The meta-analysis included three cohort studies,26,27,31 two cross-sectional studies,22,23 and one case-control study.20 Figures 2–4 show that there was no evidence of association between the prevalence of current or ever asthma and healthy (OR 1.01, 95% CI 0.78–1.31), unhealthy (OR 1.04, 95% CI 0.93–1.16), or neutral (OR 1.01, 95% CI 0.73–1.41) dietary patterns. The mixed model results show that the random effect estimates were zero, suggesting very small or negligible variance between versus within studies.