Gold Mining and Acute Respiratory Infection in Children: a Retrospective Cohort Study in Vatukoula, Fiji
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Gold Mining and Acute Respiratory Infection in Children: A Retrospective Cohort Study in Vatukoula, Fiji. A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Health Sciences Saula Matakarawa (ID: 49568935) University of Canterbury 8th June, 2018 i Dedication I dedicate this piece of work to my loving and hardworking mother, late Mrs Ruci Tinai, a mother that sacrificed her life to prepare my future; dearly missed but will always be remembered. ii Acknowledgement First and foremost, I must thank the Almighty God for his protection, guidance and wisdom throughout this journey. Secondly, I sincerely thank my sponsor, the Government of New Zealand, through the Department of Foreign Affairs and Trade, for accepting me and providing all the financial support towards my study at the University of Canterbury; and your represen- tatives (student advisors) at the university for their support. To my wonderful supervisors, Dr Arindam Basu and Professor Steven Ratuva, my sincere grat- itude for all your help. Thank you so much, Dr Arindam Basu, for helping me throughout this research, from the planning stage right to the analysis and interpretation of results. The actual realization of this thesis would not have been possible without your guidance and help. Thank you, Professor Steven Ratuva, for your guidance and help in the design and analysis of the qual- itative aspect of this study. Through both of your guidance, I am now confident to use the basic research methodology used in this study for future studies. I also thank the support rendered by all the staffs of Academic Skills Center and those from the Library Service of the University of Canterbury. Thank you, Margaret Patterson, the librarian for health sciences, for accommodating me when I needed immediate help. To the management of Vatukoula Gold Mine plc, I thank you for your support and all your contribution to this study. I sincerely acknowledge the contribution of all the key informants in this study, the staffs of Vatukoula Gold Mine and the representatives of the various government departments. Also, I acknowledge the wonderful contribution of the participants of the focus group discussion who are members of the Vatukoula residential community. I thank the staff nurses (SN Tarau of Vatukoula, SN Salome of Nailaga, SN Akata of Vunitogoloa, SN Sereana of Balevuto) of the four nursing zones who provided the acute respiratory infection data from their zones that were needed for this research. I acknowledge the support and help of all my friends at the University of Canterbury. This ac- knowledgement also goes to the Moraia Methodist Church community and the Fijian Community in Christchurch for providing much-needed family support away from home. Finally, my family has been my foundation for my masters thesis program. Thank you for your support and prayers. I must thank my wife, Ilisabeta Sili, for handling all the affairs of our family back home in Fiji while I pursue this study here in New Zealand. I also sincerely acknowledge her willingness and effort to proofreading this thesis. May God bless you all. iii Summary Air pollution exposure contributed to an alarming death toll of 7 million people yearly, making it the world's most significant single environmental health risk. Gold mining emission consists of some of the most harmful and toxic air pollutants. However, studies on the effect of gold mining air pollution on respiratory health are few, with none ever conducted in Fiji. With the unavailability of reliable air quality data, this retrospective cohort study assessed the prevalence of acute respiratory infection (\ARI"), and compared the ARI-free survival rates of children born and living in a mining region and those born and living in a non-mining region, as a way of generalising the possible effects of gold mining-related air pollution on child health. This study also assessed the effectiveness of air pollution control programs conducted in the Vatukoula Gold Mine and Fiji. Respiratory records and vital statistics of a cohort of children born in 2011 in both the regions were retrospectively followed up from birth until their fifth birthdays in 2016. Two groups were identified from the ARI dataset collected, those that had acute upper respiratory tract infection (\AURI") and those that had pneumonia. The incidence of AURI and pneumonia in the groups were estimated. The prevalent odds ratios were estimated for the exposed and the non-exposed cohorts, and their ARI-free survival rates were analysed using survival analysis. Key informant interviews and a focus group discussion were conducted to assess the effectiveness of air pollution management in Vatukoula Gold Mine. Living in non-gold-mining region (Odds Ratio = 48) and children of Indo-Fijian race were at higher risk of AURI (Odds Ratio = 2.4) Further multivariable logistic regression showed living in non-gold-mining region as an independent risk factor for AURI (OR 39.6, 95% CI: 5.36 - 292; p < 0.001); while living in gold mining region was the single independent risk factor for pneumonia in this study (p <0.05). Kaplan-Meier estimator showed living in gold mining region and I-taukei children having statistically significant AURI-free survival rates while living in the non-mining region had a statistically significant pneumonia-free rate at the end of first five years of life. Multivariable cox regression analysis showed living in the non-mining region was a statistically significant risk factor for AURI. Living in gold mining region was the only statistically significant risk factor for pneumonia after the univariate Cox proportional hazard analysis. While gold mining is the dominant activity in the gold mining region, the non-gold mining region is dominated by sugarcane farming. Air pollution from these two main activities may provide the possible explanations for the occurrence of the two acute respiratory infections (AURI and pneumonia) in the two regions. Air pollution management and control activities by the management of Vatukoula Gold Mine are yet to meet the standards required to adequately sustain the environment and health of those living within its proximity. The unresolved air pollution issues of sulphur dioxide and dust at Vatukoula over the last eight decades are yet to be resolved. Those who have legal authority over the operation of the mine have done little to resolve these outstanding air pollution issues. The health of those residing near Vatukoula Gold Mine continues to be at risk from the effects of air pollution, as highlighted by previous studies, as well as this study iv Contents List of Figures.....................................x List of Tables...................................... xi 1 Introduction 3 1 Research rationale...................................6 2 Research scope.....................................7 3 Research questions...................................7 4 Goals and objectives..................................8 5 Significance of research.................................8 2 Literature review9 1 Association between air quality and acute respiratory infections..........9 1.1 Sources of Air Pollution............................9 1.2 Criteria pollutants sources........................... 11 1.3 Health effects of criteria air pollutants.................... 13 1.4 Burden of air pollution............................. 19 1.5 Challenges to prediction of air pollution health impacts.......... 20 2 Association between gold mining and air quality.................. 20 2.1 Air pollutants generated from gold mining activities............ 22 2.2 Possible air pollutants generated from Vatukoula Gold Mine........ 25 3 Distribution and determinants of acute respiratory infections........... 26 3.1 Defining acute respiratory infection...................... 26 3.2 Distribution of acute respiratory tract infection............... 30 3.3 Risk factors for acute respiratory infection.................. 34 3 Population and Methods 37 1 Study and control site profile............................. 37 1.1 Brief profile of Fiji............................... 37 1.2 Brief description of mining and non-mining regions............. 40 2 Study design...................................... 49 3 Setting.......................................... 50 4 Population under study................................ 50 5 Variables........................................ 51 5.1 Exposure variable............................... 51 5.2 Outcome Variable............................... 52 5.3 Other variables................................. 52 6 Data sources...................................... 53 6.1 Data Analysis.................................. 53 v vi CONTENTS 7 Statistical analysis methods.............................. 53 7.1 Multivariate logistic regression........................ 53 7.2 Steps of survival analysis........................... 54 7.3 Survival analysis................................ 54 7.4 Analysis of key informant and focus group discussion responses...... 55 8 Bias........................................... 58 9 Study size........................................ 58 10 Description of quantitative and quantitative data analysis............. 59 10.1 Quantitative data analysis........................... 59 10.2 Qualitative data analysis........................... 59 10.3 Other information............................... 60 4 Results 61 1 Comparing AURI and pneumonia in the gold mining and non-gold-mining regions. 61 1.1 Descriptive data................................ 62 1.2 Outcome data................................