Issues in Environmental Epidemiological Research: The Example of Environmental Lead and Health

Abstract

Modern environmental epidemiology encompasses the “traditional” area of physico-chemical hazards, along with health hazards in the societal environment (e.g. noise, stress, social organisation), and, increasingly, supranational problems (e.g. ozone depletion, global warming). As governments undertake environmental management, improved quantitative estimates of environmental risks to health are needed. Methodological difficulties of environmental epidemiological research include problems of exposure measurement, of estimating exposure at the level of the individual, and of detecting relatively small effects (particularly at low exposure levels).

The health hazards of occupational lead exposure are well documented. The health hazards of environmental exposure to lead, within the general population, remain a focus of continuing epidemiological research. Indeed, the reported adverse effects upon the developing central nervous system of young children are now central to public health debate about environmental lead exposure standards. Recent evidence from cohort studies in several countries indicates adverse effects of environmental lead exposure upon early childhood mental development. In South Australia, a cohort study of children born in a lead smelter community, Port Pirie, has revealed evidence of such an effect. After controlling for many potential confounding factors (social, behavioural, family, and medical), cumulative postnatal lead exposure was found to be weakly associated with an adverse effect upon mental development at age two years and, more strongly, at age four years.

The relations between environmental epidemiological research and public health policy are discussed.

Keywords

Environmental epidemiology Quantitative risks Exposure standards Environmental lead Childhood development

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References

1. Marsh GM , Caplan RJ : The feasibility of conducting epidemiologic studies of populations residing near hazardous wasted disposal sites. In: Kopfler FC , Craun GF (eds). Environmental Epidemiology. Chelsea, Michigan: Lewis, 1986, pp. 67–88.

2. Wong, HBMichael AJ : Setting environmental exposure standards: The role of the epidemiologist. Int J Epid 1989; 18: 10–16.

3. Murray TH : Regulating asbestos: ethics, politics, and scientific values. Science Technology and Human Values 1986; 11: 1–13.

4. Krysko WW : Lead in History and Art. Stuttgart: Verlag, 1979.

5. Harper M : Possible toxic metal exposure of prehistoric bronze workers. Brit J Ind Med 1987; 44: 652–656.

6. Oliver T : Lead Poisoning: from the Industrial, Medical and Social Points of View. London: Lewis, 1914.

7. Smith M : Lead in History: In: Lansdown R , Yule W (eds) The Lead Debate: The Environment, Toxicology and Child Health. London: Croom Helm, 1986: 7–24.

8. Lin-Fu JS : Children and lead. New findings and concerns. N Engl J Med 1982; 307: 615–7.

9. National Health and Medical Research Council . Lead in Australians. Meeting No. 103 of Council. Canberra: Commonwealth Department of Health, 1987.

10.

10. Needleman HL , Gunnoe C , Leviton A , et al: Deficits in psychological and classroom performance of children with elevated dentine lead levels. N Engl J Med 1979; 300: 689–95.

11.

11. Winneke G , Kramer U Brockhaus U , et al: Neuropsychological studies in children with elevated tooth-lead concentrations. II. Extended study. Int Arch Occup Environ Health 1983; 51: 231–52.

12.

12. Smith M , Delves T , Lansdown R , Clayton B , Graham P : The effects of lead exposure on urban children: the Institute of Child Health/Southampton Study. Dev Med Child Neurol 1983; 25: Suppl 47.

13.

13. Lansdown R , Yule W , Urbanowicz M , Hunter J : The relationship between blood lead concentrations, intellingence, attainment and behaviour: the second London study. Int Arch Occ Environ Hlth 1986; 57: 225–35.

14.

14. Fulton M , Raab G , Thomson G , Laxen D , Hunter R , Hepburn W : Influence of blood lead on the ability and attainment of children in Edinburgh. Lancet 1987; 1: 1221–6.

15.

15. Wigg NR , Vimpani GV , McMichael AJ , Baghurst PA , Robertson EF , Roberts RJ : Port Pirie Cohort Study: Childhood blood lead and neuropsychological development at age two years. J Epidemiol Comm Hlth in press.

16.

16. McMichael AJ , Baghurst PA , Wigg NE , et al: Port Pirie Chort Study: Childhood blood lead history and neuropsychological development at age four years. N Engl J Med 1988; 319: 468–75.

17.

17. Bellinger D , Leviton A , Waternaux C , Needleman H , Rabinowitz M : Longitudinal analyses of prenatal and postnatal lead exposure and early cognitive development. N Engl J Med 1987; 316: 1037–43.

18.

18. Dietrich KN , Krafft KM , Bornschein RL , Hammond PB , Berger O , Succop PA , Bier M : Low-level fetal lead exposure effect on neurobehavioural development in early infancy. Paediatrics 1987; 80: 721–730.

19.

19. Hernberg S , Nikkanen J : Enzyme inhibition by lead under normal urban conditions. Lancet 1970; 1: 63–4.

20.

20. Otto D , Robinson G , Baumann S , et al: 5-year follow-up study of children with low-to-moderate lead absorption: electrophysiological evaluation. Environ Res 1985; 38: 168–86.

21.

21. Otto D , Benignus V , Muller K , et al: Effects of low to moderate lead exposure on slow cortical potentials in young children: Two-year follow-up study. Neurobehav Toxicol Teratol 1982; 4: 733–37.

22.

22. McMichael AJ , Baghurst PA , Robertson EF , Vimpani GV , Wigg NR : The Port Pirie Cohort Study: blood lead concentrations in early childhood. Med J Aust 1985; 143: 499–503.