BACKGROUND: The environment plays an important part in the aetiology of @entity483 , but specific causes are unknown. Exposure to hard water is thought to be a risk factor for @entity484 . We undertook an ecological study of the relation between domestic @entity3358 and the prevalence of @entity484 among Nottinghamshire schoolchildren. METHODS: Questionnaire details of 1-year period and lifetime prevalence of @entity484 were obtained from parents of 4141 randomly selected primary-school @entity1 and 3499 secondary-school @entity1 in southern Nottinghamshire. Geographical information systems (GIS) were used to link the geographical distribution of @entity484 prevalence with domestic water-hardness data (four categories). Adjustment was made for potential confounding by sex, age, socioeconomic status, and access to health care. FINDINGS: Among the primary-school @entity1 there was a significant direct relation between both 1-year period and lifetime prevalence of @entity484 and @entity3358 , both before and after adjustment for confounders. The 1-year period prevalence was 17.3% (261/1509) in the highest water-hardness category and 12.0% (94/786) in the lowest (adjusted odds ratio 1.54 [95% CI 1.19-1.99] p for trend <0.001). The corresponding values for lifetime prevalence were 25.4% (384/1509) and 21.2% (167/786; adjusted odds ratio 1.28 [1.04-1.58], p for trend=0.02). @entity484 prevalence trends in the secondary-school population were not significant (adjusted odds ratio for highest compared with lowest hardness category for 1-year prevalence 1.03 [0.79-1.33], p for trend=0.46; for lifetime prevalence 0.99 [0.83-1.23], p for trend=0.93). @entity484 prevalence in primary-school @entity1 increased in relation to @entity3878 content of water, but the trend across four @entity3878 -content categories was not independently significant after adjustment for confounders. INTERPRETATION: Exposure to hard water in the home may increase the risk of @entity484 in @entity1 of primary-school age.

@entity483 and domestic XXXX .

@entity1 :: ('9606', 'Species') :: ['children'] @entity483 :: ('MESH:D003876', 'Disease') :: ['atopic eczema'] @entity3358 :: ('MESH:D018804', 'Disease') :: ['water hardness'] @entity3878 :: ('MESH:D002713', 'Chemical') :: ['chlorine'] @entity484 :: ('MESH:D004485', 'Disease') :: ['eczema', 'Eczema']
@entity3358 :: (MESH:D018804,Disease) :: ['water hardness']
