A 30-year follow-up study in a former cadmium-polluted area of Japan: the relationship between cadmium exposure and ß2-microglobulin in the urine of Japanese people.

Cadmium (Cd) is an environmental pollutant. Long-term exposure to Cd may lead to adverse health effects in humans. Our epidemiological studies showed that urinary Cd (U-Cd) concentrations increased from 2008 through 2014, although they decreased from 1986 through 2008. The aim of this study was to elucidate the long-term effects of the changing trend of cadmium exposure levels (U-Cd) on residents' renal function within 30 years after Cd exposure ceased. In 2016, urine samples were collected from each subject by visiting 20 elderly Japanese people (9 females and 11 males) living in the Kakehashi River basin, a previously Cd-polluted area in Ishikawa, Japan. The geometric means of the ß2-microglobulin (ß2-MG) and urinary Cd (U-Cd) continued to increase from 2014 until 2016. Furthermore, Cd concentration and ß2-MG in urine were still higher than those in the non-polluted areas in Japan. Multivariate linear regression was performed to associate ß2-MG (dependent variable) and U-Cd with sex and age (independent variables). Significant correlations were found among age, U-Cd, and ß2-MG, and these were clearer in females than in males. In summary, we propose that three decades after Cd exposure ceased, age is associated with ß2-MG more strongly than Cd for bodily impact. Moreover, renal tubular dysfunction is irreversible and worsens after exposure to Cd, with females being more sensitive to exposure.

The Relationship of Dioxin Levels in Serum of 9-Year-Old Vietnamese Children and Their Mothers' Breast Milk.

In this study, we measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in the blood of 9-year-old children living in a dioxin hotspot area and a nonexposed area in Vietnam. Forty-five blood samples were collected in the hotspot area while twelve pooled blood samples were collected in the nonexposed area. We found that the dioxin level of children in the hotspot was significantly higher than that of children in the nonexposed area. The total TEQ of PCDD/Fs in the hotspot and the nonexposed was 10.7 and 3.3 pg TEQ/g fat, respectively. However, TCDD, the maker of Agent Orange, was not detected in the blood of children in the hotspot area. In the hotspot area, four congeners 1,2,3,4,6,7,8-HpCDD, 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF, and 1,2,3,4,6,7,8-HpCDF in mothers' breast milk showed a significantly positive correlation with those in children's serum although the correlations of 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF were not significant. In addition, the duration of breastfeeding also correlates with dioxins in children. These results suggested that children in the hotspot area were exposed to dioxin through mothers' milk and other foods or environmental factors. The present study is the first study that shows dioxin levels in Vietnamese children.

Decreased serum testosterone levels associated with 17ß-hydroxysteroid dehydrogenase activity in 7-year-old children from a dioxin-exposed area of Vietnam.

Since 2008, we have conducted epidemiological cohort studies on the relationship between dioxin exposure and disruption with children in the area sprayed with defoliants during the Vietnam War. In a long-term survey of children through the age of five, we observed androgen disruption due to decreased dehydroepiandrosterone (DHEA) and testosterone levels. In this study of 7-year-old, we separately elucidated androgen disruption for boys and girls, and discussed with respect to hormone disruption with sex differences on the steroid hormone biosynthesis process. This follow-up was conducted with 96 mother-child pairs in Vietnam (hotspot area: 45, non-sprayed area: 51). We took a questionnaire, the physical measurement and assayed 7 steroid hormones in their serum by LC-MS/MS. We examined the relationship between the hormone levels in the serum and dioxin levels in the maternal breast milk. The results showed that the serum DHEA level in the 7-year-old children in the hotspot recovered to levels in the non-sprayed area. The testosterone level of 66.5 pg/mL for boys in the non-sprayed area was 1.5 times the girls level of 44.6 pg/mL, a male-dominant effect. The testosterone level in boys and girls from the hotspot were significantly lower than in the non-sprayed area with no sex difference. The 17ß-hydroxysteroid dehydrogenase (17ß-HSD) activity was significantly higher in boys than in the girls from the non-sprayed area, but was significantly lower in the hotspot boys than in the non-sprayed area boys. Both the testosterone level and 17ß-HSD activity in the boys were inversely correlated with the TEQ total PCDD/Fs in the maternal breast milk. These results indicated that dioxin delayed the expression of the testosterone level and 17ß-HSD activity with growth in the 7-year-old boys. The serum DHEA in the 7-year-old children recovered to the levels of the children in the non-sprayed area.

Larvicidal and Repellent Activity of Mentha arvensis L. Essential Oil against Aedes aegypti.

Dengue is one of the most dangerous vector-borne diseases transmitted by Aedes mosquitoes. The use of mosquito repellents to protect human hosts and insecticides to reduce the mosquito population is a crucial strategy to prevent the disease. Here, we reported larvicidal and repellent activities of Mentha arvensis L. essential oil against Aedes aegypti, the main vector of the disease. The essential oil was extracted by hydro-distillation from the aromatic plant grown in Vietnam. The yield was 0.67% based on the weight of fresh leaves. The essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). The main components were menthol (66.04%), menthyl acetate (22.19%), menthone (2.51%), and limonene (2.04%). Toxicity test on Aedes aegypti larvae showed that the median lethal concentrations, LC50 and LC90 were 78.1 ppm (part per million) and 125.7 ppm, respectively. Besides, the essential oil showed excellent repellency on Aedes aegypti mosquitoes. At 25%, 50%, and 100% concentration, the respective complete protection times (CPTs) were 45 min, 90 min, and 165 min. When adding 5% vanillin to the essential oil (25%), the complete protection time of the essential oil increased up to 120 min. In conclusion, the EO from Mentha arvensis L. has been shown to be a promising natural larvicide and repellent against Aedes aegypti mosquitoes.

The Mosquito Larvicidal Activity of Essential Oils from Cymbopogon and Eucalyptus Species in Vietnam.

The larvicidal activity of essential oils (EOs) extracted from Cymbopogon citratus, Cymbopogon winterianus, Eucalyptus citriodora, and Eucalyptus camaldulensis aromatic plants grown in Vietnam was evaluated on Aedes aegypti larvae. The EOs were hydro-distilled in a Clevenger-type apparatus. The EOs were analyzed by gas chromatography-mass spectrometry (GC-MS). The mortality rates obtained from the bioassays were used to calculate the lethal concentrations (LC50) of the EOs by the probit analysis method. These essential oils exhibited toxicity to the larvae of Aedes aegypti. Results were obtained for Cymbopogon citratus (LC50 = 120.6 ppm), Cymbopogon winterianus (LC50 = 38.8 ppm), Eucalyptus citriodora (LC50 = 104.4 ppm), and Eucalyptus camaldulensis (LC50 = 33.7 ppm). The essential oils of Eucalyptus camaldulensis and Cymbopogon winterianus were found to be the most efficient, and their respective values of LC50 were 33.7 ppm, 38.8 ppm. In conclusion, this research adds to the growing body of literature on natural larvicides from essential oils against Aedes aegypti mosquitoes.

Association of dioxin in maternal breast milk and salivary steroid hormone levels in preschool children: A five-year follow-up study of a Vietnam cohort.

Recent studies have found elevated dioxin levels inside some former US military air bases in Vietnam, known as hotspots. The aim of the present study was to evaluate the association of dioxin exposure and steroid hormone in preschool children in Vietnam. In 2010, 2011, 52 primiparae mother-infant pairs in the hotspot and 52 pairs in a non-exposure region were enrolled. For the final analysis, 26 vs 26 pairs were selected, who participated at all three surveys. Univariable and multivariable linear regressions were used to evaluate associations between hormone and dioxin congeners. Geometric mean total TEQ of PCDD/DFs in the hotspot were significantly higher than in the non-exposure region, 8.7 and 3.4 pg TEQ/g lipid, respectively. In the hotspot, salivary dehydroepiandrosterone (DHEA) was significantly higher in 1-year-old children (Boys = 123 pg/mL, Girls = 120 pg/mL) than in the non-exposure region (Boys = 28 pg/mL, Girls = 27 pg/mL). In contrast, DHEA was significantly lower in 5-year-old children (Boys = 70 pg/mL, Girls = 106 pg/mL) in the hotspot than in the non-exposure region (Boys = 496 pg/mL, Girls = 654 pg/mL). Salivary testosterone was significantly lower in the hotspot (Boys = 1.9 pg/mL, Girls = 1.9 pg/m; Boys = 1.0 pg/mL, Girls = 1.1 pg/mL, respectively) than in the non-exposure region (Boys = 3.7 pg/mL, Girls = 3.8 pg/m; Boys = 5.7 pg/mL, Girls = 7.0 pg/mL, respectively) at 3 years and 5 years of age. Higher levels of highly chlorinated dioxins in breast milk were associated with higher DHEA in 1-year-old and lower DHEA and testosterone levels in 5-year-old children. Our findings indicated that dioxins were associated with changes of DHEA and testosterone levels in preschool Vietnamese children.

Androgen disruption by dioxin exposure in 5-year-old Vietnamese children: Decrease in serum testosterone level.

Dioxins have been suspected to be potential substances causing endocrine disruptions in humans. We are conducting the research in one of three dioxin exposure areas (hotspots) in Vietnam. We previously reported that the salivary dehydroepiandrosterone (DHEA) level decreased in 3-year-old Vietnamese children and that it was significantly inversely correlated with polychlorinated dibenzodioxin/dibenzofuran levels in their mother's breast milk. In this study, we investigated the influence of exposure to dioxin on steroid hormone biosynthesis in the same children when they reached 5 years of age, focusing on androgens. Thirty-five and 50 mother-child pairs from dioxin hotspot and non-sprayed areas, respectively, participated in this study. Maternal breast milk was donated at 4 to 16 weeks postpartum in 2008 to measure dioxin levels by gas chromatography/high-resolution mass spectrometry. Serum was collected from 5-year-old children in 2013. Seven steroid hormones were measured by liquid chromatography/mass spectrometry. Most dioxin congeners in breast milk were 2- to 10-fold higher in the hotspot than in the non-sprayed area. DHEA and testosterone (T) were significantly lower in the hotspot and showed negative correlations with most dioxin congeners. Similar results were observed for the activities of cytochrome P450-17, 20 lyase (CYP17 lyase), and 17ß-hydroxysteroid dehydrogenase (HSD). Conversely, the elevated androstenedione (A-dione) level and 3ß-HSD activity in children from the hotspot were positively correlated with dioxin levels. Moreover, a positive correlation was shown between T and 17ß-HSD. It is possible that dioxin inhibits 17ß-HSD activity, leading to a decrease in the T level. Multiple regression analysis indicated that dioxin had a strong association with the DHEA, A-dione, and T levels. In conclusion, the present study suggests that dioxin is associated with low levels of DHEA and T and inhibition of the activity of steroidogenic enzymes such as CYP17 lyase and 17ß-HSD in 5-year-old children.

A relationship in adrenal androgen levels between mothers and their children from a dioxin-exposed region in Vietnam.

Over the past decades, southern Vietnam has been burdened by dioxins from contaminated herbicides sprayed during the Vietnam War. In a previous study, we found that dioxin exposure decreased levels of salivary dehydroepiandrosterone (DHEA), an adrenal androgen, in 3-year-old children. In present study, to assess the relationship between adrenal hormones disruption in lactating mothers and in children, we compared mother-child pairs from dioxin- and nondioxin-contaminated regions. In 2010 and 2011, mother-child pairs from a dioxin hotspot region (n=37) and a non-contaminated region (n=47) were recruited and donated breast milk and serum samples for dioxin and steroid hormones determination. Mothers were 20-30years old and had given birth to their first child between 4 and 16weeks previously. One year later, saliva samples were collected from the children. Dioxin levels in breast milk were determined by gas chromatography/high-resolution mass spectrometry. Salivary DHEA, cortisol in children and androstenedione (A-dione), estradiol, cortisol, and DHEA in maternal serum were analyzed by liquid chromatography/tandem mass spectrometry. Concentrations of dioxin congeners in the hotspot region were 2- to 5-fold higher than in samples from the non-contaminated region. Salivary DHEA levels in children and serum A-dione levels in mothers were significantly higher in the hotspot region; no difference was found in the levels of other hormones. Moreover, there was a significant positive correlation between the elevated hormone levels in mothers and children (r=0.62, p<0.001). Several dioxin congeners exhibited strong significant dose-response relationships with salivary DHEA and serum A-dione levels. Our findings suggest that dioxin disrupts adrenal androgens in mothers and breastfeeding children through the same mechanism.

The relationship between dioxins exposure and risk of prostate cancer with steroid hormone and age in Vietnamese men.

Although Vietnam's massive herbicide exposure in 1960s and 1970s was clearly injurious to health, not all causal relationships have been clarified. We therefore explored associations among dioxins, steroid hormones, age and prostate cancer risk in men. We compared serum levels of dioxin, steroid hormones and prostate specific antigen (PSA) in men aged 56-81years from herbicide-exposed hotspots (n=50) with those from non-sprayed regions (n=48). Mean serum levels of dioxin congeners in the hotspot group were 1.5-11.3 times higher than the non-sprayed group depending on specific compound. Levels of testosterone, estradiol and 3ß-hydroxysteroid dehydrogenase (3ß-HSD) activity in the hotspot group were also significantly higher than in non-sprayed group. Estradiol levels were significantly related to levels of several specific dioxin derivatives in both group. Significant positive correlations were also found between DHT and 1234678-HpCDD or 1234678-HpCDF; and between 3ß-HSD activity and 123678-HxCDD, 123478-HxCDF, 123678-HxCDF, or HxCB#169. After adjusting for age, body mass index, and tobacco use, multiple linear regressions showed levels of dihydrotestosterone (DHT), estradiol, testosterone and 3ß-HSD activity were not associated with dioxins in the two groups; however, levels of DHT, testosterone and 3ß-HSD activity increased significantly with age in the hotspot group. The hotspot and non-sprayed groups did not significantly differ in PSA levels. But six of the hotspot subjects had PSA levels >3ng/mL, 3 of whom were suspected to have prostate cancer (PC) after digital rectal examination. Our findings suggest that dioxin exposure can lead to increased levels of several sex steroid hormones with age. The correlation of dioxin with steroid hormone levels and prostate cancer risk should be studied further.

Effects of aging on cadmium concentrations and renal dysfunction in inhabitants in cadmium-polluted regions in Japan.

The absorption of cadmium (Cd) may lead to Cd-related diseases such as renal tubular dysfunction and bone disease, and it is known to take around 10-30 years to reduce Cd concentrations to half their original levels. Urinary ß2 -microglobulin (ß2 -MG), N-acetyl-ß-D-glucosaminidase (NAG), protein, glucose and albumin were used as indicators of renal dysfunction caused by Cd exposure. Our previous study found that urinary Cd concentrations had increased recently and that age was more strongly associated with urinary ß2 -MG concentration than recent Cd body burden. Therefore, the purpose of the present study was to investigate the effect of aging on Cd concentrations and renal dysfunction. The Cd, ß2 -MG, NAG, protein, glucose and albumin concentrations in the urine of 40 Japanese subjects (20 females and 20 males) environmentally exposed to Cd were collected. They lived in the Kakehashi River basin and were divided into three age categories: 50-69, 70-79 and 80-99 years. Significant differences in urinary Cd and ß2 -MG concentrations were found among age groups, with urinary Cd levels tending to increase with age in both sexes. No significant correlations were found between urinary Cd and any indicators of renal dysfunction. The correlation between age, Cd and indicators of renal dysfunction was observed more clearly in females than in males. Age is more strongly correlated with indicators of renal dysfunction than Cd body burden. Copyright © 2017 John Wiley & Sons, Ltd.

Low birth weight of Vietnamese infants is related to their mother's dioxin and glucocorticoid levels.

We aimed to determine the relationship between dioxin congeners in maternal breast milk and maternal glucocorticoid levels with newborn birth weight after nearly 45 years of use of herbicides in the Vietnam War. The study subjects comprised 58 mother-infant pairs in a region with high dioxin levels in the soil (hotspot) and 62 pairs from a control region. Dioxin levels in maternal breast milk were measured by HRGC-HRMS. Salivary glucocorticoid levels were determined by LC-MS/MS. Dioxin congener levels in mothers from the hotspot were found to be two to fivefold higher than those in mothers from the control region. Birth weight was inversely correlated with 2,3,7,8-TeCDD and 2,3,4,7,8-PeCDF congener levels. The rate of newborns whose birth weight was less than 2500 g was threefold higher in the hotspot (12 %) than in the control region (4 %). Salivary glucocorticoid levels in mothers with low birth weight infants were significantly higher than those in the normal birth weight group. Low birth weight of Vietnamese newborns in a hotspot for dioxin levels is related to some dioxin congener levels and high glucocorticoid levels in mothers. This finding in mother-infant pairs suggests that excess maternal glucocorticoid levels are related to dioxin burden and they result in low birth weight.

Influence of dioxin exposure upon levels of prostate-specific antigen and steroid hormones in Vietnamese men.

Most studies on the relationship between Agent Orange and prostate cancer have focused on US veterans of the Vietnam War. There have been few studies focusing on the relationship between levels of prostate-specific antigen (PSA) and dioxins or steroid hormones in Vietnamese men. In 2009-2011, we collected blood samples from 97 men who had resided in a "dioxin hotspot" and 85 men from a non-sprayed region in Vietnam. Then levels of PSA, dioxins, and steroid hormones were analyzed. Levels of most dioxins, furans, and non-ortho polychlorinated biphenyls were higher in the hotspot than those in the non-sprayed region. Levels of testosterone, dehydroepiandrosterone, and estradiol differed significantly between the hotspot and the non-sprayed region, but there were no correlations between levels of PSA and steroid hormones and dioxins in either of the two regions. Our findings suggest that PSA levels in Vietnamese men are not associated with levels of dioxin or steroid hormones in these two regions.

Inverse association of highly chlorinated dioxin congeners in maternal breast milk with dehydroepiandrosterone levels in three-year-old Vietnamese children.

This study aims to evaluate the endocrine-disrupting effect of dioxin congeners on adrenal steroid hormones in mother-child pairs. In our previous study, we found that cortisol and cortisone levels were higher in the blood and the saliva of mothers living in a dioxin hotspot area than in mothers from a non-exposed region in Vietnam. In this follow-up study, we determined the salivary steroid hormone levels in 49 and 55 three-year-old children of these mothers in the hotspot and non-exposed region, respectively. Steroid hormones were determined by liquid chromatography-tandem mass spectrometry, and dioxin in the maternal breast milk was determined by gas chromatography-mass spectrometry. Dioxin levels in the breast milk of mothers from the hotspot (median total toxic equivalents polychlorinated dibenzodioxins/polychlorinated dibenzofurans; (TEQ PCDD/Fs) of 11pg/g lipid) were three to four times higher than those of mothers in the non-exposed region (median TEQ PCDD/Fs of 3.07pg/g lipid). Salivary dehydroepiandrosterone (DHEA) levels in children were found to be significantly lower in the hotspot than in the non-exposed region, while cortisol and cortisone levels were not different between the two regions. Highly chlorinated dioxin congeners, such as octacholorodibenzodioxin (OCDD), 1,2,3,4,6,7,8-heptacholorodibenzodioxin (HpCDD) and 1,2,3,4 (or 6), 7,8-hexachlorodibenzodioxin Hx(CDD), showed stronger inverse associations with the children's salivary DHEA than other lowly chlorinated dioxin congeners. Glucocorticoid levels in the mothers exhibited a significantly positive correlation with OCDD and HpCDD/F (polychlorinated dibenzofurans). In conclusion, highly chlorinated dioxin congeners are more strongly correlated with endocrine-disrupting effects on adrenal hormones, resulting in high cortisol levels in the mothers and low DHEA levels in their three-year-old children.

Dioxins and Nonortho PCBs in Breast Milk of Vietnamese Mothers Living in the Largest Hot Spot of Dioxin Contamination.

Bien Hoa Air Base is the largest dioxin contamination hot spot in Vietnam. In 2012, we recruited 216 mothers who were living in 10 communities around Bien Hoa Air Base and had delivered newborns at a prefecture hospital, and we investigated recent exposure levels of dioxins and nonortho PCBs in their breast milk. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-tetraCDD) was present at 2.6 pg/g lipid in primiparae and 2.2 pg/g lipid in multiparae. Among multiparae and total subjects, significant high prevalence of 2,3,7,8-tetraCDD≥5 pg/g lipid and 2,3,7,8-tetraCDD contribution≥40% were observed in mothers living in the five communities closest to Bien Hoa Air Base. The TEQ for nonortho PCBs was 1.6 pg-TEQ/g lipid for primiparae, and this was even lower than that in the unsprayed area. The length of residency was a strong factor to increase dioxins, including 2,3,7,8-tetraCDD. Residency in the five communities with the highest exposure was a specific risk factor for increased 2,3,7,8-tetraCDD in breast milk. Food intake might contribute partly to the increased levels of dioxin congeners other than 2,3,7,8-tetraCDD in breast milk. These results suggest that Bien Hoa Air Base has led to elevated 2,3,7,8-tetraCDD levels in breast milk of mothers in nearby areas even in the recent years.

Levels of polychlorinated dibenzodioxins and polychlorinated dibenzofurans in breast milk samples from three dioxin-contaminated hotspots of Vietnam.

We determined polychlorinated dibenzodioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in breast milk of 143 primiparae living around the three most dioxin-contaminated areas of Vietnam. The women sampled lived in the vicinity of former U.S. air bases at Bien Hoa (n=51), Phu Cat (n=23), and Da Nang (n=69), which are known as dioxin hotspots. Breast milk samples from Bien Hoa City, where residents live very close to the air base, showed high levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), with 18% of the samples containing >5 pgTCDD/g lipid. However, Phu Cat residents lived far from the air base and their samples showed lower TCDD levels, with none containing >5 pgTCDD/g lipid. In Da Nang, TCDD levels in mothers from Thanh Khe (close to the air base, n=43) were significantly higher than those in mothers from Son Tra (far from the air base, n=26), but not other PCDD and PCDF (PCDD/F) congeners. Although TCDD levels in Bien Hoa were the highest among these hotspots, levels of other PCDD/F congeners as well as the geometric mean concentration of total PCDD/F level in Bien Hoa (9.3 pg toxic equivalents [TEQ]/g lipid) were significantly lower than the level observed in Phu Cat (14.1 pgTEQ/g lipid), Thanh Khe (14.3 pgTEQ/g lipid), and Son Tra (13.9 pgTEQ/g lipid). Our findings indicated that residents living close to former U.S. air bases were exposed to elevated levels of TCDD, but not of other PCDD/F congeners.

Relationship between dioxin and steroid hormones in sera of Vietnamese men.

A recent study found an inverse correlation between serum TCDD levels and serum testosterone in the US veterans, while there is little known on the dioxin and steroid hormones about Vietnamese men. We collected blood samples from 48 men who had resided in a hotspot when exposure happened and 38 men in a non-sprayed area. Some steroid hormones levels showed significant differences between two areas. There were no correlations between steroid hormones and dioxin TEQ, after ajusting for age and other factors. Our findings indicate that steroid hormones of Vietnamese men did not correlate with dioxin TEQ in two areas.

Serum dioxin levels in Vietnamese men more than 40 years after herbicide spraying.

Recent studies have found elevated dioxin levels inside some U.S. military former air bases in Vietnam, known as hotspots. Many studies of Agent Orange have been done in U.S. veterans; however, there is little known about Vietnamese men. In 2010, we collected blood samples from 97 men in a hotspot and 85 men in an unsprayed area in Northern Vietnam. Serum concentrations of not only TCDD but also other dioxins (PCDDs), furans (PCDFs), and nonortho polychlorinated biphenyls (PCBs) were significantly higher in the hotspot than in the unsprayed area. In the hotspot, three subareas were demarcated, based on their proximity to the air base. The total toxic equivalents (TEQ) of PCDDs/PCDFs+PCBs was 41.7 pg/g lipid in the area closest to the air base, while it was around 29 pg/g lipid in the other two subareas. In the unsprayed area, the dioxin levels were no different between men who went to the South during the Vietnam War and those who remained in the North, with TEQs PCDDs/PCDFs+PCBs of around 13.6 pg/g lipid. Our findings suggested that people living close to the former U.S. air bases might have been exposed to both Agent Orange and other sources of dioxin-like compounds.

The relationship between Agent Orange and prostate specific antigen: a comparison of a hotspot and a non-sprayed area in Vietnam.

OBJECTIVES: The aim of this study was to explore the impact of Agent Orange exposure for prostate cancer with a comparison of the prostate specific antigen (PSA) levels between a hotspot and a non-sprayed area. METHODS: The study was conducted in Phu Cat district (hotspot) and Kim Bang district (non-sprayed), with a total of 101 men in the hotspot and 97 men in the non-sprayed area older than 50 years of age. About 5 mL of whole blood and a health status questionnaire were collected from each subject in August 2009-2011. RESULTS: The mean age of the subjects in the hotspot (68.0 years old) was significantly higher than that of those in the non-sprayed area (65.0 years old). No significant difference was found between the hotspot area (0.93 ng/mL) and the non-sprayed area (0.95 ng/mL) in terms of PSA levels. Likewise, this was not statistically significant after adjusting for age. The prevalence of high PSA levels (>3 ng/mL) did not differ significantly between the hotspot (14 men; 13.9 %) and non-sprayed area (9 men; 9.3 %). No significant difference was found between the hotspot area and the non-sprayed area in terms of occupation (farmer and others). In control subjects, no significant difference was found between the PSA levels in subjects exposed to Agent Orange and non-exposed subjects. Likewise, no significant difference was found between the PSA levels of combatants and civilians. CONCLUSION: The PSA levels were not significantly different between the hotspot and the non-sprayed area.

The relationship between dioxins and salivary steroid hormones in Vietnamese primiparae.

OBJECTIVE: Nearly 40 years after Agent Orange was last sprayed, we conducted a cross-sectional study to evaluate the impact of dioxin exposure on salivary hormones in Vietnamese primiparae. Our previous studies found higher levels of salivary cortisol and cortisone in one of the most highly dioxin-contaminated areas, known as a "hot-spot", than in a non-exposed area. As a result, we suggested that further research with a larger number of participants would be needed to confirm whether dioxin affects steroid hormone levels in Vietnamese primiparae. METHODS: The concentration of steroid hormones in saliva was determined by liquid chromatography (electrospray ionization tandem mass spectrometry), whereas the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in breast milk were determined by gas chromatography-high resolution mass spectrometry, for a sample of the population from a "hot-spot" (n = 16) and a non-exposed area (n = 10). All subjects were aged between 20 and 30 years and had children aged between 4 and 16 weeks. RESULTS: The mean toxic equivalence of PCDDs, PCDFs and PCDDs + PCDFs in breast milk in the hot-spot area was found to be significantly higher than in the non-exposed area (p < 0.001). Likewise, salivary cortisol, cortisone and dehydroepiandrosterone (DHEA) levels were significantly higher in the hotspot area than in the non-exposed area (p < 0.05). As a result, herein we report, for the first time, that salivary DHEA levels in primiparae are higher in a hot-spot than in a non-exposed area, and that this may be the result of dioxin exposure. CONCLUSIONS: Our findings highlight the long-term effects of Agent Orange/dioxin on steroid hormones in Vietnamese primiparae in the post-war period.