Enteric parasites and associated factors in cancer patients in Nepal.

Infection with intestinal parasites is widespread worldwide, especially in developing countries. Intestinal parasites are a major cause of diarrhea in both immunocompetent and immunocompromised people, but cancer patients are more prone to infection. This study aimed to investigate the prevalence and risk factors of intestinal parasitic infections (IPIs) among cancer patients undergoing chemotherapy at Nepal Cancer Hospital and Research Center (NCHRC) in Nepal. One hundred individuals were selected with a convenience sampling strategy. The stool samples were examined by direct wet mount, sedimentation, flotation, and acid-fast methods to determine the prevalence and intensity of IPIs in this population. The overall prevalence of IPIs was 8% (4% protozoan and 4% helminths). Altogether, three species of intestinal parasites were detected. Cryptosporidium (4%) was predominant followed by Trichuris trichiura (2%) and Ancylostoma duodenale (2%). Multivariable regression analysis revealed that "not using soap for handwashing" was significantly associated with the prevalence of overall IPIs. None of the other evaluated risk factors indicated an association with IPIs infection. In this study, the IPIs were attributable to individual hygiene behaviors, but not to nutritional status or socio-demographic characteristics. Yet, significant numbers of males reported anemia and undernutrition in this study population.

Survey of intestinal parasites in swine farms raised in Western Nepal.

BACKGROUND: Pigs (Sus scrofa domesticus), an important domestic livestock, are generally affected by helminth and protozoan parasites. Rearing pigs in rural regions in Nepal is a common practice for subsistence farming. A cross-sectional survey was conducted to determine the occurrence of gastrointestinal parasites (GIPs) in pigs raised in Western Nepal. METHODS: A total of 200 faecal samples from commercial and smallholder farms were examined by wet mounts, flotation, sedimentation and staining techniques. RESULTS: The results revealed that overall 86.5% of samples were found shedding oocysts or eggs of one or more GIPs. Three species of protozoa [Eimeria sp. (26%), Entamoeba coli (25.5%) and Coccidia (29%)] and nine species of helminths parasites (Ascaris suum (32.5%), Trichuris suis (30%), strongyle-type nematode (27.5%), hookworm (26%), Fasciola sp. (17.5%), Physaloptera sp. (17.5%), Strongyloides sp. (17.5%), Metastrongylus sp. (8%) and Oesophagostomum sp. (5.5%)] were identified. Female pigs were found to have higher protozoan infection than males, but such a difference was not noticed with regard to helminth parasites. Strongyles and Oesophagostomum infection were higher in commercial farms compared to smallholder farms, whereas the prevalences of E. coli and other protozoans were higher in smallholder farms. Among the contextual factors evaluated for association, weight and gender of pigs, and annual income and gender of managers/caretakers were significantly (p < 0.05) associated with the prevalence of GIPs in pigs. The overall prevalence of certain helminths such as strongyle-type nematode and A. suum was significantly (p < 0.05) associated with the weight of pigs after adjusting other contextual factors. CONCLUSIONS: This study detected relatively high prevalence of intestinal parasites in domestic pig facilities. Molecular epidemiological studies are essential to verify the exact zoonotic potential of parasites carried by pigs in the region. An effective periodic monitoring of GIPs of pigs needs to be carried out to minimize their further dissemination.

Circulatory health risks from additive multi-pollutant models: short-term exposure to three common air pollutants in Canada.

Numerous studies have reported adverse health effects of ambient air pollution on circulatory health outcomes mainly based on single-pollutant models. However, limited studies have focused on adjusted effect of multi-pollutant exposures on public health. This study aimed to examine short-term effects of three common air pollutants-ground-level ozone (ozone), nitrogen dioxide (NO2), and fine particulate matter (PM2.5)-through multi-pollutant models for mixed effect of adjustment. Daily data (circulatory hospitalization and mortality) and hourly data (air pollutants and temperature) were collected for 24 Canadian cities for 2001-2012. We applied generalized additive over-dispersion Poisson regression models with 1, 2, or 3 pollutants for city-specific risks, and Bayesian hierarchical models for national risks. This study found little mixed effect of adjustment through multi-pollutant models (ozone and/or NO2 and/or PM2.5) for circulatory hospitalization or mortality in Canada for 2001-2012, indicating that the 1-pollutant model did not result in considerable under- or over-estimates. It seemed weak-to-moderate correlations among air pollutants did not change the significant effect of one air pollutant after accounting for others. Inconsistent findings between other previous studies and this study indicate the need of comparable study design for multi-pollutant effect analysis.

Prevalence and burden of gastrointestinal parasites in stray cattle of the Kathmandu Valley.

Gastrointestinal parasites (GIPs) are common among cattle resulting severe infection. Prevalence of GIPs in stray street cattle may pose risk of dissemination of parasites of zoonotic importance. This study was conducted to determine the prevalence of GIPs in stray cattle of the Kathmandu valley. One hundred (n = 100) freshly voided dung samples were collected from eight sites. The samples were processed using the concentration method for microscopic examination, and modified McMaster technique for quantification of mean eggs/oocysts per gram of feces (EPG/OPG). Results revealed that 72% of the cattle were found positive for one or more species of GIPs and nine genera of GIPs were recorded (Eimeria, Ostertagia, Haemonchus, Trichostrongylus, Capillaria, Trichuris, Toxocara, Fasciola and Paramphistomum). The prevalence of parasitic infection was higher in males (73.68%) than in females (69.76%). The prevalence was found to be highest in adults (63.89%) followed by heifers or steers (27.78%) and calves (8.33%). Approximately, 76% of the cross breed and 65% of the local breed of cattle were positive for parasitic infection. The parasites differed both in prevalence and intensity. Eimeria sp. was the most prevalent (27%) species and had the highest intensity (858.02 OPG ± 63.46 SD). To our knowledge, this is the first research of its kind in relation to stray cattle in Nepal. Our findings reveal that there is a burden of helminth infections of zoonotic and socioeconomic importance in straycattle. Therefore, we recommend regular inspection of stray cattle and relevant preventive measures be put in place.

Minimum risk of intestinal parasitic infection to the visitors of Ghandruk, Kaski, Nepal: a pilot survey.

Ghandruk is one of the famous destinations of both international and domestic tourists situated in Kaski, Nepal. Travel-related diseases are an important aspect that one should consider before making a travel plan. Among diseases, zoonotically important ones make serious worries among visitors. In order to assess the existence of the zoonotically important parasitic disease in Ghandruk, a pilot survey was carried out by examining representative stool samples (n=51) of local residence, domestic animals, pet animals in Ghandruk. Samples were examined using direct smear as well as concentration methods. A questionnaire survey was conducted to see the associated risk factors among residents and their livestock of Ghandruk. None of the faecal samples from residents (n=14) found positive for any kind of intestinal parasites (IPs), while samples from most of the livestock: chicken (86%, 6/7), pigeons (75%, 3/4), cow (66%, 2/3), mule (60%, 3/5), and dog (60%, 3/5) showed heavy infection, except goat and buffalo indicated no infection. Eimeria spp., Ascardia spp. and cestodes spp. were the most prevalent IPs in livestock. Periodic deworming, walking outdoor with sandals/shoes, frequent use of soap and water for handwashing as reported by most of the residents (>80%) could be the main reason behind zero prevalence of IPs in them. The heavy infection among livestock may be incriminated to the contaminated vicinity and free-range livestock and poultry which were noticed in contact with river, sludge, and toilets during our field observation. Conclusively, it indicates that the residents of Ghandruk are conscious about their health, but have not paid satisfactory attention to the hygiene of their domestic animals including livestock, poultry and even pet. Though the observed parasites in livestock are of minimal zoonotic importance regarding safety of visitors, it is deemed necessary for at least to apply some preventive measures to mitigate the burden of parasites in their animals.

Prevalence and risk factors of gastrointestinal parasites in the Chepangs in Nepal.

Gastrointestinal (GI) infection is predominant globally, especially in people with low socio-economic status with existing illiteracy, ignorance, poor housing and lifestyle, and the surrounding environment. It has been implicated as a significant public health concern in the rural parts of many developing countries like Nepal. This study aimed to determine the diversity and prevalence of GI parasites in the highly marginalized indigenous Chepang communities in central Nepal. One hundred fresh stool samples of Chepangs were collected and preserved in 2.5% potassium dichromate solution. The samples were analyzed by direct wet mount, sedimentation, flotation, and acid-fast techniques and examined under the microscope at the total magnifications of 100Å~, 400Å~, and 1000Å~. We detected 97% prevalence rates with eight protozoan and six helminth parasites. Considering the infection's concurrency, mixed pattern of infection was found to be higher than single pattern. Mixed infections from two to seven parasitic species were differently recorded in different samples. We also found that people's eating habits were associated with GI parasitism (p=0.0034). "One Health" Approach/Principle accompanied by the detailed molecular and epidemiologic studies of parasitic transmission is required to identify the causal evidence critical in controlling and preventing parasitic infections.

Associations between urinary heavy metal concentrations and blood pressure in residents of Asian countries.

BACKGROUND: Previous studies have suggested that exposures to heavy metals (arsenic, cadmium, lead, and selenium) may be associated with differences in blood pressure. However, the findings of these studies have been inconsistent. This study was performed to examine the associations between urinary heavy metal concentrations and blood pressure among residents of four Asian countries (Bangladesh, Indonesia, Nepal, and Vietnam). METHODS: This cross-sectional study examined 1899 adults in four Asian countries. Urinary concentrations of heavy metals were measured by inductively coupled plasma mass spectrometry. A questionnaire survey was administered regarding individual characteristics. Anthropometric measurements (height and weight) were performed. Systolic and diastolic blood pressures were measured after a short rest. Multiple linear regression models were applied to investigate associations between urinary heavy metal concentrations and blood pressure after adjustments for age, sex, and body mass index. RESULTS: The geometric means of the urinary concentrations of arsenic, cadmium, lead, and selenium were 84.6, 0.885, 2.09, and 16.5 µg/g creatinine, respectively. The urinary arsenic concentrations were slightly higher than those typically reported in non-polluted populations, while urinary cadmium, lead, and selenium concentrations were equivalent or slightly lower. The urinary lead concentrations were positively associated with both systolic and diastolic blood pressure, but urinary selenium concentrations were negatively associated with them. CONCLUSIONS: Variations in the urinary concentrations of lead and selenium were associated with blood pressure at low levels of exposure/intake.

Variation in biomarker levels of metals, persistent organic pollutants, and omega-3 fatty acids in association with genetic polymorphisms among Inuit in Nunavik, Canada.

BACKGROUND: Biomarker measures of contaminant exposure and nutrient status can help increase understanding of the risks and benefits associated with the consumption of traditional foods by Inuit. While gene-environment and gene-nutrient interactions may help explain variations in biomarker measures, the role of genetic polymorphisms is largely understudied especially for vulnerable sub-populations. OBJECTIVE: The aim of this study was to characterize the relationship between single nucleotide polymorphisms (SNPs) in key genes and blood concentrations of environmental chemicals and nutrients among Inuit. METHODS: Blood samples from 665 individuals who participated in the Qanuippitaa Survey (Nunavik, Canada) in 2004 were analyzed for toxicants and nutrients. DNA was extracted and 140 SNPs in classes relevant to the toxicokinetics and/or toxicodynamics of the target contaminants and nutrients, and/or are involved in cardiovascular health and lipid metabolism were genotyped using the Sequenom iPLEX Gold platform. RESULTS: Geometric means (µg/L) of mercury (Hg), cadmium (Cd), lead (Pb), DDE, PCB-153, and selenium (Se) were 11.1, 2.8, 39.9, 2.9, 1.1 and 301.2, respectively. Red blood cell membrane levels of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were 5.1%/total fatty acid (TFA) and 1.3%/TFA respectively. Out of 106 SNPs which met our inclusion criteria, biomarker levels for Hg, Cd, Pb, DDE, PCB-153, DHA, and EPA differed (p < 0.05) by genotype for 20, 13, 12, 19, 21, 9 and 8 SNPs, respectively. Following Bonferroni correction (p < 0.0005), only 9 SNPs remained significant (rs2274976 in MTHFR, rs174602 in FADS2, rs7115739 and rs74771917 in FADS3, rs713041 in GPX4, rs2306283 and rs4149056 in SLCO1B1, rs1885301 in ABCC2/MRP2, and rs4244285 in CYP2C19; 5 associated with Hg, 2 with Pb, 2 with DDE, 4 with PCB-153, 1 with DHA). CONCLUSIONS: The findings suggest that polymorphisms in environmentally-responsive genes can influence biomarker levels of key toxicants and nutrients. While there are no immediate clinical or public health implications of these findings, we believe that such gene-environment and gene-nutrient studies provide a foundation that will inform and provide direction to future studies.

Pollutant-sex specific differences in respiratory hospitalization and mortality risk attributable to short-term exposure to ambient air pollution.

BACKGROUND: Many studies have reported associations of individual pollutants with respiratory hospitalization and mortality based on different populations, which makes it difficult to directly compare adverse health effects among multiple air pollutants. OBJECTIVES: The study goal is to compare acute respiratory-related hospitalization and mortality associated with short-term exposure to three ambient air pollutants and analyze differences in health risks by season, age and sex. METHODS: Hourly measurements of air pollutants (ozone, NO2, PM2.5) and temperature were collected from ground-monitors for 24 cities along with daily hospitalization (1996-2012) and mortality (1984-2012) data. National associations between air pollutant and health outcome were estimated for season (warm, cold vs. year-round), age (base ≥ 1, seniors > 65), and sex (females ≥ 1 and males ≥ 1) using Bayesian hierarchical models. RESULTS: Overall, the three air pollutants were significantly associated with acute respiratory health outcomes at different lag-days. For respiratory hospitalization, the increased risks in percent changes with 95% posterior intervals for a 10-unit increase in each pollutant were: ozone (lag1, 0.7% (0.4, 0.9)), NO2 (lag0, 0.7% (0.1, 1.4)), and PM2.5 (lag1, 1.3% (0.7, 1.9)). For respiratory mortality: ozone (lag2, 1.2% (0.4, 1.9)), NO2 (lag1, 2.1% (0.6, 3.5)), and PM2.5 (lag1, 0.6% (-1.0, 2.2)). While some differences in risk were observed by season and age group, sex-specific differences were more pronounced. Compared with males, females had a higher respiratory mortality risk (1.8% (0.6, 2.9) vs 0.5% (-0.3, 1.3)) from ozone, a higher respiratory hospitalization risk (0.9% (0.0, 1.8) vs 0.6% (-0.3, 1.4)) but lower mortality risk (1.4% (-1.0, 3.7) vs 2.2% (0.4, 4.0)) from NO2, and a lower hospitalization risk (0.7% (-0.2, 1.7) vs 1.8% (1.0, 2.6)) from PM2.5. CONCLUSION: This study reports significant health effects of short-term exposure to three ambient air pollutants on respiratory hospitalization (ozone≈NO2 < PM2.5 per-10 unit; ozone>NO2 ≈ PM2.5 per-IQR) and mortality (ozone≈NO2 > PM2.5) in Canada. Pollutant-sex-specific differences were found, but inconclusive due to limited biological and physiological explanations. Further studies are warranted to understand the pollutant-sex specific differences.

Comparison of hospitalization and mortality associated with short-term exposure to ambient ozone and PM2.5 in Canada.

BACKGROUND: Hospitalization and mortality (H-M) have been linked to air pollution separately. However, previous studies have not adequately compared whether air pollution is a stronger risk factor for hospitalization or mortality. This study aimed to investigate differences in H-M risk from short-term ozone and PM2.5 exposures, and determine whether differences are modified by season, age, and sex. METHODS: Daily ozone, PM2.5, temperature, and all-cause H-M counts (ICD-10, A00-R99) were collected for 22-24 Canadian cities for up to 29 years. Generalized additive Poisson models were employed to estimate associations between each pollutant and health outcome, which were compared across season (warm, cold, or year-round), age (all ages or seniors > 65), and sex. RESULTS: Overall, ozone and PM2.5 showed higher season-specific risk of mortality than hospitalization: warm-season ozone: 0.54% (95% credible interval, 0.20, 0.85) vs. 0.14% (0.02, 0.27) per 10 ppb; and year-round PM2.5: 0.90% (0.33, 1.41) vs. 0.29% (0.03, 0.56) per 10 µg/m3. While age showed little H-M difference, sex appeared to be a modifier of H-M risk. While females had higher mortality risk, males had higher hospitalization risk: for females, ozone 0.87% (0.36, 1.35) vs. -0.03% (-0.18, 0.11) and PM2.5 1.19% (0.40, 1.90) vs. 0.19% (-0.10, 0.47); and for males ozone 0.20% (-0.28, 0.65) vs. 0.35% (0.18, 0.51). CONCLUSION: This study found H-M differences attributable to ozone and PM2.5, suggesting that both are stronger risk factors for mortality than hospitalization. In addition, there were clear H-M differences by sex: specifically, females showed higher mortality risk and males showed higher hospitalization risk.

Cohort profile: health effects monitoring programme in Ndilǫ, Dettah and Yellowknife (YKHEMP).

PURPOSE: The Yellowknife Health Effects Monitoring Programme (YKHEMP) was established to examine the relationship of exposure to arsenic and other chemicals of potential concern such as antimony, cadmium, lead, manganese and vanadium and health outcomes. PARTICIPANTS: A total of 2037 individuals were recruited, including children (age 3-19) and adults (age 20+), residing in Dettah, NdilÇ« and Yellowknife, in the Northwest Territories, Canada, in two waves in Fall 2017 and Spring 2018. In Yellowknife, there were 891 (675 adults, 216 children), randomly selected participants with a participation rate of 64%. In addition, we also recruited a total of 875 (669 adults, 206 children) volunteer participants. A total of 225 (137 adults, 88 children) of the Yellowknives Dene First Nation (YKDFN), and 46 (33 adults, 13 children) of the North Slave Métis Alliance participated in the study. Each participant answered a lifestyle questionnaire as well as provided toenail clippings and urine for contaminant testing and saliva samples for testing of genetic polymorphisms associated with arsenic metabolism. Participants also provided consent to have their medical records reviewed by the research team for the past 5 years to allow for the investigation between exposure and health outcomes. FINDINGS TO DATE: The adult YKHEMP participants had lower urinary total arsenic but the children had higher inorganic arsenic than the general Canadian population. There was no difference in urinary total arsenic concentrations between adults and children, however, urinary inorganic arsenic concentrations were generally higher in children than in adults in all four YKHEMP sampling groups. The adult YKDFN participants had lower urinary total arsenic and inorganic arsenic concentrations compared with the random selected and volunteer participants. FUTURE PLANS: YKHEMP is designed as a prospective cohort study; the children participants will be re-examined in 2022 and both adult and children participants in 2027.

Health risk assessment of arsenic exposure among the residents in Ndilǫ, Dettah, and Yellowknife, Northwest Territories, Canada.

There are concerns in Yellowknife, Northwest Territories, Canada, about arsenic exposure due to past mining operations, particularly the former Giant Mine. The objective of this study was to characterize the risk of arsenic exposure and associated risk factors among the local residents. Arsenic (As) and its species were quantified in urine (n = 1966) using inductively coupled mass spectrometry. Children in the study were found to have significantly higher (p < 0.05) urinary inorganic-related As (uiAs) concentrations than children in the general Canadian population, as well as adults in the study. Additionally, uiAs concentrations in children, particularly those above the 95th percentile, are above the Biomonitoring Equivalents (BE) levels that are associated with dermal effects, vascular problems and cancer risks. Multiple linear regression results showed that market seafood (fish and shellfish) and rice consumption frequency were significantly positively associated with uiAs. Specific to children, drinking lake water was positively associated with uiAs. Specific to adults, consumption of local mushrooms and berries were significantly positively associated with uiAs while there was a significant negative association with age, smoking and recreational water activities. The risk factors identified in this research can be used for public health education to lower arsenic intake. Overall, these results support the need for an ongoing monitoring program.

Temporal trends in associations between ozone and circulatory mortality in age and sex in Canada during 1984-2012.

BACKGROUND: Considerable research has been conducted on the association between ground-level ozone (ozone) and various causes of mortality, but the relationships by age and sex (biological) have been inconsistent, and temporal trends remain unexplored. OBJECTIVES: The study goals are to investigate the adverse health effects of short-term exposure to ozone on circulatory mortality by age and sex, and to examine trends in annual health effects. METHODS: Daily ozone, temperature, and circulatory mortality counts (ICD I00-I99) were collected for 24 urban cities for 29 years (1984-2012). Associations between ozone and circulatory mortality were estimated using generalized additive Poisson models for season (warm vs. cold), age [base (≥1) vs. seniors (>65)], and sex, accounting for confounders (calendar-time, temperature, day of the week). City-specific estimates were pooled to represent national associations through Bayesian hierarchical models. RESULTS: While the cold season returned insignificant estimates, the warm season showed statistically significant associations: a 10 ppb increase in ozone was associated with 0.7% increase in circulatory mortality with a 95% posterior interval of 0.2%, 1.1%. One-day lagged ozone in the warm season showed little age differences [0.7% (0.23%, 1.12%) vs. 0.8% (0.22%, 1.27%)], but visible sex differences: females were at a higher circulatory mortality risk than males [1.1% (0.31%, 1.71%) vs. 0.3% (-0.46%, 0.98%)]. Annual estimates suggest overall up-down temporal changes; a slightly increasing trend until 2002-2004, and a generally decreasing trend thereafter. CONCLUSION: This study found noticeable sex-related differences in circulatory mortality attributable to short-term exposure to ozone. Further research is warranted to understand whether sex alone, or unknown interactions with other factors derived the differences, and to clarify the specific biological mechanisms underlying differences in risk estimates between females and males.

Genetic polymorphisms are associated with exposure biomarkers for metals and persistent organic pollutants among Inuit from the Inuvialuit Settlement Region, Canada.

BACKGROUND: Inuit are exposed to some of the highest levels of contaminants worldwide. Studies suggest that several genes that mediate the metabolism of these contaminants are polymorphic. We hypothesize that single nucleotide polymorphisms (SNPs) in such genes may underline differences in biomarker concentrations and/or modify exposure-biomarker associations. METHODS: Members from the Inuvialuit Settlement Region (Canada) were recruited. Blood concentrations of mercury (Hg), cadmium (Cd), lead (Pb), dichlorodiphenyldichloroethylene (DDE), and polychlorinated biphenyl (PCB-153) were measured. SNPs from pathways such as glutathione, metallothionein, oxidative stress, and xenobiotic transport were genotyped in 281 participants, and data from 112 SNPs were included in the analyses. Surveys were administered to obtain information on demographics, and key sources of Hg (diet) and Cd (smoking) exposure. ANOVA and linear regressions were used for data analyses. RESULTS: Geometric mean concentrations of metals were 4.6µg/L for Hg, 1.3µg/L for Cd, and 32.2µg/L for Pb. Concentrations of organic pollutants were 2.0µg/L for DDE and 0.6µg/L for PCB-153. Biomarker levels for Hg, Cd, Pb, DDE, and PCB-153 differed (p<0.05) by genotype for 4, 3, 4, 3, and 3 SNPs, respectively. In multivariable analyses (for Pb, DDE, PCB-153) adjusting age, sex and body mass index (BMI), only 2 associations (one for Pb and one for DDE) remained significant. In multivariable analyses accounting for sources of Hg or Cd exposure, 24 SNPs (9 for Hg, 15 for Cd with 4 overlapping) had significant (p<0.05) main effects on biomarker levels and/or modified exposure-biomarker associations. CONCLUSION: The findings suggest that polymorphisms in key environmentally responsive genes can influence biomarker levels and/or modify exposure-biomarker associations for contaminants of concern to Arctic populations. Consideration of such gene-environment results may help improve the ability to conduct exposure (and ultimately risk) assessments of country foods and Inuit health.

Birth Cohort Consortium of Asia: Current and Future Perspectives.

BACKGROUND: The environmental health of children is one of the great global health concerns. Exposures in utero and throughout development can have major consequences on later health. However, environmental risks or disease burdens vary from region to region. Birth cohort studies are ideal for investigating different environmental risks. METHODS: The principal investigators of three birth cohorts in Asia including the Taiwan Birth Panel Study (TBPS), the Mothers and Children's Environmental Health Study (MOCEH), and the Hokkaido Study on Environment and Children' Health (Hokkaido Study) coestablished the Birth Cohort Consortium of Asia (BiCCA) in 2011. Through a series of five PI meetings, the enrolment criteria, aim of the consortium, and a first-phase inventory were confirmed. RESULTS: To date, 23 birth cohorts have been established in 10 Asian countries, consisting of approximately 70,000 study subjects in the BiCCA. This article provides the study framework, environmental exposure and health outcome assessments, as well as maternal and infant characteristics of the participating cohorts. CONCLUSIONS: The BiCCA provides a unique and reliable source of birth cohort information in Asian countries. Further scientific cooperation is ongoing to identify specific regional environmental threats and improve the health of children in Asia.

Urinary and plasma fluoride levels in pregnant women from Mexico City.

BACKGROUND: There is need to assess the developmental neurotoxicity of fluoride. Our knowledge of prenatal fluoride exposure is challenged as few population-based studies have been conducted and these generally date back several decades, provide incomplete data on sociodemographic variables, and have methodological limitations. OBJECTIVE: To measure urinary and plasma fluoride levels across three time points in pregnant mothers who were enrolled in the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) birth cohort study. METHODS: Fluoride levels were characterized in archived urine and plasma from 872 pregnant mothers sampled from the ELEMENT cohort. Various statistical methods were used to analyze the fluoride data with particular consideration for changes across three stages of pregnancy and against sociodemographic variables. RESULTS: All samples had detectable levels of fluoride. The mean urinary and plasma fluoride levels were 0.91 and 0.0221mg/L respectively, and these were not statistically different across three stages of pregnancy. Fluoride levels correlated across the stages of pregnancy studied, with stronger correlations between neighboring stages. Urinary fluoride changed as pregnancy progressed with levels increasing until ~23 weeks and then decreasing until the end of pregnancy. For plasma fluoride, there was a decreasing trend but this was not of statistical significance. Creatinine-adjusted urinary fluoride levels did not associate consistently with any of the sociodemographic variables studied. CONCLUSIONS: This study provides the most extensive characterization to date of fluoride exposure throughout pregnancy. These results provide the foundation to explore exposure-related health outcomes in the ELEMENT cohort and other studies.

Association of cadmium and arsenic exposure with salivary telomere length in adolescents in Terai, Nepal.

BACKGROUND: Cadmium and arsenic are ubiquitous metals commonly found in the environment which can harm human health. A growing body of research shows telomere length as a potential biomarker of future disease risk. Few studies have examined the effects of metals on telomere length and none have focused on adolescents. OBJECTIVES: In this study, the impact of cadmium and arsenic on salivary telomere length was studied in adolescents in Terai, Nepal. METHODS: Adolescents aged 12-16 years old (n=351)were recruited where questionnaire interviews and both saliva and urine collection took place. Telomere length was determined by quantitative polymerase chain reaction using DNA extracted from saliva. Urinary cadmium and arsenic concentration were measured by inductively coupled plasma mass spectrometry. Multivariable linear regression was used to examine associations between urinary metals and salivary telomere length. RESULTS: The geometric means and standard deviations of cadmium and arsenic were 0.33±0.33µg/g creatinine and 196.0±301.1µg/g creatinine, respectively. Urinary cadmium concentration was negatively associated with salivary telomere length after adjustment for confounders (ß=-0.24, 95% CI -0.42,-0.07). Arsenic showed positive associations with telomere length but did not reach statistical significance. CONCLUSIONS: This is the first study to demonstrate that cadmium may shorten adolescent telomeres, even at exposure levels that may be considered low. These results agree with prior experimental and adult epidemiological studies, and also help identify the mechanism of DNA damage by cadmium. This study expanded current evidence on the harmful effects of cadmium exposure on telomere length even to adolescents.

Genetic polymorphisms are associated with hair, blood, and urine mercury levels in the American Dental Association (ADA) study participants.

BACKGROUND/AIMS: Mercury (Hg) is a potent toxicant of concern to the general public. Recent studies suggest that several genes that mediate Hg metabolism are polymorphic. We hypothesize that single nucleotide polymorphisms (SNPs) in such genes may underline inter-individual differences in exposure biomarker concentrations. METHODS: Dental professionals were recruited during the American Dental Association (ADA) 2012 Annual Meeting. Samples of hair, blood, and urine were collected for quantifying Hg levels and genotyping (88 SNPs in classes relevant to Hg toxicokinetics including glutathione metabolism, selenoproteins, metallothioneins, and xenobiotic transporters). Questionnaires were administrated to obtain information on demographics and sources of Hg exposure (e.g., fish consumption and use of dental amalgam). Here, we report results for 380 participants with complete genotype and Hg biomarker datasets. ANOVA and linear regressions were used for statistical analysis. RESULTS: Mean (geometric) Hg levels in hair (hHg), blood (bHg), urine (uHg), and the average estimated Hg intake from fish were 0.62µg/g, 3.75µg/L, 1.32µg/L, and 0.12µg/kg body weight/day, respectively. Out of 88 SNPs successfully genotyped, Hg biomarker levels differed by genotype for 25 SNPs, one of which remained significant following Bonferroni correction in ANOVA. When the associations between sources of Hg exposure and SNPs were analyzed with respect to Hg biomarker concentrations, 38 SNPs had significant main effects and/or gene-Hg exposure source interactions. Twenty-five, 23, and four SNPs showed significant main effects and/or interactions for hHg, bHg, and uHg levels, respectively (p<0.05), and six SNPs (in GCLC, MT1M, MT4, ATP7B, and BDNF) remained significant following Bonferroni correction. CONCLUSION: The findings suggest that polymorphisms in environmentally-responsive genes can influence Hg biomarker levels. Hence, consideration of such gene-environment factors may improve the ability to assess the health risks of Hg more precisely.

Association of cord blood levels of lead, arsenic, and zinc and home environment with children neurodevelopment at 36 months living in Chitwan Valley, Nepal.

BACKGROUND: Inconsistent results continue to be reported from studies linking low-level prenatal lead exposure and child development. Because of limited earlier epidemiological studies with birth cohort follow up design, it still remains inconclusive that either the associations of cord blood level of toxic, and essential elements, and postnatal raising environment on neurodevelopment of children remains constant throughout childhood or change over time. AIMS: This study aims to investigate the influence of in utero toxic [lead (Pb) and arsenic (As)] and essential elements [zinc (Zn)] levels on neurodevelopment of 36 months children in Chitwan valley, Nepal taking the postnatal environment into account. STUDY DESIGNS AND SUBJECTS: In this birth cohort study, participants (N=100 mother-infants' pairs) were recruited in Chitwan district, Nepal. We measured Pb, As and Zn concentrations in cord blood. Postnatal raising environment (i.e., Home score or home environment hereafter) was evaluated using Home Observation for Measurement of Environment (HOME) scale. Neurodevelopment of children at 36 months of age (n=70) were assessed using Bayley Scale of Infant Development, Second Edition (BSID II). Multivariate regression was performed (n=70) to see the association of in utero toxic and essential elements level and home environment with neurodevelopment score adjusted for covariates. RESULTS: Cord blood levels of Pb, As and Zn were not associated with any BSID II cluster scores of 36 months children. The children with relatively superior HOME score and concurrent nutritional status (weight at 36 months) showed better cognitive development (i.e., MDI scores) and motor functions than their counterparts, respectively. CONCLUSION: In this general population in Nepal, prenatal Pb, As and Zn levels are not important determinants of the neurodevelopment of 36- month-old children while a consistent beneficial effect of a stimulating home environment on neurodevelopmental indicators is continued.

Home environment and cord blood levels of lead, arsenic, and zinc on neurodevelopment of 24 months children living in Chitwan Valley, Nepal.

In a birth cohort living in Chitwan Valley, lowland Nepal, we have previously reported inverse associations between in utero levels of lead (Pb), arsenic (As) and neurodevelopment at birth measured by the Brazelton Neonatal Behavioral Assessment Scale, third edition (NBAS III). In the present paper, a follow-up of the same cohort was made on 24-month-old infants regarding the neurodevelopmental effects of these metals, taking the postnatal environment into account. In total, the same100 mother-infant pairs as the previous study, whose Pb, As, and Zn concentrations in cord blood were known, were recruited. Postnatal raising environment was evaluated using the Home Observation for Measurement of Environment (HOME) scale. Neurodevelopment of children at 24 months of age (n=74) was assessed using the Bayley Scale of Infant Development, Second Edition (BSID II). Multivariable regression adjusting for covariates was performed to determine the associations of in utero levels of toxic and essential elements and the home environment with neurodevelopment scores. Unlike the NBAS III conducted for newborns, none of the BSID II cluster scores in 24-month-old infants were associated with cord blood levels of Pb, As, and Zn. The total HOME score was positively associated with the mental development scale (MDI) score (coefficient=0.67, at 95% CI=0.03 to 1.31). In this cohort, a detrimental effect of in utero Pb and As on neurodevelopmental indicators observed at birth disappeared at 24 months, while an association between neurodevelopment and home environment continued.