Effects of defoliant exposure and medication use on the development of Parkinson's disease in veterans

BACKGROUND

Vietnam-era veterans were exposed to Agent Orange (AO), which is associated with a high prevalence of Parkinson's disease (PD). However, little is known about the development of PD-like symptoms caused by drug-induced parkinsonism (DIP) in such populations. This study aimed to investigate PD incidence and PD risk following exposure to AO or DIP-risk drugs in veterans.

METHODS

A retrospective cohort study was conducted using 12 years (2009-2020) of electronic medical records of the Veterans Health Service Medical Center, the largest Veterans Affairs hospital in South Korea (n = 37,246; 100% male; age, 65.57 ± 8.12 years). Exposure to AO or DIP-risk drugs, including antipsychotic, prokinetic, anti-epileptic, dopamine-depleting and anti-anginal agents, was assessed in veterans with PD, operationally defined as having a PD diagnosis and one or more prescriptions for PD treatment. The PD risk was calculated using multiple logistic regression analysis adjusted for age and comorbidities.

RESULTS

The rates of DIP-risk drug use and AO exposure were 37.92% and 62.62%, respectively. The PD incidence from 2010 to 2020 was 3.08%; 1.30% with neither exposure, 1.63% with AO exposure, 4.38% with DIP-risk drug use, and 6.33% with both. Combined exposure to AO and DIP-risk drugs increased the PD risk (adjusted odds ratio = 1.68, 95% confidence interval, 1.36-2.08, P < 0.001).

CONCLUSIONS

The PD incidence was 1.31 times higher with AO exposure alone and 1.68 times higher with AO exposure and DIP-risk drug use. The results suggest the necessity for careful monitoring and DIP-risk drug prescription in patients with AO exposure.

Possible effects of agent orange and posttraumatic stress disorder on hyperglycemia in Korean veterans from the US-Vietnam war

This study was conducted to examine whether Korean veterans from the US-Vietnam War who had a diagnosis of type II diabetes mellitus (T2DM) as well as past history of exposure to agent orange (AO) are vulnerable to hyperglycemia when receiving intra-articular corticosteroid injection (IACI) for pain relief.The current study included a total of 49 patients (n = 49) who received an injection of triamcinolone 20 or 40 mg to the shoulder under sonographic guidance or did that of dexamethasone 10 mg or triamcinolone 40 mg combined with dexamethasone 20 mg to the spine under fluoroscopic guidance. Their 7-day fasting blood glucose (FBG) levels were measured and then averaged, serving as baseline levels. This is followed by measurement of FBG levels for 14 days of IACI. Respective measurements were compared with baseline levels. The patients were also evaluated for whether there are increases in FBG levels depending on insulin therapy as well as HbA1c ≥ 7% or HbA1c < 7%.Overall, there were significant increases in FBG levels by 64.7 ± 42.5 mg/dL at 1 day of IACI from baseline (P < .05). HbA1c ≥ 7% and HbA1c < 7% showed increases in FBG levels by 106.1 ± 49.0 mg/dL and 46.5 ± 3.8 mg/dL, respectively, at 1 day of IACI from baseline (P < .05). In the presence and absence of insulin therapy, there were significant increases in them by 122.6 ± 48.7 mg/dL and 48.0 ± 20.4 mg/dL, respectively, at 1 day of IACI from baseline (P < .05). But there were decreases in them to baseline levels at 2 days of IACI.Clinicians should consider the possibility of hyperglycemia when using corticosteroids for relief of musculoskeletal pain in Korean veterans from the US-Vietnam War who had a history of exposure to AO.

Serum dioxin and DNA methylation in the sperm of operation ranch hand veterans exposed to Agent Orange

BACKGROUND

Exposure to the herbicide Agent Orange during the Vietnam War was widespread and is associated with numerous adverse health outcomes. A continuing concern of veterans is the possibility that exposure to the dioxin-containing herbicide might induce adverse reproductive outcomes. We sought to assess whether exposure to Agent Orange in Vietnam was associated with changes in DNA methylation in sperm in a subset of Vietnam veterans who participated in the Air Force Health Study (AFHS).

METHODS

We studied 37 members of the AFHS chosen to have no, low, medium or high exposure to Agent Orange, based upon serum dioxin levels obtained during a series of examinations. DNA from stored semen was extracted and DNA methylation assessed on the Illumina 450 K platform.

RESULTS

Initial epigenome-wide analysis returned no loci that survived control for false discovery. However, the TEAD3 gene had four different CpG sites that showed loss of DNA methylation associated with dioxin exposure. Analysis assessing regional DNA methylation changes revealed 36 gene regions, including the region of the imprinted gene H19 to have altered DNA methylation associated with high exposure compared to the low exposure group. Additional comparison of our data with sperm DNA methylation data from Russian boys exposed to dioxin found an additional 5 loci that were altered in both studies and exhibited a consistent direction of association.

CONCLUSIONS

Studying a small number of sperm samples from veterans enrolled in the AFHS, we did not find evidence of significant epigenome-wide alterations associated with exposure to Agent Orange. However, additional analysis showed that the H19 gene region is altered in the sperm of Agent Orange-exposed Ranch Hand veterans. Our study also replicated several findings of a prior study of dioxin-exposed Russian boys. These results provide additional candidate loci for further investigation and may have implications for the reproductive health of dioxin-exposed individuals.

Presumption of Herbicide Exposure and Presumption of Disability During Service for Reservists Presumed Exposed to Herbicides. Final rule

The Department of Veterans Affairs (VA) is adopting as final an interim final rule published on June 19, 2015, to amend its adjudication regulation governing individuals presumed to have been exposed to certain herbicides. Specifically, VA expanded the regulation to include an additional group consisting of individuals who performed service in the Air Force or Air Force Reserve under circumstances in which they had regular and repeated contact with C-123 aircraft known to have been used to spray an herbicide agent ("Agent Orange") during the Vietnam era. In addition, the regulation established a presumption that members of this group who later develop an Agent Orange presumptive condition were disabled during the relevant period of service, thus establishing that service as "active military, naval, or air service." The effect of this action is to presume herbicide exposure for these individuals and to create a presumption that the individuals who are presumed exposed to herbicides during reserve service also meet the statutory definition of "veteran" (hereinafter, "veteran status") for VA purposes and eligibility for some VA benefits.