Serum dioxin, testosterone, and subsequent risk of benign prostatic hyperplasia: a prospective cohort study of Air Force veterans.
BACKGROUND
Operation Ranch Hand veterans were involved in spraying herbicides, including Agent Orange, during the Vietnam War in 1962-1971; Agent Orange was contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). It has been hypothesized that dioxins may be partially responsible for an increase of male reproductive tract disorders such as testicular cancer, cryptorchidism, and hypospadias.


OBJECTIVE
In this study, our objective was to assess the effect of serum TCDD concentration on the risk of development of benign prostatic hyperplasia (BPH) and on serum testosterone levels.


METHODS
This study was a longitudinal, prospective cohort study made up of U.S. Air Force veterans involved in Operation Ranch Hand. Other Air Force veterans who did not spray herbicides were included as comparisons. BPH was determined by medical record review and by medical examinations conducted during the study. Data were available for 971 Ranch Hand and 1,266 comparison veterans. We investigated the relationship between BPH and serum TCDD level using the Cox proportional hazards models adjusted for testosterone levels, body mass index (BMI), and the percentage change in BMI per year.


RESULTS
In univariate and multivariate analyses, the risk of BPH decreased with increasing serum TCDD in the comparison group. The multivariate risk ratio for BPH in the comparison group was 0.84 (95% confidence interval, 0.73-0.98). Excluding men with prostate cancer, inflammatory or other prostatic diseases did not substantially alter the association. Serum testosterone levels were inversely associated with serum TCDD levels in both Ranch Hand and comparison groups.


CONCLUSIONS
TCDD exposure at general population levels is associated with a decreasing risk of BPH with higher exposure levels. TCDD exposure is also negatively associated with serum testosterone levels.
Gupta
Amit
A
The University of Texas School of Public Health, Regional Campus at Dallas, Dallas, Texas 75390-9110, USA. amit.gupta@utsouthwestern.edu
Ketchum
Norma
N
Roehrborn
Claus G
CG
Schecter
Arnold
A
Aragaki
Corinne C
CC
Michalek
Joel E
JE
D004147:Dioxins / Q000097:blood*; D004781:Environmental Exposure; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011470:Prostatic Hyperplasia / Q000453:epidemiology* / Q000209:etiology; D012306:Risk; D013739:Testosterone / Q000097:blood*; D014728:Veterans; D047829:Vietnam Conflict
D004147:Dioxins; D013739:Testosterone