north hamilton child blood lead study 2008 - 2009 health/final_cbls… · lead-associated hobby or...

Disclaimer: All information provided is believed to be accurate and reliable. We will make changes, updates and deletions as required and make every effort to ensure the accuracy and quality of the information provided. However, the City of Hamilton assumes no responsibility for any errors and are not liable for any damages of any kind resulting from the use of, or reliance on, the information contained herein. Individual layer values were provided by Hamilton’s Public Health Services and Information Services. COPYRIGHT 2012 The City of Hamilton. Produced by Business Applications, Information Services. Printed June 19, 2012. May not be reproduced without permission. THIS IS NOT A PLAN OF SURVEY

Hamilton

MOVING FORWARD• Lead exposure information provided to at-risk families through PH Nurses providing home visits to new mothers• Lead exposure prevention strategies shared through community information sessions at daycares, Ontario Early Years Centres, and Parenting & Family Literacy Centres• Distribution of water filters for lead to at-risk families participating in the home visitation program offered by PH Nurses

Hamilton Public Health Services has begun developing inter-ventions that will seek to inform families at risk and provide strategies to reduce their risk of exposure to environmental lead:

• Communication of study results/education strategy aimed at community physicians• Home risk assessments performed by PH Inspectors available in response to a physician request re: a child with a BLL of concern

ACKNOWLEDGMENTSWe recognize and express our gratitude to Dr. Lesbia Smith and Robert Kusiak of EOHP Plus Inc., Dr. Celine Pinsent and Tim Dugas of Goss Gilroy, Inc., and Aimei Fan (Health Analyst) and Erin Van Driel (GIS Technologist) of the City of Hamilton Public Health Services for their substantial contributions to this report. Thanks to Erin Van Driel and Shane Thombs (GIS Tech-nologist) for their assistance in preparation of the poster.

Blood lead levels in Hamilton children: A small proportion of Hamilton children are being exposed at levels that require interventions at an individual, clinical level. We believe the findings generally reflect the BLLs of the study area population but the lower participation rates among the more at-risk groups may have resulted in a slight underestimate of the overall BLL.

Public health promotional material and follow-up: Results suggest a substantial audience exists for promotional materials about reducing lead exposure and lead-exposure re-duction services will be well received in this community. Variation in awareness levels with other markers of SES sup-ports the use of targeted approaches.

Potential lead exposure sources and risks: The study area represented the highest theoretical risk to lead exposure within the City of Hamilton; study results show this population to be at some risk (i.e. older housing stock; long-standing lead-emitting industry, historic roadways, low SES, recent immigration, rental housing, an unofficial language spoken at home and demonstrated presence of environmen-tal lead). High proportions of families living in housing built pre-1945 indicate that awareness of lead exposure risks from home renovations in older housing stock is an important component for public health lead exposure interventions in Hamilton.

Mitigating factors: Many families in the study area were already engaged in miti-gating practices; promotional activities should continue to en-courage such behaviours.

Complexity and neighbourhood effects: BLLs varied across the study area to some extent, consistent with the pat-tern seen in risk factors, socio-economic markers and envi-

CONCLUSIONSronmental lead levels. In the analyses of association, these potential predictors of BLLs were intertwined to the extent that it was challenging to disentangle contributions to BLLs and intermediary sources.

Research demonstrates that elevated BLLs are usually found among lower socioeconomic groups and minorities who are more likely to live in older housing that is in poor repair. The importance of social determinants of health on a child’s BLL is supported by the positive association between low house-hold income and BLL.

This study’s measure of industry emissions was a proxy mea-sure that may reflect long-established, urban neighbourhoods that are also adjacent to long-established lead-emitting indus-try with unmeasured risk from multiple sources. This factor demonstrated a significant and strong association with BLLs. Such areas are therefore of particular importance to public health lead exposure reduction strategies.

Results suggest the need for a multi-pronged col-laborative approach to environmental lead expo-sure reduction, involving disciplines/programs within public health, local physicians serving iden-tified populations at risk, and community stake-holders involved in neighborhood development strategies.

The City of Hamilton Board of Health approved a collaboration with stakeholders to deliver an envi-ronmental lead awareness program and to reduce exposure to environmental lead for children under age 7 and women of child-bearing age.

Non-random samples – Random sample not achieved. We had a plan to rapidly convert design to a convenience sample.

Sample not representative of study area – Families from higher SES and located furthest from industry were more likely to participate. Engaging at-risk populations challeng-ing.

Poor quality of some measures – Questions such as presence of filters on drinking water tap, food security, were dropped from analyses. Needed redundant measures.

Housing infrastructure questions were a challenge – Many respondents were unaware, especially renters, re: types of water pipes and housing age. Collect instead via inspection?

Public Health Unit implementation of large re-search studies – Difficult to balance regular duties with study demands resulting in study delays and heavy workloads. Greater collaboration with local university would have helped.

Chose objectives conservatively – Bulk of resources was spent on cleansing of data, analyses, interpretation and report writing for secondary objectives for which the study design was not ideal. Effective use of recruitment resources – Aggressive recruitment procedures netted little difference in participation rates. Extra telephone recruitment was expensive and ineffective.

CHALLENGES & SUCCESSESImportance of community communications – Suc-cessfully recruited a relatively large number of children within study; engaged media, community organizations and net-works.

Benefits of having access to various data sources – Strengthened study findings; helpful in defining study area population, understanding relevant resident and environmen-tal characteristics and provide proxy measures in lieu of more expensive direct measures. Importance of having PH team and medical referral structure in place a priori – Clinical follow-up was com-plex; this optimized client services. Single lab used for venous retests created efficiencies.

Benefits of having multiple stakeholders involved in the study – provision of study resources (e.g. staff, diagnos-tic testing, expert advice, clinical services, mapping, clinic space, environmental sample collection, report writing and analysis) and enrichment of available data sources.

Access to research funding/political support – Fund-ing via the PHRED Program; bolstered by political support received by local Board of Health. Generous in-kind re-sources also provided by Ontario Ministry of the Environ-ment, Ontario Public Health Laboratory, and the City of Hamilton.

Model Type 1: Relationships between lead sources and BLLs (µmol/L)

Model Type 2: Lead sources and study follow-up BLLs ≥ 0.19 µmol/L Statistically significant predictor

variables Beta

Estimated % change in BLL

(95% CI)*

Estimated impact on population mean of

0.100 µmol/L * R2 Beta

Odds Ratio (95% CI) ^

Primary Source Model (interview sample N=580 children)

Constructed pre 1920 0.15 0.3% to 33.0% 0.100 – 0.133 µmol/L Age of Housing Baseline: House construction date post 1944 Constructed 1920-44 Non-significant category

Non-significant

Proximity 0-500m 0.17 30.1% to 92.9% 0.130 – 0.193 µmol/L 2.99 19.93 (4.16 – 95.41)

Proximity 501-1000m 1.12 ♣ 3.06 (0.86 – 10.86)

Proximity to Historic Lead Industry Baseline: Proximity to historic industry >2500m Proximity 1001-2500m

Non-significant categories 1.15 3.17 (1.03 – 9.73)

Income