Association between dust from gold mine dumps respiratory symptoms and diseases among adolescents and the elderly in Gauteng and North West Provinces South Africa

Abstract

Research studies have shown that both indoor and air pollution are the main risk factors for the burden of respiratory diseases, elderly people and the children are mostly affected. Various risk factors have been associated with respiratory diseases, including gender, socioeconomic status, tobacco smoking habits, occupational environment and polluting fuel used for residential cooking/heating. No studies have investigated whether exposure to dust from mine dumps or living in close proximity to mine pose an increased for respiratory diseases, whether this exposure is involved in the development of respiratory diseases or there is effect modification between various air pollution including mine dust. The aim of the study was to investigate whether the prevalence of respiratory symptoms and diseases among adolescents (13 to 14 year old children) and the elderly (55 years old and above) were associated with community s proximity to mine dumps. Adolescents and elderly persons in communities 1 km 2 km (exposed) and > 5 km (unexposed), from five pre-selected mine dumps in Gauteng and North West Provinces, South Africa were included in the study. The International Study of Asthma and Allergies in Childhood (ISAAC) Phase I and II protocols were applied among 3641 eligible school going children, age between 13 and 14 years, from 22 primary and secondary schools. Furthermore, the outdoor PM10 and SO2 levels were measured along with indoor respirable dust in 10 schools among 100 adolescents that participated in the ISAAC study. Structured interviews were conducted with 2397 elderly using a previously validated ATS-DLD -78 questionnaire. A short-term longitudinal study design with repeated measures was used among 40 children with asthma. Each participant completed a daily symptom diary and performed forced expiratory flows in the morning and at bedtime for 21 consecutive days, and the 24 h ambient air pollution concentrations such as NO2, NOx, O3, PM2.5, and PM10 Children residing in exposed communities 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). Exposed elderly persons had a significantly higher prevalence of chronic respiratory symptoms and diseases than those who were unexposed. Results from the multiple logistic regression analysis indicated that living close to mine dumps was significantly associated with asthma (OR = 1.57; 95% CI: 1.20 2.05), chronic bronchitis (OR = 1.74; 95 CI: 1.25 2.39), chronic cough (OR = 2.02; 95% CI: 1.58 2.57), emphysema (OR = 1.75; 95% CI: 1.11 2.77), pneumonia (OR = 1.38; 95% CI: 1.07 1.77) and wheeze (OR = 2.01; 95% CI: 1.73 2.54). There were higher average levels of outdoor PM10, outdoor SO2 and respirable dust in exposed classrooms compared to unexposed classrooms. The average indoor respirable dust level was 0.17 mg.m-3 in exposed and 0.01 mg.m-3 in unexposed schools. The corresponding outdoor PM10 levels were 16.42 and 11.47 mg.m-3, respectively, while SO2 levels were 0.02 ppb and 0.01 ppb, respectively. The mean 24-hour concentration of NOx and O3 of the current and previous day were significantly associated with the morning FEV1 decline of 0.762% (95% CI: -1.296 - 0.227), 0.780% (95% CI: -1.461 -0.099) and 0.716% (95% CI: -1.386 -0.045) respectively. Single pollutant models showed significant positive associations between chest tightness and cough with NO2, O3, NOx, and SO2. Medication use such corticosteroids was associated with NOx (OR = 1.07; 95% CI: 1.00 1.28) and ?2-agonist with O3 (OR = 1.57 95% CI: 1.03 2.72). The findings of this study provide evidence and add to the current body of knowledge that a community s proximity to mine dumps is associated with increased risk of respiratory symptoms and diseases among the children and the elderly in South Africa. Effective dust control measures should be implemented to reduce air pollution in these communities. The thesis proves that Mr Nkosi is conversant with the nature and purpose of this interesting and relevant investigation. From his thesis, Mr Nkosi has published four articles in the local and international journals.