Asthma and the Indoor Environment: Lessons learned from Boston’s

Healthy Public Housing Initiative

Boston-NY Healthy Public Housing SummitFebruary 15-16, 2007

• Prevalence increasing worldwide• Currently affects 5-10% of US

• >17 million Americans affected• Incidence, severity increasing• Highest in industrialized countries• Leading chronic illness among children

• Prevalence among children rose from 3.6% (1980) to 5.8% (2005)*

• In the US, costs exceed $14 billion/yr

THE ASTHMA PROBLEM

*(NEJM, 2006)

• Asthma rates highest among urban poor

(NYT, 4/19/2003)

THE ASTHMA PROBLEM

(Boston Globe, 3/27/2006)

Hypotheses–Environmental exposures–Housing conditions–Obesity–Access to health care–Genetic variants–Intrinsic factors (e.g., premature birth)–Social/psychological factors (e.g., stress, exposure to violence)

Age- and gender-adjusted asthma hospitalization rates in Boston, 1992 (Gottlieb et al., 1995)

THE ASTHMA PROBLEM - DISPARITIES

• Boston Public Housing FactsLargest apartment owner in Boston15,000 units in 68 developments25,000 residents (10,000 children)Average Income: 17% of Boston-area median• < $10,000 for a family of four

Boston Public Housing

• Public/GovernmentBoston Housing AuthorityBoston Public Health Commission

• UniversitiesBoston University School of Public HealthHarvard University School of Public HealthTufts University School of Medicine

• CommunityCommittee for Boston Public Housing, Inc.Franklin Hill Tenant Task Force, Inc. West Broadway Tenant Task Force, Inc. Public Health Initiative, South Boston Community Health Center

• PrivatePeregrine Energy GroupUrban Habitat Initiatives

Healthy Public Housing Initiative Collaborators

It takes a village

Healthy Public Housing Initiative Activities

FocusGroups and Survey

Resident Education and Employment

ManagementSystems Analysis

& Policy

Interventions &Health Outcomes

Source: HPHI Policy Advisory Council Meeting, December 2003.

Initial Environmental Assessment Survey

• Surveys - 238 TOTAL132 in West Broadway106 in Franklin Hill

• Visual Inspections done as part of survey• Environmental Sampling - 80 Total

• Project goalsImprove home environments to improve health & increase quality of life for residents of public housing in BostonBuild capacity within city agencies, community organizations, & resident groups to sustain effortImpact national policy on housing design and health care financing for asthmaEmpower residents through training, employment and shared decision-making.

Healthy Public Housing Initiative

• 60 families with asthmatic children from Boston Housing Authority developments enrolled in intervention study:

West BroadwayWashington BeechFranklin Hill

• Health data• Environmental Measurements• Interventions

Clinical – Asthma case management: training, access to peak flow meters, monthly diaries and maintaining an appropriate medication regimen.Environmental – IPM, new mattresses, pillow covers, air purifier, plastic ware, minor home improvements, industrial cleaning.

ManagementSystems

FocusGroups

Survey

Analysis&

Policy

Interventions &Health Outcomes

HPHI intervention

Concept behind intervention

• Residential exposure to indoor allergens contributes to severity of asthma symptoms, greater impact for low SES populations

• Focus groups, past studies emphasized significance of cockroaches and other pests

• Conventional pesticide use to eradicate roaches can contribute to health impacts IPM needed

• Concerns also exist about other environmental exposures, adequacy of health care, social stressors, etc.

• Resident education • Industrial Cleaning• Mattress Replacement• Integrated Pest Management (IPM)

An effective method of pest control based on modifying the physical environment and reducing the use of chemicals. Techniques include:

• eliminate sources of food and water• block entry• reduce habitation sites• monitor infestation sites

• Environmental MeasurementsTemperature/HumidityAllergen levelsRoach countsPesticide levelsAir exchange ratesNitrogen dioxide

HPHI Activities

• Design – Longitudinal intervention

• Asthma management• Base rates for symptoms, QoL survey• Monthly follow-up visits• Pre- and Post-intervention environmental assessments

HPHI Health Assessment

3 months 9-15 months

∆

Outline - Results

• Quality of Life – Health Outcomes• Allergen levels• Air exchange/Nitrogen dioxide• Pesticide levels

HEALTH OUTCOMES / QUALITY OF LIFE

Study Population

27%22%40%27%Pets25%28%29%21%Below Average Housekeeping73%33%83%97%Holes in Walls23%7%33%30%Visible Mold 44%44%20%50%High Occupant Density 2%5%0%0%Caucasian

29%21%29%35%African-American75%75%71%65%Hispanic

Race/Ethnicity*4919723# of Units

TotalWest Broadway

Washington Beech

Franklin Hill

Characteristics

Health Outcomes

• Did our interventions improve asthma-related quality of life (QOL) for children in our study?

• QOL measures (Juniper, ccores range 1-7 ): SymptomsActivity LimitationEmotional FunctionTotal

• Did symptom indicators improve?

QOL scores improved overall

mean improvement during HPHI

1

2

3

4

5

6

7

-10 -5 0 5 10 15

Months

Tota

l Jun

iper

Sco

re

Improvement is attributable to Interventions

Im p ro ve m e n t Be fo re & Afte r In te rve n tio n s (4 m o n th s)

1234567

-6 -1 4 9

M o n th s

Tota

l Jun

iper

Sco

re

Symptoms

Symptoms

ALLERGENS

Objectives – Allergen Study

• ObjectivesTo determine if cockroach allergen levels can be reduced in public housing.To determine if reductions in allergen levels can be maintained

• RationaleTo see if the type of interventions worked.To determine whether interventions should be part of BHA’soperation.To determine conditions that have to be dealt with for interventions to be successful.

Measurements

IPM: Cleaning

Bedroom Cockroach Allergen Levels

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70

Bla g 2 Bed Conc (U/g)

Cumu

lative

Perce

nt (%

)

Pre-InterventionPost 1 monthPost 3 monthsAsthma trigger level

Allergen Levels – Intervention Effect

72%

62%58%

31%

7%12%

8% 9%

0%

10%

20%

30%

40%

50%

60%

70%

80%

Pre-Intervention

Immediatelyafter

3 months after

6 months after

Perc

ent

Kitchen

Bed

Percent Kitchen/Bed Cockroach Allergen Levels Above Effect Thresholds

Estimated Kitchen Cockroach Allergen Levels

0

10

20

30

40

50

60

70

0 2 4 6 8 10

Months after Intervention

Cock

roac

h Al

lerg

en C

once

ntra

tions

(U/g

)

Bla g 1 Kitchen

Bla g 2 Kitchen

Allergen Levels by Sources of Food, Shelter and Access

(p-value=0.02)

By “Clutter” level By “Holes in Walls”

(p-value=0.08)

Conclusions – Allergen Study

• Interventions can reduce cockroach allergen levels.• May need to do building-wide.• May need to do on an on-going basis to maintain results.• Need to address sources of food and hiding spaces.• Need to address pest entry ways.

Conclusions – Allergen study

• Determinants of pest-related allergens include:Lack of housing renovationsHoles in the wallsHousekeeping practicesSeason

• IPM and cleaning worked• Integrated measures must be implemented on a

regular basis and building-wide to maintain results.• Behavior modification and improvements to physical

conditions are key to intervention success

AIR EXCHANGE / NO2

Study of Air exchange and NO2

• Indoor NO2 levels are a function of:Gas StovePilot lightVentilation rateStove exhaust/range hoodUsage patternOutdoor levelsSize of homeHumiditySmoking

Air Exchange Summary Statistics by Season

Nitrogen Dioxide Concentrations by Season

40% above EPA standard in winter

• Higher Indoor NO2 levels in our cohort• Significantly higher in heating season• Heating Season~ 40% above EPA Standard• Peak levels can be an order of magnitude higher than 2 wk avg

• AERs similar to national distribution• Air Exchange Rates significantly lower in heating season• 34% of apts. do not meet ASHRAE std. in heating season

• Indoor NO2 is a strong function of:• Air Exchange Rates• Outdoor NO2 levels

• Supplemental Heating with Gas Stove• Reported by 27% of Cohort (36% in West Broadway)• Trend between gas stove heating and increased indoor NO2

Ventilation/NO2 Study - Conclusions

PESTICIDES

Pesticides: Study Objectives

Determine prevalence and concentration of pesticides in public housing

Explore methods to classify pesticide exposures• Wipes vs. Dust (low burden on families)

• Management Files vs. Management files & Home Visit (low-cost screening tools)

Evaluate the effectiveness of Integrated Pest Management interventions (changes in pesticide concentrations)

Household Pesticides

• OrganophosphatesBlack Jack Roach & Ant KillerRaid Ant BaitRaid Ant Controller

• PyrethroidsBlack Jack Roach & Ant KillerRaid Ant & Roach KillerHot Shot Roach & Ant KillerTempo 20 WP InsecticideChinese Chalk

Target Analytes Oral LD50 in Rat (mg/kg)

Organophosphates• Chlorpyrifos* (135-163)• Diazinon* (300-400)

Pyrethroids• Cyfluthrin* (590)• Cypermethrin (250)• Deltamethrin* (135)• Esfenvalerate (458)• Permethrin (383)• Bifenthrin (70)• Cyhalothrin (114)• Allethrin (1100)• Resmethrin (>2500)• Sumithrin (>3500)• Tetramethrin (>5000)

Source - EXTOXNET. A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Michigan, Oregon State and University of California at Davis.

45<LOD<LOD<LOD16 (7)Deltamethrin*

40.4<LOD<LOD26 (11)Cyhalothrin

172.50.7<LOD67 (28)Esfenvalerate

56716.41.1<LOD71 (30)Cyfluthrin*

33116.23.7<LOD90 (38)Cypermethrin

5562.60.4<LOD98 (41)Diazinon*

22733.06.80.21100 (42)Permethrin

201.30.30.03100 (42)Chlorpyrifos*

Max75th pctMedianMin%>LOD (n)Analyte

Prevalence (%) and Pesticide Concentrations (µg/m2) in Kitchen Floor Wipes (N=42)

Kitchen Floor Wipes (N=42)

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

0 1 2 3 4 5 6 7 8 9 10 11 12

Number of Pesticides Detected

% o

f Hou

seho

lds

Prevalence of Pesticides Detected

Cumulative Frequency Distributions (N=42)

Kitchen Wipes

0

10

20

30

40

50

60

70

80

90

100

0.001 0.01 0.1 1 10 100 1000

Cum

ulat

ive

Perc

entil

e

DiazinonChlorpyrifosPermethrinCypermethrinCyfluthrin

µg/m2

Chlorpyrifos

Diazinon

Prevalence of Pesticides Detected

Vacuum Dust (N=35)

0%

5%

10%

15%

20%

25%

30%

35%

40%

0 1 2 3 4 5 6 7 8 9 10 11 12

Number of Pesticides Detected

% o

f Hou

seho

lds

Kitchen Floor Wipes (N=42)

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

0 1 2 3 4 5 6 7 8 9 10 11 12

Number of Pesticides Detected

% o

f Ho

us

eho

lds

Kitchen Floor Wipes Vacuum Dust

Predictors for identifying households at or above the 75th percentile in pesticide concentrations

Consultant’s assessment of roach problem (mild)

Residents’ self report: Severe roach problem (Y)

Work order requests at baseline (N)

Ethnicity (Hispanic)

Cypermethrin

Ethnicity (Hispanic)

In current apt. > 5 yrs

Residents’ self report: Severe roach problem (Y)

In current apt. > 5 yrs

Ethnicity (Hispanic)

CyfluthrinManagement Files & Home VisitManagement FilesPesticides

-6-5-4-3-2-1012345

Cyflu

thrin

(1 IP

M ses

sion)

Cyflu

thrin

(>1

IPM s

essio

n)

Cyper

met

hrin

(1 IP

M se

ssio

n)

Cyper

met

hrin

( >1

IPM

sess

ion)

Perm

ethr

in (1

IPM se

ssio

n)

Perm

ethr

in (>

1 IP

M ses

sion)

log t

ransfo

rmed a

bsolu

te v

alu

e o

f (p

ost-

pre

IP

M k

itchen w

ipe

concentr

ati

ons)

(ng/s

q f

t)

Lower QuartileMinimumMedianMaximumUpper Quartile

Difference in pesticide concentrations for pyrethroidsstratified by number of IPM training sessions

Summary of Study Findings

PrevalenceEvery home had at least 3 pesticides, some homes as many as 8

Chlorpyrifos found in every home 2 years following withdrawal from sales

Restricted pesticides, e.g., Tempo were found in many homes.

Methods to classify exposuresPositive correlations among target pesticides in dust matrices

Using combination of files and home visit : Sensitivity improved and ability to identify target households improved.

Predictors identified for current use pesticides (pyrethroids) are consistent with assumption that activity patterns may contribute to ‘high end exposure’ households

IPM Efficacy (reduction on pesticide loadings)

• Resident education was positively associated with reduction in cyfluthrin concentrations (active ingredient for Tempo - a restricted use pesticide)

• Found a negative association with permethrin, which may be suggestive of pesticide substitution

• Homes with poor housekeeping were higher at baseline and got better reductions

Summary of Study Findings

Pyrethroids (cypermetrin, permethrin)

N=43 homes

(households inpublic housing )

0.11-5.390.013-7.71<LOD-5.17Vinyl floor &

furnishings, e.g., sofa,

rugs

Urban -Boston,

MA

Current Study (2005)

N=7

( Commercial & residences)

1.0-4.521.65-9.941.3-1.84Wood floors, window sills &

furnishings,

e.g., sofa, rugs

Agricultural –Cape Cod,

MA

Rudel et al. 2001

(pilot study)

(min-max)(min-max)(min-max)

Range (µg/g)Range (µg/g)Range (µg/g)

Cis permethrinTrans permethrinCypermethrinSurface sampledsiteStudy

Classification and Regression Tree (CART)

Classified subgroups (nodes)

Source data-

(a) File review

Floor Wipe data dichotomized at 75th pct.

Predictors

Application of CART

Source data –

(b) File review and home visits

Overall results/recommendations

• Many environmental risks in our cohort• Interventions can reduce allergen levels• Pesticide residues are widespread• Residents are using restricted-use pesticides• Indoor NO2 levels are high in heating season• Indoor NO2 levels are a strong function of air exchange• Interventions can be designed to control exposures:

e.g. Increased ventilation for pollutantsIPM for allergen and pesticide reduction

Acknowledgements

• The HPHI team • Funders:

HUD, Boston Foundation, Jesse B. Cox Charitable Trust, W.K. Kellogg Foundation

• For more information:www.hsph.harvard.edu/hphi

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