Dwelling mould profiles and current asthma in the CONSTANCES cohort

Assessing the health effect of dwellings mould contamination is complex, as various dwelling characteristics and occupants’ behaviours may play a role. We aimed to identify dwelling mould profiles using an unsupervised method and to study their association with current asthma in adults from the French population-based cohort CONSTANCES. Based on the responses to the 2019 self-questionnaire, we selected 22 variables referring to indoor mould contamination, dwelling characteristics and occupants’ behaviours. A dimension reduction with Factor Analysis of Mixed Data followed by K-means algorithm were used to identify profiles without a priori hypothesis. Between 2019-2021, participants completed a questionnaire on respiratory health. Current asthma was defined among ever-asthmatics by self-report of asthma attacks, symptoms or treatments in the last 12 months. Multinomial logit models were adjusted for age, sex, and smoking. Among the 25,541 participants included in the analyses (53 yrs, 49% men, 7.6% with asthma), 8 dwelling profiles were identified: cluster 1 "mould-free houses" (54%), cluster 2 "mould-free apartments" (27%), cluster 3 "no mould and no window opening" (2%), cluster 4 "mould spots in bathroom" (7%), cluster 5 "mould in kitchen" (2%), cluster 6 "mould in bedroom" (3%), cluster 7 "mould in other rooms" (3%), cluster 8 "mould in all rooms" (2%). Using cluster 1 as the reference, significant associations with current asthma were observed for clusters 4, 5 and 6 (ORs=1.18, 1.66 and 1.70, respectively). Dwelling mould profiles were associated with an increased risk of current asthma in adults, highlighting the need for prevention measures.