House dust mite allergen (Der p 1) accumulation on new synthetic and feather pillows

Background We have previously demonstrated that synthetic pillows contain significantly more Der p 1 than feather pillows. The aim of this study was to compare the accumulation of Der p 1 allergen on new synthetic and new feather pillows. Methods Der p 1 was measured in dust samples from pairs of synthetic and feather pillows placed together on 12 beds over a 12-month period. Results After 12 months synthetic pillows contained higher concentrations of Der p 1 (19.28 mu g/g; 95% confidence interval: 9.76-38.07) than feather pillows (6.45 mu g/g; 2.96-14.05). There was a significant correlation between Der p 1 concentrations of pillows at 12 months and Der p 1 concentrations of the mattresses at the beginning of the study (r = 0.72; P = 0.008 for both types of pillows). Conclusions Synthetic pillows accumulate Der p 1 more rapidly than feather pillows and the accumulation rate of Der p 1 on pillows is governed by the Der D 1 concentration in the immediate environment they are placed in.