Preschool Wheeze Profiles and Early Life Associations: An Australian Prebirth Cohort

To define preschool wheeze profiles to 4-years, identify their early life associations, and impact on wheeze risk at 9-years.

A latent class analysis of eight wheeze responses (1 month-4 years) and two severity markers (respiratory presentation to emergency department and wheeze with shortness of breath) using data from a pre-birth prospective cohort study. Relative risk ratios (RRR) with 95% confidence intervals were calculated using multinomial logistic regression to examine associations between early life risk factors and wheeze at 9-years.

Four distinct preschool wheeze profiles were identified: "never/infrequent" with minimal wheeze (n = 538), "early persistent" wheeze from 3 months to 4 years (n = 83), "transient" from 6 to 18 months (n = 263) and "late-onset" from 18 months to 4 years (n = 148). Relative to "never/infrequent", maternal asthma history was associated with increased risk of all adverse wheeze profiles, the highest for "early persistent" wheeze [RRR 5.06; 2.96-8.67]. Breastfeeding at 6 months decreased the risk of "early persistent" wheeze [RRR 0.53; 0.31-0.90] and at 12 months protected against all adverse wheeze profiles. Eczema, food allergy, aeroallergen and food sensitisation all increased the risk of "early persistent" and "late-onset" wheeze. "Early persistent" [RRR 7.25; 3.92-13.42] and "late-onset" [RRR 3.93; 2.24-6.89] wheeze profiles were associated with increased risk of wheeze at 9-years.

Early life exposures and atopy measures had distinct associations with data-derived preschool wheeze profiles. Maternal asthma and the absence of breastfeeding emerged as unifying risk factors. Investigation of the underlying mechanistic pathways is required to inform novel primary prevention strategies.