Paraoxonase in Persian Gulf War veterans.

Serum paraoxonase (PON1) is responsible for the metabolism of organophosphates in serum, and PON1 activity is a major determinant of their toxicity in humans. There have been reports linking lowered PON1 activity to physical symptoms after deployment to the Persian Gulf War (PGW) of 1990 to 1991. Therefore, the object of this study was to determine (1) whether PON1 activity was decreased among symptomatic PGW veterans compared with asymptomatic PGW veterans and (2) to determine whether PGW veterans as a whole had lower PON1 activity compared with other military control groups. This was a case control study nested in occupational cohort study of military personnel. Four groups of military personnel were identified from a large epidemiological study of health effects of deployment to the PGW and Bosnia: (1) symptomatic PGW veterans, n = 115; (2) healthy PGW veterans, n = 95; (3) symptomatic Bosnia peacekeeping veterans, n = 52; and (4) symptomatic nondeployed military controls, n = 85. The main outcome measures were PON1 activity and genotype for PON1-55 and -192. We found significant differences in PON1 activity among these four groups, and although the two Gulf groups did not differ in PON1 activity, those deployed to the Gulf had significantly lower PON1 activity compared with the non-PGW groups (median difference = 70.9; 95% CI: 20.2, 121.5, P = 0.012). These differences were not explained by a range of potential confounders, or differences in PON1 coding region polymorphisms. PON1 activity is reduced in PGW veterans compared with military control groups. The effect is independent of ill health in PGW veterans.