Browsing by Author "Jeebhay, Mohamed"
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- ItemOpen AccessA prospective cohort study on ambient air pollution and respiratory morbidities including childhood asthma in adolescents from the western Cape Province: study protocol(2017) Olaniyan, Toyib; Jeebhay, Mohamed; Röösli, Martin; Naidoo, Rajen; Baatjies, Roslynn; KYnzil, Nino; Tsai, Ming; Davey, Mark; de Hoogh, Kees; Berman, Dilys; Parker, Bhawoodien; Leaner, Joy; Dalvie, Mohamed AqielAbstract Background There is evidence from existing literature that ambient air pollutant exposure in early childhood likely plays an important role in asthma exacerbation and other respiratory symptoms, with greater effect among asthmatic children. However, there is inconclusive evidence on the role of ambient air pollutant exposures in relation to increasing asthma prevalence as well as asthma induction in children. At the population level, little is known about the potential synergistic effects between pollen allergens and air pollutants since this type of association poses challenges in uncontrolled real life settings. In particular, data from sub-Sahara Africa is scarce and virtually absent among populations residing in informal residential settlements. Methods/design A prospective cohort study of 600 school children residing in four informal settlement areas with varying potential ambient air pollutant exposure levels in the Western Cape in South Africa is carried-out. The study has two follow-up periods of at least six-months apart including an embedded panel study in summer and winter. The exposure assessment component models temporal and spatial variability of air quality in the four study areas over the study duration using land-use regression modelling (LUR). Additionally, daily pollen levels (mould spores, tree, grass and weed pollen) in the study areas are recorded. In the panel study asthma symptoms and serial peak flow measurements is recorded three times daily to determine short-term serial airway changes in relation to varying ambient air quality and pollen over 10-days during winter and summer. The health outcome component of the cohort study include; the presence of asthma using a standardised ISAAC questionnaire, spirometry, fractional exhaled nitric-oxide (FeNO) and the presence of atopy (Phadiatop). Discussion This research applies state of the art exposure assessment approaches to characterize the effects of ambient air pollutants on childhood respiratory health, with a specific focus on asthma and markers of airway inflammation (FeNO) in South African informal settlement areas by considering also pollen counts and meteorological factors. The study will generate crucial data on air pollution and asthma in low income settings in sub-Sahara Africa that is lacking in the international literature.
- ItemOpen AccessA prospective cohort study on ambient air pollution and respiratory morbidities including childhood asthma in adolescents from the western Cape Province: study protocol(BioMed Central, 2017-09-16) Olaniyan, Toyib; Jeebhay, Mohamed; Röösli, Martin; Naidoo, Rajen; Baatjies, Roslynn; Künzil, Nino; Tsai, Ming; Davey, Mark; de Hoogh, Kees; Berman, Dilys; Parker, Bhawoodien; Leaner, Joy; Dalvie, Mohamed ABackground: There is evidence from existing literature that ambient air pollutant exposure in early childhood likely plays an important role in asthma exacerbation and other respiratory symptoms, with greater effect among asthmatic children. However, there is inconclusive evidence on the role of ambient air pollutant exposures in relation to increasing asthma prevalence as well as asthma induction in children. At the population level, little is known about the potential synergistic effects between pollen allergens and air pollutants since this type of association poses challenges in uncontrolled real life settings. In particular, data from sub-Sahara Africa is scarce and virtually absent among populations residing in informal residential settlements. Methods/design: A prospective cohort study of 600 school children residing in four informal settlement areas with varying potential ambient air pollutant exposure levels in the Western Cape in South Africa is carried-out. The study has two follow-up periods of at least six-months apart including an embedded panel study in summer and winter. The exposure assessment component models temporal and spatial variability of air quality in the four study areas over the study duration using land-use regression modelling (LUR). Additionally, daily pollen levels (mould spores, tree, grass and weed pollen) in the study areas are recorded. In the panel study asthma symptoms and serial peak flow measurements is recorded three times daily to determine short-term serial airway changes in relation to varying ambient air quality and pollen over 10-days during winter and summer. The health outcome component of the cohort study include; the presence of asthma using a standardised ISAAC questionnaire, spirometry, fractional exhaled nitric-oxide (FeNO) and the presence of atopy (Phadiatop). Discussion: This research applies state of the art exposure assessment approaches to characterize the effects of ambient air pollutants on childhood respiratory health, with a specific focus on asthma and markers of airway inflammation (FeNO) in South African informal settlement areas by considering also pollen counts and meteorological factors. The study will generate crucial data on air pollution and asthma in low income settings in sub-Sahara Africa that is lacking in the international literature.
- ItemOpen AccessAllergic sensitization and work related asthma among poultry workers in South Africa(2016) Ngajilo, Dorothy; Jeebhay, Mohamed; Baatjies, RoslynnObjective: The aim of the study was to determine the risk factors associated with allergic sensitisation and various asthma phenotypes in poultry workers. Methods: A cross-sectional study of 230 currently employed poultry workers used a modified ECRHS questionnaire, spirometry, fractional exhaled nitric oxide, Phadiatop and ImmunoCAP for specific IgE to poultry farming associated allergens (chicken meat, feathers, serum protein, droppings, sunflower seeds, storage mite) and mould mix to investigate workrelated asthma. Results: The mean dust particulate concentration (geometric mean (GM) =11.04mg/m³) was highest in the rearing department while mean (1-3)-ß-D-glucan (GM=148 ng/ m³) and endotoxin levels (GM=2298 EU/m³) were highest in the catching department. Worker's mean age was 37±9 years, 68% were male, 43% current smokers, 34% atopic and 5% casual workers. The prevalence of non-atopic asthma (NAA=10%) was higher than atopic asthma (AA=6%) or probable occupational asthma (OA=5%). Sensitisation to at least one poultry work related allergen was 24%, with sunflower seed and storage mite sensitisation being the most prevalent (13%). In multivariate adjusted models, workers sensitised to chicken specific allergens were more likely to be atopic (OR=20.9, 95% CI: 4.7-93.2) or have casual job status (OR=6.0, 95% CI: 1.1-35.9). Workers with work-related chest symptoms were more likely to work in the rearing department (OR=3.2, 95% CI: 1.2-8.3) and to report episodes of high gas/dust/fume exposures causing asthma symptoms (OR=4.8, 95%CI: 2.4-9.6). Reversible obstructive airway obstruction was more strongly associated with employment in small broiler farms (OR=11.6, 95% CI: 1.0-129.0) as well as casual work (OR=6.4, 95% CI: 1.4-28.0). Furthermore, NAA was strongly associated with casual work (OR=5.0, 95% CI: 1.3-19.0) as well as working in the automated egg laying system (OR=8.0, 95% CI: 1.0-68.6). Further analysis revealed that the proportion of workers sensitised to at least one poultry work related allergen declined with increasing years of service (chi-square trend p=0.023), with workers having <2 years employment demonstrating a higher risk compared to those with >6 years employment (OR=4.0, 95% CI: 1.2-13.8). Conclusion: Non-atopic asthma is the most common asthma phenotype among poultry workers with work in the rearing department demonstrating an increased respiratory risk. The increased risk of reversible airway obstruction among workers in small broiler farms and the declining prevalence of sensitisation with increasing employment duration suggests a healthy worker effect. Preventive measures, including appropriate training, are recommended to reduce respiratory health risks, particularly in novice workers.
- ItemOpen AccessAssessing the health impact of intervention in supermarket bakeries using fractional exhaled nitric oxide (FeNO) and other clinical endpoints for baker’s allergy and asthma(2018) Al-Badri, Faisal; Jeebhay, Mohamed; Baatjies, RoslynnAim: To assess the health impact of an intervention in supermarket bakeries using fractional exhaled nitric oxide and other clinical endpoints for baker’s allergy and asthma after a one-year follow-up period. Methods: A field randomised controlled trial of 31 bakeries initially assigned to one of two intervention groups (bakery mixer lid and training) (n=244) and a control group (n=93). Health data prior to and after the intervention included a modified ECRHS questionnaire; Phadiatop ® and serum specific IgE to cereal flours (wheat, rye, alpha-amylase); and FeNO performed during the work shift using NIOX MINO®. The data of the two intervention groups was combined into one intervention group for the analysis. Data was analysed using STATA (version 12). Results: The two groups were comparable with regard to age (32-33 years), proportion of females (55%-57%) and smoking status (38%-40%). The intervention group had a significantly higher prevalence of workers with atopy (42%, p=0.025), work-related chest symptoms (25%, p=0.044) and sensitisation to cereal flour allergens (35%, p=0.042) at baseline than the control group (25%, 15%, 23% respectively). At one year of follow-up, the incidence and level of decline of work-related ocular-nasal and chest symptoms, sensitisation status and elevated FeNO (FeNO >25ppb) was similar in the two groups. The mean difference in FeNO was similar across the two groups (2.2ppb vs 1.7ppb, p=0.860). However, when stratifying according to baseline FeNO >25ppb, the FeNO decline was greater in the intervention group (16.9 ppb) than in the control group (7.7ppb), although not statistically significant (p=0.237). Multivariate logistic regression models (adjusting for smoking, baseline sensitisation to cereal flour, baseline FeNO >25ppb) did not demonstrate an appreciable decline in FeNO (>10%) in the intervention compared to the control group. However, stratification according to the presence of work related ocular-nasal symptoms at baseline demonstrated a significant decline (>10%) in FeNO in the intervention group compared to the control group (OR=3.73, CI: 1.22-11.42). Conclusion: This study demonstrates some evidence of an intervention effect on exhaled nitric oxide (FeNO) one year after the intervention, particularly among bakers reporting work-related ocular-nasal symptoms at baseline. The lack of a demonstrably stronger effect on other clinical endpoints can be attributable to the short follow-up period.
- ItemOpen AccessDeterminants of work-related skin symptons and dermatitis associated with cleaning agents among health workers of two tertiary hospitals in Southern Africa(2023) Sonday, Zahida; Jeebhay, Mohamed; Baatjies RoslynnBackground: Cleaning products and related agents are increasingly associated with occupational irritant and allergic contact dermatitis in health workers (HWs), but limited information is available on predictors for these outcomes. This study investigated the prevalence and risk factors for work-related skin symptoms (WRSS) and skin disease phenotypes in HWs exposed to diverse cleaning agents in two Southern African tertiary hospitals. Methods: A cross-sectional study of 697 HWs used an interviewer administered questionnaire and assessed the presence of atopy using Phadiatop. Results: The median age of HWs was 42 years (IQR: 32 – 51), 77.0% were female and 42.5% were atopic. The lifetime prevalence of WRSS was 18.7% and WRSS in the last 12 months was slightly lower (14.8%). Among the skin disease phenotypes, 12.3% had probable contact dermatitis and 3.2% probable contact urticaria. In multivariate regression models, adjusted for family history of allergy and domestic cleaning frequency, technicians (ORadj 4.45, 95% CI: 1.21-21.48) and work activities involving cleaning and disinfection of skin wounds (ORadj 2.70, 95% CI: 1.64-4.57) was associated with WRSS in the past year. A consistent trend was observed for job tasks and cleaning agents related to these work activities. Risk factors for probable contact dermatitis included the use of liquid hand soap (ORadj 1.67, 95% CI: 1.03- 2.72), sterilising instruments manually (ORadj 1.94, 95% CI: 1.15-3.19) or automatically (ORadj 3.28, 95% CI: 1.01-9.32), disinfecting skin prior to procedures (ORadj 2.29, 95% CI: 1.45-3.66) and the use of adhesives for wounds (ORadj 1.91, 95% CI: 1.20-3.07). Risk factors for probable contact urticaria included specimen preparation (ORadj 2.65, 95% CI: 1.06-6.38) and wound cleaning and disinfection (ORadj 3.10, 95% CI: 1.24-8.81). Training on protection against adverse health effects of cleaning agents (ORadj 0.54, 95% CI: 0.31-0.89) was protective against WRSS in the past year. Conclusion: Workplace activities and related factors associated with cleaning and disinfecting of patients' skin and wounds are important risk factors for WRSS in HWs. Training on the adverse health effects of cleaning agents can contribute to decreasing risks in HWs. Keywords: health workers, skin symptoms, cleaning agents
- ItemOpen AccessHealth-related quality of life among Macassar residents with persistent lower respiratory symptoms and(2010) Rajani, Mayuri; Jeebhay, MohamedTo determine the health-related quality of life (HRQoL) in Macassar residents with persistent lower respiratory symptoms and/or asthma (PLRS and/or asthma), six years after a sulphur stockpile fire disaster.
- ItemOpen AccessMolecular characterisation of parvalbumin and analysis of cross-reactivity in five fish species using sera from fish-allergic consumers and occupationally exposed workers(2008) Beale, Janine; Lopata, Andreas; Jeebhay, MohamedParvalbumin, the fish major allergen, accounts for over 95% of clinical symptoms in allergic fish consumers. Importantly, this allergen displays lgE cross-reactivity thus allergic sufferers can exhibit clinical symptoms after the ingestion of non-sesitising fish species. In an occupational setting, fish products have also been shown to cause allergic disease in fish-processing factory workers. Whether parvalbumin is a causative allergen in this occupational environment is unknown. The aim of this study was to evaluate IgE reactivity to parvalbumin and other fish fillet proteins using sera from domestic consumers with ingestion-induced fish allergies and sera from occupationally exposed allergic workers. In addition, cross-reactivity among parvalbumins from five highly consumed fish species in South Africa were assessed by immunoblotting and the most cross-reactive species was characterised further. Pilchard parvalbumin was identified as the most cross-reactive allergen in fish-allergic consumers. The cDNA sequenceß form of pilchard parvalbumin was determined. This is the first time that parvalbumin from the fish order, Clupeiformes, has been characterised and represents a crucual primary step towards the generation of a recombinant form for potential diagnostic and therapeutic use in allergic individuals. Interestingly, sera IgE from fish-processing factory workers displayed no bing to parvalbumin, nor any other fish fillet proteins in immunoblotting. This result has raised several intriguing questions. Namely, does parvalbumin lack the intrinsic features required for eliciting allergic symptoms via inhalation and/or contact, as are primary routes of exposure in workers? Alternatively, could causative occupational allergens that appear to be absent in the fillet of fish occur in the enzyme-rich digestive tract or potentially the skin of fish species? Future studies aim to addess these questions amongst others, which will contribute to preventative and therapeutic strategies of occupational allergies in workers.
- ItemOpen AccessObstructive Lung Disease among tobacco farmers in Malawi(2020) Moyo, Yotam Mgonjetsi; Adams, Shahieda; Jeebhay, MohamedIntroduction and aim Tobacco farmers are exposed to toxic workplace hazards such as nicotine and pesticides in addition to known agriculture related hazards like dust, and ergonomic factors. Nicotine and pesticide exposure have been linked to the development of chronic respiratory diseases. This study was aimed at determining the prevalence of obstructive lung disease among tobacco farmers in Malawi and its association to nicotine and pesticide exposure. Methods A cross-sectional study was conducted comprising of 279 current workers across four flue-cured tobacco farms in rural Zomba district of Malawi during a tobacco growing season. The assessment involved the use of a modified ECRHS questionnaire and questions on pesticides and nicotine exposure. Voluntary HIV testing was offered to individuals who did not know their HIV status. Health outcomes assessment involved the use of both symptom and spirometry-based diagnoses of obstructive lung disease. The data was analyzed using STATA 14 computer software and included bivariate and multivariate logistic regression analysis. Results The study had predominantly male participants (68%) with a total mean age of 37.7 years, majority (73%) of whom had attained primary education or higher, with 20% being current smokers. Participants had a mean employment duration of 7.3 years and 62% indicated that they worked mainly with tobacco while 57% were involved in pesticides application. HIV prevalence was 16%. The prevalence of current asthma (ECRHS) was 20% whilst for asthma score≥2 it was 23%. The prevalence of chronic bronchitis, work related ocular nasal symptoms and work- related chest symptoms were 17%, 20% and 29%, respectively. Airflow Limitation measured as FEV1 < LLN was 14% (NHANES and sample reference). The prevalence of moderate to severe obstruction was 4%. The prevalence of green tobacco sickness (a proxy for nicotine exposure) in the past year was 26% with an average of 3 episodes within that period. Most workers were exposed to pesticides with 72% reporting exposure during spraying of pesticides while 83% reported re-entry into fields soon after spraying. The main pesticide in use was organophosphates (18%). The majority (51%) of participants reported use of organophosphate pesticides at home. In multivariate analysis nicotine exposure and associated tasks were significantly associated with all respiratory outcomes (OR range 1.78-7.26). Pesticide application was positively associated with all the symptom-based respiratory outcomes (OR 1.96- 2.62) except for work related chest symptoms. Exposure during spraying was significantly associated with asthma score≥2 (OR 2.09, CI 1.01-4.31), current asthma (OR 2.57, CI 1.22-5.40), and work related ocular nasal symptoms (OR 2.43, CI 1.17- 5.04) while pesticide drift was associated with current asthma (OR 2.62, CI 1.00-6.86) and work related ocular nasal symptoms (OR 3.00, CI 1.18-7.62). In spirometry-based outcomes duration of pesticide exposure was significantly associated with FEV1/FVC< LLN (OR 5.11, CI 1.57-16.66), FEV1/FVC< 70% (OR 4.58, CI 1.17-17.98) and moderate to severe obstruction (OR 13.25, CI 1.69-103.93). Nicotine exposure was not significantly associated with spirometry-based outcomes. Conclusion In conclusion, this study showed that tobacco farmers in Malawi have a higher prevalence of asthma and chronic bronchitis compared to the general population or tobacco farmers in other settings. Additionally, exposure to nicotine and pesticides is strongly associated with the prevalence of obstructive lung diseases among these farmers.
- ItemOpen AccessPostgraduate Diploma in Occupational Health (DOH) - Module 3(2014-09-19) Jeebhay, Mohamed; Myers, JonnyDesigned to help teach doctors currently practising occupational health. The third module of a total of 8 modules for a two year part-time flexible distance learning course aimed primarily at medical doctors currently practising occupational health. It includes a residential block release component which consists of between 3 or 4 weeks over the two year cycle for practicum. While the course is aimed primarily at medical doctors currently practicing occupational health, it is also suited to selected graduates with appropriate University qualifications in relevant health sciences, as long as these individuals are currently practicing professionally in an occupational health setting. There are 8 modules (the two included here cover Occupational Hygiene and Epidemiology and Biostatistics). Each module has a theme around which the inputs are organised. Teaching inputs are intended to be non-didactic, and to allow student participation wherever possible. Candidates are expected to undertake substantial homework preparation and activities as well as self-directed learning. They will be expected to read widely and intensively around topics, and to provide teaching inputs themselves either directly or by way of specially structured interactive debates and role-play simulations. The content of these activities will include critical appraisal of the occupational health literature, project work, presentations by students as well as epidemiological, bio statistical, toxicological and occupational clinical assignments. Module 3 deals with basic occupational medicine and toxicology. Module 4 covers intermediate occupational medicine and toxicology, and Module 5 is advanced occupational medicine and toxicology.
- ItemOpen AccessPredictors of occupational skin disease among seafood processing workers in the Western Cape(2012) Burdzik, Amy; Jeebhay, Mohamed; Todd, GailOccupational skin disease is common in seafood processing workers. While previous studies have reported an increased prevalence of symptoms (as high as 50%) and protein contact dermatitis (3-11%), the prevalence and patterns of type IV allergic contact dermatitis have not been well characterised in epidemiological studies. The aim of this study was to identify host and environmental risk factors for symptoms, clinical eczema, positive patch tests, possible and probable allergic contact dermatitis in seafood processing workers. A cross-sectional study of 594 seafood processing workers was conducted in two seafood processing plants in the Western Cape Province of South Africa. The study used an interviewer administered questionnaire to collect information on demographic characteristics, occupational history, work practices and skin symptoms in the preceding 12 months. A subgroup of symptomatic workers (n=120) were investigated further and compared to a group of randomly selected asymptomatic workers (n=134). Both groups underwent clinical examination by experienced dermatologists and patch testing with a battery of standard allergens (adapted British Contact Dermatitis Group Standard Series) supplemented by various seafood products and additives used in the factory. Data of skin prick tests to common aeroallergens and seafood products, and serum omega-3 fatty acid (Eicosopentaenoic acid) collected in a previously reported study were also used.
- ItemOpen AccessThe relationship between pesticide metabolites and asthma outcomes among women farm workers(2013) Mwanga, Hussein Hassan; Jeebhay, Mohamed; Dalvie, Mohamed AqielVarious studies have demonstrated an association between exposure to pesticides and adverse respiratory health outcomes including non-specific respiratory symptoms, rhinitis and asthma. Few studies have investigated the relationship between pesticide metabolites and asthma outcomes and only a limited number have explored mechanisms for allergic and non-allergic airway inflammation in individuals exposed to pesticides. A previous sub-study of this group reported an association between allergic airway inflammation as determined by fractional exhaled nitric oxide (FeNO) and low levels of whole blood cholinesterase among women farm workers. The main objective of this study was to investigate the relationship between exposure to different pesticides (ascertained through pesticide metabolites concentrations in urine) and asthma phenotypes (based on respiratory symptoms, cytokine patterns and exhaled nitric oxide profiles) among rural women in the Western Cape Province.
- ItemOpen AccessRespiratory allergy and asthma associated with pesticide exposure amongst women in rural Western Cape(2012) Ndlovu, Vuyelwa; Dalvie, Mohamed Aqiel; Jeebhay, MohamedPesticide exposure has been increasingly associated with adverse respiratory health effects including asthma and allergy. However, few studies have been conducted among women and workers in developing countries. South Africa is one of the largest users of pesticides on the continent and the Western Cape is one of the main agricultural areas in the country, with uncontrolled use posing an increased health risk to farm workers. This study focused on determining the association between pesticide exposure (predominantly organophosphates and carbamates) and the presence of allergy and asthma among women farm workers and residents. A cross-sectional study was conducted on 211 women including those working and living on farms (farm dwellers, n=121) and those residing in neighbouring farm areas (town dwellers, n=90). Outcome measurements included the abbreviated European Community Respiratory Health questionnaire, fractional exhaled nitric oxide (FeNO) levels and immunological tests (a positive Phadiatop test indicating atopy and quantification of specific IgE to house dust mite, storage mite and spider mite). The outcome variables included doctor diagnosed asthma, adult onset asthma, current asthma, allergic sensitisation, allergic airway inflammation and the asthma symptom score. The asthma symptom score was a continuous outcome generated as the sum of positive responses to four questions on asthma symptoms in the last 12 months including wheeze with breathlessness, woken up with chest tightness, attack of shortness of breath at rest and woken by attack of coughing. The asthma symptom score values ranged from from 0 for no symptoms to 4 for all symptoms.
- ItemOpen AccessSkin symptoms (allergic and non-allergic) predicting the development of allergic respiratory outcomes and asthma in bakers(20198) Chongo-Faruk, Vânia; Jeebhay, Mohamed; Baatjies, RoslynnBackground: Recent studies have suggested that aside from the inhalational route, skin exposure may also play an important role in the sensitization to allergens, resulting in adverse allergic respiratory outcomes including asthma in workers exposed to these agents. This appears to be reported more commonly for low molecular weight agents such as isocyanates and some cleaning agents. This study investigated whether skin symptoms, in the presence or absence of allergic sensitization, can predict the development of allergic respiratory outcomes and asthma in bakery workers. Methods: A cohort study investigated 263 bakery workers using a modified ECRHS questionnaire; immunological tests including skin prick tests for common local aeroallergens (ALK-Abello´ A/S, Horsholm, Denmark), Phadiatop and serum-specific IgE to bakery allergens (wheat, rye and fungal α-amylase); and pulmonological tests including spirometry, non-specific bronchial hyperresponsiveness, and fractional exhaled nitric oxide (FeNO), after a 4 year period. Results: Workers’ median age was 32 years (IQR: 26-38), 50% were female, 54% were ever smokers and 32% were atopic. At baseline, 26% of workers were sensitized to bakery allergens, skin symptoms were present in 22% and 11% reported work-related skin symptoms (WRSS). 3 While the incidence of general upper (19%) and lower (22%) respiratory symptoms over the follow-up period were very similar, work-related upper (29%) respiratory symptoms were higher than lower (20%) respiratory symptoms. However, the incidence of allergic sensitization to bakery allergens was only 8% and a new asthma diagnosis present in 4% over this period. In multivariate adjusted (gender, atopy and smoking status) regression models, having a history of skin symptoms was associated with an increased risk of developing work-related lower respiratory symptoms - WRLRS (RR=2.2, 95% CI: 1.03-4.83), while having clinically significant symptoms of eczema or urticaria was associated with an increased risk of reporting general upper respiratory symptoms (RR=5.5, 95% CI: 1.30-24.20) as well as WRLRS (RR= 4.8, 95% CI: 1.60-14.40). Furthermore, WRSS was associated with an increased risk of general upper respiratory symptoms (RR=5.1, 95% CI: 1.31-19.81), WRLRS (RR=4.1, 95% CI: 1.43-11.85) and elevated FeNO levels (FeNO>25ppb: RR=2.9, 95% CI: 1.19-7.28). The association between clinically significant skin symptoms or WRSS and new onset upper or lower respiratory symptoms were modified by use of dermal personal protective equipment. Infrequent or absent glove usage was associated with a higher risk (RR=5.3, 95% CI: 1.54-18.43) of having new onset WRLRS. Conclusion: Skin symptoms, more so if work-related, appear to be associated with future development of general and work-related upper and lower respiratory symptoms and inflammatory markers suggestive of asthma in bakery workers.
- ItemOpen AccessThe relationship between reproductive hormones and asthma-related outcomes in boys residing in the rural Western Cape(2023) Phuti, Mandy; Jeebhay, Mohamed; Dalvie AqielBackground: Asthma is more prevalent and severe among boys but this pattern reverses after puberty. It has been suggested that reproductive hormones may play a role in explaining these sex differences after puberty, but the evidence is still limited especially for children living in low- and middle-income countries. Objective: This study investigated the association between reproductive hormones and asthmarelated outcomes among boys residing in a rural setting. Methods: A cross-sectional study of 470 boys (6-18 years), residing in the rural Western Cape province of South Africa was conducted. General questionnaires were administered to the boys and their caregivers including an abbreviated International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Testosterone (TST and FT), luteinizing hormone (LH), serum follicle-stimulating hormone (FSH), oestradiol and serum hormone-binding globulin (SHBG), were assessed using electrochemiluminescence immunoassays. A total of 314 (66.8%) boys had valid asthma outcome information and hormone level measurements that were analysed further. Multivariate logistic regression models were used to assess the relationship between asthma and measured endocrines levels. Results: The mean age of the boys was 11.2 (Standard deviation -1.7 years). Current wheeze (CW), asthma symptom score ≥ 2 (ASS) and parental reported asthma (PA) prevalence were 6.1%, 6.7% and 8.0%, respectively. In the adjusted multivariate logistic regression models, total serum testosterone (TST) levels were negatively associated with CW (OR=0.66, 95% CI: 0.45- 0.98), ASS (OR=0.64, 95% CI: 0.43-0.95) and PA (OR=0.86, 95% CI: 0.59-1.25). Free testosterone (FT) levels were similarly negatively associated with all three asthma-related outcomes. Similar associations were also found for LH and FSH, but there were no clear associations for estradiol and SHBG with asthma-related outcomes. The concentration-response curves confirmed that higher levels of testosterone (TST and FT) were associated with reduced risk of asthma-related outcomes. Conclusions: This study provides evidence that increasing testosterone levels are associated with reduced asthma risk among rural boys in South Africa
- ItemOpen AccessThe 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, ToyibBackground: 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.