The effect of chronic exposure to lead on postural balance was studied in 162 six-year-old children examined in the Department of Environmental Health, and Children’s Hospital Medical Center, University of Cincinnati Medical School, Cincinnati, OH. The five-year geometric mean blood lead concentration was 11.9 mcg/dL (range 4-28 mcg/dL). Most children reached peak PbB concentrations by 18-24 months. Increases in blood lead in CDC Class III category (<20mcg/dL) were significantly associated with increase in postural sway and poor postural balance, indicative of damage to vestibular/proprioceptive systems. Postural balance was measured with eyes open and eyes closed using a microprocessor-based strain gauge-type force platform system. 
COMMENT. Because of the epidemiological nature of the study, the authors note that the results imply an association between elevated lead levels and impaired postural balance rather than a cause. However, because other neurotoxin exposures such as methylmercury and organochlorines were excluded, the association between lead exposure and ataxia most likely reflects an adverse effect of the lead on the developing nervous system. This postural balance measurement may be useful in assessing gross motor function of children at or below the CDC Class III category (<20mcg/dL) of lead exposure.