Low dose prenatal alcohol
exposure linked to behavior problems
Prenatal Alcohol Exposure
and Childhood Behavior at Age 6 to 7 Years: I.
Dose-Response Effect
The study is a significant
one. Take note:
Maternal alcohol consumption
even at low levels was adversely related to child behavior; a dose-response
relationship was also identified. The effect was observed at average
levels of exposure of as low as 1 drink per week.
Here is the abstract:
PEDIATRICS Vol. 108
No. 2 August 2001, p. e34
Beena Sood*, Virginia
Delaney-Black*, Chandice Covington, Beth Nordstrom-Klee*, Joel Ager§,
Thomas Templin, James Janisse§, Susan Martier, and Robert J. Sokol
. From the * Department of Pediatrics, School of Medicine, College
of Nursing, § Center for Healthcare Effectiveness Research, School
of Medicine, and Department of Obstetrics and Gynecology, School
of Medicine, Wayne State University, Detroit, Michigan.
Objective. Moderate
to heavy levels of prenatal alcohol exposure have been associated
with alterations in child behavior, but limited data are available
on adverse effects after low levels of exposure. The objective of
this study was to evaluate the dose-response effect of prenatal
alcohol exposure for adverse child behavior outcomes at 6 to 7 years
of age.
Methods. Beginning
in 1986, women attending the urban university-based maternity clinic
were routinely screened at their first prenatal visit for alcohol
and drug use by trained research assistants from the Fetal Alcohol
Research Center. All women reporting alcohol consumption at conception
of at least 0.5 oz absolute alcohol/day and a 5% random sample of
lower level drinkers and abstainers were invited to participate
to be able to identify the associations between alcohol intake and
child development. Maternal alcohol, cigarette, and illicit drug
use were prospectively assessed during pregnancy and postnatally.
The independent variable in this study, prenatal alcohol exposure,
was computed as the average absolute alcohol intake (oz) per day
across pregnancy. At each prenatal visit, mothers were interviewed
about alcohol use during the previous 2 weeks. Quantities and types
of alcohol consumed were converted to fluid ounces of absolute alcohol
and averaged across visits to generate a summary measure of alcohol
exposure throughout pregnancy. Alcohol was initially used as a dichotomous
variable comparing children with no prenatal alcohol exposure to
children with any exposure. To evaluate the effects of different
levels of exposure, the average absolute alcohol intake was relatively
arbitrarily categorized into no, low (>0 but <0.3 fl oz of
absolute alcohol/day), and moderate/heavy (0.3 fl oz of absolute
alcohol/day) for the purpose of this study. Six years later, 665
families were contacted. Ninety-four percent agreed to testing.
Exclusions included children who missed multiple test appointments,
had major congenital malformations (other than fetal alcohol syndrome),
possessed an IQ >2 standard deviations from the sample mean,
or had incomplete data. The Achenbach Child Behavior Checklist (CBCL)
was used to assess child behavior. The CBCL is a parent questionnaire
applicable to children ages 4 to 16 years. It is widely used in
the clinical assessment of children’s behavior problems and has
been extensively used in research. Eight syndrome scales are further
grouped into Externalizing or undercontrolled (Aggressive and Delinquent)
behavior and Internalizing or overcontrolled (Anxious/Depressed,
Somatic Complaints, and Withdrawn) behaviors. Three syndromes (Social,
Thought, and Attention Problems) fit neither group. Higher scores
are associated with more problem behaviors. Research assistants
who were trained and blinded to exposure status independently interviewed
the child and caretaker. Data were collected on a broad range of
control variables known to influence childhood behavior and/or to
be associated with prenatal alcohol exposure. These included perinatal
factors of maternal age, education, cigarette, cocaine, and other
substances of abuse and the gestational age of the baby. Postnatal
factors studied included maternal psychopathology, continuing alcohol
and drug use, family structure, socioeconomic status, children’s
whole blood lead level, and exposure to violence. Data were collected
only from black women as there was inadequate representation of
other racial groups.
Statistical Analyses.
Statistical analyses were performed using the SPSS statistical package.
Frequency distribution, cross-tabulation, odds ratio, and 2 tests
were used for analyzing categorical data. Continuous data were analyzed
using t tests, analyses of variance (ANOVAs) with posthoc tests,
and regression analysis.
Results. Testing
was available for 501 parent-children dyads. Almost one fourth of
the women denied alcohol use during pregnancy. Low levels of alcohol
use were reported in 63.8% and moderate/heavy use in 13% of pregnancies.
Increasing prenatal alcohol exposure was associated with lower birth
weight and gestational age, higher lead levels, higher maternal
age, and lower education level, prenatal exposure to cocaine and
smoking, custody changes, lower socioeconomic status, and paternal
drinking and drug use at the time of pregnancy. Children with any
prenatal alcohol exposure were more likely to have higher CBCL scores
on Externalizing (Aggressive and Delinquent) and Internalizing (Anxious/Depressed
and Withdrawn) syndrome scales and the Total Problem Score. The
odds ratio of scoring in the clinical range for Delinquent behavior
was 3.2 (1.3-7.6) in children with any prenatal exposure to alcohol
compared with nonexposed controls. The threshold dose was evaluated
with the 3 prenatal alcohol exposure groups. One-way ANOVA revealed
a significant between group difference for Externalizing (Aggressive
and Delinquent) and the Total Problem Score. Posthoc tests revealed
the between group differences to be significant (no and low-exposure
group) for Aggressive and Externalizing behavior suggesting that
the adverse effects of prenatal alcohol exposure on child behavior
at age 6 to 7 years are evident even at low levels of exposure.
For Delinquent and Total Problem behavior, the difference was significant
between the no and moderate-heavy exposure group, suggesting a higher
threshold for these behaviors. Prenatal alcohol exposure remained
a significant predictor of behavior after adjusting for covariates.
Although maternal psychopathology was the most important predictor
of behavior, gender was also a significant predictor, with boys
having higher scores on Externalizing (Delinquent) and Attention
Problems. The amount of variance uniquely accounted for by prenatal
alcohol exposure ranged between 0.6% to 1.7%.
Conclusions.
Maternal alcohol consumption even at low levels was adversely related
to child behavior; a dose-response relationship was also identified.
The effect was observed at average levels of exposure of as low
as 1 drink per week. Although effects on mean scores for Externalizing
and Aggressive behaviors were observed at low levels of prenatal
alcohol exposure, effects on Delinquent behavior and Total Problem
Scores were observed at moderate/heavy levels of exposure. Children
with any prenatal alcohol exposure were 3.2 times as likely to have
Delinquent behavior scores in the clinical range compared with nonexposed
children. The relationship between prenatal alcohol exposure and
adverse childhood behavior outcome persisted after controlling for
other factors associated with adverse behavioral outcomes. Clinicians
are often asked by pregnant women if small amounts of alcohol intake
are acceptable during pregnancy. These data suggest that no alcohol
during pregnancy remains the best medical advice.
Key words: Child
Behavior Checklist, child behavior, alcohol-related neurobehavioral
effects.
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