TY - JOUR

T1 - Prevalence of atopic dermatitis in infants by domestic water hardness and season of birth

T2 - Cohort study

AU - Engebretsen, Kristiane A

AU - Bager, Peter

AU - Wohlfahrt, Jan

AU - Skov, Lone

AU - Zachariae, Claus

AU - Nybo Andersen, Anne-Marie

AU - Melbye, Mads

AU - Thyssen, Jacob P

N1 - Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

PY - 2017/5

Y1 - 2017/5

N2 - BACKGROUND: Atopic dermatitis (AD) appears to be more common in regions with hard domestic water and in children with a fall/winter birth. However, it is unknown whether a synergistic effect exists.OBJECTIVE: We sought to evaluate the association between domestic water hardness and season of birth, respectively, with onset of AD within the first 18 months of life in a large Danish birth cohort.METHODS: Of children from the Danish National Birth Cohort, 52,950 were included. History of physician-diagnosed AD and population characteristics were obtained from interviews. Birth data were obtained from the Civil Registration System, and domestic water hardness data were obtained from the Geological Survey of Denmark and Greenland. The relative prevalence (RP) of AD was calculated by using log-linear binomial regression.RESULTS: The prevalence of AD was 15.0% (7,942/52,950). The RP of AD was 5% (RPtrend, 1.05; 95% CI, 1.03-1.07) higher for each 5° increase in domestic water hardness (range, 6.60-35.90 German degrees of hardness [118-641 mg/L]). Although the RP of AD was higher in children with a fall (RP, 1.24; 95% CI, 1.17-1.31) or winter (RP, 1.18; 95% CI, 1.11-1.25) birth, no significant interaction was observed with domestic water hardness. The population attributable risk of hard domestic water on AD was 2%.CONCLUSION: We observed that early exposure to hard domestic water and a fall/winter birth was associated with an increase in the relative prevalence of AD within the first 18 months of life. Although the 2 exposures did not interact synergistically, a dose-response relationship was observed between domestic water hardness and AD.

AB - BACKGROUND: Atopic dermatitis (AD) appears to be more common in regions with hard domestic water and in children with a fall/winter birth. However, it is unknown whether a synergistic effect exists.OBJECTIVE: We sought to evaluate the association between domestic water hardness and season of birth, respectively, with onset of AD within the first 18 months of life in a large Danish birth cohort.METHODS: Of children from the Danish National Birth Cohort, 52,950 were included. History of physician-diagnosed AD and population characteristics were obtained from interviews. Birth data were obtained from the Civil Registration System, and domestic water hardness data were obtained from the Geological Survey of Denmark and Greenland. The relative prevalence (RP) of AD was calculated by using log-linear binomial regression.RESULTS: The prevalence of AD was 15.0% (7,942/52,950). The RP of AD was 5% (RPtrend, 1.05; 95% CI, 1.03-1.07) higher for each 5° increase in domestic water hardness (range, 6.60-35.90 German degrees of hardness [118-641 mg/L]). Although the RP of AD was higher in children with a fall (RP, 1.24; 95% CI, 1.17-1.31) or winter (RP, 1.18; 95% CI, 1.11-1.25) birth, no significant interaction was observed with domestic water hardness. The population attributable risk of hard domestic water on AD was 2%.CONCLUSION: We observed that early exposure to hard domestic water and a fall/winter birth was associated with an increase in the relative prevalence of AD within the first 18 months of life. Although the 2 exposures did not interact synergistically, a dose-response relationship was observed between domestic water hardness and AD.

KW - Journal Article

U2 - 10.1016/j.jaci.2016.11.021

DO - 10.1016/j.jaci.2016.11.021

M3 - Journal article

C2 - 28017882

VL - 139

SP - 1568-1574.e1

JO - Journal of Allergy and Clinical Immunology

JF - Journal of Allergy and Clinical Immunology

SN - 0091-6749

IS - 5

ER -