Serum dioxin, insulin, fasting glucose, and sex hormone-binding globulin in veterans of operation ranch hand

We studied insulin, fasting glucose, and sex hormone-binding globulin (SHBG ) in Air Force veterans exposed to Agent Orange and its contaminant, 2,3,7, 8-tetrachlorodibenzo-p-dioxin (dioxin), during the Vietnam War. The index s ubjects were veterans of Operation Ranch Hand, the unit responsible for aer ial herbicide spraying in Vietnam from 1962-1971. Other Air Force veterans who served in Southeast Asia during the same period but were not involved w ith spraying herbicides served as comparisons. We assigned each Ranch Hand veteran based on his dioxin level to one of three exposure categories, name d background, low, and high. Among nondiabetic veterans, we found the mean of the logarithm of insulin significantly increased in the high dioxin cate gory. Additionally, in nondiabetic veterans the relation between SHBG and i nsulin interacted significantly with dioxin category on the log scale withi n strata defined by age and percent body fat. Among young (age, less than o r equal to 53 yr), lean (percent body fat, less than or equal to 25%) nondi abetic veterans in the high category, the slope relating the logarithm of S HBG and the logarithm of insulin was significantly decreased. These finding s suggest a compensatory metabolic relationship between dioxin and insulin regulation.