Risk Factors for Lower Respiratory Tract Infections in Young Children

Thomas Hennessy, MD, MPHCDC Arctic Investigations Program

Anchorage, Alaskatbh0@cdc.gov.

n Why focus on risk factors?

Southwest Alaska Respiratory Virus Study:

Hospitalized cases, Year 1

0

5

10

15

20

25

30

35

40

45

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sept

Nu

mb

er o

f ca

ses

RSV

HMPV

ParaFlu

Flu

Pertussis

Total tested

| 2005 | 2006 |

Para-1Para-3

Definitions and Data Qualityn Site of infection

n Lower respiratory tract infection (LRTI) vs.n Upper respiratory infection

n Hospitalized vs outpatient illnessesn Specific diagnosis vs. syndrome

n Respiratory syncytial virus vs. bronchiolitis

n Different populationsn Medically high risk vs. general vs. special population

n Data is difficult to assessn No randomized controlled trials of Risk Factors!

Person

Pathogen Environment

Risk Factors Related to the Person

n Males, 1.5X increasen Gestational age < 36 weeksn Low birthweightn Age at time of epidemic

n < 6 months for RSVn > 6 months for hMPV

n Nutritionn Breast feeding is protectiven Vitamin A if severe deficiencyn Vitamin D?

n Race: African-American, AI/AN, Maori, Aboriginal

Risk Factors Related to the Person, continued

n Immunityn Passive Immunity

n Level of maternal immunoglobulinn RSV and influenza

n RSV monoclonal antibody: palivizumabn Immunization status

n Hib, pneumococcal, pertussis, influenza, measles

n Immune deficiencyn Inherited: Complement deficiency- pneumococcal

n X-linked Severe Combined Immune Deficiencyn Acquired: Cancer, stem cell transplantation, HIV

n Conditions affecting the lungsn Bronchopulmonary dysplasian Congenital heart diseasen Cystic Fibrosis

Number of RSV infections vs. month of birth

1 58 10

1525 25

4030

155 5

0 00 0 0 15 4 4

15

40

88

33

148

2

-10 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

Month of Birth RSV infections

Glezen, J Pediatrics , 1981

Risk Factors Related to the Pathogen

n Severity of annual epidemicsn RSV types A and Bn Influenza types: H3 more severe than H1

n Timing of concurrent respiratory epidemicsn hMPV and RSVn H1N1 influenza in 2009n PCV7 use reduced RSV hospitalization in S. Africa

n Influenzan Antiviral resistancen Mismatch with vaccine: 2003-4

Risk Factors Related to the Environment

n Household crowdingn Persons per room, number in a bed, number sleeping

in same roomn Number of children, older siblings

n Daycare attendancen Smoke exposure

n Tobacco: in utero and within householdn Biomass fuels for heat, cooking: 2X increase LRI

n Fairbanks: association between air pollution (PM 2.5) and respiratory hospitalizations. Epi bulletin; Aug 30, 2010

n Lack of in-home running water

Risk Factors Related to the Environment, continued

n Socioeconomic factorsn Parental educationn Povertyn Older paternal status

n Weather-related n Low temperaturesn Low humidity

n Wall-to-wall carpetingn Outpatient illness with hMPV, Denmark

Risk Factor Studies in Alaska

n RF for Severe RSV among AN Childrenn Bulkow, et al. Pediatrics, 2002

n Matched case-controln 204 Hospitalized, < 3 y.o. cases with ARI and +RSVn 338 Controls age- and village-matched

n Independent Risk Factors, < 6 month oldsn Medically high risk, OR 4n Breastfeeding, OR 0.33n 4 or more children in HH, OR 3n HH crowding (≥ 2 per room), OR 2

Risk Factor Studies in Alaska, II

n Respiratory Virus Studyn Singleton, J Medical Virology, 2010 and unpublished

n Case control studyn Hospitalized, < 3 y.o., 2006 – 07, SW Alaska n Controls: Age and region matchedn 128 cases, 186 controls

n PCR swab for viruses: RSV, Influenza, Paraflu, Adeno, Coronavirus, Rhino, hMPV

n Independent risk factorsn Medically high risk, woodstove, bottle fed, vomiting during feedsn Protective: 2 or more rooms with sinks in homen Not breastfeeding, smoking although both showed a trend

Respiratory Virus Study:

Hospitalized cases, Year 2

0

5

10

15

20

25

30

35

40

45

Oct Nov Dec Jan Feb Mar Apr May June

Num

ber

of c

ases

RSVhMPVParaFluFluPertussisCoronaTotal tested

| 2006 | 2007 |

Year 2

Risk Factor Studies in Alaska, III

n Lack of Piped Water Assoc. with LRTIn Gessner, J Pediatrics, 2008

n Community-level analysis, 1998 - 2003n Children < 2 enrolled in Medicaid, 108 communitiesn Regression of LRTI vs. water service

n Controlled for HH crowding, unemployment, education, tobacco, wood stove, poverty

n Water service associated with inpatient and outpatient LRTIn Outpatient: < HS education, prenatal tobaccon Inpatient: < HS education, prenatal tobacco

LRI Incidence Among Alaska Children < 2 years old, Enrolled in Medicaid 1998-

2003

Community in-home water service

Inci

denc

e p

er 1

00 c

hild

-yea

rs

Risk Factor Studies in Alaska, IV

n In-home water service & risk of infectionsn Hennessy, AJPH, 2008

n “Ecologic” study of admin & research datan Rural Alaska Housing and Sanitation Indexn I.H.S. ICD9 hospitalization data, Surveillance,

Outbreaks

n Demonstrated a relationship between lack of in-home water and respiratory infectionn Skin infection, but not Gastrointestinal

18

Proportion of US homes with complete plumbing

0102030405060708090

100

1940 1950 1960 1970 1980 1990 2000

USAlaskaDistrict of ColumbiaMississippiRural Alaska Native

19

Hospitalization Rates for “High” and “Low” Water Service Regions, Alaska,

2000-2004

0

50

100

150

200

250

Diarrhea

Pneumonia

RSVSkin Infections

MRSA

Low ServiceHigh Service* *

*

*

* P < 0.05

Rat

e pe

r 10,

000

20

Hospitalization rates for Alaska Native infants, according to percent of homes with water service

1999 - 2004*

050

100150200

250300350400

Lower Resp.Tract Infection

Pneumonia Resp. SyncytialVirus

< 10%10 - 79%>= 80%TownAll ANAll USR

ate

per

1,00

0 bi

rths

* Hennessy, AJPH, 2008

21

Serious infections with Streptococcus pneumoniae in children < 5 years old,

Southwest Alaska, 2001-2007

0

50

100

150

200

250

300

350

400

450

< 10%10 - 79%>= 80%US, overallR

ate

per

100,

000 Water Service

* J Wenger, 2010 Peds Infect Dis J.

Risk Factors for ARI in Greenlandic Children

n Inuit living in Greenlandn Koch, Am J Epi, 2003

n Cohort study 288 children, 1996 - 1998n 2 year follow-upn Weekly follow-up, illness episodes monitored

n NP swabs taken

n Risk Factors for LRTIn Males, RR 1.5n Day care center attendance, RR 3.3, PAR 48%n Passive smoking, RR 2, PAR 47%n Sharing a bedroom with children 0 – 5 y.o.. RR 2.0n Breastfeeding protective

Risk Factors for Hospitalization for LRTI in Canadian Inuit Children

n Banerji, Ped Infectious Disease J, 2009n Case control study, Nunavut

n 101 Children < 2, hospitalized in Iqaluitn RSV 39%, No virus: 27%

n Age matched controls

n Risk factorsn Not breastfed OR 3.6n Smoking during pregnancy, OR 4n Rural residency, OR 2.7n Crowding (> 5 people per home), OR 2.5n Inuit race, OR 3.7

Person

Pathogen Environment

Males, Gestational age < 36 weeksLow birthweightAge at time of epidemicNutrition

Breastfeeding protectiveRaceImmunityImmune deficiencyConditions affecting the lungs

Severity of annual epidemicsTiming of concurrent respiratory epidemicsAntiviral resistanceMismatch with vaccine:

Household crowdingDaycare attendanceSocioeconomic factors

Education, povertyWeather-related Smoke exposure

Tobacco: in utero and within householdBiomass fuels for heat, cookingLack of in-home running water

How can we use Personal risk factors to reduce illness?

Personal Risk Factorsn Males, Racen < 36 weeks gestation,

Low birthweightn Age at time of epidemicn Nutritionn Immunity

n Immune deficiencyn Conditions affecting the

lungs

Responsen Nonen Prenatal care, smoking

cessationn Birth planningn Breastfeedingn Maternal & childhood

Imm., palivizumabn Diagnosis and caren Prevent preterm birth,

diagnosis and care

How can we use Pathogen risk factors to reduce illness?Pathogen Risk Factorsn Severity of annual

epidemics

n Timing of concurrent respiratory epidemics

n Antiviral resistance

n Mismatch with flu vaccine

Responsen Surveillance and

reporting, timing of palivizumab use

n Use available immunizations

n Monitor resistance, use antivirals appropriately

n Good virologicsurveillance

How can we use Environmental risk factors to reduce illness?

Environmental Factorsn Household crowding

n Daycare attendance

n Smoke exposure

n Lack of in-home water

Responsen Increase house size,

reduce family sizen Infection control

practices, delay entry until after 6 months, longer paid parental leave

n Stop in utero and infant tobacco exposure

n Upgrade wood stoves

n Running water in every home

What about the Risk Factors for the Risk Factors?

n Low education level, poverty, poor housing, lack of running water, smoking prevalence, low birthweight are all linked

n “Social Determinants of Health”n Address the conditions that lead to

behaviors or situations that result in poor health status.

What else is needed?

n Make sure providers are informed about risk factors, prevention, surveillance and management

n What are the best ways to use this information for parental education and action?

What else is needed?

n Use public policy to help prevent infectionsn Smoking bans, education, taxes, cessation servicesn Health insurance to support optimal prenatal care,

prophylaxis use, immunization and care for ill childrenn Extend paid parental leaven In-home sanitation services for everyone

n Optimize use of public health data to inform public and providers about epidemics, antiviral resistance, recommendations.

Thanks to…n Arctic Investigations

Program Staffn Lisa Bulkown Dana Brudenn Debby Hurlburtn Helen Petersn Kim Boyd-Hummeln Debby Parksn Karen Rudolphn Karen Miernykn Carolynn Debylen Jay Wenger

n U of Washingtonn Jan Englund

n ANTHCn Ros Singletonn Troy Rittern Jeff Smithn Jay Butler

n State of Alaskan Brad Gessner

n CDC Atlantan Larry Andersonn Bob Holman

n YKHCn Joe Klejkan Lori Chikoyak

Disclaimer

n “The findings and conclusions in this presentation are those of the author and do not necessarily represent the views of the Centers for Disease Control and Prevention.”

References

Risk Factors for Lower Respiratory Tract Infections in Young ChildrenSlide Number 2Southwest Alaska Respiratory Virus Study: �Hospitalized cases, Year 1Definitions and Data QualitySlide Number 5Risk Factors Related to the PersonRisk Factors Related to the Person, continuedNumber of RSV infections vs. month of birthRisk Factors Related to the PathogenRisk Factors Related to the EnvironmentRisk Factors Related to the Environment, continuedRisk Factor Studies in Alaska Risk Factor Studies in Alaska, IIRespiratory Virus Study: �Hospitalized cases, Year 2Risk Factor Studies in Alaska, IIILRI Incidence Among Alaska Children < 2 years old, Enrolled in Medicaid 1998- 2003Risk Factor Studies in Alaska, IVProportion of US homes with complete plumbingHospitalization Rates for “High” and “Low” Water Service Regions, Alaska, 2000-2004Hospitalization rates for Alaska Native infants, according to percent of homes with water service� 1999 - 2004*Serious infections with Streptococcus pneumoniae in children < 5 years old,� Southwest Alaska, 2001-2007Risk Factors for ARI in Greenlandic ChildrenRisk Factors for Hospitalization for LRTI in Canadian Inuit Children�Slide Number 24How can we use Personal risk factors to reduce illness?How can we use Pathogen risk factors to reduce illness?How can we use Environmental risk factors to reduce illness?�What about the Risk Factors for the Risk Factors?What else is needed?What else is needed?Thanks to…DisclaimerReferences