Maternal caffeine intake during pregnancy and the risk of childhood asthma by 10 years of age-Evidence from The Generation XXI birth cohort study.

Background: We aimed to investigate the association between maternal caffeine intake during pregnancy and asthma in children by 10 years of age.

Methods: We considered 5585 mother-child pairs enrolled in a population-based birth cohort. Consumption of regular and decaffeinated coffee, black and green tea, and cola beverages before and during pregnancy was obtained through face-to-face interviews within 72 h after giving birth, and total caffeine intake (mg/day) was estimated. Medical diagnosis of asthma was assessed and spirometry with bronchodilation was performed at 10 years of age. We used adjusted regression models to estimate the association between the caffeine intake/day during pregnancy with asthma by 10 years of age, and a quadratic relationship was verified between them. Consumption of caffeine before pregnancy, gestational age, maternal years of schooling, maternal self-reported medical diagnosis of asthma, smoking status before and during pregnancy, and children's sex were considered as confounders. We used nonlinear least squares models to estimate the knot point and its respective confidence interval (CI).

Results: A higher intake of caffeine/day decreased the odds of having childhood asthma at 10 years of age (adjusted odds ratio [OR] = 0.60, 95% CI: 0.41; 0.88). The estimated knot point was 92.7 mg of caffeine/day (95% CI: 36.3, 163.3), where the risk was 7.2%, while for no intake (0 mg) the risk was 8.8%.

Conclusion: Maternal caffeine intake up to an estimated intake of approximately 93 mg/day during pregnancy decreased childhood asthma risk by 10 years of age. Nonetheless, further studies are required to confirm our results.

Key Message: Maternal caffeine intake during pregnancy up to an estimated intake of approximately 93 mg/day decreased the risk of asthma in children by 10 years of age, but considering caffeine's potential adverse effects on other health outcomes, further studies are needed to explore its link to childhood asthma.