High exposures of Vietnam veterans to 2,3,7, 8-Tetrachlorodibenzo-p-dioxin, a
dioxin contained in the
herbicide mixture
Agent Orange, have previously been demonstrated to be associated with an increased prevalence of diabetes and
hyperinsulinemia in non-diabetic subjects. Sixty-nine persons were identified who were in good health and had normal
glucose levels during
glucose tolerance testing. These subjects lived within 25 miles of the Vertac/Hercules Superfund site located in Jacksonville, Arkansas. The blood sera
lipid concentrations of
TCDD for the 69 subjects ranged between 2 and 94 ppt. When subjects with blood sera
lipid TCDD levels in the top 10% (
TCDD > 15 ppt, n = 7) were compared to subjects with lower levels (2-15 ppt, n = 62), there were no group differences in age,
obesity, gender distribution, total
lipids, or
glucose levels. However, plasma
insulin concentrations, at fasting and 30, 60, and 120 min following a 75 g
glucose load, were significantly higher in the group with high blood
TCDD levels. These finding could not be explained by other known risk factors for
hyperinsulinemia. The finding of the
TCDD-
hyperinsulinemia relationship is consistent with studies of Vietnam veterans and suggests that high blood
TCDD levels may cause
insulin resistance.