A preliminary investigation of chlorinated hydrocarbons and chronic fatigue syndrome.

OBJECTIVE

To determine whether serum levels of chlorinated hydrocarbons are elevated in patients with chronic fatigue syndrome.

METHODS

Chlorinated hydrocarbon levels were measured in 22 patients with chronic fatigue syndrome (CFS) (as defined by the Centers for Disease Control [CDC]); in 17 patients with CFS symptoms whose history of exposure to toxic chemicals excluded them from the research definition of CFS; and in 34 non-CFS control subjects matched for age and sex.

RESULTS

DDE (1,1-dichloro-2,2-bis (p-chlorophenyl) ethene) was detected in all serum samples at levels over 0.4 ppb. The incidence of hexachlorobenzene (HCB) contamination (> 2.0 ppb) was 45% in the CFS group, compared with 21% in the non-CFS control group (P < 0.05). The CFS group had a significantly higher total organochlorine level (15.9 ppb; SEM, 4.4) than the control group (6.3 ppb; SEM, 1.1; P < 0.05). The toxic exposure group also had a higher mean organochlorine level (13.6 ppb; SEM, 6.2) than the control group, but the difference was not statistically significant. DDE and HCB comprised more than 90% of the total organochlorines measured in each of the groups.

CONCLUSIONS

The results suggest that recalcitrant organochlorines may have an aetiological role in CFS. There were no significant differences in serum organochlorine concentrations between CFS patients and chronic fatigue patients with a history of toxic chemical exposure. Therefore, exclusion of patients from the CDC research definition of CFS on the basis of a reported history of known exposure to toxic chemicals is not valid. The role of low-level organochlorine bioaccumulation in the development of CFS symptoms requires further investigation.