According to the report, a person’s reading level is a measure of their “cognitive reserve,” an indicator of how well the brain is able to function while sustaining various forms of damage.
The concept of cognitive reserve first came from studies on Alzheimer’s disease, but it has since been applied to brain dysfunction from a number of other causes, including stroke, HIV infection, Parkinson’s disease, and multiple sclerosis. By contrast, little research has looked at the impact cognitive reserve might have on the damage caused by exposure to heavy metals like lead.
In the new study that appears in the journal Neurology, thinking ability, movement ability and lifetime lead exposure were assessed in 112 lead-smelt workers in New Brunswick, Canada. The subjects were divided into high and low cognitive-reserve groups based on whether their reading ability was at the 12th grade level or below.
Even though the groups had similar lead exposure, thinking impairments were more pronounced in workers with low reading ability. By contrast, the effect of lead on movement speed was comparable in both groups, lead author Dr Margit L Bleecker, from the Center for Occupational and Environmental Neurology in Baltimore, commented in a statement.
Further studies are needed to better understand how increased cognitive reserve, as assessed by reading ability, may protect against lead-induced brain dysfunction, the report indicates.