Subclinical white matter integrity in subjects with cumulative lead exposure.

PURPOSE

To evaluate microstructural changes in the white matter of patients who were exposed to lead and to compare differences in fractional anisotropy (FA) between these patients and control subjects.

MATERIALS AND METHODS

Institutional review board approval and subject informed consent were obtained for this HIPAA-compliant study. Nineteen factory workers who had been exposed to lead and 18 healthy volunteers who had not were enrolled. FA values and T2-weighted fluid-attenuation inversion-recovery magnetic resonance images were obtained at several regions of interest (the bilateral parietal, frontal, occipital, and temporal white matter and the genu and splenium of the corpus callosum). Lead levels were measured in the blood, midtibia, and patella. The Student t test was used to compare the difference in continuous variables between the two groups. Pearson correlation coefficients were used to assess the association between two variables.

RESULTS

There were no significant differences in sex, age, body mass index, smoking history, betel nut consumption, or alcohol consumption between the factory workers and the volunteers. The number of milk drinkers among factory workers was significantly higher than that among volunteers (P < .001). The factory workers had significantly higher blood (P < .001), patella (P < .001), and midtibia (P = .005) lead levels than did the volunteers. Mean FA in the factory workers was lower than that in the volunteers at the same anatomic location; significant differences between the groups were noted bilaterally in the parietal, frontal, occipital, and temporal white matter. There was no significant difference in mean diffusivity values and mean T2 ratios between the factory workers and the volunteers.

CONCLUSION

Decreased FA was associated with exposure to lead. Negative correlations between FA and blood, midtibia, and patella lead levels suggest that FA may be a useful index of early white matter damage.

SUPPLEMENTAL MATERIAL

http://radiology.rsnajnls.org/cgi/content/full/2522080653/DC1.