, according to a cross-sectional study.
Philip A. May, PhD, of the University of North Carolina, Gillings School of Global Public Health, and his coauthors assessed 6,639 first-grade children from four communities in the Rocky Mountain, Midwestern, Southeastern, and Pacific Southwestern regions of the United States.
In their report, published Feb. 6 in JAMA, they identified 222 cases of fetal alcohol spectrum disorders, representing conservative prevalence estimates ranging from 11.3 to 50 cases per 1,000 children ().
Of these children, 27 met the criteria for fetal alcohol syndrome, 104 met the criteria for partial fetal alcohol syndrome, and 91 met the criteria for alcohol-related neurodevelopmental disorder.
“These prevalence estimates are consistent with mounting evidence that harmful fetal alcohol exposure is common in the United States today and highlight the public health burden due to fetal alcohol spectrum disorders,” the authors wrote.
The finding was much higher than previous estimates of the prevalence of fetal alcohol spectrum disorders in the United States. The authors pointed out that routine surveillance methods may have previously underestimated the prevalence because so many children are either misdiagnosed or not diagnosed at all. But even two previous single-site, active-case ascertainment studies conducted in the United States found prevalence rates of 10 and 24 per 1,000 children.
“This consortium study, to our knowledge, was the first to apply active case ascertainment, common methodology, a single classification system, and expert in-person evaluation for a continuum of fetal alcohol spectrum disorders including alcohol-related neurodevelopmental disorder to a large number of children from communities across the United States,” the authors wrote. “These data have highlighted the need for a larger study with broader representation of U.S. communities with general population samples.”
Only 2 of the 222 children had actually been previously diagnosed with a fetal alcohol spectrum disorder, “although many parents and guardians were aware of the learning and behavioral challenges facing their children,” the researchers noted.
“These data confirm that missed diagnoses and misdiagnoses of children are common,” the authors wrote, pointing to a previous study in U.S. schoolchildren that found only one in seven children identified as having fetal alcohol syndrome had been previously diagnosed.
The assessment of fetal alcohol spectrum disorder was based on four domains: growth, dysmorphology, neurodevelopment, and prenatal alcohol exposure – the latter being assessed by interviewing the mother in person or by telephone.
The lowest prevalence – 11.3 per 1,000 children – was seen in the Midwestern community, while the highest – 50 per 1,000 – was in the Rocky Mountain community.
The main weakness of the study was that no individual sample included the entire eligible population because of differing policies on access to children for recruitment and variability in willingness to consent.
“Consent rates for screening ranged from 36.9% to 92.5% in individual samples and overall consent rates for screening averaged only 59.9% of eligible children,” the authors wrote. “If nonconsented children differed from consented, this could have biased prevalence estimates in either direction.”
The researchers acknowledged that the absence of a definitive biomarker for fetal alcohol spectrum disorder meant it was impossible to know for certain that the observed deficits were actually the result of fetal alcohol exposure, and that the prevalence estimates may therefore be overestimated.
The study was funded by grants from the National Institute on Alcohol Abuse and Alcoholism. One author declared grant support from the National Institute on Alcohol Abuse and Alcoholism and personal fees and honorarium from the Alcohol Center. No conflicts of interest were declared.
SOURCE: May, P et al. JAMA 2018;319:474-82. .