Lead: assessing the environmental burden of disease at

1,24

MB

national and local level.

73

stron

1321

ID

World Health Organization

2004

rok

TABLE OF CONTENTS

Preface .. v

Affiliations and acknowledgements.. vi

Summary vii

1. Background1

1.1 Summary of the method. 1

2. Sources of lead and exposure pathways . 3

3. Lead toxicity .5

3.1 Nervous system effects and intelligence 5

3.2 Systemic effects . 6

3.3 Effects of lead on reproduction.. 7

4. Exposure-risk relationships..8

4.1 Anaemia and gastrointestinal effects .. 9

4.2 Loss of IQ points and estimation of mild mental retardation .. 10

4.3 Increase in blood pressure and cardiovascular disease 13

5. Exposure assessment . 16

5.1 Assessing levels of lead in blood 16

5.2 Overall output .. 19

6. Estimating the disease burden .. 21

6.1 An example problem: assessing the disease burden effects of a programme to reduce lead in

gasoline . 21

6.2 Adjusting blood lead levels for the effects of the programme to reduce lead in gasoline. 22

6.3 Calculating weighted means . 22

6.4 Combining standard deviations .. 23

6.5 Calculating the population at risk.. 24

6.6 Estimating disease rates in children.. 28

6.7 Estimating the disease burden due to increased blood pressure . 29

6.8 Summary of steps for estimating the disease burden 30

7. Uncertainties .. 31

7.1 Blood lead measurements .. 31

7.2 Are the data representative?.. 31

7.3 Adequacy of adjustment factors . 31

7.4 Ranges of reported exposure-response relationships 32

7.5 Quantitative estimation of uncertainty. 32

8. Research needs and recommendations . 33

9. Disease burden and policy .. 34

References. 35

Annex 1 Country groupings for global assessment 39

Annex 2 Measuring blood lead. 40

Annex 3 Using exposure scenarios to inform policy actions 43

Table of Contents

Annex 4 Estimating the global disease burden of environmental

lead exposure . 50

Annex 5 Calculation spreadsheet for lead .. 65