Diet and childhood asthma in a society in transition: a study in urban andrural Saudi Arabia

Background-The causes of the worldwide increases in asthma and allergic dis eases in childhood, which seem to relate to increasing prosperity, are unkn own. We have previously hypothesised that a reduction iu. the antioxidant c omponent of the diet is an important factor. An investigation was undertake n of dietary and other risk factors for asthma in Saudi Arabia where major Lifestyle differences and prevalences of allergic disease are found in diff erent communities. Methods-From a cross sectional study of 1444 children with a mean age of 12 (SD 1) years in Jeddah and a group of rural Saudi villages, we selected 11 4 cases with a history of asthma and wheeze in the last 12 months and 202 c ontrols who had never complained of wheeze or asthma, as recorded on the IS AAC questionnaire. Risk factors for asthma and allergies (family history so cial class, infections, immunisations, family size, and diet) were ascertai ned by questionnaire. Atopy was assessed by skin prick testing. Results-In univariate analyses, family history, atopy, and eating at fast f ood outlets were significant risk factors for wheezy illness, as were the l owest intakes of milk and vegetables and of fibre, vitamin E, calcium, magn esium, sodium, and potassium. These differences were present also in the ur ban children considered separately. Sex, family size, social class, infecti ons, and parental smoking showed no relationship to risk. In multiple logis tic regression analysis, urban residence, positive skin tests, family histo ry of allergic disease, and the lowest intakes of vitamin E, magnesium and sodium related significantly and independently to risk. The lowest tertile of intake of vitamin E was associated with a threefold (95% CI 1.38 to 6.50 ) increase in risk when adjusted for the other factors. Intake of milli and vegetables both showed inverse Linear relationships to being a case. Conclusions-This study suggests that dietary factors during childhood are a n important influence in determining the expression of wheezy illness, afte r allowing for urban/rural residence, sex, family history and atopy. The fi ndings are consistent with previous studies in adults and with the hypothes is that change in diet has been a determinant of the worldwide increases in asthma and allergies.