Gestational diabetes and a lower socioeconomic status are the latest environmental factors to be associated with an increased risk of attention-deficit/hyperactivity disorder (ADHD), according to new research.
The German study found that children born to mothers who developed high blood sugar during pregnancy (gestational diabetes) were almost twice as likely to have ADHD as children born to mothers without gestational diabetes. The study also found more than double the risk of ADHD for children born into a family with a low socioeconomic status compared to those in the highest socioeconomic class. Children in the middle class had almost a 60% higher rate of ADHD compared to the upper-class children.
"This study found interesting associations that have public health implications," said Dr Andrew Adesman, chief of developmental and behavioural paediatrics at the Steven and Alexandra Cohen Children's Medical Center of New York, in New Hyde Park, NY Adesman wasn't involved in the current research.
Impact of gestational diabetes
"The US is experiencing an increasing epidemic of obesity, which is a risk factor for gestational diabetes. We need to be mindful of the broader implications of these unfortunate trends. They won't just have an impact on the mother's health, but can also affect the offspring," Adesman said.
The good news from this study is they found that breast-feeding appeared to be protective. Children who were breast-fed were almost 20% less likely to develop ADHD, according to the study.
Results of the study were published online as a research letter in the Archives of Pediatrics & Adolescent Medicine.
In the United States, more than 5 million children between three and 17 years of age have been diagnosed with ADHD, a neurobiological condition that often persists into adulthood. ADHD is characterised by difficulty focusing on tasks and controlling behaviour, unusual restlessness and impulsiveness.
The authors of the new study noted they had seen a US study suggesting that gestational diabetes and socioeconomic status might be linked to ADHD. So, they reviewed health information from a national German database and focused on more than 13 000 children and teens from three years to 17 years old.
Of that group, nearly 5% had an ADHD diagnosis.
Smoking ups risk by 50%
In addition to the gestational diabetes and socioeconomic status findings, the researchers found a number of factors associated with the development of ADHD. Boys were more than four times as likely to develop the condition as girls were, according to the study.
Maternal smoking was associated with a nearly 50% increased risk of ADHD in the child. Perinatal health problems (such as birth defects, preterm birth and low birthweight) increased the risk of a child developing ADHD by 69%, according to the study. Researchers also found that having the allergic skin condition eczema was associated with a 62% increased risk of ADHD.
"During pregnancy and for the first few years after birth, the brain is undergoing active development, and is vulnerable to a range of influences," Adesman said.
Dr Mary Rosser, an assistant professor of obstetrics, gynaecology and women's health at Montefiore Medical Center, in New York City, said the study covers new ground.
"We've known for a while that perinatal factors have been cited as potential causes for many childhood problems," Rosser said. "Smoking during pregnancy has always been one of the factors that has been linked to ADHD in kids. This study is one of the first I've seen that's looking at gestational diabetes and ADHD."
Noting that "an unfavourable uterine environment can cause developmental issues," Rosser recommended that women see an obstetrician before getting pregnant, and that they continue prenatal care throughout their pregnancies. This can help prevent or treat some of the issues, such as gestational diabetes, that may contribute to ADHD in the child.
In addition, she recommended that women breast-feed their babies. Breast-feeding may be protective for ADHD, and it's known to be beneficial for the baby's overall health, she said.
The study did not prove that gestational diabetes and a lower socioeconomic status cause ADHD, it merely found an association.
Gestational diabetes linked to long-term incontinence
Learn more about attention-deficit/hyperactivity disorder from the U.S. National Institute of Mental Health.
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