In epidemiological studies, associations of dioxin and dioxin-like (dl)-compound exposure with metabolic diseases, including diabetes and metabolic syndrome, in adults and with neurodevelopmental ...problems and earlier/later puberty in children have been suggested in the general population and in environmentally exposed populations ....
The association between cadmium exposure and risk of lung cancer is still unclear. We quantitatively reviewed the observational studies that investigated the association between cadmium exposure and ...lung cancer risk in both general and occupational populations published through April 2015. The final data set is comprised of three cohort studies in the general population totaling 22,551 participants (354 events) with a mean follow-up of 15 years, five occupational cohort studies including 4205 individuals (180 events) with an average follow-up of 31 years, and three occupational case-control studies including 4740 cases and 6268 controls. Comparing the highest to the lowest category of cadmium exposure, the weighted relative risk and 95% confidence interval of lung cancer in the general population was 1.42 (95% CI (0.91, 2.23)); the weighted risk estimates (95% CIs) of lung cancer in three occupational cohort studies and three case-control studies were 0.68 (95% CI (0.33, 1.41)) and 1.61 (95% CI (0.94, 2.75)), respectively. No linear association was found. When comparing participants exposed to cadmium with non-exposed based on available data, the association became statistically significant. According to findings from this meta-analysis, the possibility that cadmium exposure may increase risk of lung cancer cannot be completely ruled out in either general or occupational population.
Objective To investigate the longitudinal effects of perinatal exposure to dioxin on neurodevelopment and physical growth of a birth cohort during the first 3 years of life. Study design A total of ...217 mother–infant pairs living in a dioxin-contaminated area in Vietnam were followed up. Perinatal dioxin exposure of infants was estimated by the measurement of dioxin levels in breast milk of nursing mothers. Neurodevelopment of infants and children, including cognitive, language, and motor development, was determined at 4 months, 1 year, and 3 years of age. Physical growth, including weight, height, and head and abdominal circumferences, was measured at birth, 1 and 4 months, and 1 and 3 years of age. Multivariate mixed models were applied for analyzing repeated measures. Results In boys, composite motor and gross motor scores were decreased with increasing exposure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TetraCDD). The high toxic equivalent of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs-TEQ) group showed a significant decrease in expressive communication score. In girls, there was no decreased score in any neurodevelopment aspects in high-exposure groups. All body size measures in boys were decreased in the high-exposure groups of 2,3,7,8-TetraCDD and PCDDs/PCDFs-TEQ. In girls, high 2,3,7,8-TetraCDD and PCDDs/PCDFs-TEQ exposure was associated with increased head and abdominal circumferences. Conclusions Perinatal dioxin exposure affects physical growth and neurodevelopment of infants and children in the first 3 years of life in a sex-specific manner.
Fifty-five children aged 2 years from a birth cohort in the largest dioxin-contaminated area in Bien Hoa city, Vietnam participated in this survey to examine gaze behavior. Exposure levels were ...indicated by 2,3,7,8-tetrachlorodibenzo-p-dibenzodioxin (TCDD) and toxic equivalent of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (TEQ-PCDD/Fs) levels in maternal breast milk. The percentage of the total fixation duration on the face (% Face), mouth (% Mouth), and eye areas (% Eyes) when viewing silent and conversation scenes was used as gaze behavior indices. When they reached 3-year-old, autistic behavior was assessed using the Autism Spectrum Rating Scale (ASRS). A general linear model adjusted for confounding factors was used to compare gaze indices and ASRS scores between high and low dioxin exposure groups. Effects of perinatal dioxin exposure on gaze behavior were found only when viewing conversation scenes indicated by lower % Face for boys in high TCDD exposure group and lower % Eyes for girls in high TEQ-PCDD/Fs group. Increased autistic traits showed by higher ASRS scores at 3-year-old were found in both gender in the high TCDD exposure group. These findings indicate that perinatal TCDD and TEQ-PCDD/Fs exposure may reduce gaze behavior in 2-year-old children, predicting increased autistic traits at 3-year-old.
Bien Hoa airbase is the most contaminated area of dioxin contamination from Agent Orange in Vietnam, but little is known about the neurodevelopmental effects of perinatal dioxin exposure on children ...living nearby. We recruited 210 mother–newborn resident pairs in 2012 and 78 pairs in 2015 and followed them for 2 years to assess the children's neurodevelopment. As a control group, we used 120 mother–child pairs recruited in 2014 in the Ha Dong district of Ha Noi City, an unexposed area. Perinatal dioxin exposure levels were indicated by levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and toxic equivalency values of polychlorodibenzodioxins, polychlorodibenzofurans, and nonortho-polychlorinated biphenyls (TEQ-PCDD/Fs/noPCBs) in maternal breast milk. The Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) were used to assess neurodevelopment, and scores in each domain were compared between children with different exposure levels using general linear regression models and stratification by sex. Decreased expressive and composite language scores in boys and gross motor scores in girls were found in children exposed to TCDD ≥ 5.5 (pg/g lipid) compared with children with TCDD < 1.8. However, in matched pair analysis between children with TCDD ≥ 5.5 and <1.8 (pg/g lipid), lower expressive and composite language scores in boys exposed to TCDD ≥ 5.5 were significant, but lower gross motor scores in girls did not reach statistical significance. In addition, significant association was found between levels of PCDD congeners other than TCDD and gross motor scores in boys. These findings suggest that perinatal exposure of TCDD and other PCDD congeners affects development of language and gross motor skills, respectively, in boys at 2 years of age exposed to dioxins originating from Agent Orange in Vietnam.
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•Decreased language scores were found in boys exposed to high TCDD.•Gross motor scores decreased at borderline significance in girls with high TCDD.•Gross motor scores decreased in boys with high PCDD congeners other than TCDD.
For 8 years, we have followed up a birth cohort comprising 241 mother-and-infant pairs living around the Da Nang airbase, a hot spot of dioxin contamination in Vietnam, and have reported the impacts ...of perinatal dioxin exposure on the neurodevelopment of children at various ages. In the present study, 9 years after birth, we investigated the effects of perinatal dioxin exposure on mu and theta rhythms by analyzing EEG power during the execution and observation of hand movements, which indicate mirror neuron system activity.
One hundred fifty-five 9-year-old children (86 boys and 69 girls) from the Da Nang birth cohort participated in the EEG examination with free viewing of hand movements. The dioxin levels in their mothers’ breast milk, measured 1 month after birth, were used as perinatal dioxin exposure markers. A log transform of the ratio of EEG power during execution or observation of the hand movements relative to the power during observation of a bouncing ball for theta and mu rhythms was used to evaluate mirror neuron activity.
In both brain hemispheres, the log power ratio in the theta band was significantly higher (i.e., less reduction of power) during observation of hand movements in girls exposed to high levels of TCDD. In boys, however, dioxin congeners other than TCDD, including HxCDDs and several PCDF congeners, contributed to increased log power ratios in the theta band. Particularly for PCDF congeners, the log power ratios in the lowest group among 4 exposure groups were lowest and significantly increased (i.e., decreasing reduction of power) with increasing dose.
Perinatal TCDD exposure may influence the mirror neuron system of the brain, which plays an important role for social-emotional behavior in children, particularly in girls living in a hot spot of dioxin contamination in Vietnam.
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•Perinatal TCDD exposure decreased mirror neuron activity in 9-year-old girls.•Increasing some PCDF congeners significantly decreased mirror neuron activity in boys.•Mirror neuron impairment may be involved in developmental deficits due to dioxin exposure.
The aim of the present study was to evaluate the effect of environmental cadmium (Cd) exposure indicated by urinary Cd (U-Cd) on cancer mortality in the general Japanese population. A 19-year cohort ...study was conducted in 1107 men and 1697 women who lived in three Cd non-polluted areas in Japan. Mortality risk ratio and 95% confidence interval (95%CI) for continuous U–Cd were estimated for all malignant neoplasms and specific cancers using a Fine and Gray competing risks regression model. The all-cause, including cancer and non-cancer mortality rates per 1000 person-years were 29.8 and 13.9 in men and women, respectively. By using Fine and Gray's method, continuous U–Cd adjusted for creatinine (+1 μg/g cre) was significantly related to mortalities for all malignant neoplasms (risk ratio = 1.06, 95%CI: 1.02–1.11) and pancreas (risk ratio = 1.13, 95%CI: 1.03–1.24) in women. In the present study, U–Cd was significantly associated with increased cancer mortality in the general Japanese population, indicating that environmental Cd exposure adversely affects the life prognosis in Cd non-polluted areas in Japan.
Eating alone and poor dental status have been reported to influence dietary intake in older adults. First, we compared nutrient and food intake and dental markers between women eating alone and ...together, who participated in a home health management program conducted by Kanazawa Medical University. The results showed the significantly higher intake of fresh fruit and some micro-nutrients and a lower decayed, missing, and filled teeth (DMFT) index (better dental status) in women eating alone after adjusting for age, suggesting that dental status may mediate the association between commensality and dietary intake. Then, we investigated nutrients and foods at risk for insufficient intake and associated with increasing dental markers. The risks for the insufficient intake of protein and
-3 and
-6 polyunsaturated fatty acids (PUFAs) were significantly increased with an increasing DMFT index. The risk for
-3 PUFA intake also increased with increasing numbers of missing teeth in women. Foods at risk for insufficient consumption included beans for women with an increasing DMFT index and green and yellow vegetables, fresh fruits, and meat and fish for women with increasing numbers of missing teeth. These findings suggest that good health management, including the treatment of decayed teeth, is important for the prevention of malnutrition in community-dwelling healthy older women.
We previously reported the adverse effects of perinatal dioxin exposure on child neurodevelopment around a former US military airbase in Vietnam. In the present study, we investigated the effects of ...maternal dioxin exposure on fetal brain development, which may predict neurodevelopmental outcomes in early childhood. A total of 55 newborns with mothers from dioxin-contaminated areas were recruited in the prefecture hospital in Bien Hoa, Vietnam. Dioxins in maternal breast milk collected 1 month after birth were used as a maternal exposure marker. Relative powers and coherence were computed from neonatal electroencephalogram (EEG) records during active sleep stages. Relationships between the EEG parameters and dioxin exposure markers were analyzed using linear regression and a general linear model after adjusting for gestational age, body length, and head circumference of infants at birth. Using data from 47 infants whose neurodevelopment was examined in a 2-year follow-up study, associations between EEG parameters and neurodevelopment were analyzed after adjusting for confounding factors. On the right frontal and parietal regions, relative delta powers were significantly decreased, and relative alpha and beta powers were significantly increased with increasing dioxin exposure. Increases in delta power and decreases in alpha power on the right frontal and parietal regions were associated with an increase in language scores at 2 years of age. Furthermore, intra- and inter-hemispheric coherence in theta and alpha bands were positively and inversely correlated with dioxin exposure, respectively, and increased intra-coherence in the right hemisphere was associated with lower language scores. These findings suggest that prenatal dioxin exposure affects neuronal activity and functional connectivity between brain regions, and may lead to poor language development.
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•Prenatal dioxin exposure affects neuronal activity estimated from neonatal EEG.•Relative power and coherence of neonatal EEG are good markers for brain development.•Alteration of neonatal EEG might lead to poor language development at 2 years of age.
Previous studies have reported that dioxin exposure alters sexual dimorphism of play behavior in pre-pubertal children. We aimed to investigate the effects of perinatal dioxin exposure, indicated by ...dioxins in breast milk, on sexual dimorphism of gaze behavior after adjusting for salivary testosterone (T). Participants were pre-pubertal children in a hot spot for dioxin contamination originating from herbicide spraying in Vietnam.
We used eye tracking to assess gaze behavior in 172 children (100 boys and 72 girls) aged 8–9 years. Two sets of 15 pairs of pictures, one oriented towards boys and one oriented towards girls, containing 5 pairs of toy photos (non-biological stimuli) and 10 pairs of human line drawings (biological stimuli) were shown to all children. The total fixation duration for each picture was extracted using Tobii studio software and a feminine index of gaze behavior was defined as the ratio of the summed fixation duration for the girl- vs boy-oriented versions of each stimuli.
When viewing non-biological stimuli, feminine index scores significantly increased with TCDD (β = 0.294) in girls only. For biological stimuli, however, feminine index scores significantly increased with TEQ-PCDD/Fs (β = 0.269) in boys and with TCDD in girls (β = 0.286). These associations were significant even after adjusting for salivary T levels, which were inversely associated with some dioxin congeners in girls. In addition, increased feminine index scores for biological stimuli were associated with lower cognitive scores for hand-movement and word-order tests in boys and for face-recognition tests in girls examined at 5 years of age.
In conclusion, these results suggest that perinatal dioxin exposure may increase visual interest in girl-oriented objects through impairment of cognitive abilities in pre-pubertal Vietnamese children. PCDD congeners were associated with gaze behavior independently of T levels in boys, while this was only the case for TCDD levels in girls.
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•Dioxin effects on behavioral sexual dimorphism were investigated in Vietnamese 8-year-olds.•Salivary testosterone was significantly decreased with increasing TEQ-PCDFs in girls.•Feminine scores for any stimuli were increased with increasing TCDD in girls.•Feminine scores for biological stimuli were increased with increasing TEQ-PCDD/Fs in boys.•Increased feminine gaze behavior may be associated with impairment of cognitive abilities.
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