Association of childhood TB with indoor air pollution
Indoor air pollution has been associated with increased risk for lung diseases. The number of cigarette pack years has been associated with the risk of acquisition and development of TB in adults. Passive smoke and other air pollutants exposures are associated with a 1 to 5 fold increased risk of acquisition of childhood tuberculosis as determined by questionnaires about the use of biofuels in cooking, heating and lighting in households.
No studies to date have measured the exposure of indoor pollutant levels directly. This study aims to investigate the association between exposure to indoor air pollutant level and childhood pulmonary tuberculosis (PTB) by quantifying pollutant levels.
A case controlled study of households of children 14 years and younger with and without culture confirmed PTB will be undertaken. Five hundred and thirty four participants are expected to be recruited for the study. Prior to commencement of the study, a pilot of 20 participants and households will be used to optimise the methodology. Questionnaires and air monitoring equipment will be used. Environmental assessment of the children’s homes will be conducted using walkthrough checklist and indoor monitoring of air pollutants (particulate matter, sulphur dioxide, nitrogen dioxide and metals) for a 24 hour at least period three times in each household. Child’s health and socioeconomic conditions of the children’s households will be assessed as well using a child caregiver questionnaire. Statistical models, such as logistic regression, will be used to determine the association between PTB as an outcome variable and indoor pollution levels as independent variables. Covariates, such as socioeconomic status, crowding, etc. will be factored in.
We expect that the level of indoor pollutants will be directly related to the risk of acquisition of TB as a result of direct injury of the respiratory epithelia by air pollutants. This allows easy entry of TB bacillus. The outcomes of this study will include understanding the dose-response relationship of PTB and indoor pollutant levels in homes. This will in turn highlight some mechanisms that maybe useful in understanding the disease.
This is a PhD project of Nkosana Jafta supervised by Prof Rajen Naidoo and co-supervised by Prof Prakash Jeena. A pilot study of this project is funded by South African TB and HIV/AIDS Training (SATBAT).
Occupational Health needs of Women working on Small-Scale and Emerging Farms
This project is being led by Dr. Saloshni Naidoo. Collaborators on this study are the Occupational and Environmental Health Research Unit at the University of Cape Town, the Institute for Risk Assessment Sciences, at the University of Utrecht, and the Department of Public Health, Erasmus MC, University Medical Centre Rotterdam in the Netherlands.
This was an interventional study, which was conducted in three phases. In the first two phases of the study data was collected to identify the occupational health needs of women working on small-scale farms in rural South Africa. In the first phase the results of the focus groups found that women have some knowledge about pesticides and the safety practices required to protect themselves from adverse health effects. Despite this knowledge women experience pesticide related health effects and in the presence of economic constraints are unable to protect themselves from pesticide exposure.
In the second phase of the study, an administered questionnaire surveyed 911 women working on the Irrigation Scheme and Dry-lands of the Makhatini Flats. Use of World Health Organization class I and II pesticides were reported in both areas. In total 67% (n=574) of women reported chronic musculoskeletal pain. The 12- month’s prevalence of pain ranged from 63.9% to 73.3% and the prevalence of chronic pain lasting more than 3 months ranged from 42.8% to 48.3%. Older age, hectarage cultivated, carrying heavy loads, working with hands above shoulder height and frequently squatting and kneeling were associated with chronic musculoskeletal pain. Farm ownership, age less than 30 years, and being a sprayer, were all associated with having knowledge about the names of the pesticides sprayed. This analysis thus far suggested that women on the Dry-lands are at greater risk for adverse ergonomic health outcomes and women from both areas are equally at risk for adverse pesticide related health outcomes.
Based on the interim findings for the third phase of the study we developed a training manual on pesticides. We have trained 12 Environmental Health officers and Agricultural Extension officers on pesticide classification, safety and health effects in 2008. These officers trained 100 women interviewed in the second phase of our study. These women have been interviewed after 6 months of training in July to determine if there are improvements in their pesticide knowledge from baseline.
The field work for this study has been completed. Data analysis and write up is taking place.
Respiratory Health of Informal Stonecrushers
This project is part of the WAHSA Programme, and has been done jointly by the DOEH and the Tanzanian Occupational Health Service (TOHS) an NGO from Dar-es-Salaam. The prevalence of dust-related respiratory problems and relationships between health endpoints and respirable dust were investigated among stonecrushers in an informal sector quarry in Dar-es-Salaam, Tanzania. Exposure and respiratory health outcomes were assessed in 200 workers, employed for at least one year. A randomly selected subset (n=60) had assessments.
Associations were investigated between exposure measures and respiratory outcomes, based on questionnaires and spirometry.
Area dust levels ranged from 7.5mg/m3 – 10.3mg/m3 (mean = 9.8mg/m3). The mean exposure duration of this sample was 7.5 years (range: 1 – 62 years). Smoking was common – 19.5% were current and 1.5% were ex-smokers. Reported prevalences of doctor-diagnosed respiratory diseases were: asthma (3%), chronic bronchitis (3%), emphysema (0%) and tuberculosis (2%). This contrasted with the reporting of respiratory symptoms of chronic cough (13.5%), chronic phlegm (15%), wheeze (87%) and breathlessness (20%).
Age and height adjusted mean forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) was 2.78L/min and 3.76L respectively, among the men and 2.18L/min and 3.00L respectively among women. Although years worked in stonecrushing was not statistically significant, it contributed a small adjusted loss in FEV1 of 2ml per year worked. Doctor-diagnosed TB was a statistically significant predictor of adjusted FEV1 and FVC, accounting for a loss of approximately 600 ml and 800ml of FVC and FEV1 respectively. While the adjusted risk for symptoms outcomes due to high exposure (as compared to medium exposure) was consistently in the expected direction (with odds ratios ranging from 1.7 for frequent cough; 3.4 for frequent episodes of phlegm; 2.0 for symptoms of chronic bronchitis), this was only statistically significant for frequent phlegm production, after controlling for smoking status and doctor-diagnosed TB.
Stonecrushers in the informal sector of Dar-es-Salaam seem to be at increased risk for the development of adverse respiratory outcomes, in a dose-response manner. Cost effective interventions are necessary to protect these marginalised self-employed workers with little resources for engineering dust controls. The low levels of doctor-diagnosed diseases compared with the higher levels of symptoms suggests restricted access to health care.
TB transmission in health facilities in the eThekwini municipality
The occupational risk of Tuberculosis (TB) in health care facilities is a growing concern in South Africa as the burden of community acquired TB increases. The Ethekwini Municipality manages more than seventy primary health clinics delivering primary health care to the community. Management’s concern about the potential occupational risk of TB presented to employees in health care facilities resulted in a request for research which would identify the occupational risks associated with TB in health care workers employed in their facilities. This study was conducted in a selection of 51 primary health care clinics in the Ethekwini municipality. Risk assessments were conducted in these 51 clinics and health interviews and examinations were conducted in health care workers employed in these clinics to identify administrative and engineering risks associated with transmission of TB to health care workers employed in this clinic. The data collection on this study has been completed and data analysis is currently taking place. The study was funded by the Ethekwini Municipality and DANIDA.
Birth Outcomes and Ambient Pollution
A follow up to better understand the impact of pollution on the health of children, a more comprehensive study, following a life cycle approach, commencing with in-utero effects. This study intends to describe birth outcomes among a sample of pregnant mothers exposed to industrial pollution, compared to those without such exposures and to test methodological approaches for a longitudinal study investigating the association between environmental pollution and respiratory outcomes among children. To achieve these objectives, 100 pregnant women of which 50 were selected from the industrially polluted south Durban and 50 from the less polluted, north Durban, were selected. Pollutant data from environmental monitoring stations managed by the eThekwini municipality will be used to describe the exposure of all participants. Participants were interviewed about their health status, obstetric history, exposure history and nutritional history. Biomarkers for oxidative stress, allergy, and atopy were obtained from the mothers, genetic polymorphisms and inflammatory markers, together with cord blood for heavy metal exposure and dried blood spot from the baby for genetic polymorphisms, are being conducted.
This is a study still in progress. 50 participants have already been recruited in the South Durban area and 20 in the North Durban area. Samples are currently been analysed for antioxidant levels. Descriptive data will be presented, including pregnancy and labour histories, exposure history and biochemical assay information. This is a pilot study is proposed to serve as preparation and proof of concept for a full scale longitudinal birth cohort study.
Chronic Obstructive Pulmonary Disease and Occupational Exposures
Occupational exposures are associated with chronic obstructive pulmonary disease (COPD). This study investigated this association among a population with a high prevalence of tuberculosis and smoking. Cases (n=110), diagnosed by pulmonologists were selected from specialist respiratory clinics at public sector hospitals. Frequency sex and age matched controls (n=102) were selected from other clinics at the same institutions. Lifetime occupational exposure histories were obtained through interviews. Exposure variables derived from the ALOHA Job Exposure Matrix (JEM) were used to complement the self-reporting variables in the analyses. Odds ratios (OR) were calculated from logistic regression models, adjusting for smoking and past history of tuberculosis.
The adjusted OR’s for risk of COPD from the JEM derived high cumulative biological dust exposure, high cumulative mineral dust exposure and high cumulative gas and fumes exposure were 2.1 (95% CI 1.1-4.2), 1.1 (95% CI 0.6-2.4) and 1.8 (95% CI 0.8-3.9) respectively. Self-reported occupational exposures were associated with higher risks, with adjusted OR’s for high dust exposure-years and high chemical, gases and fume exposure-years of 5.9 (95% CI 2.6-13.2) and 3.6 (1.6-7.9) respectively. Among ever smokers, there was an increased risk for COPD with OR’s ranging from 5.0-5.5 in the different models. TB was a strong risk factor for the development of COPD, with OR ranging from 7.7-8.1.
Lifetime occupational exposures contribute to the risk of COPD, adjusted for smoking. These risks are present in populations with a high burden of tuberculosis which is generally considered an important causative factor.
Earth Observation and ENVironmental modelling for the mitigation of HEAlth risks (EO2HEAVEN)
This is a European Union Framework 7 funded project. The project consists of a consortium of 13 organisations including several in various European countries and three from Southern Africa, including UKZN. EO2HEAVEN contributes to a better understanding of the complex relationships between environmental changes and their impact on human health. The project will monitor changes induced by human activities, with emphasis on atmospheric, river, lake and coastal marine pollution. EO2HEAVEN will follow a multidisciplinary and user-driven approach involving public health stakeholders who will work closely with technology and service providers in both the earth observation and in-situ environmental monitoring domain. The result of this collaboration will be the design and development of a GIS based upon an open and standards-based Spatial Information Infrastructure (SII) envisaged as a helpful tool for research of human exposure and early detection of infections.
The key factors of the EO2HEAVEN system will be 1) an enhanced integration of remotely sensed and in-situ environmental measurements, and 2) the development of models to relate these environmental data to exposure and health data. Throughout the life span of the project the stakeholder requirements from three different use cases (in Europe and Southern Africa) will be assessed and the technical solutions proposed by EO2HEAVEN will be evaluated through an iterative process, thus ensuring that the solutions can be applied on a global scale.
The UKZN participation is through the development of a use case based on the ambient pollution in south Durban, and the creation of a system that will provide risk mapping and early warning alerts of adverse environmental conditions that will increase the risk for poor health outcomes.
Gene-Environment Interaction
There is increasing evidence that the effects of air pollution varies among individuals because of the variation in susceptibility levels. Our work investigates the role of functionally significant genetic polymorphisms involved in response to oxidative stress and how this influences susceptibility to respiratory effects of air pollution. While large cohort studies on children’s’ respiratory health and genetics have been done or currently underway in several countries in the developed world, to date there has been no similar work done on the African continent. In fact, we are the only group in Southern Africa active in this area of research. Large sample sizes with longitudinal study designs are required in such research and one requires a team of multidisciplinary scientists with expertise in the areas of genetics, epidemiology, biostatistics and exposure monitoring to effectively conduct such research. Due to the lack of national expertise, we have established international collaborations with US scientists active in the field of genetic epidemiology. In our study, we evaluated whether polymorphisms in GSTM1 and GSTP1 confer increased susceptibility to adverse effects of exposure to ambient air pollutants among children with asthma and related phenotypes.
In our study, the GSTM1null and GSTP1 AG/GG genotypes were detected in 28.9% and 64.9% of our population respectively. Based on symptoms, 20.4% of children from the random sample had persistent asthma and 10.3% had marked BHR (PC20? 2 mg/ml). Carrying one or more copies of the GSTP1 minor allele was significantly associated with known or probable persistent asthma (OR=2.74, CI: 1.29-5.84, p=0.00), but was not significantly associated with atopy or BHR (OR =0.93, CI: 0.29-1.99, p=0.59; and OR=0.94, CI: 0.43-2.04, p=0.88 respectively). GSTM1null was not associated significantly with any respiratory health related phenotypes, however statistically significant associations of NO2, NO, and SO2 with FEV1 and PEF outcomes in the expected direction were more frequent for individuals carrying the GSTM1null genotype. Potential applications of this research include primary prevention (such as aiding at understanding the biology of diseases, potentially leading to the development of strategies based on mass intervention or target risk intervention approaches, this could facilitate the setting up of a genetic risk profile for the development of asthma and would enable us, for the first time, to take preventative early in life for children with an increased genetic risk to allergic diseases), secondary prevention (such as the development of primary tests for population wide screening) and therapy (such as choosing among alternative interventions or assist in the design of new drugs which are more specific, effective and safe.
Toxicological analysis of indoor house dust from Durban homes
As part of the South Durban Health Study, indoor environments of elected households were conducted to describe the levels of pollution. In this particular sub-study, the objectives were to isolate, identity and quantify mould incidence in house dust samples, to investigate the occurrence of heavy metals (mercury, arsenic and lead) that are associated with indoor air pollution; and to investigate the cytotoxicity of house dust on human cell lines (Human Lung Carcinoma Epithelial – A549 and Human Bronchial Epithelial – BBM). A total number of 130 households participating in the SDHS were recruited to participate in the sub-study. The house dust samples were collected from the surface areas of living room couches, beds mattresses and carpets.
Among the 105 genera identified, only 10 were predominant which have been reported elsewhere to be associated with poor indoor air quality and human health effects: Cladosporium, Penicillium, Alternaria, Aspergiullus, Mucor, Rhizopus, Curvularia, Spondenema, Geotrichum and Fusarium. Heavy metals were detected in the dust: As (mean, 4.26 µg/g), Pb (mean 171.66 µg/g), and Hg (mean, 2.22 µg/g), respectively. The cytotoxicity investigation is being conducted
Diabetes and Traditional Medicine
The project, led by Dr Renee Street, is on research and development of a traditional medicine for the treatment or management of diabetes. The objectives of this project include the identification of the active components of the plant, product development and toxicological evaluation and clinical evaluation of the product.
Cancer and the Environment Surveillance Unit (CESU): A Pilot Project
During our ongoing interaction with the communities in south Durban, the concerns about environmental pollution and cancer were substantial. There have been several media reports that have suggested elevated risk, and this was confirmed in a health risk assessment conducted by our Department during the South Durban Health Study. Our recommendations to the community, as well as the eThekwini Municipality’s Department of Health was to establish a CESU to better understand the prevalence of cancer and association with pollution.
The overall aim of this project was to set up a pilot institute that will determine the relationship between cancer outcomes and environmental risk factors among communities in south Durban. Of the 46 institutions in Durban three, namely RK Khan, King Edward and St Aidan’s Hospitals; were used for part of the data sources for this pilot project. Data on cancer patients seen from 01 Jan 2009 to 31 August 2009 was collected from these institutions.
A structured tracing of cancer cases within the hospitals was important as not to miss any cases that have come through these institutions. A systematic way of tracking cases in these institutions’ medical records department was established during this study. Although cases could be tracked not all the required information needed for surveillance purpose was found in the files and that prompted the use of both admission and discharge ward registers for identification of cases for surveillance purpose and only data from ward registers was used in the study.
During the 9 months’ time period of interest, the wards of the 3 visited hospitals had 708 patients diagnosed or suspected as having cancer. Of these cases, 477 were patients with confirmed cancer living in eThekwini Municipality with female (270) more than males (207). On the number of cases seen from Thekwini Municipality area, south Durban contributed 59 (10.6%) and of these 52 (88.2%) were confirmed cases.
This study found that a CESU is likely to provide information about the relationship of cancer to environmental agents. However, this pilot study suggested that much more stakeholder participation through legislation is necessary before such a unit can be effective, and can provide answers environment and cancer. To assure sustainability of an institution like CESU our recommendation was the establishment of two structures, i.e. a cancer registration unit and another unit collecting data on environmental risk factors. .
This project was managed by Mr. Nkosana Jafta, with Prof Rajen Naidoo as Principal Investigator.