With an increasing number of children taking drugs for attention-deficit hyperactivity disorder — some 2.7 million in 2007 — researchers are looking more closely at the learning disability known as ADHD.
A new review of studies by Mary Burke, a Bay Area child psychiatrist, and Mark Miller, director of UCSF’s Pediatric Environmental Health Specialty Unit (PEHSU), makes a strong case for looking closely at a child’s environment as part of the work-up for for ADHD medication.
One possible culprit? The old neurological foe, lead.
Although banned from residential use in 1978, it continues to linger in the dust and paint in old buildings, as well as ceramics, toys, jewelry, folk remedies, cosmetics and other everyday places. Children are more likely to ingest lead in the environment than adults — they’re closer to the ground, they put their hands in their mouths more often, and their bodies absorb lead three times as efficiently as adults.
Moreover, lead is found most often in older homes, and in 1998 the San Francisco Department of Health concluded that 68 percent of the city’s homes were built before 1950 and 98 percent before 1978, when the ban went into effect.
As the oldest neighborhood in the city, the Mission is particularly vulnerable. Voluntary screening for a 1998 study by the city’s Child Lead Prevention Program estimated that there were “897 children in San Francisco with undiagnosed elevated lead levels.”
Again, with the oldest housing, the Mission had the most children with elevated levels.
Children are also especially vulnerable to lead in utero. Lead readily crosses the placenta and enters the fetal brain. Prenatal exposure to lead is linked to a loss of IQ and symptoms of ADHD in children, according to Burke.
Perversely, children in areas where they are at greater risk for lead exposure — such as near industrial areas, freeways or waste-treatment plants — may also be more likely to have vitamin deficiencies and lack access to fresh produce and generally good nutrition, which can help to mitigate the effects of lead.
Shortages of calcium, zinc and iron heighten the negative effects of lead exposure.
Although the Mission offers plenty of fresh produce markets, the Department of Education’s fitness test results indicate that Mission students are probably eating more fast food than their counterparts in other neighborhoods. The Mission’s middle school students lagged behind others in the city in aerobic fitness by as much as 30 percent in 2010.
Burke and Miller recommend that the guidelines laid down by the Centers for Disease Control, little known in the mental health world, be more widely adopted.
Under those guidelines, a lead screening would be required for any child who is a recent immigrant, who is eligible for Medicaid, who has family members who work in factories, who likes to eat dirt, who lives in an area known to have risk for lead exposure, who plays with children who have been discovered to have high lead levels, or who is in any way suspected to be at risk for lead exposure. Pregnant mothers and women considering becoming pregnant should also be tested.
They should also, Burke adds, make an extra effort to eat leafy green vegetables. It seems self-evident: Eat your vegetables. But sometimes it takes a lot of science to come to a simple conclusion.