RSV and The Ulu: The Cutting Edge of Research into the Causes of Severe Recurrent Lower Respiratory Tract Infections in Inuit Infants
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RSV and The Ulu:The Cutting Edge of Research into the
Causes of Severe Recurrent Lower Respiratory Tract Infections in Inuit
Infants
Tom Kovesi MDPediatric RespirologistAssociate Professor of PediatricsChildren’s Hospital of Eastern OntarioUniversity of OttawaOttawa, Canada
Bronchiolitis
Bronchiolitis isan infection, causedby a virus, of thevery tiny airwaysin a baby’s lungs
0
100
200
300
400
500
Hospitalization Rate per 1000 infants
All United States
Yukon-KuskowkwimDelta (Alaska)
Baffin Region,Nunavut
Northern Communities Have the Highest
Incidence of Severe RSV Bronchiolitis in the World
Karron, J Infect Dis 1999; Banerji, CMAJ 2001
Nunavut has the highest rate of Tuberculosis infection in Canada
0
20
40
60
80
100
120
140
160
TB rates per 100,000 persons
Canada (general)
CanadianAboriginals
Inuit
What the Houses? Indoor Air?
Do they play a role?
What About Ventilation?
Cape Dorset Pilot Project: Kovesi, Indoor Air 2006Multi-Community Study: Kovesi, CMAJ 2007
Occupancy Distribution
Number of People Per House
12.010.08.06.04.02.0
12
10
8
6
4
2
0
Number of Houses
Median number occupants: 6, mean 5.9, range 2-12
Cape Dorset, 20 houses of Inuit Infants
(Kovesi, Indoor Air 2006)
Environmental Tobacco Smoke Exposure
5%90%
5%
Smoking Reported
Likely Smoking
No Smokers
Smokers present 90% (probably 95%) of households
Ventilation
• 96 Inuit children in 4 communities: • Mean ventilation 5.6 L/s/person• Mean CO2 1358 ppm (Kovesi, CMAJ 2007)
Recommended
BelowRecommended
20.1%
79.9%
Ventilation within recommendedCanadian standards (7.5 L/s/person)
Mean CO2 > 1000
< 1000
> 1000
33.3%
66.7%
ppm
1321N =
Pneumonia
PresentAbsent
Mea
n CO
2 (p
pm)
3000
2000
1000
0
Risk of Lower Respiratory Tract Infection
1525N =
Pneumonia
PresentAbsentO
ccup
ancy
12
10
8
6
4
2
• Ventilation also known to be important risk factor for TB (Menzies, Ann Int Med 2000)• *too few non-smoking households to test the effect of smoking
Heat Recovery Ventilators• Heat Recovery Ventilators bring fresh outside air
into furnace, transfer heat from stale air to fresh air to maintain energy efficiency, and move stale air out of house
• Trial of HRV’s installed in homes of Inuit children 5 years & less in 4 communities
• HRV’s were installed in fall-winter 2006-2007:– Clyde River– Igloolik– Pangnirtung– Pond Inlet
Study HRV’s• Venmar Constructo 1.0 HRV,
– (Venmar Ventilation Inc.) • Determined that additional 25-30
L/second ventilation needed to provide 7.5 L/s/person
• Active HRV’s provided this ventilation
• Placebo units circulated air in the house, but not increase the house’s outside (fresh) air
• Placebo units were reprogrammed as functional devices at end of study (reprogram internal circuit board)
Conducting Research in Nunavut
– Community Support• Town Hall Meetings: Pilot & Multi-community
Studies; mainly assumed for HRV study• Qikiqtani Inuit Association, Nunavut
Tunngavik Inc.• Approval from Nunavut Research Institute,
Ministry of Health and Social Services
– Need for community research coordinators with good organizational and computer skills (“too few and in too much demand”
– Capacity-building: enlisted high school students to help with collecting data
Heat Recovery Ventilator
Venmar HRV, Pond Inlet, Nunavut
HRV Study Findings - Engineering
• Installations– 68 HRV’s installed– 51 available for analysis
• Units (6) in Clyde River couldn’t be powered• 3 families dismantled units• Children in 4 families moved
• HRV’s significantly reduced indoor CO2 (33%)– Mean CO2 1385 ppb placebo units– Mean CO2 924 ppb active units
Effect of HRV’s on Reported Wheezing
• Significant reduction in risk of reported rhinitis (not associated with cold air exposure) (p = 0.0044)
Challenges• HRV’s significantly reduced relative humidity
(25.6 vs 30.9%) & tended to reduce indoor temperature
• Occupant complaints (house colder, drier…) • 21% active houses, • 27% placebo houses
• Units unplugged > 50% of study period in ~20% houses (counter data, questionnaires)
Research Questions
• Are Heat Recovery Ventilators the answer?– Maintenance and installation issues– Dry air– Small but real electricity cost– Retrofits
• Can Heat Recovery Ventilators be engineered better for very cold weather performance?– Issue of drafts
• Role of overcrowding/need for new homes versus ventilation (e.g. heat recovery ventilators)
• Role of surface v.s. airborne transmission virus
Future Research (2)• How to deal with environmental
tobacco smoke• Human architecture of Inuit housing• Capacity-building – research in
Nunavut
Acknowledgements• Program of Energy Research and
Development, NRCan• Nassivik Centre, CIHR• Canada Mortgage and Housing
Corporation• Natural Resources Canada• Qikiqtani Inuit Association• Venmar Ventilation Inc. • Nunavut Housing Corporation• Health Canada• Children’s Hospital of Eastern
Ontario Research Institute• Department of Health and Social
Services, Government of Nunavut
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