Comparing participants included and excluded in these analyses.

Of the 14,062 participants, 8,365 had genetic data (after genetic quality control filters excluding individuals with incorrect sex assignments, minimal or excessive heterozygosity, disproportionate levels of missingness, cryptic relatedness, and non-European ancestry). 4,835 individuals had both genetic data and data on BMI and current asthma at 7–7½ y, and these individuals form the core sample for these analyses.*Chi-squared tests and t-test were used as appropriate.**General Certificate of Education level (school leaving certificate at 16 y) or lower, compared with A-level (qualification at 18 y) or degree level.