Research Confirms Perinatal Risk Factors for ADHD

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(PET scan). From Zametkins et al. (1990)

A recent German study confirms that there are, in fact, perinatal risk factors associated with ADHD. A combination of low socioeconomic status and gestational diabetes mellitus or GDM are strong risk factors for ADHD.

Perinatal health problems, atopic eczema, and smoking during pregnancy all raise the risk of a child developing ADHD. On the other hand, the study shows breastfeeding seems to protect against ADHD no matter what the duration.

Results from Queens College City University of New York Study

A study published earlier this year by Yoko Nomura, PhD, MPH, from the Department of Psychology, Queens College, City University of New York, and colleagues. This study included 212 children who were of preschool age, and of low socioeconomic status, and whose mother had gestational diabetes mellitus, which together increased the risk of the child having ADHD.

Results from Technical University Dresden Study – The German Study

On September 10, 2012, the study was published online in The Archives of Pediatrics and Adolescent Medicine.[1]

These latest findings from Dr. Schmitt and Dr. Romanos repeat the findings in a large nationwide representative sample of children ranging in age from 3- to 17  who participated in the German Health Interview and Examination Survey for Children and Adolescents (n = 13,488).

The outcome of interest was childhood ADHD, and the primary exposures of interest were self-reported physician-diagnosed GDM (absent or present) and SES, classified as low, medium, or high on the basis of parental education, professional qualification, professional status, and family income. Age, sex, and a broad set of environmental exposures in the prenatal and perinatal period and in infancy as competing risk factors in multivariate analysis were also considered.

The study involved a total of 660 children (4.9%) had ADHD; the prevalence of GDM and low SES was 2.3% (n = 280) and 25.5% (n = 3420), respectively.

Their findings confirm those of Dr. Nomura and colleagues by showing an association between low socioeconomic status, maternal gestational diabetes mellitus, and ADHD.  The researchers say their study also confirms breastfeeding may have protective effects on childhood ADHD, which confirms what the earlier study said.

“Modification of these environmental risk factors by evidence-based prevention programs may help to decrease the burden of ADHD,” write co-investigators Jochen Schmitt, MD, MPH, of Technical University Dresden, and Marcel Romanos, MD, from the University Hospital of Würzburg, in Germany.

What Dr. Nomura has to Say

Dr. Nomura told Medscape Medical News, “Being able to duplicate our findings in a different sample and a much larger sample is important. I’m not sure if most doctors know that GDM is a risk factor for ADHD; biological and environmental risk factors for ADHD is a fairly new scientific field.”

“ADHD is a highly hereditary illness, but it’s not only hereditary; we are beginning to gather information about environmental or biological causes and beginning to focus on perinatal risk factors for ADHD,” said Dr. Nomura.

“The fetus is a captive audience,” she noted, “and it seems like in utero exposure to a variety of things like excessive insulin, smoking, plastic materials, food dyes, toxic chemicals may cause epigenetic changes in brain development that may show up later in life.”

Conclusion

If parents to be were to take anything away from this study, it would seem that just as we’ve suspected, the fetus is at risk from exposure to all of the toxic components invetro, just as adults are. This would indicate that pregnant women should try to avoid as many toxins as possible – this would include those toxins that are obvious but also those toxins that are more difficult to recognize.

While the study clearly shows a link between lower socioeconomic status and gestational diabetes, along with the hereditary factor, it would appear that the ADHD issue goes a lot deeper than that. In fact, one might begin to question whether it is truly a hereditary factor or more so related to a lifestyle factor, in that many areas of lifestyle are passed from parent to child, and then the cycle repeats itself.

There is also the concern of environmental toxins that are for the most part out of a pregnant womans power to control. These toxins could be related to where one lives such as big city where environmental toxins would be significantly higher than in a small village. There are also questions about exposure to industry, plants, etc.

What does become apparent is while we continue to learn more about ADHD more and more questions arise and it seems we are still a ways away from having the answers.

Sources:
1) Arch Pediatr Adolesc Med. Published online September 10, 2012. Abstract