Title: Health effects of environmental and occupational exposures in children of Pakistan
Other Titles: Gezondheidseffecten van milieuverontreiniging en kinderarbeid in Lahore, Pakistan
Authors: Sughis, Muhammad; S0165894
Issue Date: 24-May-2012
Abstract: The increasing trend of immigration from villages and small cities to larger cities resulted in increased social and commercial activities in the metropolitan cities of developing countries, for example, Pakistan. The urbanization resulted in increased vehicular traffic which contributes to outdoor environmental air pollution, in addition to other pollutants including trace elements entering the environment from other sources. Particulate air pollution (PM) has various health effects. The impact can be either short term or long term. The effect on human health depends on the type of pollutant, concentration, duration of exposure, and personal susceptibility. A large body of published scientific evidence shows increased hospital visits, cardiopulmonary morbidity and mortality on days with higher PM. Physiological systems of children being in the growing stage, place them among the most vulnerable populations affected by PM. According to the guidelines of WHO the annual permitted value of PM below 2.5 and 10 µm aerodynamic diameter (PM2.5 and PM10) is 10 and 20 µg/m3, respectively. Unlike the developed world where the legislation has already been made and implemented to regulate PM, developing countries stand behind. In Pakistan, though the legislation is present in its preliminary form, the authorities are not able to implement it fully. As a result, the environmental pollution is high in mega-cities like Lahore, where PM10 has been reported >300 µg/m3. Child labour is prevailingextensively in Asia and the Pacific (with an estimated 127.3 million children at work). In Pakistan, the National Child Labor survey conducted in 1996 by the Federal Bureau of Statistics, reported 3.3 million of the40 million children (in the 5-14 years age group) to be economically active on a full-time basis. Epidemiologic studies and research on young workers suggest that children have higher health risks than adults when exposed to hazardous working environments. Moreover, several potential adverse health impacts of occupational exposures need to be studied in children. Few studies have investigated health consequences of child labour. The aim of the present research was a) to study the health effects of outdoor PM among apparently healthy schoolchildren, b) to estimate the urinary concentrations of metals in schoolchildren and working children, and c) to study the health effects of occupational exposures among children employed in selected industries, that is, brick kiln, carpetweaving and surgical instruments manufacturing.In chapter 2, we report the exposure to PM2.5 and PM10 among schoolchildren from a low and ahigh pollution area in Lahore, Pakistan. Exposure assessment was done by measuring PM with a portable laser operated mass analyzer. Blood pressure (BP) was measured with an automated instrument. We found that children living and attending school in an area of very high traffic-related air pollution had a substantially higher systolic (7.6 mmHg) and diastolic (4.5 mmHg) BP compared with children living in an area with lower PM. In chapter 3, we report the relation between exposure to low level environmental cadmium (Cd) exposure and urinary excretion of calcium (Ca)and deoxypyridinoline (DPD), a marker of bone resorption. Exposure assessment was carried out by estimation of urinary Cd by inductively-coupled plasma mass spectrometry (ICP-MS) and DPD by enzyme linked immunosorbent assay (ELISA). We found a consistent association between biomarkers of bone resorption and bone demineralization and Cd exposure in 10-year old children. For each doubling in urinary Cd excretion, bone resorption estimated by DPD increased by 1.72 nmol/mmol creatinine.In chapter 4, we report the work-related exposure to metals among children working in surgical instruments manufacturing units. Estimation of 20 metals was done in spot urine samples by ICP-MS. 8-Hydroxydeoxyguanosine (8-OHdG), a marker of DNA damage was measured by ELISA. Among child workers, this biomonitoring study revealed a substantial exposure to several metals, especially chromium (Cr) and nickel (Ni), which are established carcinogens. Concentrations of Ni were associated with evidence of increased oxidative DNA damage.In chapter 5, we report the respiratory health and metal exposure among schoolchildren and working children from brick kilnand carpet weaving industries. Exposure assessment was done by estimating metals in spot urine by ICP-MS. Respiratory health was assessed by performing spirometry and measuring fractional exhaled nitric oxide (FeNO). We found a high prevalence of respiratory symptoms in children exposedto urban air pollution and in working children, as well as evidence of a high exposure to several toxic metals. The concentrations of urinary As are in the order of those found in other Asian regions with high environmental exposure to As. The sources and pathways of exposure and the health significance of these findings need to be further investigated.Among the selected populations of schoolchildren and children working ineither brick kiln, carpet weaving or surgical industry, we estimated the environmental and occupational exposures. We found a) significantly increased systolic and diastolic blood pressure among schoolchildren from high pollution urban area, b) association of markers of bone resorption (DPD) and bone demineralization (Ca) and Cd exposure, c) high exposures to Cr and Ni among children working in surgical industry and the association of Ni with 8-OHdG, and d) high prevalence of respiratory symptoms in schoolchildren and working children as well as high levels of urinary As.Although our cross-sectional findings have limitations, they haveidentified and confirmed significant health threats among children in Pakistan. Hence, general and specific preventive and control measures should be implemented.
Publication status: published
KU Leuven publication type: TH
Appears in Collections:Occupational, Environmental and Insurance Medicine (-)

Files in This Item:
File Status SizeFormat
Sughis-Full Thesis-Final with titles.pdf Published 6926KbAdobe PDFView/Open Request a copy

These files are only available to some KU Leuven Association staff members


All items in Lirias are protected by copyright, with all rights reserved.