Determinants of house dust, endotoxin, and β-(1→3)-D-glucan in homes of Danish children

Little is known about the geographic variation and determinants of bacterial endotoxin and -(1,3)-d-glucan in Danish house dust. In a population of 317 children, we: (i) described loads and concentrations of floor dust, endotoxin, and -(13)-d-glucan and (ii) their correlations and (iii) assessed their determinants; (iv) Finally, we compared our findings with previous European studies. Bedroom floor dust was analyzed for endotoxin content by the kinetic limulus amoebocyte lysate assay and for -(13)-d-glucan by the inhibition enzyme immunoassay. The parents answered questions regarding potential determinants. We found: geometric means (geometric standard deviations) 186mg/m(2) (4.3) for dust; 5.46x10(3)EU/m(2) (8.0) and 31.1x10(3)EU/g (2.6) for endotoxin; and 142g/m(2) (14.3) and 0.71x10(3)g/g (7.3) for -(13)-d-glucan. High correlations (r>0.75) were found between floor dust and endotoxin and -(13)-d-glucan loads, while endotoxin and -(13)-d-glucan concentrations were moderately correlated (r=0.36-0.41) with the dust load. Having a carpet was positively associated with dust load and with endotoxin and -(13)-d-glucan concentrations. Pet keeping, dwelling type, and dwelling location were determinants of endotoxin concentrations. No other determinants were associated with -(13)-d-glucan concentrations. Compared with other European studies, we found lower -(13)-d-glucan loads and concentrations but higher endotoxin loads and concentrations suggesting a geographically determined different composition of Danish floor dust compared with other European regions.