engleski

Association of bacterial load in drinking water and allergic diseases in childhood

Background: Treatment of drinking water may decrease microbial exposure. Objective: To investigate whether bacterial load in drinking water is associated with altered risk of allergic diseases. Methods: We recruited 1, 110 school children aged 6-16 years between 2011 and 2013 in Požega-Slavonia County in Croatia, where we capitalized on a natural experiment where by individuals receive drinking water through public mains supply or individual wells. We obtained data on microbial content of drinking water for all participants ; 585 children were randomly selected for more detailed assessments, including skin prick testing. Since water supply was highly correlated with rural residence, we compared clinical outcomes across four groups (Rural/Individual, Rural/Public, Urban/Individual and Urban/Public). For each child, we derived quantitative index of microbial exposure (bacterial load in the drinking water measured during the child's first year of life). Results: Cumulative bacterial load in drinking water was higher (median [IQR]: 6390 [4190-9550] vs 0 [0-0] ; P < .0001), and lifetime prevalence of allergic diseases was significantly lower among children with individual supply (5.5% vs 2.3%, P = .01 ; 14.4% vs 6.7%, P < .001 ; 25.2% vs 15.1%, P < .001 ; asthma, atopic dermatitis [AD] and rhinitis, respectively). Compared with the reference group (Urban/Public), there was a significant reduction in the risk of ever asthma, AD and rhinitis amongst rural children with individual supply: OR [95% CI]: 0.14 [0.03, 0.67], P = .013 ; 0.20 [0.09, 0.43], P < .001 ; 0.17 [0.10, 0.32], P < .001. Protection was also observed in the Rural/Public group, but the effect was consistently highest among Rural/Individual children. In the quantitative analysis, the risk of allergic diseases decreased significantly with increasing bacterial load in drinking water in the first year of life (0.79 [0.70, 0.88], P < .001 ; 0.90 [0.83, 0.99], P = .025 ; 0.80 [0.74, 0.86], P < .001 ; current wheeze, AD and rhinitis). Conclusions and Clinical Relevance: High commensal bacterial content in drinking water may protect against allergic diseases.

atopy ; bacterial load ; children ; drinking water ; microbiota ; well water

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