Fetal Alcohol Disorder Rates Far Higher Than Earlier Estimates

Deborah Brauser

February 07, 2018

There is a significantly greater number of children in the United States with fetal alcohol spectrum disorder (FASD) than previously estimated, new research suggests.

The observational study, which was funded by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), included more than 6600 first-graders from four US regions. It found that "conservative prevalence estimates" for FASD ranged from 11 to 50 per 1000 children — which is much greater than previous reports, which estimated FASD prevalence at 10 per 1000 children.

In addition, weighted prevalence estimates in the new study were even higher, at 31 to almost 99 per 1000 children.

"These results don't surprise me at all because we've known from previous work and our own experience that many children are not being recognized as having fetal alcohol spectrum disorders — or are being misdiagnosed with something else," co–lead investigator Christina D. Chambers, PhD, professor of pediatrics at the University of California, San Diego, in La Jolla, told Medscape Medical News.

Dr Christina Chambers

She noted that the take-away message for clinicians is to recognize that this is not a rare event.

"The new estimates are in the ballpark of, at a minimum, 1% to 5%. So in terms of the public health agenda, coming up with a national strategy for prevention, intervention, and treatment is important," said Dr Chambers.

The findings were published online February 6 the Journal of the American Medical Association.

Missed Diagnoses

FASD includes fetal alcohol syndrome as well as partial fetal alcohol syndrome and alcohol-related neurodevelopmental disorder.

"The commonly accepted [FASD] estimate for the United States of 10 per 1000 children affected was derived from clinic-based studies or studies of single communities using small samples and different research methods," write the investigators.

In addition, a study published in Pediatrics in 2015 found that the rate of missed diagnoses of FASD was 80.1%. Together, this "may have led to underestimates" of prevalence rates, the current researchers suggest.

Because "passive surveillance methods in the past...have led to results that are unlikely to be very accurate," the current investigators wanted to conduct an active case-ascertainment study, said Dr Chambers.

"This means actively going out and sampling the population, and having expert diagnosticians actually see these kids and do an evaluation."

The study's four participating communities were classified as Midwest sites, Southeast sites, Pacific Southwest sites, and Rocky Mountain sites.

"Even though it's only four regions, we think this gives a closer-to-the-truth estimate of prevalence. It gives us a much better handle from a public health perspective of how common of a condition this is," Dr Chambers explained.

Between 2010 and 2016, a total of 13,146 children enrolled in first-grade classes. Of these, 6639 (52% boys; mean age, 6.7 years) were selected for assessment.

All were examined for FASD through four domains: prenatal alcohol exposure (determined through maternal interviews), physical growth, neurobehavioral development, and dysmorphic features. FASD prevalence was the primary outcome measure.

As Common as Autism?

Results showed that there were 222 cases of FASD among all participants. This contributed to a prevalence estimate that ranged from a low of 11.3 (95% confidence interval [CI], 7.8 - 15.8) per 1000 children for one Midwest sample to a high of 50.0 (95% CI, 39.9 - 61.7) per 1000 children for one Rocky Mountain sample.

In comparison, the Centers for Disease Control and Prevention released a report in 2012 that estimated that the prevalence of autism spectrum disorders in 8-year-olds in the United States was 14.6 per 1000 children.

Among the 222 FASD cases, the most common subdisorder was partial fetal alcohol syndrome (n = 104), followed by alcohol-related neurodevelopmental disorder (n = 91). Interestingly, only two of these children had received a diagnosis of fetal alcohol-related disorder previously.

The investigators also estimated weighted prevalence rates, "accounting for the sampling schemes and using data restricted to children who received a full evaluation."

These estimates for FASD ranged from 31.1 (95% CI, 16.1 - 54.0) per 1000 children to 98.5 (95% CI, 57.5 - 139.5) per 1000.

Weighted prevalence estimates for subcategories of FASD ranged as follows:

  • 0 to 7.8 per 1000 for fetal alcohol syndrome,

  • 9.7 to 50.4 per 1000 for alcohol-related neurodevelopment disorder, and

  • 8.4 to 59.1 per 1000 for partial fetal alcohol syndrome.

Public Health Problem

"These findings may represent more accurate US prevalence estimates than previous studies, but may not be generalizable to all communities," write the investigators.

Still, the results "confirm that FASD is a significant public health problem, and strategies to expand screening, diagnosis, prevention, and treatment are needed to address it," George F. Koob, PhD, director of the NIAAA, said in a press release.

The investigators "talked to some general pediatricians who said they've never seen a case of fetal alcohol syndrome, and we think that's probably not true," noted Dr Chambers.

"We think they have seen kids with this disorder, but it didn't occur to them that this is what it might be," she said. "It's important from the clinician's standpoint to think of this as a possibility and to understand that this is a group of disorders that is as common or more common than autism spectrum disorders."

She added that when it comes to counseling women who are pregnant or are planning to become pregnant, "the surgeon general's recommendation to avoid alcohol entirely in pregnancy is the most prudent approach."

The researchers are now planning to investigate the general characteristics of the study participants, including neurobehavioral profiles, as well as the mothers to see whether there are factors, such as maternal nutrition, that make some babies more susceptible to FASD than others.

"Substantial Implications"

In an accompanying editorial, Shannon Lange, MPH, Center for Addiction and Mental Health in Toronto, Ontario, Canada, and colleagues note that the new estimates "are up to 10 times higher than those previously reported using similar methods from 2 single-site studies, and up to 5 times higher than a recent meta-analysis of 6 studies from the United States with a pooled prevalence of 2%."

This finding that FASD is not a rare condition "has substantial implications for clinicians and researchers," they add.

These include the need for additional support for affected children and adults, better surveillance systems (such as establishing a national and international FASD system), and improved prevention efforts.

As for the problem of many cases being missed or misdiagnosed, "a universal diagnostic approach needs to be accepted or developed. Ideally, novel and reliable biomarkers for detecting fetal alcohol effects will be identified."

In addition, better education is needed about the consequences to the fetus of drinking while pregnant; and primary care clinicians "should routinely include appropriate screening for alcohol use among all women of childbearing age," the editorialists write.

"As suggested by the American Academy of Pediatrics, the message...should be clear and consistent: there is no safe amount, time, or type of alcohol to drink during pregnancy or when trying to get pregnant."

The study was funded by grants from the NIAAA. Dr Chambers, the editorialists, and all but one of the other study authors report no relevant financial relationships. The remaining study author has received grant support from the NIAAA and personal fees and honorarium from the Alcohol Center.

JAMA. Published online February 6, 2018. Abstract, Editorial

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