Risk of Autism and Birth Certificate Data:

A Utah Population Based Study

Robert Satterfield1, EpidemiologistJudith P. Zimmerman2, Ph.D.

Shaheen Hossain1, Ph.D. Lynne M. MacLeod1, M.Stat.

Judith Miller2, Ph.D.William McMahon2, MD.

1 Utah Department of Health2 Utah Registry of Autism and Developmental Disabilities

Background

Autism and Developmental Disabilities Monitoring Network (ADDM)

Utah Registry of Autism and Developmental Disabilities (URADD)

Special project to study how many individuals with ASDs and developmental disabilities there are in Utah

Public awareness campaign

Self-reporting registry

Background: Autism and Developmental Disabilities Monitoring Network (ADDM)

Background: Impact of ASD

Frequency: Recent increases Severity: Lifelong impairment Identified in all races, ethnic groups, social classes Costs: Significant – $90 billion in 2000* Preventability: Unknown cause but genetics

implicated; other exposures have been blamed Environmental contaminants Vaccines

*Jarbrink K, Knapp M, 2001 London School of Economics, 2001

Other Autism Studies

Male / female ratio varies from 1.33 to 16.0 with a median ratio of 2.55 (mean 3.7)

Cognitive impairment in classic autism – ~80% Less in PDD-NOS Not associated with Aspergers

Seizures: range 4.8-26.4% with a median rate of 16.7%

2006 Israeli study suggests offspring of men 40 years or older were 5.75 times more likely to have ASD

Fombonne, 1999Reichenberg, et. al. 2006

Changing Prevalence

Numerous studies with different methodologies

Pre-1985: 2 cases per 10,000 for classic autism; 4-5 cases per 10,000 for all ASDs

Post-1985: 20-40 cases per 10,000 for classic autism; 34-67 cases per 10,000 for all ASDs

2005: NHIS Autism Estimates 5.7 per 1000

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Chronological Autism Studies from 1966 - 2003

Adapted from Fombonne, 2001

Utah School Autism Exceptionality Prevalence Data: 1996-2005

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1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

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Purpose

To determine the prevalence of ASDs and also to identify potential risk factors related to ASDs

Study Question

Is there an association between certain maternal pregnancy / delivery complications and the risk of autism?

Utah Demographics

Population: 2,358,330

Growth Rate: 7th (1.6% from 2003-04)

Fertility Rate: 1st (2.56 births)

Household Size: 1st (3.13 persons)

Age of Population: 1st (youngest, 27.5 years)

*Pupil/Teacher Ratio: 22.4 (U.S. average 15.9)Governor’s Office of Planning and Budget, *2005 National Center for Education Statistics, 2006

Study Demographics

Utah’s 2002 study year population

Born in 1994

Lived in Davis, Salt Lake, and/or Utah Counties in 2002

Received special education and/or diagnoses associated with ASD and/or cognitive impairment before 12/31/02

Demographics

Number Percentage

State of Utah 38,751

Males 19,991

Females 18,760

100.0%

51.6%

48.4%

Study Area 26,108

Males 13,464

Females 12,644

67.6%

51.6%

48.4%

Salt Lake 14,856 38.3%

Davis 4,423 11.4%

Utah 6,829 17.6%

Methodology

Utah birth certificate and URADD data were used for this study

Data were linked using SAS version 9, with a deterministic followed by probabilistic approach

Performed multivariate logistic analysis

Results

Characteristics Autism Cases Birth Cohort(n=114) (n=26,830)

Male 82.5%** 51.7%

Female 17.5%** 48.3%

Avg. Birth Weight (grams) 3192* 3338

Prenatal Care in 1st trimester 92.0% 86.3%

Avg. Prenatal Care Visits 11.4 10.9

* Significant at <.05** Significant at <.001

Results

Risk Factors Adjusted OR* Confidence Intervals

Breech 2.39 (1.24 - 4.63)

Primary C-Section 1.96 (1.15 - 3.34)

Assisted Ventilation <30 0.36 (0.05 - 2.60)

Assisted Ventilation >30 3.67 (1.42 - 9.48)

* Model controlled for multiple gestations, tobacco use during pregnancy, gestational age, maternal age, maternal education, maternal marital status, and parity

Method of Delivery

MOD Autism Cases % Birth Cohort %

Vaginal 67.5** 80.8

Primary C-Section 20.2** 9.2

Repeat C-Section 5.3* 6.9

VBAC 7.0* 3.0

* Significant at <.05** Significant at <.001

Maternal Characteristics

Characteristics Autism Cases Birth Cohort

Maternal Age (years) 27.2 26.6

Maternal Education (years) 13.8 13.3

Hispanic Origin 4.4% 7.0%

Paternal Characteristics

Characteristics Autism Cases Birth Cohort

Paternal Age (years) 29.3 29.2

Paternal Education (years) 14.2 14.0

Hispanic Origin 4.5% 6.5%

Conclusions

The study found a nearly 5 to 1 autism occurrence in males vs. females (82.5% p < .0001)

Autism cases had significantly higher histories of breech presentation (AOR=2.39 CI 1.24 – 4.63)

Autism cases had significantly higher occurrences of Primary C-section (AOR=1.96 CI 1.15 – 3.34)

Conclusions

Significant differences were found in average birth weight for children with autism compared to the general birth cohort (3192 grams verses 3338 grams, p <.005)

Autism cases had significantly higher occurrences of Assisted ventilation > 30 minutes (AOR=3.67 CI 1.42 – 9.48)

Analyses showed no statistically significant association between risk of autism and parity, number of PNC visit and entry into prenatal care

Implications

Invaluable use of multi-sourced linked data Early identification of risk factors related to

autism may facilitate early intervention and treatment and can significantly improve a child’s development

The recent rise in medial attention on causes of autism, clearly deserve more resources and investigation into these areas

Future direction, Merging with: Hospital Discharge, prescription medication database, Medicaid data

Acknowledgement

Centers for Disease Control and Prevention (funded by Cooperative Agreement UR3/CCU822365)

Utah State Office of Education Alpine, Davis, Jordan, Granite, Murray, Nebo, Provo, & Salt Lake

School Districts Utah School for Deaf and Blind University of Utah Hospital and Clinics Intermountain Health Care Valley Mental Health & Carmen B. Pingree School of Autism Wasatch Mental Health & GIANT Steps Autism Program Davis Mental Health & Northern Utah Autism Program The Children’s Center Utah Attorney General’s Office Local Health Departments Utah Department of Health, Office of Vital Records and Statistics

Questions?

Thank You!

Contact Information:

Robert Satterfield, Epidemiologist II

UDOH / CFHS / MCH / DRP

(801) 538-6967

rsatterfield@utah.gov