Bellinger comments on the findings of a study by Reuben and colleagues. The study results indicated that among 565 participants in the long-running Dunedin Multidisciplinary Health and Development Study in New Zealand, blood lead concentration at 11 years of age was significantly and inversely related to intelligence at 38 years of age. Each 5-µg/dL increase in blood lead concentration at age 11 years was associated with a 1.6-point lower IQ score. A blood lead concentration greater than 10 µg/dL (until 2012 the CDC's "action level") was associated with a reduction of 2.7 points in adult IQ and a reduction of 1.7 points relative to IQ at age 11 years. The latter finding is striking given that in the Dunedin cohort, blood lead concentration at age 11 years was already inversely associated with IQ measured concurrently.