Lead and cognition

A long-term study of 134 workers in Pennsylvania compared the cognitive abilities of those who had been exposed to lead (while making batteries) during their working lives and those who had not. The study, which was carried out in 2004, was a follow-up to a study of lead levels originally carried out in 1982. The researchers measured the current levels of lead in the men's blood and the levels of lead in their bones where lead eventually accumulates in the body. They also tested the men's cognition. Among the men who had been exposed to lead those with a higher level of lead in their bones had significantly lower cognitive scores; this was particularly true of spatial ability, learning and memory. The scores were worse even when people's current lead levels were lower suggesting that even when men no longer worked at the battery plants their earlier prolonged exposure was enought to affect their cognitive abilities.