Researchers conducted a systematic review and meta-analysis of 51 studies across eight research areas to examine the impact of early life exposures and interventions on asthma, wheezing, atopy and growth in children. Nutritional interventions during pregnancy (OR = 0.89, 95% CI: 0.74–1.07, I² = 68%) and early probiotic/microbiota modulation did not show significant results. The combination of viral prophylaxis with maternal influenza vaccination was protective against wheezing, asthma and LRTI (OR = 0.78, 95% CI: 0.72–0.85, I² = 68%). Respiratory viral infections in early life increased the risk of wheezing and asthma (OR = 1.59, 95% CI: 1.39–1.82, I² = 90%), accompanied by allergen exposures (OR = 1.40, 95% CI: 1.30–1.50), environmental exposures (OR = 1.27–1.42), and infant clinical factors (OR = 1.29, 95% CI: 1.13–1.46, I² = 82%). Longitudinal cohort studies have confirmed a consistent effect of early life risk factors on asthma and allergic conditions (OR = 1.41, 95% CI: 1.35–1.48). Studies on viral prophylaxis, respiratory infections and allergen exposures showed publication bias. Early exposure to viral infections, allergens, environmental pollutants and clinical factors in infants is strongly associated with the development of respiratory disorders and allergic diseases in children. Nutritional and probiotic treatments have had limited results, suggesting the need for specific preventive methods at an early age.