1. Longitudinal analysis of the effect of water hardness on atopic eczema: evidence for gene–environment interaction.
- Author
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Jabbar‐Lopez, Z.K., Craven, J., Logan, K., Greenblatt, D., Marrs, T., Radulovic, S., McLean, W.H.I., Lack, G., Strachan, D.P., Perkin, M.R., Peacock, J.L., and Flohr, C.
- Subjects
WATER hardness ,ATOPIC dermatitis ,GENOTYPE-environment interaction ,WATER analysis ,FILAGGRIN ,CROSS-sectional method - Abstract
Summary: Background: Several studies have identified an association between water hardness and atopic eczema (AE); however, there is a paucity of longitudinal data in early life. Objectives: To examine whether water hardness is associated with an increased risk of AE and skin barrier dysfunction in infants and to assess effect modification by filaggrin (FLG) loss‐of‐function variants. Methods: We performed a longitudinal analysis of data from infants in the Enquiring About Tolerance (EAT) study, who were enrolled at 3 months and followed up until 36 months of age. Results: Of 1303 infants enrolled in the EAT study, 91·3% (n = 1189) attended the final clinic visit and 94·0% (n = 1225) of participants' families completed the 36‐month questionnaire. In total, 761 (58·4%) developed AE by 36 months. There was no overall association between exposure to harder (> 257 mg L−1 CaCO3) vs. softer (≤ 257 mg L−1 CaCO3) water: adjusted hazard ratio (HR) 1·07, 95% confidence interval (CI) 0·92–1·24. However, there was an increased incidence of AE in infants with FLG mutations exposed to hard water (adjusted HR 2·72, 95% CI 2·03–3·66), and statistically significant interactions between hard water plus FLG and both risk of AE (HR 1·80, 95% CI 1·17–2·78) and transepidermal water loss (0·0081 g m−2 h−1 per mg L−1 CaCO3, 95% CI 0·00028–0·016). Conclusions: There is evidence of an interaction between water hardness and FLG mutations in the development of infantile AE. What's already known about this topic? Several cross‐sectional studies have found an association between domestic water hardness exposure and atopic eczema (AE) risk.Loss‐of‐function mutations in the skin barrier gene filaggrin (FLG) are the strongest genetic risk factor for AE. What does this study add? There was no overall association between AE risk and exposure to harder vs. softer domestic water in a large, well‐phenotyped cohort of infants living in England and Wales followed up at 3–36 months of age.However, infants with at least one FLG loss‐of‐function mutation exposed to harder water have a threefold increased risk of developing AE up to age 36 months compared with infants with wild‐type FLG exposed to softer water. Linked Comment: Arents and Leonardi-Bee. Br J Dermatol 2020; 183:203–204. Plain language summary available online [ABSTRACT FROM AUTHOR]
- Published
- 2020
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