Browsing by Author "Levin, Michael E"

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    Open Access
    A cross-sectional study of Ig-E mediated food sensitisation and food allergy in an unselected population of South African children aged 12-36 months
    (2014) Basera , Wisdom; Levin, Michael E
    Background: Food allergy (FA) is a significant and often life-threatening health problem affecting about 4-6% of children and their families globally. In some developed countries FA prevalence has reached 10% and it is believed that developing economies may follow a similar trend since there is a reported rise in the global burden of other allergic diseases like asthma, allergic rhinitis and eczema. However, there is a dearth of population studies at global level documenting challenge-proven Ig-E mediated food allergy (FA) prevalence. As such, we studied an unselected population of children attending crèches in Cape Town, South Africa. Methodology All children aged 12-36 months attending the selected crèches between February 2013 and October 2013 were eligible for the study. Participants were assessed with an allergy questionnaire, had skin prick tests (SPTs) done and if they qualified, were invited for an oral food challenge (OFC) at the Red Cross Hospital Paediatric Allergy Clinic (RCHPAC). The SPT wheal size results were categorised into ≥1mm, ≥3mm and ≥7mm. We gave a general description of the study sample with respect to the demographic characteristics and compared participants and non-participants. We reported sensitisation pattern towards foods in the panel i.e. egg white extract, peanut, cow’s milk, wheat(flour), soy, hazelnut and fish (cod) according to the SPT categories. The effects of age, ethnicity, sex and concomitant allergy on sensitisation patterns were assessed. Associations between the potential predictor variables and sensitisation were assessed by Z-test for proportions and Chi-square/Fisher’s exact. PART I presents the study protocol with a brief motivation for the relevance of the study and the methodology used. PART II presents a structured literature review on FA and FS in large populations of selected and unselected cohorts. It provides an overview of empirical evidence on prevalence estimates from both the developed and developing world, and the potential risk factors causing Fav. PART III summarises the methodology, results and interpretation of the analysis conducted in a journal-ready manuscript according to Current Allergy and Clinical Immunology Journal requirements. Results The sample consisted of; 39% black African, 20% Caucasian and 41% mixed race participants, with a median age 26 months (IQR: 22-31). Amongst 121 participants (66% response rate, 92% participation rate and 94% completion rate), the prevalence of SPT≥1mm to any food was 16%, SPT≥3mm 12% and SPT≥7mm 4%. The prevalence of challenge-proven Ig-E mediated raw egg allergy was 1.7% and peanut allergy 0.8%. Black African participants had higher sensitisation rates (23%) of SPT≥1mm to any food, when compared to Caucasian (13%) and mixed race (10%) participants despite the difference not reaching statistical significance (p=0.17). Conclusions: This study was acceptable and feasible in this population that has a low prevalence of Ig-E mediated FA that is comparable to other studies from developed countries using objective measures in unselected cohorts. The prevalence of FS is appreciably high in this sample and there are ethnic differences that require further investigation. The findings seem to suggest an existing burden of Ig-E mediated FAs in the South African context that is un-diagnosed and therefore not managed
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    Open Access
    The influence of socio-economic status on the prevalence of food sensitisation and food allergy in children 12 to 36 months in urban Cape Town, South Africa
    (2016) Hobane, Lelani; Colvin, Christopher J; Levin, Michael E
    Background: Globally, food allergies (FAs) have become a public health concern with research suggesting a rising prevalence. FAs affect both the individual and their family advocating for a need to understand the extent of the problem. Allergies have increasingly been recognised as diseases of life-style resulting from interaction between genes and the environment in both the pre and post-natal periods. Various factors including socio-economic status (SES) have been identified from studies as risk factors that are associated with FAs in children. Generally higher SES has been correlated with improved health outcomes, however, in respiratory allergies higher SES may be associated with higher prevalence. With regards to SES as a risk factor for food allergy development, literature has indicated evidence of a relationship between SES and allergies but with conflicting results of both high and low SES postulated as risk factors. Methodology: This study is a sub-study of the South African Food sensitisation and Food Allergy (SAFFA) study, an on-going cross-sectional, observational study of IgE-mediated food allergy in an unselected population of children aged 12-36 months. The aim is to explore the influence of SES on food sensitisation and food allergy prevalence in children. We used a variety of measures of SES including household size, parental education, employment status and household income to investigate the association between SES and food allergy prevalence using sensitisation, self-reported respiratory and skin allergy and challenge proven food allergy data from children across the urban Cape Town Metropole. Associations between the SES variables and sensitisation/allergy were assessed using the Z-test for proportions and Chi-square/Fisher's exact. Part A comprises the protocol which describes the methodology of the research. Part B is the review of literature on food allergy prevalence and risk factors associated with food allergy development. Section C presents the "journal ready" manuscript according to the requirements of the Annals of Allergy, Asthma & Immunology Journal (Appendix 3). Results: The prevalence of low level sensitisation (at Skin Prick Test (SPT) ≥1mm) to any food was 12.3%, medium level (at SPT≥3mm) was 9.6%, high level (at SPT≥7mm) was 4.5% and challenge proven IgE mediated FA was 2.4%. Of the total 739 participants in the sample, 91 were sensitised to 1 or more foods. A trend of increased sensitisation at SPT≥1mm, ≥3mm, ≥7mm and proven food allergy in children of parents with tertiary education was observed (14.8%, 11.9%, 5.8% and 2.9%) compared to parents who attained primary/secondary education (10.5%, 7.9%, 3.5%, and 2.1%) respectively though these results did not reach statistical significance. Highest risk for food sensitisation (FS) and FA were in children with parents who are employed (p=0.03) and in children who are from homes with higher household income (p=0.02). Household size showed no association with FS and FA. No significant differences in sensitisation patterns were noted between ethnic groups. Conclusion: The analysis showed an existing burden of IgE mediated FAs in South African children advocating for diagnosis and management. SES is associated with food allergy in young children with a positive relationship to parental employment status and income.
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    Molecular epidemiology of Staphylococcus aureus in African children from rural and urban communities with atopic dermatitis
    (2021-04-13) Ndhlovu, Gillian O N; Abotsi, Regina E; Shittu, Adebayo O; Abdulgader, Shima M; Jamrozy, Dorota; Dupont, Christopher L; Mankahla, Avumile; Nicol, Mark P; Hlela, Carol; Levin, Michael E; Lunjani, Nonhlanhla; Dube, Felix S
    Abstract Background Staphylococcus aureus has been associated with the exacerbation and severity of atopic dermatitis (AD). Studies have not investigated the colonisation dynamics of S. aureus lineages in African toddlers with AD. We determined the prevalence and population structure of S. aureus in toddlers with and without AD from rural and urban South African settings. Methods We conducted a study of AD-affected and non-atopic AmaXhosa toddlers from rural Umtata and urban Cape Town, South Africa. S. aureus was screened from skin and nasal specimens using established microbiological methods and clonal lineages were determined by spa typing. Logistic regression analyses were employed to assess risk factors associated with S. aureus colonisation. Results S. aureus colonisation was higher in cases compared to controls independent of geographic location (54% vs. 13%, p < 0.001 and 70% vs. 35%, p = 0.005 in Umtata [rural] and Cape Town [urban], respectively). Severe AD was associated with higher colonisation compared with moderate AD (86% vs. 52%, p = 0.015) among urban cases. Having AD was associated with colonisation in both rural (odds ratio [OR] 7.54, 95% CI 2.92–19.47) and urban (OR 4.2, 95% CI 1.57–11.2) toddlers. In rural toddlers, living in an electrified house that uses gas (OR 4.08, 95% CI 1.59–10.44) or utilises kerosene and paraffin (OR 2.88, 95% CI 1.22–6.77) for heating and cooking were associated with increased S. aureus colonisation. However, exposure to farm animals (OR 0.3, 95% CI 0.11–0.83) as well as living in a house that uses wood and coal (OR 0.14, 95% CI 0.04–0.49) or outdoor fire (OR 0.31, 95% CI 0.13–0.73) were protective. Spa types t174 and t1476, and t272 and t1476 were dominant among urban and rural cases, respectively, but no main spa type was observed among controls, independent of geographic location. In urban cases, spa type t002 and t442 isolates were only identified in severe AD, t174 was more frequent in moderate AD, and t1476 in severe AD. Conclusion The strain genotype of S. aureus differed by AD phenotypes and rural-urban settings. Continued surveillance of colonising S. aureus lineages is key in understanding alterations in skin microbial composition associated with AD pathogenesis and exacerbation.
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    The relationship between immunization and food allergy and sensitisation in South African children
    (2017) Ndhlovu, Nomathamsanqa; Levin, Michael E; Davies, Mary-Ann
    Abstract The prevalence of food allergies is higher in children compared to adults and it is increasing. The factors that influence food allergies in children are not clear. In light of the hygiene hypothesis, vaccinations may contribute towards to a predominant allergen specific response or exposure to the virus or microbe in the vaccine may decrease the risk for allergy. Previous studies have shown that the effect of vaccinations on food allergy and food sensitisation varies. Therefore, the aim of this study is to determine if a relationship exists between vaccinations and food allergies and food sensitisation in children in the first 18 months of life who live in urban Cape Town and in rural Mqanduli in the Eastern Cape. Secondary data analysis of an observational cross sectional study was carried out which involved univariate logistic regression to calculate odds ratios between self-reported immunisation status and food sensitisation and food allergy at a 95% confidence interval in children between 12 and 36 months of age. The same method was employed to investigate the relationship between immunisation and atopy. Multivariate analysis was utilised to adjust for potential confounders. Food sensitisation and food allergy were determined through skin prick tests (SPT) and oral food challenges respectively. The results indicate that, the number of participants positive for food sensitisation and allergy, eczema, hay fever and asthma were significantly greater in the urban sample (n= 708) compared to the rural sample (n= 400) (P<0.05). Further, in 708 urban children, those who had a BCG vaccine at birth were 0.05 (OR 0.05; 95% CI: 0.004 - 0.6) times less likely to have an SPT ≥ 7mm. The BCG unvaccinated cohort consisted of three individuals. There were no other significant associations between childhood vaccinations and food sensitization at SPT ≥ 1mm ,≥ 3mm and ≥ 7mm. There was no significant association between vaccinations and food allergy or other forms of atopy. In conclusion, there was very little evidence of an association between BCG vaccination in children and food allergic sensitisation or food allergy. However, in a small subgroup, there was evidence in an association between BCG and SPT ≥ 7 mm.