Risk factors for rhinitis, allergic conjunctivitis and eczema among schoolchildren in Uganda

Abstract

AbstractBackgroundThe prevalence of allergy-related diseases (ARDs), including rhinitis, allergic conjunctivitis and eczema, is on the increase in Africa and globally. The causes of this increase are not well established.ObjectivesTo investigate the risk factors for ARDs among schoolchildren in Uganda.MethodsWe conducted a secondary data analysis of a large asthma case-control study involving 1,700 schoolchildren, 5-17 years, in urban Uganda. ARDs were defined according to the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Skin prick testing (SPT) was conducted using standard procedures and allergen-specific IgE (asIgE) using ImmunoCAP®. We used inverse probability weighting to account for the differences in the sampling fractions in all our analyses.ResultsThe lifetime prevalence of reported rhinitis, allergic conjunctivitis and eczema was 43.3%, 39.5%, and 13.5%, respectively. There was overlap of ARDs, with 66.3% of 1,193 schoolchildren who reported having ever an ARDs (including asthma) reporting two or more. The important risk factors for ‘rhinitis ever’ were city residence at birth [adjusted odds ratio (95% confidence interval) 1.97 (1.26-3.10) compared to rural]; father’s [2.08 (1.57-2.75)] and mother’s history of allergic disease [2.29 (1.81-2.91)]; frequent de-worming in the last 12 months [1.80 (1.32-2.45), ≥2 versus none]; current high frequency of ‘trucks passing on the street near home’ [1.90 (1.19-3.03), ‘almost all the time’ versus rarely] and positive SPT [1.56 (1.24-1.96)] but not asIgE [1.33 (0.81-2.18)]. The same pattern of risk factors was observed for allergic conjunctivitis and eczema.ConclusionWe found extensive multi-morbidity of, and overlap in the risk factors for, rhinitis, conjunctivitis, and eczema - similar to asthma risk factors - among schoolchildren in urban Uganda. This suggests a similar underlying cause for all ARDs, associated with exposure to urban lifestyles and environment in Uganda. Thus, epidemiological research should investigate causes of all ARDs as one disease entity.