Prenatal and adolescent blood lead levels in South Africa: child, maternal and household risk factors in the Birth to Twenty cohort.

INTRODUCTION: The risk factors for lead exposure in developing countries have not been fully described. This study looks at child, maternal and household factors associated with increased risk of lead exposure at birth and at 13 years of age in the Birth to Twenty cohort. METHODS: Mothers were recruited from antenatal clinics in the Johannesburg-Soweto metropolitan area in 1990 (n=3273). Lead levels were analysed in cord blood collected at birth (n=618) and at 13 years (n=1546). Data on selected child, maternal and household factors were collected using a structured questionnaire in the third trimester and at 13 years of age. Statistical analyses were conducted to determine the associated risk factors. RESULTS: The mean blood lead level at birth was 5.85 microg/dl, and at 13 years of age it was 5.66 microg/dl. The majority of children had blood lead levels above 5 microg/dl (52% at birth and 56% at 13 years). At birth, being a teenage mother and having low educational status were strong predictors for elevated cord blood lead levels. Being a male child, having an elevated cord blood level, and lack of household ownership of a phone were significant risk factors for high blood lead levels at 13 years. CONCLUSION: Significant associations found in the study point to the low socio-economic status of lead-affected mothers and children. These poor circumstances frequently persist into later childhood, resulting in continued high lead levels. Thus broader measures of poverty alleviation and provision of better education may help decrease the risk of exposure.

Toward a global agenda for research in environmental epidemiology.

The global environment is in critical decline. Whether one's concern about environmental epidemiology stems from the perspectives of environmental health, climate change, ecological collapse, or growing inequity, clear problems exist. Natural capital resources are being depleted; disregard for the integrity of ecosystems is entrenched in current business practices. Indeed, despite increasing rhetoric to the contrary, the disregard displayed by those who hold power globally toward long-term sustainability and, thus, the health and well-being of future generations, could be described as wanton. Six years ago, the Millennium Development Goals were announced by the United Nations as a rallying point for action to achieve a sustainable future, particularly by reducing the gap between the "have mores" and "have nots." The attainment of these Goals is now endangered, as is, apparently, the spirit of optimism and idealism that inspired them at the Millennium Summit. We call for a reinvigoration of both concern about-and action on-sustainability. In particular, we appeal to those engaged in the field of environmental epidemiology (and other specialties with whom they engage) to consider how they might help by incorporating sustainability issues (including global ecological integrity and global environmental justice) into their own research programs. This incorporation would make a vital contribution to protect both present and future generations and to reduce resource and health gaps between North and South. Simply put, we propose that sustainability becomes integral to advancing the science of environmental epidemiology and related environmental disciplines.

Reductions in blood lead levels among school children following the introduction of unleaded petrol in South Africa.

Epidemiological studies have indicated that in the 1980s and early 1990s (a period in which petrol lead concentrations in South Africa ranged from 0.836 to 0.4 g/L), large proportions of urban South African children were at risk of excessive exposure to environmental lead. In 1991, when the maximum permissible petrol lead concentration in the country equaled 0.4 g/L, a study determined that the mean blood lead level among children attending inner city schools in the Cape Peninsula equaled 16 microg/dL, with well over 90% of children having blood lead levels equaling or exceeding the internationally accepted guideline level of 10 microg/dL. Socio economic status, housing conditions, and proximity of children's schools and homes to heavily trafficked roads were among the factors significantly associated with blood lead concentrations. In 1996, unleaded petrol was introduced in South Africa. A study undertaken in 2002 (at the same schools as in 1991), when unleaded petrol constituted around 30% of the market share of petrol in the country, has shown significant reductions in the mean blood lead concentration among Cape Peninsula inner city children and in the proportion of children with elevated blood lead levels. The mean blood lead level for the total sample (n = 429) of children whose mean age equaled 7 years (range: 5-11 years) was 6.4 microg/dL (range: 1.0-24.5 microg/dL) and 10% of children had blood lead levels equalling or exceeding 10 microg/dL. The mean blood lead levels among children attending schools in an inner city and in a less heavily trafficked periurban suburb were 6.9 and 4.8 microg/dL, respectively.

The World Summit on Sustainable Development: reaffirming the centrality of health.

The World Summit on Sustainable Development (WSSD) was held in Johannesburg in 2002 to review progress since the Rio conference in 1992, and to agree a new global deal on sustainable development. Unlike its predecessor, it was primarily concerned with implementation rather than with new treaties and targets, although a number of new targets were agreed, for example one on sanitation. Failure to agree a target on renewable energy was regarded as a major disappointment of the conference. While relatively modest in its achievements, and with difficulties in achieving consensus in key areas such as energy, trade, finance and globalisation, WSSD nevertheless succeeded in placing sustainable development back on the political agenda, giving new impetus, in particular to the environment and development needs of Africa, with a strong focus on local issues like household energy, water and sanitation. Health was singled out as one of five priority areas, along with water, energy, agriculture and biodiversity, and was devoted a separate chapter in the resulting Plan of Implementation, which highlighted a range of environmental health issues as well as issues relating to health services, communicable and non-communicable diseases. A number of new partnerships were formed at WSSD, including the Healthy Environments for Children Alliance (HECA) launched by WHO, which will form an important platform for implementation. The Commission on Sustainable Development has been designated main responsibility for monitoring and follow up, with its programme of work reorganised to focus on thematic clusters of issues. From the perspective of health, WSSD must be seen as a reaffirmation of the central place of health on the sustainable development agenda, and in the broader context of a process which began in Rio and was given added impetus with the Monterrey Financing for Development conference and the World Trade Organisation meeting held in Doha. Translating policies into action at all levels- global to local - remains the single biggest challenge in the years that lie ahead.

Lead poisoning in South African children: the hazard is at home.

Lead is a toxic heavy metal that has been used extensively in modern society, causing widespread environmental contamination even in isolated parts of the world. Irrefutable evidence associates lead at different exposure levels with a wide spectrum of health and social effects, including mild intellectual impairment, hyperactivity, shortened concentration span, poor school performance, violent/aggressive behavior, and hearing loss. Lead has an impact on virtually all organ systems, including the heart, brain, liver, kidneys, and circulatory system, resulting in coma and death in severe cases. In recent years, a consensus was reached regarding the absence of a threshold for the key health effects associated with lead exposure and the permanent and irreversible nature of many health and social consequences of lead exposure. The public health problem of environmental lead exposure has been widely investigated in developed countries like the United States of America, where actions taken have led to significant reductions in children's blood lead concentrations. In contrast, there is a relative dearth of information and action regarding lead poisoning in developing countries, particularly in African countries, despite evidence of widespread and excessive childhood lead exposure. In this paper, we will review the information from available published papers, the 'grey literature', and unpublished reports to give an overview of lead exposure in South African children over the past two decades, with particular emphasis on sources of exposure in the home environment.

A study of pediatric blood lead levels in a lead mining area in South Africa.

This study aimed to determine the blood lead distributions among young children in the lead mining town of Aggeneys in South Africa's Northern Cape Province, and in the comparison community of Pella, about 40 Km away. A further objective of the study was to explore factors associated with elevated blood lead levels. Children aged between 6 and 10 years (average age, 8 years) were studied, 86 from Aggeneys and 68 from Pella. The results showed that blood lead levels among the children of Aggeneys averaged around 16 microg/dL, while in Pella the mean blood lead level equaled 13 microg/dL. Overall, children with raised blood lead levels performed less well at school relative to other children. Within Aggeneys, fathers of "high" lead children tended to shower at work rather than at home, which may have been insufficient to prevent lead from being transported into the home. In conclusion, more stringent environmental control measures are needed, as well as stricter personal hygiene measures, to prevent childhood lead exposure in the mining community.

The health impact of environmental pollutants: a special focus on lead exposure in South Africa.

Studies have shown blood lead levels of some children in South Africa at levels of health concern. New studies show even relatively low lead levels to have detrimental effects on cognitive function in young children. Large numbers of South African inner-city and other children have been shown to have unacceptably high blood lead levels. Studies indicate that blood lead levels of children living in South Africa's urban areas are higher than those of children in most developed countries, including Great Britain, Europe, and the United States. Although data and reported studies are very sparse, mean blood lead levels of approximately 15 microg/dl have been reported in children. Elevated blood lead levels were associated with socioeconomic status and housing conditions. Key environmental risk factors for elevated blood levels were contaminated soil and dust in the urban environment, and the still large number of automobiles using leaded gasoline. In view of emerging evidence linking lead at increasingly lower levels to adverse effects in children, the South African government is taking actions to reduce lead exposure among vulnerable groups. Currently, South Africa has no national lead surveillance program. The government, therefore, has developed international and regional partnerships to prevent and address the problem of lead exposure.

Health-and-environment indicators in the context of sustainable development.

This paper gives a broad overview of issues relevant to the development and use of health-and-environment indicators in the broader context of sustainable development. Criteria for the construction of indicators are given, and their key characteristics are highlighted. Selected international indicator initiatives are discussed, as well as the concept and use of core indicators in policy and planning. Finally, an organizational framework for the consideration of health-environment-development linkages is presented, which can be used in the development of health-and-environment indicators in various contexts. This framework is the Driving forces-Pressures-State-Exposures-Health Effects-Actions framework (DPSEEA) of the World Health Organization (WHO). It is a descriptive representation of the way in which various driving forces generate pressures which affect the state of the environment, and ultimately human health through the various exposure pathways by which people come into contact with the environment. Throughout the paper, emphasis is placed on work done within the UN system, in particular that of the WHO, and examples of suites of indicators developed and in use are provided.

Health and sustainable development: can we rise to the challenge?

The forthcoming World Summit on Sustainable Development is an unprecedented opportunity to place health higher on the environmental and development agenda. The world's leaders will be grappling with some of the major challenges of our times--how to eradicate poverty and meet the world's development needs in a way that does not destroy the environment. Topping the agenda are water, energy, health, agriculture, and biodiversity. Improvement of access of the world's poor people to clean water, sanitation, and safe sources of household energy would have a huge effect on the main killers of young children--pneumonia and diarrhoea. Similarly, improved environmental management could substantially affect many infectious disease outcomes. At the same time, the growing epidemic of non-communicable diseases could be reversed if people's consumption patterns and lifestyles could be put on a more sustainable and healthy footing. A shared health, environmental, and development agenda could address the large share of the burden of disease that is environmentally related, and vice versa. The health sector increasingly needs to work in partnership with others rather than work alone. New tools are needed to ensure that intersectoral action becomes embedded in the way that the health sector does business. Improving coordination might be one of the most important ways in which we can help put the planet back on a healthy and sustainable path.