Nutrition and allergic diseases in urban and rural communities from the South African Food Allergy cohort

Abstract

This study describes and compares allergic diseases and sensitisation in urban and rural children in the SAFFA study cohort as well as infant feeding patterns and nutritional status. We assessed the relationship between nutritional status, breastfeeding, complementary feeding patterns and atopic diseases including aero‐ and food allergen sensitisation, self‐reported atopic dermatitis, allergic rhinitis, asthma, and challenge proven food allergy. Methodology 1185 urban and 398 rural toddlers aged 12‐36 months were screened for food sensitisation and food allergy using skin prick testing and oral food challenges. Of these, 535 and 347 respectively were additionally screened for aeroallergen sensitisation. Information was collected on infant feeding practices and anthropometric measurements and clinical signs for atopy were documented. Results Markedly higher rates of allergy (asthma 9.0% vs 1.0%, eczema 25.6% vs 2.0%, rhinitis 25.3% vs 3.3% and food allergy 2.5% vs 0.5%) exist in urban vs rural children. 13.1% unselected urban South African children were sensitised to aeroallergens compared to 3.8% of their rural counterparts and 9.0% to any food compared to 0.5%. Exclusive breastfeeding duration was longer and there was a later introduction of allergenic foods in rural communities. Obesity rates were similar between the two groups, but rural children were more likely to be stunted. Being overweight was associated with asthma in urban but not rural settings. In the urban cohort, children with food sensitisation and allergy were thinner than their peers. Conclusion Allergy and sensitisation rates are significantly higher in unselected urban South African toddlers than their rural counterparts. Risk and protective factors for allergy and atopy may differ between urban and rural settings.