Journal of Pediatric Gastroenterology & Nutrition:
Environmental Contributions to the Leading Causes of Disease Burden Among Australian Children
Norman, Rosana E.*; Veerman, J. Lennert†; Scott, James‡; Fantino, Emmanuelle*; Bailie, Ross||; Sly, Peter D.*; Cleghorn, Geoffrey§
*Queensland Children's Medical Research Institute, Herston
†School of Population Health
‡Centre for Clinical Research
§School of Medicine, University of Queensland, Herston, Queensland
||Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia.
Address correspondence and reprint requests to Dr Rosana E. Norman, University of Queensland, Queensland Children's Medical Research Institute and School of Population Health, Herston, Queensland 4006, Australia (e-mail: firstname.lastname@example.org).
Received 18 October, 2012
Accepted 16 December, 2012
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The authors report no conflicts of interest.
Although the effect of adverse environments on the well-being of children is an important global health issue, it remains underrecognized in health care (1) and underconsidered in terms of both research and public policy. Children have developmentally distinct patterns of environmental exposure and susceptibilities that increase their risk of disease. Young children, especially those who are impoverished, have disproportionately heavier exposures to environmental threats in a given environment. They also have decreased metabolic capacity to detoxify and eliminate contaminants. Furthermore, rapid growth and development before and after birth and the continuing growth and postnatal maturation of the respiratory, immune, and neurological systems, in particular, make them increasingly vulnerable to environmental threats (2).
There is emerging evidence that the origins of many adult diseases are found during fetal development and early childhood (3). These early environmental exposures can affect adult health either by cumulative damage over time or by the biological embedding of adversities during sensitive developmental periods (4). It is also important to recognize that for children, exposure to lifestyle risk factors such as diet and tobacco smoke are not lifestyle choices but rather environmental exposures imposed on them by others. In spite of Australia's high standard of living, Australian children do experience health consequences of adverse environmental exposures.
A major gap in health outcomes and life expectancy exists in Australia between Indigenous and non-Indigenous populations (5,6). The colonization of Australia involved a series of unjust and misguided policies against Aboriginal and Torres Strait Islander peoples that led to disruption of social systems, dispossession of land, economic exploitation, discrimination, and cultural devastation, resulting in severe inequalities in health status (5,6). Aboriginal and Torres Strait Islander children and young people in Australia account for 4.2% of the Australian population ages 0 to 24 years. Children younger than 14 years comprise 38% of the Aboriginal and Torres Strait Islander population, compared with 19% of the non-Indigenous population. Almost one-third of Aboriginal and Torres Strait Islander children and youth (32%) live in major cities, 44% live in regional Australia, and almost one-fourth (24%) live in remote Australia (7). The health of Indigenous children, especially those in regional and remote communities, remains seriously compromised by a combination of social disadvantage, inadequate housing and overcrowding, poor hygiene, malnutrition, environmental contamination, and prevalent infections (8).
Aboriginal people living in remote communities in the Northern Territory are the most disadvantaged group in Australia according to all measurable determinants of health (9). In these locations young children live in highly contaminated home and community environments (10–12). When respiratory, skin, and gastrointestinal tract infections are endemic, extremely young children are at an additional risk because of their exploratory behavior and because they are dependent on others for their care. Most infection is transmitted primarily by direct person-to-person contact or contact with contaminated fomites or animals (13,14). The situation is worsened by microbial contamination of food and water. The high prevalence of hand contamination in remote communities is a result of frequent inoculation rather than long bacterial survival times (14).
Infants and young children living in remote Aboriginal communities in the Northern Territory experience a high burden of infection (15–17). An Indigenous infant between 4 weeks and 1 year old is 7 to 8 times more likely to be admitted to hospital than a non-Indigenous child of the same age, particularly for gastrointestinal tract and respiratory infections, with common comorbidity (16). The median number of presentations per child in 1 year for 1 remote clinic was 16 (23 in the first year of life) (18).
About 15% of Aboriginal children younger than 5 years in Australia's Northern Territory are underweight, 11% are stunted, and 9% are wasted (19). Important in the causal pathway leading to poor nutritional status is the malnutrition–infection cycle, whereby children who are underweight are at increased risk for infectious diseases such as diarrhea and respiratory infections and at substantially increased risk for mortality. Gastrointestinal and parasitic infestations are particularly important because of their damaging effects on intestinal digestion and absorption of nutrients, minerals, and vitamins. The simultaneous presence of undernutrition and infection significantly increases the risk of child mortality, with extended duration of diarrheal infections among malnourished children playing an important role.
The pattern of disease, however, is changing and for young Indigenous and non-Indigenous Australians obesity has emerged as an increasingly important threat. After tobacco, obesity is the biggest contributor to the burden of disease for Indigenous Australians (6). The social, health, and economic costs for the individual and society as a whole are enormous. Inroads have been made with respect to tobacco cessation in Australia through political commitment, legislation, and community support; however, this is not the case for obesity. Paradoxically, it is the poor who are most affected, and many remote Indigenous households are now dealing with the double burden of overnutrition in adult members and undernutrition in children. Among children, undernutrition is more prevalent in remote communities, but obesity is more common in urban areas.
In Australia as a whole, the prevalence for the combined overweight and obese categories in all primary school-age children has increased from around 12% in 1985 to 27% in 2003 (20,21). The trend seems to have stabilized in recent years (22), but at a high level. According to the 2007 Australian National Children's Nutrition and Physical Activity survey, using international standard body mass index cutoffs (23), 5% of children ages 2 to 16 years were classified as underweight, 17% were classified as overweight, and 6% were classified as obese; hence, 23% were in the combined overweight and obese category (24). Data on Aboriginal children were not reported separately. Regarding Indigenous children, with updating to the WHO growth charts, the Northern Territory Government Healthy Under Five Kids data collection program (25) is now able to report on growth assessment, which was not the case in the past. No national-level data on obesity have been reported for Indigenous children and no longitudinal data that we are aware of are available to report on trends on obesity among Indigenous children over time. A study in central Australia using weight and height data from the Healthy School Age Kids program, which included 26 communities and students ages 3 to 17 years, showed that 21.4% of children were overweight and 5.4% obese as estimated by body mass index-for-age (26). This differs from that reported by the Aboriginal Birth Cohort (ABC) study (1998–2001), which included 344 children ages 8 to 14 years in which 10% of children were classified as overweight and 4% as obese (27), although different standards were used between these 2 studies. Nevertheless, these figures appear unlikely to reflect the 4 times greater burden of chronic diseases in this population compared with all Australians, and it has been argued that waist circumference may be a better predictor of chronic disease risk than body mass index-for-age in this population (26).
Obesity has consequences for health and quality of life during childhood (28), but obese children also tend to become obese adults prone to diabetes, cardiovascular disease, cancer, and many other health problems. There is general agreement that this childhood obesity “epidemic” is ultimately caused by changes in children's food and physical activity environment, and that changes to this “obesogenic” environment are key to tackling what has been termed the primary childhood health problem in developed nations (29). Complex causal chains link childhood obesity to the physical, social, and economic environment. Relevant factors include the opportunities for active play and transport in the built environment, the accessibility and availability of fruit and vegetables in remote areas, and marketing of energy-dense foods with relatively low price of such foods compared with healthier options (30) making a healthy diet unaffordable to many Australians. Multifaceted community capacity-building programs promoting healthy eating and physical activity for children have been successful (31). Society-wide measures to improve nutrition are also promising (32). Although the obesogenic environment is mostly understood as comprising physical, social, and economic factors, the effect of chemical exposures is frequently ignored. The living environment of children, like that of adults, contains an increasing range of chemicals. Epidemiological evidence suggests a link between developmental exposure to endocrine-disrupting chemicals and obesity and type 2 diabetes mellitus (33). Factors in pregnancy and early childhood partly determine body mass later in life (34), and further research is necessary to investigate the role of environmental chemical exposures during these vulnerable windows of development. Partly related to the rise in childhood obesity is the rise in childhood diabetes. The incidence of type 1 diabetes mellitus in Australia is high compared with that in other countries, and, as in Europe (35) and the United States (36), it is rising (37). Although the causes of type 1 diabetes mellitus are largely unknown, environmental influences are likely driving this increase, but the nature of those influences remains unclear. Some chemicals are known to have the potential to interfere with pancreatic β-cell function, and this could compound the effect of an increased body mass index that makes children more prone to diabetes mellitus (33).
The 12-month prevalence of any mental disorder in Australian children is 14% (38), and anxiety and depression are among the leading causes of disease burden among Australian children younger than 14 years (39). Socioeconomic disadvantage (40), maltreatment in the family environment (41), and exposure to bullying at school (42) are common environmental factors that increase the risk of mental illness in children. It is recognized that to reduce the high prevalence of mental disorders in children, effective interventions to address the risk of exposure of children to adversity are necessary (43). There is evidence that nurse home visitation programs for children younger than 2 years and parenting programs for preschool and primary school age children can reduce the risk of maltreatment in the home. Similarly, school programs can significantly reduce the prevalence of childhood bullying (44). To date, there are no national programs in Australia that address these common environmental risk factors for mental illness in children. Few data exist on exposure to or the effect of neurotoxic chemicals on children in Australia.
The present prevalence of asthma in Australia is high by international standards, and it is the leading cause of disease burden accounting for about 17% of all disability-adjusted life-years among children younger than 14 in Australia (39). Various environmental exposures, including viral infections, tobacco smoke, air pollutants, and chemicals, are likely to play a role (45–52 [references 51–61 can be viewed at http://links.lww.com/MPG/A194]) Understanding the effects of environmental exposures on lung growth and development, as well as repair and response to injury and respiratory infections in children, is a major, if challenging, area of research interest (53).
The increased awareness about the special vulnerability of children to environmental exposures has led to new research programs and international agreements, which specifically promote healthy environments for children (54). In Australia, public performance does not match research ability, although recently, significant attempts have been made to develop a cooperative agenda for children's environmental health research aiming to assess the burden of disease that could be prevented through healthy environments by reducing exposure to environmental risks (55). The environment is complex and rapidly changing, with emerging risks around technological advances, changes in food processing, increased urbanization, and climate change. The adequate protection of children against environmental threats, often not encountered by previous generations, requires a major revision of present approaches to toxicity testing and risk assessment (2). Chemical exposures early in life are preventable causes of disease in children and adults, and there remains an urgent need to review our approach to children's environmental health in Australia, as reflected in governmental, professional, and community-based policies.
Poor housing and household overcrowding remains a significant problem in most remote Aboriginal communities in the Northern Territory (56). Essential health hardwares (taps, toilets, showers, sinks, drains) are frequently nonfunctional. Housing repairs and maintenance systems in remote communities are not well developed and function at variable levels of efficiency (57). Some tenants are also not sufficiently empowered to report nonfunctional items and some are unaware of how the reporting system operates (58). In many houses soap is not present in the bathroom, kitchen, or laundry (59).
Responsiblity for improving personal and household hygiene in remote Aboriginal communities is shared by a number of government agencies (health, education, housing, local government), with no specific agency having clear primary responsibility. There is presently little capacity (or apparent desire) within agencies to take lead responsibility for addressing the high rates of infection among young children (58). Last attempts to address the problem have largely overlooked the contribution of poor personal, domestic, and community hygiene to high rates of infection. Cultural and social influences on household and community living circumstances have also been largely overlooked in efforts to improve the living environment (58). Aboriginal community workers, Indigenous environmental health workers, and others with similar limited training have been expected to take up positions and function to a high level to address these complex problems, often with minimal support. These workers commonly resign from their positions within weeks or months of appointment (60).
The focus of health service action is to reduce inequalities in Indigenous health needs to include culturally appropriate and uniquely targeted approaches for nonremote and remote areas as the majority of the health gap affects residents of nonremote areas (6). The recently introduced Close the Gap Campaign aims to close the health and life expectancy gap between Aboriginal and Torres Strait Islander peoples and non-Indigenous Australians within a generation. When it signed the Statement of Intent (61), the Australian Federal Government committed to developing a comprehensive, evidence-based, long-term plan of action to address the existing inequalities in health services, to achieve equality of health status and life expectancy, and to ensure the full participation of Aboriginal and Torres Strait Islander peoples and their representative bodies in all aspects of addressing their health needs. The campaign requires adequate resources to in fact close the gaps in health, disease, disability, and mortality and to address socioeconomic inequities between Indigenous and non-Indigenous Australians; however, closing the life-expectancy gap by 2031 remains a challenge. Ultimately, the government needs to lead social change and place the Close the Gap Campaign back on the national agenda.
Furthermore, it remains important to assess whether existing policies take appropriate account of the many different levels of environmental risks and whether such policies are being effectively implemented. It is also critical to determine how these risks affect the health of Australian children as a function of geography, ethnicity, and other social-demographic factors. Action to reduce the burden of disease among Australian children requires a focus on prevention, tackling the causes of disease at their environmental source.
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