Health outcomes in populations living close to landfill sites

Health outcomes in populations living close to landfill sites The Small Area Health Statistics Unit (SAHSU), Department of Epidemiology and Public Health, Imperial College Lars Jarup, David Briggs, Cornelis de Hoogh, Christopher Hurt, Tina Kold Jensen, Sara Morris, Jon Wakefield and Paul Elliott Modelling exposures from landfill sites: Methods and issues The Small Area Health Statistics Unit (SAHSU), Department of Epidemiology and Public Health, Imperial College Cornelis de Hoogh, David Briggs, Christopher Hurt, Lars Jarup and Paul Elliott Background  Excess risk of adverse birth outcomes and certain cancers have been reported, primarily in the USA (hazardous waste sites)       Low birthweight (Goldberg et al, 1995; Kharazzi et al, 1997; Berry and Bove, 1998) Stillbirth (Kharazzi et al, 1997) Congenital anomalies (Geschwind et al, 1992, Croen et al, 1997) Mallin, 1980 (bladder cancer) Goldberg et al, 1995 (several cancers including liver) Willams et al, 1998 (brain cancer) Background  Two recent European and UK studies  EUROHAZCON (1998) neural tube, cardiac and vascular defects  decrease in risk by distance, BUT  several landfills in “reference area” not accounted for   Nant-y-Gwyddon (2000)  increased risk of malformations also before site opening Aims  Primary objectives: to test the hypotheses that living near a landfill site is associated with excess risk of congenital anomalies, stillbirth, low birthweight or very low birthweight Secondary objective: to test the hypothesis that living near a landfill site is associated with an excess risk of certain cancers  Industrial emissions Click for larger picture Vehicle emissions Atmospheric dispersion Inhalation Gaseous emissions Mineral dusts Prior land use Excavation Waste disposal Solid waste Capping/ restoratio n Animal/bird dispersion Afteruse Dermal contact Soil contamination Drainage/ Leaching Waste handling Aqueous emissions Runoff Plant uptake Water pollution Ingestion Analyses  Effects of socio-economic status and other explanatory variables   urban-rural differences maternal age (for abdominal wall defects)  Landfill sites classified as receiving „special‟ (hazardous) or „non-special‟ waste Periods before and after opening of landfill sites Poisson regression    99% confidence intervals Study area   “Exposed” population defined as living within 2 km from a landfill site  80% of the national population Likely limit of dispersion (WHO 2000)  1 - 2 km depending on pathway Study period Lag Health outcome Congenital malformations Birthweight, stillbirth Childhood leukaemias Adult leukaemias Bladder, brain, hepatobiliary cancers Years 1 1 1 5 5 England and Wales Health period 1983-98 1983-98 1983-94 1987-94 1987-94 Exposure period 1982-97 1982-97 1982-93 1982-89 1982-89 Scotland Health period 1988-96 1983-98 1983-96 1987-96 1987-96 Exposure period 1987-95 1982-97 1982-95 1982-91 1982-91 Nr of la ndfill sites per 5 x 5 km2 1 2 3-4 5-8 9 - 68 Click for larger picture Start Start postcode postcode Has there ever been a a landfill landfill Has there ever distance?? site within bufferbeen site within buffer distance?? yes yes IsIs the landfill open at this moment? the landfill open at this moment? no no Was the landfill site closed Was the landfill site period? earlier during the study closed earlier during the study period? no no Was the landfill site closed before Was the landfillstudyclosed before the start ofof thesite period? the start the study period? no no Was the landfill site opened later Was the the study period? later during landfill site opened during the study period? no no Was the landfill site opened after Was theof the studyopened after the end landfill site period? the end of the study period? no no Incomplete data Incomplete data Click for larger picture no no 1 1 Reference Reference yes yes 2 2Operating Operating yes yes 3 3Closed Closed yes yes 4 4Exclude Exclude yes yes 5 5Before Before yes yes 6 6Exclude Exclude yes yes 7 7Exclude Exclude Resi dual postcodes Residualpostcodes Resi dual postcode Residual postcode 8 8Exclude Exclude 19,196 landfill sites x 1.6 million postcodes x 16 years x 2 lag periods = 1011 buffering operations! 8.0 7.0 Ratio: exposed/unexposed 6.0 5.0 4.0 3.0 2.0 1.0 0.0 0-9 10 - 19 20 - 29 30 - 39 40 - 49 50 - 59 60 - 69 70 - 79 80 - 89 90 - 100 Percentage Urban 9.0 Click for larger picture 8.0 Ratio of exposed/unexposed population 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 <0 0-1 1-2 2-3 3-4 4-5 5-6 6-7 >7 Air quality index (NOx, PM10, SO2 and Benzene) Exposure by socio-economic status Most affluent Exposed 30.4 Intermediate Most deprived 35.3 34.2 Unexposed 43.1 32.4 24.4 Excluded 35.2 33.2 31.5 Results - congenital anomalies Birth outcome All congenital anomalies Neural tube defects Cardiovascular defects Hypospadias and epispadias Abdominal wall defects Hospital admissions Abdominal wall defects Surgical corrections Gastroschisis and exomphalos Hypospadias and epispadias 1.19 (1.05- 1.34) 0.96 (0.90 – 1.02) 1.07 (0.98- 1.18) All operating and closed sites, by waste type All wastes Special waste Non-special waste 1.01 (1.01 -1.02) 1.07 (1.04-1.09) 1.02 (1.01-1.03) 1.05 (1.01-1.10) 1.07 (0.95-1.20) 1.06 (1.01-1.12) 0.96 (0.93-0.99) 1.11 (1.03-1.21) 0.95 (0.91-0.98) 1.07 (1.04 - 1.10) 1.10 (1.02-1.20) 1.07 (1.03-1.11) 1.08 (1.01 - 1.15) 1.03 (0.86-1.25) 1.07 (0.99-1.16) 1.08 (0.82-1.42) 1.05 (0.94-1.16) 1.10 (0.77-1.58) 0.98 (0.81-1.19) 1.18 (1.03-1.34) 0.96 (0.90-1.04) Birth outcome All congenital anomalies Neural tube defects Cardiovascular defects Hypospadias and epispadias Abdominal wall defects Sites that opened during the study period Before During operation or after closure opening 1.02 (0.99-1.05) 1.00 (0.99-1.01) 0.98 (0.82-1.16) 0.92 (0.81-1.04) 1.08 (0.98-1.19) 1.24 (0.97-1.60) 1.05 (0.99-1.10) 0.92 (0.88-0.95) 1.05 (1.02-1.09) 1.06 (0.98-1.14) Hospital admissions Abdominal wall defects 2.26 (1.23-4.15) 1.12 (1.01-1.25) Surgical corrections Gastroschisis and exomphalos Hypospadias and epispadias 1.33 (0.46-3.81) 1.42 (0.94-2.16) 1.24 (1.09-1.42) 0.93 (0.86-1.00) Results - stillbirth and birth weights Birth outcome Stillbirths Low birth weight All operating and closed sites, by waste type All wastes Special waste Non-special waste 1.00 (0.99 -1.02) 1.05 (1.05 -1.06) 1.04 (1.03 -1.05) 0.99 (0.95-1.03) 1.05 (1.04-1.06) 1.03 (1.00-1.06) 1.00 (0.99-1.02) 1.06 (1.05-1.06) 1.04 (1.03-1.06) Very low birth weight Results - stillbirth and birth weights Birth outcome Stillbirths Low birth weight Very low birth weight Sites that opened during the study period Before opening During operation or after closure 1.01 (0.96-1.06) 1.01 (0.99-1.02) 0.98 (0.94-1.02) 1.02 (1.00-1.03) 1.07 (1.062-1.072) 1.04 (1.03-1.05) Results – cancers Relative risk, adjusted for age, sex, year and region (99% CI) 1.04 (1.03 – 1.05) Relative risk, adjusted for age, sex, year, region and deprivation (99% CI) 1.01 (1.00-1.02) Bladder cancer Brain cancer Hepatobiliary cancer Adult leukaemia Childhood leukaemia 0.98 (0.96 – 0.99) 1.05 (1.03 – 1.07) 0.99 (0.97 – 1.00) 0.93 (0.89 – 0.98) 0.99 (0.98-1.01) 1.00 (0.98-1.03) 0.99 (0.98-1.01) 0.96 (0.91-1.00) Click for larger picture Discussion    The largest study to report on the possible association between residence near landfill and health outcomes Deprivation adjustment may incompletely account for individual-level characteristics associated with risk of congenital anomalies and cancers Need to take account of the complexity of the system, and data limitations, in using GIS for exposure assessment Conclusion    80% of population live within 2km of a landfill site No causal mechanisms currently available to explain our findings Alternative explanations possible   data artefacts residual confounding  Further understanding of the potential toxicity of landfill emissions and possible exposure pathways is needed in order to help interpret the epidemiological findings References    Elliott P, Briggs D, Morris S, de Hoogh C, Kold Jensen T, Maitland I, Richardson S, Wakefield J, Jarup L. Risk of adverse birth outcomes in populations living near landfill sites. BMJ 2001;323:363-8. http://www.bmj.com/ http://www.doh.gov.uk/whatsnew/index.html