Relationship of asthma and rhinoconjunctivitis with obesity, exercise and Mediterranean diet in Spanish schoolchildren.

BACKGROUND Although several studies have investigated the influence of diet on asthma in schoolchildren, none of them has evaluated how obesity can modify this effect. A study was undertaken to evaluate the association of various foods and a Mediterranean diet with the prevalence of asthma and rhinoconjunctivitis, adjusting for obesity and exercise. METHODS A cross-sectional study was performed in 20 106 schoolchildren aged 6-7 years from eight Spanish cities. Using the ISAAC phase III questionnaire, parents reported chest and nose symptoms, food intake, weight, height and other factors, including exercise. A Mediterranean diet score was developed. A distinction was made between current occasional asthma (COA) and current severe asthma (CSA). RESULTS Independent of the amount of exercise, each Mediterranean score unit had a small but protective effect on CSA in girls (adjusted OR 0.90, 95% CI 0.82 to 0.98). Exercise was a protective factor for COA and rhinoconjunctivitis in girls and boys (the more exercise, the more protection). Obesity was a risk factor for CSA in girls (adjusted OR 2.35, 95% CI 1.51 to 3.64). Individually, a more frequent intake (1-2 times/week and>or=3 times/week vs never/occasionally) of seafood (adjusted ORs 0.63 (95% CI 0.44 to 0.91) and 0.53 (95% CI 0.35 to 0.80)) and cereals (adjusted OR 0.56 (95% CI 0.30 to 1.02) and 0.39 (95% CI 0.23 to 0.68)) were protective factors for CSA, while fast food was a risk factor (adjusted ORs 1.64 (95% CI 1.28 to 2.10) and 2.26 (95% CI 1.09 to 4.68)). Seafood (adjusted ORs 0.74 (95% CI 0.60 to 0.92) and 0.67 (95% CI 0.53 to 0.85)) and fruit (adjusted ORs 0.76 (95% CI 0.60 to 0.97) and 0.71 (95% CI 0.57 to 0.88)) were protective factors for rhinoconjunctivitis. CONCLUSIONS A Mediterranean diet has a potentially protective effect in girls aged 6-7 years with CSA. Obesity is a risk factor for this type of asthma only in girls.