The amount of fish a woman eats while pregnant may affect her child’s chances of developing attention-deficit/hyperactivity disorder (ADHD).
Eating fish twice a week was linked to about a 60% lower risk of a child developing certain ADHD-like symptoms, according to research from the Boston University School of Public Health.
But the type of fish eaten is the key.
Elevated mercury levels, which can occur from eating certain types of fish, such as tuna and swordfish, were also tied to a higher risk of developing ADHD symptoms such as a short attention span, restlessness or being easily distracted.
“The really important message is to eat fish,” said assistant professor Sharon Sagiv, the study’s lead author.
Sharon Sagiv added that pregnant women should avoid “big” fish, such as tuna and swordfish, which typically contain the most mercury. Instead, they should opt for haddock or salmon.
The research was published in the Archives of Pediatrics & Adolescent Medicine.
Past studies looking at the link between mercury and ADHD – a condition estimated to affect up to 5% of school-aged children – have produced conflicting results.
Most children are diagnosed between the ages of three to seven, with boys more commonly affected.
Many people with ADHD also have learning difficulties and sleep disorders.
For the new study, the researchers followed 788 children born in Massachusetts between 1993 and 1998.
They used hair samples taken from the mothers after delivery to test their mercury levels, and food diaries to see how much fish they had eaten.
Then, once the children were about eight years old, the researchers asked their teachers to evaluate the children’s behavior to see how many exhibited ADHD-like symptoms.
After taking all of the information into account, the researchers found that one microgram of mercury per gram of a mother’s hair – about eight times the average levels found in similar women’s hair in another analysis – was linked to a 60% increase in the risk of their child exhibiting ADHD-like behaviors.
But there was no link below one microgram of mercury per gram of a mother’s hair.
The children appeared to be 60% less likely to exhibit impulsive or hyperactive behaviors if their mothers had eaten two or more servings of fish per week.
A recent study indicates that infants, under 3 years old, exposed to at least two general anesthesia procedures might have a higher risk of developing attention deficit hyperactivity disorder (ADHD).
The study was published this month in the journal Mayo Clinic Proceedings.
For the research, the Mayo Clinic scientists processed the data from a previous epidemiological study, that involved children born between 1976 and 1982 in Rochester, Minnesota, and identified those with learning disabilities or ADHD. There were 341 children younger than 19 with ADHD
Researchers looked for exposure to surgery and anesthesia before age 3 in the medical records of the Rochester Epidemiology Project, a decades-long database of all patient care in Olmsted County, Minnesota.
ADHD appeared in 7.3% of the children with no exposure to anesthesia and surgery, and the percentage in the children with one exposure to anesthesia and surgery was around 11.
“With Cesarean section with a general anesthetic, only a single anesthetic, we didn’t find any effect,” said study author Dr. Juraj Sprung, professor of anesthesiology at the Mayo Clinic.
Multiple general anesthesia exposures in infants under 3 might be associated with ADHD.
When children had at least two exposures to anesthesia and surgery, the percentage of ADHD rose to 17.9.
The scientists made adjustments for other factors (gestational age, sex, birth weight, co-morbid conditions, maternal age and education), but the rate of ADHD was still high.
These results may not be applicable to all racial or ethnic groups.
“The population in 1976 and 1982 was mostly white/Caucasian here in Minnesota,” said Dr. Juraj Sprung.
A previous research published in Pediatrics in November 2011, suggested an association between early multiple anesthesia exposures and learning disabilities in language, reading, and math. The study was performed by the same team.
There were animal studies that showed how anesthetics could affect the brain. Rats had damages in the cortical areas of the brains and became hyperactive after anesthesia. The abilities to perform tasks involving executive function were affected in monkeys exposed to ketamine for 24 hours as new-born.
However, it is important to take in consideration the influences of both procedures (anesthesia and surgery), as well as other factors that may lead to ADHD.
“Essentially, we did an observational study and we examined whether there is association with exposure to anesthesia, but not only to anesthesia,” said Dr. Juraj Sprung.
“This is an observational study. A wide range of other factors might be responsible for the higher frequency of ADHD in children with multiple exposures. The findings certainly do suggest that further investigation into this area is warranted, and investigators at Mayo Clinic and elsewhere are actively pursuing these studies,” said study author Dr. David Warner, Mayo Clinic pediatric anesthesiologist.
This study does not suggest that parents should avoid surgery for their infants (as a method to prevent ADHD), if the surgery is needed.
“At the present time, we shouldn’t make any recommendations based on the study, to do or don’t do the surgery. If you need the surgery, if you need the procedure, you certainly should go for it. What I would personally say: If it’s the type of surgery, the type of procedure that can wait, maybe it’s better to wait,” said Dr. Juraj Sprung.
ADHD appears in around 3-5% of children world wide and it is diagnosed in about 2-16% of children over 6 years old. It is a chronic disorder and almost half of those diagnosed in childhood have symptoms into adulthood. Around 4.7 percent of American adults have ADHD, it is estimated. Genetic and environmental factors are implicated in the development of this disorder. ADHD impede attention and focus, and includes restless and impulsive behavior.