Anxiety, inattention, poor decisions increase in kids with higher lead levels

Higher blood lead levels in children were associated with specific learning and behavior changes, including more anxiety and deficits in planning, abstract thinking and determining appropriate behavior, finds this large study from India.


A study of young children in India has found that higher blood lead levels are associated with a suite of behavioral and thinking problems that can alter attention, abstract thinking and appropriate behavior. The largest effects and most vulnerable areas found were on executive function and inattention.

This study is one of the first to pinpoint specific childhood behaviors and cognitive skills affected by lead exposure, most notably anxiety, social problems and overall executive function (planning, problem solving, behavior control). The study also contributes further information about newly found links between increased lead exposure and more ADHD-like behavior – especially inattention rather than hyperactivity – in children.

A low threshold level for exposure to the metal was not found, which agrees with prior studies that also have found no “safe” level for childhood lead exposure. The results have implications for policies regarding lead exposure levels in the US and around the world, say the authors.

Lead is a notorious neurotoxin – so called because it affects learning, memory and other brain functions to lower IQ. Many countries have banned its use in common products, such as paint and gasoline. These bans have propelled blood levels to drop in people worldwide. Other products, such as inexpensive jewelry, keys, electronics and some children's toys, still contain lead. Older buildings with the leaded paint and contaminated soil still represent major sources of lead exposure for children.

To examine lead's impact on certain behaviors, researchers measured blood lead levels in 756 children from ages 3-7 who were attending preschools and elementary schools in Chennai, India. Teachers assessed the children's cognition, attention and behavior using standardized testing tools and questionnaires. Statistical methods were used to compare the levels of lead biomarkers with measures of anxiety, social problems, hyperactivity, inattention, Attention Deficit/Hyperactivity Disorder (ADHD) and executive function.

The measured mean blood lead level was 11.4 micrograms per deciliter. The Centers for Disease Control's level of concern for blood lead is 10 micrograms per deciliter.

The researchers found that children with higher blood levels also had statistically significant higher anxiety and poor sociability and a greater risk of ADHD. A significant association was also found between higher lead levels and poor executive function – the ability to plan, think abstractly, problem solve, remember and determine/control appropriate behavior.

The authors report that they "identified no threshold for these effects" and point out that it is an "important finding for policy decision making as it suggests that there might be no safe level of lead exposure