Bedding materials and early infant wheezing: A randomised controlled trial

Various observational studies have suggested that infants and young children who regularly sleep in synthetic bedding materials are more likely to experience wheezing and asthma, while children who use feather duvets and/or feather pillows are less likely to wheeze.

In Wellington, New Zealand, we conducted a three-armed, parallel, randomised trial of 460 infants who were assigned to use different bedding materials: synthetic, wool or feather bedding in the form of sleepsacks from 3 months of age to 2 years of age to test the hypothesis that children exposed to feather materials are less likely to develop wheezing. Pregnant women were recruited before birth. Parents were unaware of the primary research hypothesis and were told this was a study of child warmth and wheezing. We have reported wheezing (parental and GP), a variety of respiratory health parameters and atopic status at 2 years.

One hundred and forty-seven infants received a synthetic sleepsack, 150 wool and 144 feather. We have found no significant differences in reported or doctor-diagnosed wheezing or other respiratory health measures by bedding material used. For frequency of wheezing presentation at GP surgery, there was a significant increased rate for children using feather materials compared to synthetic, relative rate 2.00 (95% CI: 1.14, 3.52).

This study does not support earlier observational studies that suggest higher rates of wheezing for children using synthetic bedding or lower rates for feather materials, at least for early childhood wheezing. Our study suggests that the explanation for the observational study findings may lie in selection bias, where the parents of at-risk children avoid feather bedding materials.