Letter to the Editor

Abstract

Needleman and other distinguished investigators of lead toxicity raise three issues.

1. Whether lead is a neurotoxin. Here there is full agreement. As I stated in my editorial, "Lead is a poison, and the less of it in the bodies of growing children the better."¹ Adverse effects in young children possibly may occur at blood lead (BPb) levels <10 µg/dL However, neither the epidemiologic studies cited by Needleman and colleagues nor any references I could find demonstrate that BPb <20 µg/dL at age I year causes a clinically important decrease in intelligence or an increase in neurobehavioral problems by the time a child enters school.