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Chapter 4: Mine dumps, wheeze, asthma and rhinoconjunctivitis among adolescents in South Africa: any association?
Abstract
Background: The study investigated the association between community proximity to mine dumps, and current wheeze, rhinoconjunctivitis and asthma among adolescents. This study was conducted during May-November 2012 around five mine dumps in South Africa.
Methods: Adolescents in communities 1 km – 2 km (exposed) and > 5 km (unexposed), from pre-selected mine dumps in Gauteng and North West Province, in South Africa were included in a cross-sectional study. The study participants completed a self-administered questionnaire based on the International Study of Asthma and Allergies in Childhood Phase I protocol.
Results: Communities in close proximity to mine dumps had an increased likelihood of current wheeze OR 1.38 (95% CI: 1.10 – 1.71), rhinoconjunctivitis OR 1.54 (95% CI: 1.29 –1.82), and a protective association with asthma OR 0.29 (95% CI: 0.23 – 0.35). Factors associated with health outcomes included other indoor and outdoor pollution sources.
Conclusion: Wheeze and rhinoconjunctivitis appear to be a public health problem in these communities. The findings of this study serve as a base for further detailed epidemiological studies for communities in close proximity to the mine dumps e.g. a planned birth cohort study.
Keywords: mine dumps, asthma, wheeze, rhinoconjunctivitis, adolescents, South Africa
[This chapter was published in the International Journal of Environmental Health Research: Nkosi V, Wichmaan J, Voyi K. Mine dumps, wheeze, asthma, and rhinoconjunctivitis among adolescents in South Africa: any association? Int J of Environ Health Res. 2015; 25(6):583-600.]
Introduction
A recent review1 indicated that current wheeze, asthma and rhinoconjunctivitis prevalence is increasing globally, including developing countries like South Africa.2 Various lifestyle risk factors have been associated with existing symptoms of asthma (i.e. wheeze) and rhinoconjunctivitis, such as diet,3,4,lack of physical activity,5,6 and active smoking.7,8 Demographic factors such as sex9, age10 and ethnicity11,12 have also been associated with existing symptoms of these health outcomes.
Evidence is also increasing that environmental factors, such as various air pollution sources, significantly increase the risk of existing symptoms of asthma (i.e. wheeze) and rhinoconjunctivitis.13 Environmental factors are beyond the control of the individual and therefore of great importance. Numerous studies in both developed and developing countries thus far investigated the following air pollution sources: environmental tobacco smoke (ETS) exposure at home or school,14,15 traffic16–18 and polluting fuel use for residential cooking /heating.19–21 Whether air pollution, lifestyle and demographic factors actually are involved in the development of asthma and rhinoconjunctivitis is still being investigated.
Mine dumps facilities are major generators of wind-blown dust and are one of the main sources of air pollution with potential adverse health implications for nearby residents.23 One of the biggest challenges facing mine industry is inadequate waste disposal. Mine dumps consist of crashed sand-like waste material which is generated by extraction and grinding methods of ground ore during mining24,25 The material contains a complex mixture of metals, dust particles or particulate matter that is released and transported to the surrounding communities by air, soil or water contamination. Exposed communities are of lower socio-economic status, often elderly people and children.These communities comprise historically marginalised ethnic groups living in government-funded houses, informal settlements and retirement homes.27 Epidemiological studies have shown that living near mine dumps is a major risk for exposure to particulate matter and metals such as cadmium, manganese, lead and arsenic.24,28,29 Children are particularly vulnerable because their respiratory system is still developing.30 Higher prevalence of respiratory diseases was observed and correlated with toxic metals in the blood in people living near mining sites in Campos de Jales, Portugal as compared to a control group living 45 km in Vilar de Macada.
Studies that have reported on the prevalence of asthma symptoms in South Africa applied the International Study of Asthma and Allergies in Childhood (ISAAC) protocol and a wide variability in the prevalence of asthma, wheeze, and rhinoconjunctivitis in residential areas situated near industries was observed. ISAAC is the largest worldwide collaborative respiratory research project that studies asthma and its symptoms among children.
No studies have investigated whether exposure to dust from mine dumps or living in close proximity to mine dumps pose an increased risk for existing symptoms of asthma (i.e. wheeze) and rhinoconjunctivitis, whether this exposure is involved in the development of these health outcomes or whether there is effect modification between various air pollution sources, including mine dust.
This study is part of the bigger project initiated by Mine Health Safety Council of South Africa (MHSC) around communities located near mine dumps in Gauteng and North West. This study is, to the best of our knowledge, the first study that investigated the prevalence, association between potential risk factors and wheeze and rhinoconjunctivitis among adolescents staying in communities situated near mine dumps in South Africa. The aim of the study was to investigate the prevalence, association between community proximity to mine dumps, and current wheeze, rhinoconjunctivitis, and asthma among adolescents. Effect modification between community proximity to mine dumps and other air pollution sources was also investigated i.e. type of fuel use for residential cooking/heating, frequency of truck traffic near homes, ETS exposure at home and school.
Methods
Study area and demographics
A cross-sectional epidemiological design was applied. Communities in urban areas living 1 km – 2 km (exposed) and > 5 km (unexposed) from pre- selected five mine dumps in Gauteng and North West of South Africa were included in the study during May to November 2012. Table 4.1 lists the selected communities and Figure 4.1 shows the map of the study area. The socio-economic and demographic profile of exposed and unexposed communities was similar.
The study focused on 13-14 year old pupils who attended schools located in the 11 selected communities. The study participants were selected and interviewed during school hours at their respective schools. Exposed communities had 23 schools (primary and secondary) in total a identified by the investigators. Seven junior primary schools were excluded and 16 schools were contacted and invited to participate. Junior primary schools comprise of pupils under the age of 12 with classes starting from grade zero to four and primary schools pupils from 5 to 15-year olds with classes begin from grade zero to seven. Four of the 16 schools declined and 12 schools participated in the study.
Fourteen schools, both primary and secondary in the unexposed area, were randomly selected to match the number of schools in exposed communities. Four schools declined and 10 schools participated in the questionnaire survey.
Twenty-two schools were included in the study, of which 13 were secondary and nine were primary schools. In each school, all eligible pupils who were 13-14 years old and who resided in one of the selected 11 communities were requested to participate. Each exposure group consisted of 3000 pupils that were invited to participate.
Exclusion criteria
Schools and pupils that did not grant permission prior to the start of the fieldwork, or showed lack of cooperation and pupils residing in communities other than the 11 selected communities (i.e. home and school communities not necessarily the same) were excluded from the study. Figure 2 shows a flowchart of the procedure followed to recruit study participants and the participation rate.
Health outcomes
The study participants completed a self-administered questionnaire based on the (ISAAC) Phase I protocol.35 Data were collected using the English version of ISAAC written questionnaire composed of modules such as asthma and rhinitis, each comprising up to eight easily understood questions. The medium of instruction in all the schools that participated in the study was English. According to the ISAAC Phase 1 protocol current wheeze, asthma and rhinoconjunctivitis symptoms were classified on the basis of positive answers to the following questions:
Current wheeze: “Have you had wheeze or whistling in the chest at any time in the past 12 months?”
Asthma: “Have you ever had asthma?”
Rhinoconjunctivitis symptoms: “Have you ever had a problem with sneezing, or a runny, or blocked nose when you did not have a cold or flu?” and “In the past 12 months have you ever had a problem with sneezing, or a runny, or blocked nose when you did not have a cold or flu?” and “In the past 12 months has this nose problem been accompanied by itchy-watery eyes?”
DECLARATION
ETHICS STATEMENT
PUBLICATIONS
PUBLISHED ABSTRACTS
NEWSPAPER ARTICLE
CONFERENCE PRESENTATIONS
DEDICATION
ACKNOWLEDGMENTS
FINANCIAL ASSISTANCE
LIST OF ABBREVIATIONS
ABSTRACT
TABLE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
1. Chapter 1: Introduction
1.1 What are mine dumps?
1.2 Metal composition of mine dumps
1.3 Environmental pollution
1.4 Toxicity of particulate matter from mine dumps and health effects
1.4.1 Mechanism of particulate matter-induced toxicity
1.4.2 Exposure to dust from mine dumps
1.4.3 Children/adolescents and the elderly are most vulnerable to the effects air pollution
1.4.4 Socio-demographic profile of people living near mine dumps in South Africa.
1.5 Research question
1.6 Aim
1.7 Objectives
1.8 Study hypothesis
1.9 Relevance of the study
1.10 References
2. Chapter 2: Research methodology
2.1 Study location
2.2 Study design, population and sample selection
2.2.1 Phase I: Cross-sectional study – ISAAC questionnaire survey
2.2.2 Phase II: Cross-sectional study – ATS – DLD – 78 community questionnaire survey
2.2.3 Phase III: Personal and outdoor air pollution measurements at schools
2.2.4 Panel studies
2.2.5 Ethical considerations
2.3 Funding of the project
2.4 Reporting of results
3. Chapter 3: Reliability of an adult respiratory symptom questionnaire in a community located near a mine dump in South Africa: Pilot study
3.1 Abstract
3.2 Introduction
3.3 Methods
3.4 Statistical analysis
3.5 Results
3.6 Discussion
3.7 References
4. Chapter 4: Mine dumps, wheeze, asthma and rhinoconjunctivitis among adolescents in South Africa: any association?
4.1 Abstract
4.2 Introduction
4.3 Methods
4.3.1 Study area and demographics
4.3.2 Exclusion criteria
4.3.3 Health outcomes
4.3.4 Main exposure factor
4.3.5 Confounders
4.3.6 Statistical analyses
4.4 Results
4.5 Discussion
4.6 Conclusions
4.7 Conflict of interest
4.8 Ethical considerations
4.9 Acknowledgements
4.10 List of abbreviations
4.11 References
5. Chapter 5: Chronic respiratory disease among the elderly in South Africa: any association with proximity to mine dumps?
5.1 Abstract
5.2 Background
5.3 Methods
5.4 Results
5.5 Discussion .
5.6 Conclusion
5.7 Acknowledgements
5.8 Contributors
5.9 Funding
5.10 Competing interest
5.11 Abbreviations
5.12 References
6. Chapter 6: Comorbidity of respiratory and cardiovascular diseases among the elderly residing close to mine dumps in South Africa: A cross-sectional study
6.1 Abstract
6.2 Introduction
6.3 Objectives
6.4 Methods .
6.5 Results
6.6 Discussion
6.7 Study limitations
6.8 Conclusion
6.9 Acknowledgments
6.10 References
7. Chapter 7: Indoor and outdoor PM10 levels at schools located near mine dumps in Gauteng and North West, South Africa
7.1 Abstract
7.2 Introduction
7.3 Methods
7.4 Results
7.5 Discussion
7.6 Conclusion
7.7 Ethical considerations
7.8 Contributors
7.9 List of abbreviations
7.10 Acknowledgements
7.11 Conflict of interest
7.12 Funding
7.13 References
8. Chapter 8: Acute respiratory health effects of air pollution on asthmatic adolescents residing in a community close to Crown Gold Recoveries mine dump in South Africa: Panel study
8.1 Abstract
8.2 Introduction
8.3 Methods
8.4 Results
8.5 Discussion
8.6 Study limitation
8.7 Study strengths
8.8 Conclusion
8.9 Conflict of interest
8.10 Ethical considerations
8.11 Contributors
8.12 Acknowledgements
8.13 Funding
8.14 References
9. Chapter 9: Acute respiratory health effects of air pollution on asthmatic adolescents residing in a community close to East Rand Proprietary Mine dump in South Africa: Panel study
9.1 Abstract
9.2 Introduction
9.3 Methods
9.4 Results
9.5 Discussion
9.6 Study limitations
9.7 Study strengths
9.8 Conclusion
9.9 Conflict of interest
9.10 Ethical considerations.
9.11 Contributors
9.12 Acknowledgements
9.13 Funding
9.14 References
10. Chapter 10: Conclusion and recommendations
10.1 Background
10.2 Main findings
10.3 Potential bias and limitations
10.4 Study strengths
10.5 Conclusion and recommendations for future studies
10.6 Future perspective
10.7 References
Appendix 1: Letter of approval from the Academic Advisory Committee
Appendix 2: Letter of approval from the Research Ethics Committee
Appendix 3: Letter of approval from the Gauteng Department of Education
Appendix 4: Letter of approval from North West Department of Education
Appendix 5: Research request letter to the school principals
Appendix 6: Consent forms to the parents
Appendix 7: Assent form
Appendix 8: ISAAC questionnaire
