Meteorological, ozone, maternal and individual-level risk factors for childhood diseases in Singapore: A prospective birth cohort study from 2009 to 2019.

BACKGROUND: The children of today are growing up in an environment characterised by accelerated climate change and air pollution. Few studies have examined the effects of these phenomena on childhood respiratory and allergic diseases in tropical countries, hence we aim to bridge this research gap. METHODS: We ascertained the first occurrence of eczema, wheeze and bronchiolitis in 1124 mother-child pairs in GUSTO, a prospective birth cohort from tropical Singapore. We assigned daily measures of meteorological conditions and outdoor air quality exposures averaged over each month from 2009 to 2019 based on participant's residential address, spanning the in utero period to eight years of age. We applied adjusted Poisson regression to examine the associations between these exposures with the time to first onset of childhood disease. RESULTS: increase) was associated with a trend of lower risk of eczema [Hazard Ratio (HR): 0.958 (95% CI: 0.883-1.041)], wheeze [HR: 0.927 (0.855-1.006)] and bronchiolitis [HR: 0.929 (0.852-1.014)]. Family history of allergy was significantly associated with these illnesses [Eczema HR: 2.206 (95% CI: 1.638-2.971), wheeze: 2.308 (1.684-3.163) and bronchiolitis: 1.923 (1.420-2.606)]. Males/boys had a significantly higher risk of eczema compared to females/girls. Maternal age and parity were associated with the higher [HR: 1.031 (1.003-1.060)] and lower [HR: 0.698 (0.590-0.825)] risk of eczema respectively. There was a positive association between ozone exposure and the risk of bronchiolitis in males/boys [HR: 1.168 (1.020-1.336)] but not in females/girls, suggesting effect modification by sex (p = 0.024). SIGNIFICANCE: Our findings demonstrated that while genetic predisposition remains as the primary driver of childhood respiratory and allergic diseases, the environment also plays a subtle but essential role in shaping these outcomes. CLINICAL TRIAL NUMBER: Not applicable.