The MR odds ratio per standard deviation decrease in log-transformed 25OHD was 1.03 (95% confidence interval [CI] 0.90–1.19, p = 0.63) for asthma, 0.95 (95% CI 0.69–1.31, p = 0.76) for childhood-onset asthma, and 1.12 (95% CI 0.92–1.37, p = 0.27) for atopic dermatitis, and the effect size on log-transformed IgE levels was −0.40 (95% CI −1.65 to 0.85, p = 0.54). This evidence concerns the gene IGHE and childhood onset asthma.