Slide 1
Pregnancy risk factors and birth outcomes within Oregon's American Indian/Alaska Native population, 2008-2010
Suzanne Zane
MCH Epidemiologist
Northwest Tribal EpiCenter
Improving Data & Enhancing Access (IDEA-NW) Project
Logo Northwest Portland Area Indian Health Board, Indian Leadership for Indian Health
Presented at:
Oregon Public Health Association
Corvallis, OR Oct. 8, 2012
Slide 2
Outline
- Background
- MCH data
- IDEA-NW Project (linkage)
- Race coding on birth certificates
- Oregon's AI/AN population
- Methods
- Results
- Conclusions
- Next steps & recommendations
Slide 3
Background
- American Indians/Alaska Natives (AI/AN) at higher risk for many health conditions and indicators, including obesity, diabetes, preterm birth, smoking, domestic violence, injury
- Infant mortality rates (IMR) for AI/AN in Pacific Northwest lower than for AI/AN people in rest of U.S.; however, the IMR remains twice that for white infants
- Limited MCH data available to tribes and Indian health programs; race-specific data rarely published due to small numbers
Slide 4
IDEA-NW Project
- Racial misclassification a well-documented problem for AI/AN in surveillance systems
- Our Northwest Tribal Registry (NTR) consists largely of the Portland Area Indian Health Service registration file
- All AI/AN registered at an IHS or tribal clinic (RPMS) in Idaho, Oregon, or Washington; documentation of tribal enrollment status required for eligibility
- Demographic data only, no health status or diagnostic info
- Comparing this list of known AI/ANs to other health data sources can improve ascertainment of AI/AN records and therefore increase accuracy of health status data
- Linkages routinely completed with cancer, death certificates, communicable disease/STI, and other registries to identify and correct racial misclassification
- This is the first linkage between NTR and birth certificates
Slide 5
Race coding on birth certificates
- Race of baby assigned by maternal race
- Self-reported (always?)
- Collected by...
- Multiple race responses allowed
- Tribal affiliation write-in
- Father's race also collected
- Does racial "misclassification" happen on birth certificates?
- From a service standpoint, baby with AI/AN mother or father who uses IHS/tribal clinical services is likely to become an IHS/tribal patient
Slide 6
Oregon AI/AN population
- 9 federally-recognized Tribes
- Census estimate: 81,786
- Includes 18,209 women ages 15-44
- 8 of 9 tribes have clinics, plus Chemawa IHS clinic
- Limited prenatal & OB services
- Some tribal WIC programs
Map showing where Oregon tribes reside, the largest areas marked are for Warm Springs and Umatilla.
Slide 7
Methods — linkage & analysis
- Probabilistic linkage on mothers' identifiers (name, DOB, address, etc.)
- CDC's Link Plus software
- Examined race & tribal affiliation fields in combination with match results
- De-identified data retained for analysis
- AI/AN births: those with...
- Any mention of AI/AN race for mother, and/or
- Any mention of AI/AN race for father, and/or
- Match of mother to the Tribal Registry
- Comparison population: birth records for Non-Hispanic white mothers (single race)
- Rate calculations: AI/AN mothers or Tribal Registry match (numerator), NCHS bridged-race pop estimates (denominator)
Slide 8
Results - race classification
2008-2010 births
- Pre-linkage (mother and/or father race): 6,654 AI/ANs
- Linkage
- 1,837 matches between Tribal Registry and mothers' identifiers
- 402 (22%) were coded on birth certificate as non-AI/AN mothers
- Post-linkage: 7,035 AI/AN in analysis
- Including matches: 9.7% increase above mother's race on birth certificate alone
- Overall, AI/AN births comprised 4.9% of file, as compared to Non-Hispanic white mothers, single race (66.0%)
Slide 9
Demographics
AI/AN births
- Mean maternal age = 25.8
- 55% unmarried
- 22% less than 12th grade education
- 57% Medicaid/OHP
- 58% WIC use
- 1.1% pre-pregnancy diabetes
Graphic picture of pregnant woman
Slide 10
Maternal risk factors
Bar chart. Percentage of births. Overweight or obese (B M I > 25): A I A N 54.1, white 45.5. Pre-pregnancy diabetes: A I A N 1.1, white 0.7. Gestational diabetes: A I A N 5.5, white 4.5. Pre-pregnancy hypertension: A I A N 1.5, white 1.5. Gestational hypertension: A I A N 6.4, white 5.3.
Slide 11
Maternal risk factors
Bar chart. Percentage of births. Any tobacco use: A I A N 25.3, non-Hispanic white 16.2. Any alcohol use: A I A N 1.2, non-Hispanic white 0.6. Any S T Ds present/treated: A I A N 7.3, non-Hispanic white 5.0.
Slide 12
Pregnancy care
Stacked bar chart. Percentage distribution of trimester in which mother entered prenatal care. AI/AN: first 75.3, second 19.3, third 3.5, no PNC 1.9. Non-Hispanic white: first 82.6, second 13.4, third 2.5, no PNC 1.5.
Slide 13
Pregnancy care
Stacked bar chart. Percentage distribution on Kotelchuck PNC index. AI/AN: intensive 28.3, adequate 43.2, intermediate 11.5, inadequate 14.5, No PNC 2.5. Non-Hispanic white: intensive 28.3, adequate 48.2, intermediate 11.5, inadequate 9.4, No PNC 2.6.
Slide 14
Pregnancy care
Slide 15
Pregnancy care
Line chart. Percentage of moms reporting any smoking by trimester. AI/AN: 3 months of pregnancy 24.3, first trimester 20.3, second trimester 17.5, third trimester 16.7. These values show a 31.4% decrease. Non-Hispanic white: 3 months of pregnancy 15.7, first trimester 13.3, second trimester 11.5, third trimester 11.1. These values show a 29.8% decrease.
Slide 16
Birth outcomes
| |
AI/AN |
NHW |
| Gestational age |
| Early preterm (<34 wks) |
2.6% |
2.0% |
| Preterm (34 to <37 wks) |
6.9% |
5.8% |
| Term (>=37 wks) |
90.4% |
92.1% |
| Method of delivery |
| Vaginal |
69.6% |
70.9% |
| Cesarean |
30.4% |
29.1% |
| Birth weight |
| Very low (<1500 g) |
1.3% |
1.0% |
| Low (1500 - <2500 g) |
5.9% |
5.1% |
| Normal (2500 - <4500g) |
91.2% |
92.3% |
| High (>4500 g) |
1.7% |
1.6% |
Slide 17
Birth outcomes
- NICU admission
- Breastfeeding at discharge
(>12% unknown/missing data)
Slide 18
Highlights/ Conclusions
- Birth/fertility rates 2-3 times higher
- Greatest disparity among 15-17 year olds: fertility rate almost 5x higher than NHW
- AI/ANs have elevated prevalence of pregnancy risk factors
- Birth outcomes (those that we looked at) not vastly different than NHW
- AI/ANs doing somewhat better than NHW on HIV screening and smoking reduction
- IHS/Tribal initiatives, GPRA
- PRAMS comparison?
Slide 19
Next steps & Recommendations
- Future planned analyses
- MCH strategic plan
- Focus on teen moms
- Prenatal care
- Prevention efforts: WeRNative, PRT, etc.
- Consider using dads' race data for service-based analyses
Slide 20
Limitations
- Our selection of AI/AN cases not standard (including linked records and dads' race info) - not comparable with other data
- NTR doesn't cover entire Oregon AI/AN population
- Urban population under-represented
Slide 21
Acknowledgments
- Coauthors
- Megan Hoopes, Jenine Dankovchik, Meena Patil, and Victoria Warren-Mears
- Center for Health Statistics, Oregon Health Authority
- Joyce Grant-Worley
- Sarah Hargand
- Alicia Parkman
- Ken Rosenberg
- Board babies and mamas
Slide 22
Contact information
Suzanne Zane
503-416-3293
szane@npaihb.org
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