Browsing by Author "Dalvie, Aqiel"

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    Maternal alcohol consumption and socio-demographic determinants of neurocognitive function of school children in the rural Western Cape
    (2020) Viglietti, Paola; Dalvie, Aqiel; Chetty-Mhlanga, Shala
    Background. Within the South African context there is a large body of research regarding the associations between maternal gestational drinking and diagnosable child FASDs. However, there remains a paucity of local research regarding the impacts of other kinds of maternal drinking behaviours (e.g. past and present maternal drinking) and related socio-demographic factors on developmentally sensitive areas of child neurocognitive functioning, such as executive functioning (EF). Methods. This study was cross-sectional in design, utilising a gender balanced sample of N=464 children between the ages of 9.00 and 15.12 (year.months) in three rural areas within the Western Cape. Information regarding maternal drinking behaviours (before, during and after pregnancy) and related socio-demographic factors was collected via structured interviews with mothers or proxy respondents. Six subtests from the Cambridge Automated Neuropsychological Battery (CANTAB), were used to assess three aspects of child EF namely: (1) processing speed, assessed by the MOT and RTI subtests, (2) attention, assessed by the MTT and RVP subtests and (3) memory, assessed by the SWM and PAL subtests. Findings. For all three maternal alcohol use behaviours examined, there was an apparent non-significant trend whereby children of mothers who reported alcohol use (before, during and after pregnancy) performed worse (on average) than children of mothers reporting non-alcohol use on the EF subtests. Several of the socio-demographic factors were found to act as significant predictors of subtest specific EF performance including child sex (RTI: B=.46, p<. 01; MTT: B=.05, p<.05), child age (RTI: B=.27, p<.05; MTT: B=.11, p<.01), home language (MOT: B=- .13, p<.05), maternal employment (MTT: B=-.04, p<.05) and household size (SWM: B=-1.29, p<.05). Conclusions. These study findings provide initial insights into the impacts of different types of maternal drinking behaviours and related socio-demographic factors on child EF outcomes within the context of an LMIC, South Africa.
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    Modification by sex and atopy of the effect of chemical air pollutions and biological air pollutants including pollen and fungal spores on children respiratory health in the Western Cape, Cape South Africa
    (2024) Mahmoud, Hussein Yasmeen; Dalvie, Aqiel
    Asthma continues to be a leading cause of morbidity and mortality among children in SubSaharan Africa. Ongoing under-diagnosis and treatment in low-and middle-income countries, together exposure to airborne pollutants and allergens contribute to this disease burden. A cross-sectional study that recruited 590 school children residing in four informal settlements in the Western Cape province was conducted to assess the role of sex and atopic status on the association between air pollutants and childhood asthma. Exposure to NO2 and PM2.5 were estimated for individual homes using a land-use regression model, while pollen and fungal spores were measured using spore traps positioned in each study area during the follow-up study between May 2016 and September 2016. Asthma-related outcomes were obtained using the International Study of Allergy and Asthma in children (ISAAC) questionnaire, spirometry, and fractional exhaled nitric oxide (FeNO) testing. The study found that increased annual grass pollen levels and annual NO2 levels were positively associated with airway obstruction (OR: 2.26, 95% CI: 1.02-5.03) for annual grass pollen and FeNO (OR: 2.43, 95% CI:1.19-4.98) for annual NO2 and (OR: 3.43, 95% CI: 1.07-10.99) for grass pollen. Furthermore, there was evidence of effect modification by sex and atopy since associations were much stronger among boys and atopic children. Annual NO2 levels were positively associated with FeNO>35ppb among boys (OR:2.77, 95% CI: 1.02-7.47) but not girls. A strong positive association was also observed between higher annual grass pollen levels and FEV1< LLN in atopic children (OR: 4.46, 95% CI: 1.28-15.59). The study provides evidence that sex and atopy modify the association between annual long-term exposure to grass pollen and NO2 and asthma-related outcomes in children
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    The adverse health effects associated with drought in Africa: working towards developing a vulnerability index
    (2020) Asmall, Taherah; Dalvie, Aqiel; Abrams, Amber
    Africa is uniquely vulnerable to the occurrence of drought. A rise in temperatures over Southern Africa occurs at almost twice that of the global rate. South Africa has begun to experience an increase in the frequency of drought, particularly in the Western and Eastern Cape. Droughts are associated with several health effects. The direct and indirect risks of climate change to human health have become a global concern. The most recent systematic review available on the adverse health effects associated with drought was published in 2013, and as such, an up-to-date review focusing on Africa is needed to inform a Cape Town specific health vulnerability index. This study aims to provide a review of available research exploring the association between drought and adverse health effects in Africa. The rationale for this study is to provide a solid research foundation from which a drought-specific health vulnerability index for Cape Town can be developed. A narrative review of original studies and published reviews was conducted. An extensive electronic literature search was performed using a combination of keywords, Medical Subject Heading (MeSH) terms and free text words. The Critical Appraisal Toolkit (CAT) was used to assess the quality of included studies. A total of 1922 publications were identified, of which twenty-four articles were included in this review. The main drought-related health effects that emerged were divided into 4 main categories: (1) drought and nutritional health including malnutrition, poor childhood health outcomes (wasting, stunting and underweight), mortality, anaemia, and nutritionrelated disability; (2) drought and food consumption including micronutrient deficiencies and motor neuron diseases; (3) drought and water-borne, water-washed and water- related diseases including cholera outbreaks, diarrhoeal diseases, protozoa parasite transmission, scabies outbreaks, trachoma, vector-borne disease outbreaks and malaria-related mortality; and (4) drought and health behaviours including health perceptions and health-seeking behaviours, HIV prevention and care behaviours and family planning practices. There was generally limited evidence in all health categories with several limitations. These limitations include studies with methodological weaknesses (e.g. a lack of comparison to a non-drought period), the singularity of published studies on health effects associated with drought and studies which did not account for potential confounders. While the evidence from the included studies is limited, this study highlights gaps in literature to encourage further research into understanding the direct and indirect impacts of drought on health, particularly in vulnerable groups. Furthermore, the results of this study emphasized the contextual factors which lower an individual's adaptive capacity and identified key indicators that can be used to begin to develop a broad framework for a vulnerability index
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    The association between ambient air pollution and cardiorespiratory health outcomes of adults residing in informal settlements of the Western Cape in a 12 month period
    (2025) Allie, Tasneem; Dalvie, Aqiel
    Background: There is limited data on the association between ambient air pollution cardiorespiratory outcomes among adults especially among populations with low socio-economic status in low- and middle income countries. Objectives: A cross-sectional cohort study was conducted in four informal settlements of the Western Cape to determine the association between annual NO2 and PM2.5 air pollution exposure and cardiorespiratory outcomes in adults. Methods: A questionnaire was administered to 506 participants who were guardians of learners in a primary study, to collect information on cardio-respiratory symptoms and relevant covariates. Land use regression modelling in R was used to estimate the annual average PM2.5 and NO2 exposure at each household. Cardio-respiratory outcomes included wheezing in the last 12 months, doctor diagnosed asthma, asthma symptoms score (calculated as the sum of positive responses to 3 asthma questions), chest pain, hypertension and hypercholesterolaemia. The quantile g computation package in R was used to assess the joint-effect of PM2.5 and NO2 on the outcome of interest. A concentration curve was determined, while adjusting for confounders (paraffin exposure, mould exposure, smoke exposure, low education, unemployed, sex and age). Results: Most of the participants were female (89.9%), with a median age of 40 (IQR=12.8). The annual median concentration of PM2,5 9.8 μg/m3 and NO2 was 16.86 μg/m3 , below the National Ambient Air Quality Standards (NAAQS) There was positive association between NO2 and shortness of breath on exertion (OR:4.02, 95% CI:2.21-7.65) adjusting for PM2,5 and other confounders. There were no other significant associations found between PM2.5 and NO2 levels and other cardiorespiratory outcomes including indoor air pollution. The concentration curve indicates an increased risk in self-reported shortness of breath on exertion with increasing NO2 concentrations above 10μg/m3 . Conclusion: The study found evidence of an association between annual NO2 and shortness of breath on exertion. The study also provides policy-relevant information from the concentration-response curve in demonstrating elevated risk at a level four-times lower than the current National Ambient Air Quality Standard (NAAQS) of 40µg/m3 . This indicates that the NAAQS should be more in keeping with the WHO Ambient Air Quality guidelines for NO2 at 10 μg/m3 and lower in low- and middle-income countries where underlying susceptibility may increase the observed risk.
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    The relationship between urinary organophosphate pesticide metabolites and asthma-related outcomes at 12-month follow-up in school children residing in informal settlements in the Western Cape
    (2021) Mthethwa, Mashudu; Dalvie, Aqiel; Jeebhay, Mohamed; Olaniyan, Toyib
    Background: Evidence on the relationship between pesticide exposure and respiratory outcomes is mostly from farm workers. In most settings, poor /rich there is limited information on non-agricultural settings, particularly in children. Objective: This study investigated the relationship between urinary concentrations of the organophosphate pesticide (OP) metabolites and asthma-related outcomes among schoolchildren in four informal settlements in the Western Cape in South Africa. Methods: This study was a longitudinal study of 590 schoolchildren, with a 12-month follow up period. A standardised questionnaire adopted from the International Study of Asthma and Allergies in Childhood (ISAAC) was administered to caregivers for child's respiratory symptoms and household characteristics. Spirometry and fractional-exhaled nitric oxide (FeNO), including a phadiatop test (atopy status) and urinary dialkyl phosphate (DAP) metabolites diethylphosphate (DEP), dimethylthiophosphate (DMTP)] were measured at baseline and follow-up. Dimethylphosphate (DMP) was measured only at baseline. Results: Mean ages of schoolchildren were (9.9 ± 0.91 years) and median DAP was 32.9 ng/ml (18.4 – 52.9 ng/ml) at baseline. Incidence proportions of new asthma outcome cases at 12- months were 2.2 % doctor diagnosed asthma, 17.8 % asthma-symptom score ≥ 2, 14.5 % forced expiratory volume 1< lower limit of normal, and 5.9 % airway inflammation across all areas. In the linear mixed and fixed effect model, no consistent patterns of increased risk of new asthma-associated outcomes at the 12-month was found. However, there was a significant increase in airway inflammation (β:2.99 (95% CI: 0.48 - 5.50) in the 3rd DEP quintile (1.9 – 3.0 ng/mL) compared to the reference quintile (1.10 ng/ml). Conclusion: DAP concentrations among school children were found to be higher than those of children in other settings. However, the study did not find consistent associations between urinary concentrations of DAP metabolites and asthma related outcomes over a 12-month follow-up period among schoolchildren. Future studies with a longer follow-up period and repeated OP pesticide biomonitoring are recommended.