the SIDRIA-2 study. Occup Environ Med 2005; 62:616-622.

2. Tavernier GO, Fletcher GD, Frencis HC et al. Endotoxin exposure in asthmatic children and matched healthy controls: results of IPEADAM study. Indoor Air 2005; 15 suppl 10:25-32.

3. Dales RE, Miller D, Mc Mullen ED. Indoor air quality and health: validity and determinats of reported home dampness and moulds. Int J Epidemiol 1997; 26:120-125.

4. Belanger K, Beckett W, Triche E, et al. Symptoms of wheeze and persistent cough in the first year of life: association with indoor allergens, air contaminants, and maternal history of asthma. Am J Epidemiol 2003;158:195-202.

5. Douwes J, Pearce N. Is indoor mold exposure a risk factor for asthma? Am J Epidemiol 2003;158:203-6.

Send letter to journal:
Re: The validity of self-reported measures of mould/dampness

Dear Editor

In an interesting study published in the September 2005 issue of Occupational and Environmental Medicine, Simoni and collegues reported the relation between mould and/or dampness exposure and respiratory disorders in children and adolescents in Italy [1]. The authors concluded that wheeze and asthma can often be explained by exposure to home mould and dampness, particularly in early life.

Although the authors acknowledged the use of questionnaire data alone to assess mould and dampness exposure will have limited their study, they state that the validity of using questionnaires has been established.

In our own study, we investigated indoor exposure to dampness in 200 asthmatic and non-asthmatic children aged 4-17 [2]. We found that self- reported dampness (by the parent/guardian) was significantly associated with an asthmatic household, but no such association was found for dampness observed by the field investigator or objective measures (using an industrial dampmeter). Additionally, we have previously demonstrated that the concordance between self-reported dampness and objective measures is very poor [3]. In fact, there was almost complete disagreement between self-reported dampness, visual inspection by a trained investigator and measurement using an industrial dampmeter.

A study of the validity and determinants of reported home dampness and moulds conducted by Dales et al reported evidence of systematic reporting bias and recommended that objective measures rather than questionnaires be used to clarify the health effects of indoor fungi [4].

Bearing in mind the evidence from these past studies, we feel that the positive findings of Simoni et al should be interpreted with caution and that all research involving home dampness should have some objective data to back it up.

References

1) Simoni M, Lombardi E, Berti G et al. Mould/dampness exposure at home is associated with respiratory disorders in Italian children and adolescents: the SIDRIA-2 study. Occup Environ Med 2005; 62: 616-622.

2) Tavernier GO, Fletcher GD, Francis HC, Oldham LA, Fletcher AM, Blacklock G, Stewart L, Gee I, Watson A, Frank TL, Frank P, Pickering CA, Niven RM. Endotoxin exposure in asthmatic children and matched healthy controls: results of IPEADAM study. Indoor Air. 2005;15 Suppl 10:25-32.

3) Frank TI, Pickering CAC, Fletcher G, Francis HC, Oldham LA, Kay S, Frank P, Niven RMcL. (1999). Relationship between self reporting, visible inspection and objective measurement of damp for determining damp or mould contamination in houses. Proceedings of the 8th Internationional Conference on Indoor Air Quality and Climate-Indoor Air '99, Vol. 2, pp564 -566.

4) Dales RE, Miller D and McMullen ED. Indoor air quality and health: validity and determinants of reported home dampness and moulds. International Journal of Epidemiology 1997; 26: 120-125.