Years of lead

As I recall there was a study showing that when lead wasn’t used in everything anymore violent crime went down. Now lead was removed from paint in 1978, from water pipes in 1986 and gasoline in 1996. Lead has literally been in too many things to avoid it back in the day. With this fact among other unstated factors we might still be dealing with an entire generation of people in charge that are secretly suffering from lead poisoning symptoms which include decreased cognitive ability which is irreversible. Just wondering peoples thoughts on this.