Health conditions of male military personnel in three dioxin contaminated airbases: Bien Hoa, Da Nang and Phu Cat

To evaluate health conditions including the prevalence of diseases in male military personnel working in three airbases contaminated with dioxin: Bien Hoa, Da Nang and Phu Cat.

Journal of military pharmaco-medicine no9-2019 HEALTH CONDITIONS OF MALE MILITARY PERSONNEL IN THREE DIOXIN-CONTAMINATED AIRBASES: BIEN HOA, DA NANG AND PHU CAT Nguyen Thi Thu1; Phan Van Manh2; Pham The Tai2 Nguyen Minh Phuong2; Do Phuong Huong1 SUMMARY Objectives: To evaluate health conditions including the prevalence of diseases in male military personnel working in three airbases contaminated with dioxin: Bien Hoa, Da Nang and Phu Cat Subjects and methods: Cross-sectional description study on total 677 male military personnel in the three airbases from August to December of 2017 Each subject was interviewed and examined by medical doctors for health condition, including recent health problems, history of chronic diseases and surgical diseases Results and conclusions: The prevalence of upper respiratory infection was the most common problem of recent health condition, especially in Phu Cat airbase (24.6%) For the chronic diseases, incidence of gastrointestinal diseases was the highest in all three airbases (6.2%), followed by the incidence of osteoarthritis (5.0%), hepatitis B virus (4.0%) Incidence of hypertension of total subjects was 4.0%, however, the distribution was prominent in Bien Hoa airbase (6.2%) rather than in Da Nang (2.8%), and Phu Cat (1.8%) Regarding to surgical diseases, incidences of traumatic fracture and appendicitis were the highest ones (approximately 4%) Next, the otolaryngological diseases accounted for 2.5% and urinary stones and benign tumors accounted for 1.8% and 1.5%, respectively On the utrasonic examinations, fatty liver was frequently observed in military personnel of all three airbases, especially in Bien Hoa (23.5%) and Da Nang (22.0%) * Keywords: Dioxin; Health conditions; Male military personnel INTRODUCTION In 1962, the US military initiated the usage of herbicides in Vietnam for general defoliation and crop destruction through a program codenamed Operation Ranch Hand [8] The herbicides were predominantly contaminated with 2,3,7,8tetrachlorodibenzo-p-dioxin (2,3,7,8TetraCDD), which is the most toxic congener of dioxins The presence of dioxins in the environment inside and around former US military airbases in Vietnam was a direct result of storage, spillage, and improper disposal of empty herbicide barrels [9] Even though herbicides spraying campaign was ceased since 1971, several key former Ranch Hand airbases such as Bien Hoa, Da Nang and Phu Cat were heavily contaminated with dioxins until now Military personnel inside the airbases and general populations living in the vicinities may suffer from a high risk of dioxin exposure, which leads to adverse effects on human health [7] 103 Military Hospital Vietnam Military Medical University Corresponding author: Pham The Tai (phamthetai@vmmu.edu.vn) Date received: 06/10/2019 Date accepted: 28/11/2019 209 Journal of military pharmaco-medicine no9-2019 Among the three airbases, Bien Hoa is the most dioxin-contaminated one in terms of scale and level Data provided by the US military indicated that over 98,000 barrels of agent orange, 45,000 barrels of agent white and 16,000 barrels of agent blue were stored at Bien Hoa [10] Soil and sediment samples collected from Bien Hoa airbase showed extremely high levels of dioxins, especially in the southwest area of the airbase According to a thorough survey of the environment and the individuals living in and around the airbase from 2006 to 2009, the 2,3,7,8TetraCDD concentration in soil was up to 361,000 pg/g dry weight, which was hundreds times higher than the Vietnamese standards (1,000 pg/g in soil) and guidelines for this toxic chemical [11] Da Nang was one of the key US Operation Ranch Hand sites in Vietnam, and was second only to Bien Hoa in terms of number of spraying sorties by C-123 aircrafts Significant quantities of 2,3,7,8TetraCDD, the dioxin congener specified for agent orange detected in soil samples was analyzed in December 2006 Dioxins spread into lakes on and around the airbase, then intergrade to the food chain and finally enter the human body Dioxin congener profiles confirmed that main source of dioxin contamination at Da Nang airbase was agent orange The highest dioxin concentration recorded in soil samples was 365,000 ppt and over 99% contributed from 2,3,7,8-TetraCDD [12] Phu Cat airbase stored 17,000 barrels of agent orange and 119,000 barrels of other herbicides during the spraying campaign An area of 2,400 m2 was contaminated by dioxins basing on 210 estimation in 1999, with the highest level of dioxin as 11,400 ppt TEQ in soil samples In 2012, total 7,000 m of contaminated soil was collected and separated in concrete tanks for prevention of dioxin releasing into environment As a result, Phu Cat airbase was less contaminated with dioxin as compared with the Bien Hoa and Da Nang airbases There were many human studies that identified the effects of dioxin on human health The National Academies of Sciences, Engineering, and Medicine of US comprehensively evaluated scientific and medical informations regarding the health effects of exposure to agent orange, other herbicides used in Vietnam, and the various components of those herbicides, including 2,3,7,8-TetraCDD [13] Diseases related to dioxin exposure are divided into categories basing on evidences from scientific researches: 1) Sufficient evidence of an association; 2) Limited or suggestive evidence of an association; 3) Inadequate or insufficient evidence to determine an association; 4) Limited or suggestive evidence of no association However, the list of diseases in each category is revised and updated basing on evidences from upcoming studies The present study was conducted with aims: To evaluate the health conditions including the prevalence and incidence of diseases in male military personnel working in three airbases in Bien Hoa, Da Nang and Phu Cat SUBJECTS AND METHODS Subjects and locations From August to December of 2017, total 677 male military personnel in three Journal of military pharmaco-medicine no9-2019 dioxin-contaminated airbases of Bien Hoa, Da Nang and Phu Cat were recruited for the study * Criteria for selection: - Military personnel stayed in target airbases for at least year - Age range was from 20 - 50 years old Based on the list of military personnel matched for criteria, medical officers in each airbase randomly selected them for the study As the most contaminated airbase, number of subjects was the highest in Bien Hoa (n = 291), followed by Da Nang (n = 215) and Phu Cat (n =171) Written informed consent was obtained from all of the military personnel according to a process reviewed and approved by the local medical units in the each airbase and Vietnam Military Medical University The biomedical ethics committee at Vietnam Military Medical University approved the study design (No 2061/QD-HVQY) Methods Cross-sectional epidemiologic study * Health examination: The subjects were invited to the local health station in each airbase Each subject was interviewed and examined by a medical doctor for health condition, including recent health problems, history of diseases and surgeries Medical records of subjects were also reviewed for further health informations Regarding to the recent health problems, subjects were asked to report any health problems that needed treatment by medicines or surgeries within one month Blood presure measurement and EEC were used for screening the cardiovascular diseases Utrasonic examination was used for diagnosing abnormal signals of liver and kidney and other abdominal organs Medical information were recorded in a unique study form for all subjects * Statistical analysis: By SPSS (version 21.0) software package for Windows (SPSS Inc., Armonk, New York) was used for statistical analysis The health indexes were descripted as mean and standard deviation (SD) or number and frequencies (%) for each airbase as well as for whole subjects RESULTS AND DISCUSSION Table 1: Characteristics of subjects Bien Hoa Da Nang Phu Cat Total Characteristics Mean SD Mean SD Mean SD Mean SD Age (years) 44.6 4.9 39.9 7.8 38.7 6.6 41.6 6.9 Education (years) 12.7 1.4 12.6 1.5 12.8 1.6 12.7 1.5 Height (cm) 167.1 4.6 167.8 4.8 167.2 4.7 167.3 4.7 Weight (kg) 65.8 8.2 65.2 4.8 65.4 7.6 65.5 7.9 BMI (kg/m ) 23.5 2.5 23.1 2.2 23.4 2.4 23.4 2.4 Systolic blood pressure (mmHg) 124.3 15.5 118.4 13.2 117.4 14.1 120.3 14.6 211 Journal of military pharmaco-medicine no9-2019 Diastolic blood pressure (mmHg) 77.9 10.1 76.2 7.5 73.4 9.6 76.1 9.3 Working period (years) 19.9 11.2 17.7 8.5 15.3 7.3 18 7.7 n % n % n % n % Smoking 179 61.5 142 66 110 64.3 431 63.7 Drinking alcohol 264 90.7 206 95.8 162 94.7 632 93.4 Marriage 278 95.5 192 89.3 162 94.7 632 93.4 Habitation in airbase 61 21 75 34.9 77 45 213 31.5 Military personnel had a long working period in airbases (> 15 years) The average BMI of all subjects were within normal limits (23.4 kg/m2) Almost military personnel were married (93.4%) and approximate 1/3 of them were living inside the airbase zones Table 2: Recent health conditions of military personnel in three airbases Bien Hoa Health problems Da Nang Phu Cat Total n % n % n % n % Upper respiratory tract infection 31 10.7 30 14.0 42 24.6 103 15.2 Osteoarthritis 1.0 1.4 1.8 1.3 Gastrointestinal disease 2.4 1.4 0.0 10 1.5 Gout 1.0 0.0 0.0 0.4 Dengue fever 0.7 0.9 1.2 0.9 Headache 0.7 0.5 0.0 0.4 Others 2.7 10 4.7 1.2 20 3.0 The prevalence of upper respiratory tract infection was the highest in all airbases, especially in Phu Cat airbase (24.6%) Gastrointestinal diseases mostly were contributed from military personnel in Bien Hoa airbase (2.4%) Osteoarthritis accounted for a prevalence of 1.0% By the end of 2017, there was a dengue fever epidemic in southern Vietnam and it affected the military personnel in airbases Other health problems were less common Table 3: Distribution of chronic diseases of military personnel in three airbases (Bien Hoa, Da Nang and Phu Cat) Diseases Bien Hoa Da Nang Phu Cat Total n % n % n % n % Diabetes 2.7 0.5 1.2 11 1.6 Hepatitis B virus 10 3.4 3.7 5.3 27 4.0 Gastrointestinal disease 18 6.2 12 5.6 12 7.0 42 6.2 Osteoarthritis 22 7.6 2.3 4.1 34 5.0 212 Journal of military pharmaco-medicine no9-2019 Hypertension 18 6.2 2.8 1.8 27 4.0 Sinusitis 2.1 1.9 5.3 19 2.8 Chronic pharyngitis 1.4 1.4 4.1 14 2.1 Urinary stones 10 3.4 0.9 2.3 16 2.4 Gout 1.7 0.5 0.0 0.9 Others 19 6.5 4.2 12 7.0 40 5.9 Incidence of gastrointestinal diseases was the highest in all three airbases (6.2%), followed by osteoarthritis (5.0%), hepatitis B virus (4.0%) Incidence of hypertension was prominent in Bien Hoa airbase (6.2%), rather than in Da Nang (2.8%) and Phu Cat (1.8%) Incidence for sinusitis, chronic pharyngitis, and urinary stones were approximate - 3% in 2000, with adjustment for age, rank, smoking, drinking, domestic herbicide exposure, physical activity, education, income, and BMI, the risk of type diabetes mellitus was nominally higher for those with a high potential for herbicide exposure than for those with low exposure [14] In another study conducted on 90 men living around the airbase area of Da Nang and Bien Hoa (mean age of 38.8), the incidence of diabetes was only 1.1% [3], which was lower than that in general population in Vietnam (4.7%) [2] However, incedence of diabetes increased with ages such as 1.7% for the age range of 30 - 39 and 5,3% for the age range of 40 - 49 [6] In fact, Vietnamese populations in these studies were still young (around 40 years old) for a high risk of diabetes Type diabetes was classified by the Ministry of Health as one of 17 dioxin-related diseases [1] However, there is limited or suggestive evidence of an association between exposure to dioxins and diabetes [12] An exceptionally large epidemiologic study of Korean veterans who served in the Vietnam war reported on diabetes prevalence [14] and mortality [15] For more than 111,000 Korean veterans alive Table 4: Distribution of surgical diseases of military personnel in three airbases (Bien Hoa, Da Nang and Phu Cat) Surgical diseases Bien Hoa Da Nang Phu Cat Total n % n % n % n % Thyroid diseases 0.0 0.9 0.6 0.4 Traumatic fractures 15 5.2 4.2 2.3 28 4.1 Urinary stones 1.4 2.3 1.8 12 1.8 Hemorrhoids 1.4 0.9 0.6 1.0 Benign tumors 2.7 0.9 0.0 10 1.5 Appendicitis 11 3.8 3.7 4.1 26 3.8 Otolaryngological diseases 2.1 1.9 4.1 17 2.5 Hepatobiliary diseases 0.0 1.9 0.6 0.7 Others 2.4 3.7 0.6 16 2.4 213 Journal of military pharmaco-medicine no9-2019 Trauma fracture was the most common one (4.1%) among surgical diseases of military personnel in airbases Whereas, only two cases of cancer, one was nonHodgkin lymphoma and the other was colon cancer, were detected at Bien Hoa airbase The studies around the world supported sufficient evidence of an association between exposure to dioxins and non-Hodgkin lymphoma In analyses of cancer incidence, Yi et al reported a small excess risk of non-Hodgkin lymphoma (HR = 1.09, 95%CI: 0.81 - 1.47) in the internal comparison of the high- and-low exposure groups Similarly for non-Hodgkin lymphoma mortality, Yi et al reported a modestly increased risk for the high- versus low- exposure groups (HR = 1.18, 95%CI: 0.79 - 1.77) [14] However, with regard to mortality from colorectal cancers, Yi et al reported no evidence of an increase in mortality from these cancers combined for high- versus low-exposure opportunity groups (HR = 0.96, 95%CI: 0.78 - 1.19) [15] Table 5: Results of abdominal ultrasound tests Bien Hoa Da Nang n % n % n % n % Fatty liver 63 23.5 45 22.0 18 10.7 126 19.7 Gallbladder polyps 1.9 3.9 1.8 16 2.5 Gallstones 3.0 1.0 3.6 16 2.5 Hemangiomas in the liver 0.7 0.0 0.6 0.5 Kidney-urinary stones 32 11.9 13 6.3 4.8 53 8.3 Kidney cyst 1.9 0.5 1.2 1.2 Benign prostatic hyperplasia/prostate calcifications 2.2 2.0 1.8 13 2.0 Others 1.1 3.4 10 6.0 20 3.1 Ultrasound results Among lesions detected on ultrasound, fatty liver accounted for the highest proportion, especially in Bien Hoa (23.5%) and Da Nang (22.0%) There were many causes lead to fatty liver, most often due to alcohol, in addition to obesity or malnutrition, diabetes, toxic poisons or drugs In this study, subjects were male military personnel with BMI within normal limits (23.4 kg/m2) but the proportion of subjects using alcohol were high (93.4%), thus high fatty liver may be partly due to this reason According to another 214 Phu Cat Total study of 40 dioxin victims living near Da Nang airbase in 2015, the results of histopathology of liver parenchyma showed a high rate of fatty degeneration of liver (35%) [4] Moreover, another study in populations living around Bien Hoa and Da Nang airbases showed very high rates of abnormal GOT and GPT (70.8% and 42.7%, respetively), eventhough the rate of alcohol drinking was 58.9% [5] Further studies need to confirm the associations of dioxin exposure and effects on liver organ Journal of military pharmaco-medicine no9-2019 Next, urinary stones showed a rate of 8.3% Some other lesions were detected on ultrasound examination included benign prostatic hyperplasia/prostate calcification, gallbladder polyps, and gallbladder stones CONCLUSION This cross-sectional study on health status of military personnel at three dioxin-contaminated airbases in Bien Hoa, Da Nang and Phu Cat in 2017 showed that common diseases were gastrointestinal diseases, osteoarthritis and hypertension Results of abdominal ultrasound tests showed that image of fatty liver accounted for a high proportion Although the diseases closely related to dioxin exposure such as diabetes, thyroid diseases, and cancers accounted for low rates at the present study, it does not exclude the possibility that these diseases would increase up with the ages of the subjects REFERENCES Bộ Y tế Thông tư Hướng dẫn khám bệnh nghề nghiệp 2006 Tổ chức Y tế Thế giới (WHO) Vài nét bệnh đái tháo đường quốc gia 2016 Phạm Thế Tài Đánh giá tình trạng sức khỏe người dân sinh sống khu vực ô nhiễm dioxin thuộc Thành phố Đà Nẵng Biên Hòa Tạp chí Sinh lý học Việt Nam 2015, 12, tr.68-74 Nguyễn Bá Vượng, T.V Tú, P.Q Phú Nghiên cứu đặc điểm lâm sàng, hình ảnh mơ bệnh học nhu mơ gan, số xét nghiệm sinh hóa gan mật người phơi nhiễm với chất da cam/dioxin Tạp chí Y Dược học Quân 2015, 2, tr.56-60 Phạm Thế Tài, Đỗ Minh Trung, Nguyễn Văn Long, Nguyễn Tùng Linh, Hoàng Văn Lương Đánh giá tình trạng sức khỏe người dân sinh sống khu vực ô nhiễm dioxin thuộc Thành phố Đà Nẵng Biên Hòa Tạp chí Sinh lý học Việt Nam 2015, 19 (4), tr.68-74 Pham Ngoc Minh, Karen Eggleston Prevalence and determinants of diabetes and prediabetes among Vietnamese adults Diabetes Research and Clinical Practice 2016, 113, pp.116-124 Pham The T Dioxin concentrations in breast milk of Vietnamese nursing mothers: A survey four decades after the herbicide spraying Environ Sci Technol 45:6625-6632 doi: 10.1021/es201666d National Academy of Science The effects of herbicides in south Vietnam National Academy of Science Press, Washington D.C 1974, Summary, pp.S1-S6 Dwernychuk L.W Dioxin reservoirs in southern Vietnam: A legacy of agent orange Chemosphere 2002, 47, pp.117-137 10 Stellman J.M The extent and patterns of usage of agent orange and other herbicides in Vietnam Nature 2003, 422, pp.681-687 11 Hatfield consultants Comprehensive assessment of dioxin contamination in Danang airbase, Vietnam: Environmental levels, human exposure and options for mitigating impacts 2009 12 Hatfield consultants Environmental and human health assessment of dioxin contamination at Bienhoa airbase, Vietnam 2011 13 IOM (Institute of Medicine) Veterans and agent orange Update 11 2018 14 Yi S.W et al Agent orange exposure and disease prevalence in Korean Vietnam veterans: The Korean veterans health study Environmental Research 2014, 133, pp.56-65 15 Yi S.W et al Agent orange exposure and risk of death in Korean Vietnam veterans: Korean veterans health study International Journal of Epidemiology 2014, 43 (6), pp.1825-1834 215 ... prevalence and incidence of diseases in male military personnel working in three airbases in Bien Hoa, Da Nang and Phu Cat SUBJECTS AND METHODS Subjects and locations From August to December of 2017,... December of 2017, total 677 male military personnel in three Journal of military pharmaco-medicine no9-2019 dioxin- contaminated airbases of Bien Hoa, Da Nang and Phu Cat were recruited for the... less common Table 3: Distribution of chronic diseases of military personnel in three airbases (Bien Hoa, Da Nang and Phu Cat) Diseases Bien Hoa Da Nang Phu Cat Total n % n % n % n % Diabetes