Soil and lead poisoning

Mary Jo Trepka, MD, MSPH

Outline

• Importance of childhood lead poisoning

• Childhood lead poisoning in Miami-Dade County

• Risk factors in Miami-Dade County

• Health department services

• Relevance to students

• What we still don’t know

What is so important about childhood lead poisoning?

• Can lead to permanently lowered IQs

• Children more susceptible

• Ubiquitous in environment

• Urban poor and minorities disproportionately affected

What is a safe lead level?

• Current action level = 10 μg/dL

• Estimated 2.6-5.8 point IQ decline for increase from 10 to 20 μg/dL

• Under 10 μg/dL safe? – 7.4 point IQ decline for 1-10 μg/dL– Cognitive and academic deficits for BLL <

5 μg/dL

(Schwartz, et al, Env Res 1994, Bellinger, et al Pediatrics 1992, Canfield, et al NEJM 2003, Lanphear, et al Pub Health Rep 2000)

What is so important about childhood lead poisoning?

• Can lead to permanently lowered IQs

• Children more susceptible

• Ubiquitous in environment

• Urban poor and minorities disproportionately affected

What is so important about childhood lead poisoning?

• Can lead to permanently lowered IQs

• Children more susceptible

• Ubiquitous in environment

• Urban poor and minorities disproportionately affected

Sources of lead

• Soil• Dust• Paint• Pottery• Occupation/hobbies• Folk remedies • Tiles• Water

Sources of lead

• Soil• Dust• Paint• Pottery• Occupation/hobbies• Folk remedies • Tiles• Water

Occupations with possible lead exposure

• Auto repair/radiator repair• Painting• Construction work• Steel welding and cutting• Plumbing• Police work• Maritime industry

Hobbies with possible lead exposure

• Fishing sinkers• Working with cars, car parts, or car batteries• Painting• Stained-leaded glass work• Shooting guns at firing ranges• Working with model cars or boats• Pottery work

What is so important about childhood lead poisoning?

• Can lead to permanently lowered IQs

• Children more susceptible

• Ubiquitous in environment

• Urban poor and minorities disproportionately affected

NHANES blood lead levels among children aged 1-5 years, United States, 1976-2000

Year Geometric mean BLLS

Prevalence BLLs

> 10 μg/dL

Estimated no. children with BLLs > 10 μg/dL

1976-80 14.9 88.2% 13.5 million

1988-91 3.6 8.6% 1.7 million

1991-94 2.7 4.4% 0.9 million

1999-2000

2.2 2.2% 0.4 million

Source: CDC MMWR 2003;52:SS10

Prevalence of lead poisoning by housing age

• Nationwide 2.2 % of 1-5 year-olds• Housing

• 8.6% Pre-1946• 4.6% 1946-73• 1.6% Post-1973

Source: CDC, 1999-2000 NHANES

Prevalence of lead poisoningby race/ethnicity and income among

those in pre-1946 housing

• Differs by race/ethnicity• 22% black• 13% Mexican American• 6% white

• Differs by income• 16% low• 4% middle• 1% high

Source: CDC, 1999-2000 NHANES

Childhood lead poisoning in Miami-Dade County

• Prevalence– Florida: 3.2% (Hopkins, et al, J Fla Med Assoc.

1995)– Miami-Dade

• Countywide: unknown • Central urban area: estimated 8%

• Surveillance: average 431 cases a year among children (1998-2002)

• Underscreening– Florida 17% (GAO Report)– Miami-Dade 23% (analysis of Medicaid data)

Lead poisoning cases by gender, Miami-Dade County – 2002

63%

37% Male

Female

Source: Miami-Dade County Health Department, Vital and Morbidity Statistics 2002

Un-known

5%

Non-His-panic White

3%

Haitian20%

African Ameri-

can22%

His-panic50%

His-panic48%

African Ameri-

can/Haitian

25%

Non-His-

panic White23%

Other4%

Population < 6 years, 2000, and reported lead poisoning cases by race and ethnicity, 1999-2001, Miami-Dade County

Population Cases

Source: 2000 US Census and Miami-Dade County Health Department

Sources of lead hazards based on environmental home inspections

Lead Hazards found in Environmental Home Inspections 1999-2003 (N=188)

3127 28

22

16

6 7

13

05

101520253035

Sources of Lead Hazards

Num

ber

of H

azar

ds

• 188 inspections• 89 (47%)

inspections found no hazards (55 of these inspections in imported cases)

• ‘Other sources’: fishing weights, parental occupations, hobbies, water, objects/statues

Source: Miami-Dade County Health Department Childhood Lead Poisoning Prevention Program 2003

Risk factors for lead poisoning in Miami-Dade County

• Living in a home built prior to 1950

• Living in central urban area

• Low socio-economic status

• Living in a recently remodeled home

• Sibling or playmate with lead poisoning

• Refugee status

Percent of Housing Units Built Before 1950 by ZipcodeMiami-Dade County

33178

3303533034

33187

33196

33031

33030

33032

33018

33033

33157

33156

33170

33177

3317633186

33185

33192

33166

33182

33054

33172

3314333193

331753315533165

33140

33147

33142

33014

33169

33126

3301533055

33138

33161

33056

33012

33122

33183 33173

33139

33179

3316233160

33149

33189

33141

33134

33137

33016

33039

33167

33181

33013

33194

33133

33010

33125

33158

33150

33168

33190

33180

33146

33127

33154

33184 331443317433145

33132

33135

33136

33129

3313033128

3313133109

N

EW

S

% Housing Built Before 19500 - 2020 - 26>=27

33178

33018

3303433035

33030

33031

33187

33196

33032

33177

33186 33176

33192 33182

331753318533155

33143331733318333193

33156

33157

33039

3301533055 33056 33169

33179

33160

33180

33162

33161

33138

33140

33139

33149

33142

33147

3305433014

33012

33166

33122

33125

33134

33146

33133

33141

3315433168

33150

33127 33137

33194 33184 33174 33144

33126

33181

33135

33145

331 30

331 36

331 32

331 29

331 31

33189

3319033170

331 28

33165

33172

33013

33033

33158

331 09

33010

33167

Reported Lead Poisoning Cases in Miami-Dade County 1995-1998

N

Lead Poisoning Cases 0-25 Cases26-60 Cases >60 Cases

Lead poisoning prevalence among children screened at the

Refugee Health Assessment Center*,July 1, 2001 to June 30, 2002

Total Positive 85

Total Screened 992

Prevalence

85/992 = 9%

Childhood Lead Poisoning Prevention Program

• Screening

• Surveillance

• Follow-up

• Public and professional education

• Primary prevention

• Evaluation

Relevance to students’ lives

• May live in neighborhoods with soil lead hazards and may have younger siblings at risk

• May become parents and will need to know about preventing lead poisoning in their own children

• May be exposed in workplace or during hobbies in future

What we still don’t know

• How to remove lead from soil• How to cover soil to prevent exposure• If there is a safe lead level• Extent of behavioral effects• How to bring about lead abatement• Risk factors among immigrant children