High body mass index with the risk of allergic conjunctivitis in children: a case-control study in Southwest China.

Purpose: To assess the correlation of body mass index (BMI), diet and lifestyle with allergic conjunctivitis (AC) in children.

Methods: This prospective case-control study included 105 children with AC and 105 age- and sex-matched children with no AC. Clinical data were collected, including BMI, dietary habits, physical activity, and sleep time. Multivariate regression analysis was used to analyze the risk factors for AC.

Results: Dietary habits including vitamin A supplement use (χ2 = 0.00; P = 1.00), the consumption of sweet food (χ2 = 6.70; P = 0.08), fast food (χ2 = 3.74; P = 0.29), beverages (χ2 = 1.17; P = 0.76), and seafood and fish (χ2 = 6.15; P = 0.10) and snacking before sleep (χ2 = 2.23; P = 0.53), were not associated with AC. There were significant differences in physical activity (χ2 = 12.64; P < 0.01) between the children with AC and healthy children. Physical activity of less than 1 h per day is more found among AC and more than 2 h of exercise per day is more found in healthy children. There were no differences in sleep duration (χ2 = 5.39; P = 0.07). Multivariate regression analysis revealed that a high BMI (overweight and obesity) (OR = 3.05; 95% CI: 1.30-7.20; P = 0.01) was a significant risk factor for AC. The consumption of fish oil supplements (OR = 0.38; 95% CI: 0.17-0.81; P = 0.01) and having been breastfed (OR = 0.34; 95% CI: 0.16-0.72; p = 0.005) were protective factors against AC.

Conclusion: A high BMI (overweight and obesity) can increase the incidence of AC. Breastfeeding and dietary supplementation with fish oil are recommended for children susceptible to AC.