1. Lead Exposure What the Community Physician Should Know
Sarah Morse, PGY-4
Children’s Hospital of Eastern Ontario
January 20th, 2017

2. Objectives Introduction and background to lead exposure
Consequences of elevated blood lead levels
Sources of lead in the environment
Management of lead toxicity
Prevention of lead exposure
Screening for lead
Role of the physician

3. Introduction
Since 4000BC lead has been used for glazing pottery, in piping, utensils, and as a wine sweetener
Common cause of morbidity/mortality in ship builders, potters and wine drinkers
Occupational exposure became environmental exposure in the 20th century
Lead-based paint
Lead gasoline
Levels >10 mcg/dL (0.48 mcmol/L) have decreased from 88% to 1.21% in children over 3 decades
Children are among the most vulnerable population to the effects of lead
Due to continued increase in industrialization and persisting lead in the environment, exposure is still a significant public health concern

4. Lead Exposure in Children
Young children absorb lead more efficiently than older children and adults with a greater half-life
Nutritional deficiencies of iron and calcium increases lead absorption in children
Immature/developing nervous system more vulnerable to its toxic effects
Rapid elevation in blood lead between months with peak at months
increase motility
hand to mouth exploratory behaviour
U.S. Centers for Disease Control and Prevention

5. Clinical Effects of Elevated Lead
Clinical effects vary according to the individual, as well as timing, duration, and dose of exposure
Signs and symptoms depend on degree of toxicity ranging from asymptomatic to causing abdominal pain, colic, constipation, anemia, growth failure, hearing loss, renal disease, seizures, encephalopathy, death
Peripheral neuropathy is more prominent in adults versus central effects (cognition) in children
only peripheral effects are reversible with treatment
Most children with elevated levels are asymptomatic; clinical symptoms require high lead levels
Lead concentrations >60 mcg/dL (2.9 mcmol/L); severe abdominal colic (“lead colic”) and irritability, while lead >100 mcg/dL (4.8 mcmol/L); protracted emesis, encephalopathy, death
Lead levels less than 5 mcg/dL (0.24 mcmol/L) can result in cognitive deficits in children

6. Lab Changes
CBC: low hemoglobin with normochromic normocytic anemia or hypo chromic microcytic anemia
Basophilic stippling at high lead levels only
Elevated BUN/Cr and uric acid if renal effects

7. Consequences of Elevated Lead
Greatest concern is the neurotoxic potential particularly in children and its effects on cognitive and neurobehavioral development
Low lead concentrations <5 mcg/dL (0.24 mcmol/L); decreased IQ, neurobehavioral disorders, antisocial and delinquent behaviours
=/>5 mcg/dL (0.24 mcmol/L) now used as reference level for intervention
2.6% children 1 to 5 years old had lead levels >5 mcg/dL
No safe level of lead exposure

8. Consequences of Elevated Lead
A study (Canfield, 2003) looked at IQ scores for lifetime lead levels above 10 mcg/dL (0.48mcmol/L) and below 10 mcg/dL (0.48 mcmol/L):
Loss of 4.6 IQ points for each increase in BLL of 10 mcg/dL (0.48 mcmol/L)
Loss of 7.4 IQ points up to a BLL of 10 mcg/dL (0.48 mcmol/L)
Greater IQ loss with a given change in blood lead level less than 10 mcg/dL (0.48 mcmol/L)

9. Consequences of Elevated Lead
Cross-sectional studies are limited as only one blood level is reported so sequence of events and outcomes are more difficult to assess
One study (Tong, et. al. 2000) looked at the pattern of blood lead levels (10 mcg/dL) at three age ranges and their effect on cognitive index; results indicate an inverse relationship between cognitive index and lead level up to 48 months with peak effects of prior lead exposure occurring at months

10. Sources of Lead
Houses in particular before 1950 but even up to 1978 with residential lead paint bans
renovations remain a risk
Exterior paints with higher lead levels
All plumbing prior to 1986
Water fountains in older schools
Toys imported from China
Toys and furniture painted before 1976
Hobbies or parental occupation

11. Sources of Lead
Source identification is difficult with influx of uncommon materials such as ethnic accessories, toys, utensils, folk remedies and alternative medicines
Hispanic culture:
candy ingredients- tamarind and chill powder
Greta and azarcon- remedy for upset stomach and teething
East Indian culture:
Ghasard- health tonic
Sindoor and surma- used as cosmetics
Asian culture:
Day Tway - Thai digestive aid
Ba-baw-san- Chinese colic remedy

12. Case of Lead Toxicity in Ontario
Elevated lead >100 mcg/dL (>5.0 mcmol/L) found while doing work up for an adult with a tremor
Lead toxicity was secondary to consumption of a traditional medicine
Ayurveda medicine from India and South Asia

13. Diagnosis
Diagnosis can be challenging due to varying and often vague symptoms
USPSTF recommends against routine screening in asymptomatic children age 1-5 years old and there is insufficient evidence to even recommend screening in those at high risk of exposure
Consider lead exposure in the differential for a child with intermittent abdominal colic and neurologic deficits or a child with abdominal symptoms and anemia

14. Elevated Lead Levels
What to do?

15. Management
CDC stratified lead levels to 5 classes with recommended action
Environmental management; inspection of home and testing by Professionals
Dietary management; deficiency in Fe, calcium, zinc and vitamin C
Medical management; no recommendations for X-rays, assessment of gingiva, or testing renal function
Pharmacotherapy; chelation therapy not recommended below 45 mcg/dL (2.2 mcmol/L)

16. Management
BLL between mcg/dL- Succimer used orally as single agent (1st line) but EDTA may also be used as a single agent (2nd line)
BLL >70 mcg/dL- EDTA is given in combo with BAL
If any child receives chelation, they must be moved to a lead-free environment as chelation increases GI avidity for lead
No treatment ameliorates the permanent developmental and neurocognitive effects of lead toxicity

17. Exposure Prevention
What physicians should know

18. Prevention
Key to preventing elevated lead in children is removing persistent sources of environmental exposure
Federal standards in place for levels of lead tolerated in and around homes/communities
Lead exposure is cumulative without an apparent “safe” level, therefore all sources should be eliminated
Lead level increases by 3.8 mcg/dL (0.18 mcmol/L) with an increase in ppm lead concentration in soil

19. Prevention
Lead levels dropped with the ban of lead based paint in 1978 and by removal of lead from gasoline by 1986
Public health efforts to decrease lead exposure in the general population continue to be a success
In the US, cost-benefit estimates for lead risk reduction in housing is comparable to that of childhood vaccines

20. Prevention Paradox
“For a given level of exposure, lead- associated IQ decrements are proportionately greater at the lowest blood lead concentrations.”
The paradox is that most disability occurs in the low to moderate risk groups
Larger number of IQ points lost per child above the reference value of 5mcg/dL (0.24 mcmol/L)
More cumulative IQ points are lost within a population at lower lead levels
Primary prevention of lead exposure is key, rather than therapeutic interventions

21. Prevention
Some of the newer evidence from recent studies do indicate low levels of blood lead having negative effects on the neurocognitive development of children
Population-level effects that were not reliably observed in individual patients
Therefore, further measures to reduce lead exposures would be beneficial from a public health standpoint
From a clinical standpoint, individual identification of a patient with elevated lead would allow for source determination and assist with eliminating or decreasing exposure on a more public level

22. Role of the Physician
Lead in clinical practice

23. Screening for Lead No Canadian Screening Guidelines
Canadian Task Force on Preventative Health Care found evidence supporting screening in high-risk children and infants but no evidence to support Universal screening of asymptomatic individuals
Rourke Baby Record includes screening questions for 12 months and 24 months
High risk groups as per the CDC are those with ‘yes’ to any of the first three Rourke Baby Record questions

24. Screening for Lead
Draft Guide for screening from Environmental and Occupational Health of Public Health Ontario
Another special consideration includes developmental delay or Autism Spectrum

25. Management
“A blood lead level can confirm whether findings are likely attributable to lead exposure”
Key Steps:
Remove source/provide resources to prevent exposure
Contact local Public Health Unit
Specialist Contact
Ontario Posion Control:
Occupational and Environmental Health Clinic at St. Michael’s Hospital:

26. Source Identification
Table 7. Screening questionnaire
Source Identification
Make sure to examine family member’s BLL, trace the child’s habitual and recreational activities, get a good PMHx and dietary history, find out all medications/herbal supplements/traditional medicines used, document food, utensils, cosmetics or other imported items
Source may not be obvious or identifiable immediately so a screening questionnaire going more into depth on possible source
Public Health
Clinical Toxicology vol. 46 no Atypical sources of childhood lead poisoning

27. Role of the Physician
Improving procedures of health risk assessment, improving promotion of understanding and awareness to lead exposure, increased emphasis on adequate nutrition, and particular attention to socioeconomic conditions that may exacerbate risk
Policy Statement from July 2016 (AAP) recommends:
individual assessments of older housing (<1960)
be familiar with current screening process and test for lead accordingly
screening of immigrant, refugee, and Internationally adopted children
screen children between 12 and 24 months if live in community where >25% of housing was built before 1960
ensure comprehensive environmental inspection in homes of children with BLL >5 mcg/dL (0.24 mcmol/L)
EDUCATION

28. Role of the Physician
Providing information to families on prevention of lead exposure is important, however, there has been minimal effect of these interventions at the level of the individual and/or family.
Preventing lead paint exposure; questioning and education on housing, renovations and state of repair
Assess drinking water; homes, school and community. Let water run until cold before using.

29. Ontario Resources How to contact the Public Health Unit
Patient address in the Health Services Locator map at
ges/default.aspx
Health unit contact information is available at
ations.aspx
Medical Officer of Health (MOH) in the health units are physicians who should be able to consult on these cases

30. Ottawa Resources

31. Ottawa Resources

32. Other than the Physician
Public Health Officials should work along with Physicians to enforce strict legal standards of allowable levels of lead in the air, soil, water, house dust and consumer products
Given no safe level of lead has been determined and with the knowledge of lower lead levels having neurocognitive effects at the level of the population, complete elimination of lead in all sources and products may be the next step in control of lead exposure…

33. Summary
Children are among the most vulnerable population to the effects of lead
Lead levels less than 5 mcg/dL (0.24 mcmol/L) can result in cognitive deficits, decreased IQ, neurobehavioral disorders, and antisocial and delinquent behaviours
“For a given level of exposure, lead-associated IQ decrements are proportionately greater at the lowest blood lead concentrations.”
No safe level of lead exposure and its reported effects at low levels occurs at the level of the population rather than the individual
Several unique sources of lead from Immigrant Communities
No treatment ameliorates the permanent developmental and neurocognitive effects of lead toxicity
Key to preventing elevated lead in children is removing persistent sources of environmental exposure
Main role of the physician is on education and appropriate screening when needed, otherwise Public Health Officials need to work with Physicians to eliminate lead sources

34. References
The 2016 Cochrane review: Nussbaumer-Streit B1, Yeoh B, Griebler U, Pfadenhauer LM, Busert LK, Lhachimi SK, Lohner S, Gartlehner G. Cochrane Database Syst Rev Oct 16;10:CD Household interventions for preventing domestic lead exposure in children.
Gorospe EC, Gerstenberger SL. Clin Toxicol (Phila) Sep;46(8): doi: / Atypical sources of childhood lead poisoning in the United States: a systematic review from
Case of Lead Toxicity in Ontario from Ayurvedic Medicine, Public Health of Ontario, Statement, 2015.
Blood Lead Testing – Indications and Interpretation: A guide for health care providers, June 2014.
Bellinger, D.C. Lead. Pediatrics Apr; 113(4):
Lanphear, B.P. Prevention of Childhood Lead Toxicity. Pediatrics July; 138(1): 1-15.
Chandran, L., Cataldo, R. Lead Poisoning: Basics and New Developments. Pediatrics in Review Oct; 31(10):
Abelsohn, A.R., Sanborn, M. Lead and Children: Clinical Management for Family Physicians. Can Fam Physician 2010 June; 56:
Koller, K. et al. Recent Developments in Low-Level Lead Exposure and Intellectual Impairment in Children. Environmental Health Perspectives June; 112(9):
Tong, S. et al. Environmental lead exposure: A public health problem of global dimensions. Bulletin of the World Health Organization. 2000; 78(9):
Schnaas, L. et al. Temporal pattern in the effect of postnatal blood lead level on intellectual development of young children. Neurotoxicology and Teratology July; 22:
Protecting your child from lead. Canadian Family Physician, June 2010.