Michael E Levin1, Maresa Botha2, Wisdom Basera3, Heidi E Facey-Thomas2, Ben Gaunt4, Claudia L Gray2, Wanjiku Kiragu5, Jordache Ramjith6, Alexandra Watkins2, Jon Genuneit7. 1. Division of Paediatric Allergy, Department of Paediatrics, University of Cape Town, Cape Town, South Africa; inVIVO Planetary Health Group of the Worldwide Universities Network (WUN). Electronic address: michael.levin@uct.ac.za. 2. Division of Paediatric Allergy, Department of Paediatrics, University of Cape Town, Cape Town, South Africa. 3. School of Public Health and Family Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa. 4. Zithulele Hospital, Eastern Cape Department of Health, Bisho, South Africa; Division of Primary Health Care, Health Sciences Faculty, University of Cape Town, Cape Town, South Africa. 5. Department of Paediatrics, Aga Khan University Hospital, Nairobi, Kenya. 6. Department for Health Evidence, Biostatistics Research Group, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands; Division of Epidemiology & Biostatistics, School of Public Health & Family Medicine, University of Cape Town, Cape Town, South Africa. 7. Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany; Center for Pediatric Research Leipzig, Hospital for Children and Adolescents, University of Leipzig Medical Center, Leipzig, Germany.
Abstract
BACKGROUND: The prevalence of allergic diseases differs in urban and rural populations. OBJECTIVE: We sought to assess associations between environmental and dietary factors with allergic diseases in urban and rural South African children. METHODS: Toddlers aged 12 to 36 months were assessed for food allergen and aeroallergen sensitization, atopic dermatitis, allergic rhinitis, asthma, and challenge-proved food allergy. Information was collected on family history of allergic diseases, household size, socioeconomic status, delivery mode, antibiotic and probiotic use, exposure to fermented and unpasteurized milk, antihelminth treatment, sunlight exposure, pet and farm animal exposure, cigarette smoke, and household cooking and heating fuels. Antenatal exposures to pets, livestock, and cigarette smoke were assessed. A subsection completed questions on consumption of fruits and vegetables, fast foods, soft drinks/fruit juices, and fried/microwaved meat. RESULTS: Risk and protective factors differed between urban and rural settings. Exposure to farm animals in infants and their mothers during pregnancy was protective against allergic outcomes in the rural population. Consumption of unpasteurized milk is uncommon in this group of rural children and is unlikely to be an important factor in rural protection. In urban children birth by cesarean section is associated with food allergy, and consumption of fermented milk products is associated with reduced asthma and atopic dermatitis. In both cohorts antenatal maternal smoking and environmental smoking exposure were predominantly associated with asthma, and consumption of fast foods and fried meats were associated with allergy. CONCLUSION: In this rural environment exposure to livestock is the strongest protective factor. In urban communities, where animal contact is rare, risk factors include cesarian section, and protective factors include consumption of fermented milk products. Modifiable risk factors urgently require interventions to prevent increasing allergy rates in countries undergoing rapid urbanization.
BACKGROUND: The prevalence of allergic diseases differs in urban and rural populations. OBJECTIVE: We sought to assess associations between environmental and dietary factors with allergic diseases in urban and rural South African children. METHODS: Toddlers aged 12 to 36 months were assessed for food allergen and aeroallergen sensitization, atopic dermatitis, allergic rhinitis, asthma, and challenge-proved food allergy. Information was collected on family history of allergic diseases, household size, socioeconomic status, delivery mode, antibiotic and probiotic use, exposure to fermented and unpasteurized milk, antihelminth treatment, sunlight exposure, pet and farm animal exposure, cigarette smoke, and household cooking and heating fuels. Antenatal exposures to pets, livestock, and cigarette smoke were assessed. A subsection completed questions on consumption of fruits and vegetables, fast foods, soft drinks/fruit juices, and fried/microwaved meat. RESULTS: Risk and protective factors differed between urban and rural settings. Exposure to farm animals in infants and their mothers during pregnancy was protective against allergic outcomes in the rural population. Consumption of unpasteurized milk is uncommon in this group of rural children and is unlikely to be an important factor in rural protection. In urban children birth by cesarean section is associated with food allergy, and consumption of fermented milk products is associated with reduced asthma and atopic dermatitis. In both cohorts antenatal maternal smoking and environmental smoking exposure were predominantly associated with asthma, and consumption of fast foods and fried meats were associated with allergy. CONCLUSION: In this rural environment exposure to livestock is the strongest protective factor. In urban communities, where animal contact is rare, risk factors include cesarian section, and protective factors include consumption of fermented milk products. Modifiable risk factors urgently require interventions to prevent increasing allergy rates in countries undergoing rapid urbanization.
Authors: Antonina Karsonova; Ksenja Riabova; Sergio Villazala-Merino; Raffaela Campana; Verena Niederberger; Julia Eckl-Dorna; Renate Fröschl; Thomas Perkmann; Yury V Zhernov; Olga G Elisyutina; Elena S Fedenko; Musa R Khaitov; Daria Fomina; Evgeniy Beltiukov; Marianne van Hage; Hans Grönlund; Rudolf Valenta; Alexander Karaulov; Mirela Curin Journal: Allergy Date: 2020-05-27 Impact factor: 13.146
Authors: Gillian O N Ndhlovu; Regina E Abotsi; Adebayo O Shittu; Shima M Abdulgader; Dorota Jamrozy; Christopher L Dupont; Avumile Mankahla; Mark P Nicol; Carol Hlela; Michael E Levin; Nonhlanhla Lunjani; Felix S Dube Journal: BMC Infect Dis Date: 2021-04-13 Impact factor: 3.090