Changing blood lead levels and oxidative stress with duration of residence among Taiwan immigrants

Hair Trace Element Levels in Han and Indigenous Hualien Inhabitants in Taiwan

The objective of the present study was to assess the impact of ethnicity on hair trace element content in Han and aboriginal inhabitants of Hualien in Taiwan. Fifty Han (female/male = 35/15) and 50 aboriginal (female/male = 40/10) Hualien inhabitants aged 40-60 years were involved in the present study. Anthropometric data and dietary patterns were recorded. Hair mineral, essential, and toxic trace element levels were assessed using inductively coupled plasma mass spectrometry at NexION 300D (PerkinElmer Inc., USA) equipped with ESI SC-2 DX4 autosampler (Elemental Scientific Inc., USA). No group difference in gender, age, body weight, height, or physical activity was observed. Fish intake was more frequent in Han inhabitants, whereas aborigines consumed significantly more nuts. Indigenous people were characterized by higher hair Al (45%), Ca (threefold), Co (71%), Fe (twofold), I (74%), K (60%), Mg (2.5-fold), Na (62%), P (6%), Sn (78%), and V (46%) content. In turn, Han Hualien inhabitants had higher hair Be (twofold), Li, Se, Si levels as compared to indigenous counterparts. Multiple regression analysis demonstrated that ethnicity was significantly associated with hair Ca (β = 0.302), Mn (β = 0.284), P (β = 0.387), and Se (β = - 0.310) levels after adjustment for other confounders. At the same time, the overall models were significant for Ca, Mn, Se, and As. The obtained data may provide a background for monitoring and correction of trace element status in patients of different ethnic groups. However, further detailed studies are required to highlight the mechanisms underlying the observed associations.

Associations of Internal-Migration Status with Maternal Exposure to Stress, Lead, and Selenium Deficiency Among Pregnant Women in Shanghai, China

Internal migration and urbanization are occurring on a global scale. Although the risk of exposure to stress/lead/low selenium is assumed to be high among migrant pregnant women, population-based evidence is limited. This study aims to explore the association of internal-migration status with maternal exposure to lead, low selenium, and stress among pregnant women. A total of 1931 pregnant women were investigated in 2010. The internal-migration status was grouped based on their hukou (registered residence) and length-of-residency in Shanghai. Maternal blood lead and serum selenium concentrations were assessed. Life event stress and emotional stress were evaluated using "Event-Stress-Scale-for-Pregnant-Women" and "Symptom-Checklist-90-R-Scale" (SCL-90-R), respectively. Logistic regression and general linear models were used to evaluate associations between migration status and lead/stress/low selenium exposure. Compared with the local (with Shanghai hukou and length-of-residency ≥ 5 years), new migrants (without Shanghai hukou and length-of-residency < 2 years) had lower social-economic-status (SES), higher lead, life event and emotional stress, and lower selenium levels. After adjusting for SES, new migrants had higher risks of emotional stress (for interpersonal sensitivity of SCL-90-R, OR = 2.10, 95% CI 1.22-3.64) and low selenium [lg(selenium): beta = - 0.08, 95% CI - 0.11, - 0.05], but no significant risks for life event stress and high lead. Compared with the local, migrant pregnant women in big cities may have emotional stress and low selenium independent of SES, and high lead and life event stress dependent on SES.

Association between self-reported length of time in the USA and blood lead levels: National Health and Nutrition Examination Survey 2013-2016

OBJECTIVES

The aim of this study is to determine the association between length of time in the USA with blood lead (BPb).

DESIGN

Population-based cross-sectional study using data from the 2013-2016 National Health and Nutrition Examination Survey.

SETTING

USA.

PARTICIPANTS

5933 men and women (≥15 years); subgroups of men only (n=2867), women only (n=3064) and women of childbearing age (15-45 years) (n=1580).

PRIMARY AND SECONDARY OUTCOMES

The primary outcome was BPb concentration. The main exposure variable was self-reported number of years spent in the USA, categorised as: born in the USA; 0-4 years; 5-9 years; 10-19 years and ≥20 years. We used linear regression models adjusted for race/ethnicity, education, blood cotinine, age, sex (as appropriate) and accounted for complex survey design.

RESULTS

Women of childbearing age who have lived 0-4 years in the USA have, on average, a 54% (95% CI 36% to 75%) higher BPb compared with women born in the USA. Corresponding results for all women, men and the entire population were 49% (95% CI 34% to 66%), 49% (95% CI 28% to 75%) and 49% (95% CI 33% to 66%), respectively. Similar, statistically significant, results were observed for other time periods (5-9 years, 10-19 years and ≥20 years); the magnitude of the association decreased with increasing time in the USA.

CONCLUSIONS

This study provides additional evidence that newcomers to the USA may be a population at higher risk of elevated BPb.

Oxidative stress and DNA damage in a long-term hexavalent chromium-exposed population in North China: a cross-sectional study

OBJECTIVE

The International Agency for Research on Cancer classifies hexavalent chromium (Cr(VI)) as a human carcinogen. As reported, cancer mortality was higher in Cr(VI)-contaminated areas. Scientists have recommended studying its health impact on people living in contaminated areas. This study aims to evaluate the health risk for people living in Cr(VI)-contaminated areas.

DESIGN

We conducted a cross-sectional study in rural areas of north-eastern China. Malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) were used as oxidative stress parameters, and 8-hydroxy-2 deoxyguanosine (8-OHdG) as a DNA damage biomarker. We collected information on demographics, lifestyles and length of residence from all participants using a questionnaire. Biological specimens and environmental media samples were collected on the same day as the survey was done. We used t-test, χ² test, Wilcoxon rank-sum test and multivariate linear regression analysis.

PARTICIPANTS

The study included 319 participants exposed to Cr(VI) and 307 unexposed participants, with 447 women and 179 men. These participants met the following criteria: (1) living in the areas for more than 10 years; (2) age older than 18 years; and (3) without occupational chromium exposure.

RESULTS

Our study revealed that serum concentration of MDA (p<0.001), serum activities of CAT (p<0.001) and GSH-Px (p<0.001), as well as urine concentration of 8-OHdG (p=0.008) in the exposed group were significantly higher than those in the unexposed group. However, serum SOD activity was significantly lower in the exposed group, compared with that in the unexposed group (p<0.001). Cr(VI) exposure and smoking have an interaction effect on GSH-Px activity (p<0.05). Cr(VI) exposure and alcohol drinking also have an interaction effect on GSH-Px activity (p<0.05). Longer residence in the exposed areas increased the oxidative levels (p<0.05).

CONCLUSIONS

The findings of this study showed elevated oxidative stress and DNA damage in people exposed to Cr(VI).

The Relation Between Low-Level Lead Exposure and Oxidative Stress: a Review of the Epidemiological Evidence in Children and Non-Occupationally Exposed Adults

Experimental studies in animals and observational studies in occupationally exposed adults indicate that higher lead exposure results in higher biomarkers of oxidative stress. However, this evidence cannot be extended to the general population who typically experience lower levels of lead exposure. This systematic review evaluates the epidemiological evidence on the association between lead and oxidative stress in non-occupationally exposed general population, with a particular focus on the pediatric population. Studies were identified through a systematic search of Medline and Web of Science. Ultimately, evidence from 15 studies conducted in children and 22 studies in adults from the general population was reviewed. Overall, the published findings are inconsistent, and there are very few well-designed studies on the relation between lead exposure and oxidative stress in the general population. The strength of the current evidence is discussed in light of the methodological approaches employed, and recommendations are made for future research directions. These include designing prospective studies with repeat measurements of clinically relevant oxidative stress markers to answer the question of causality and sensitive windows and reanalyzing previously published data, but using multivariable statistical approaches and adjustment for relevant explanatory factors.

Blood cadmium concentrations and environmental exposure sources in newcomer South and East Asian women in the Greater Toronto Area, Canada

BACKGROUND

Immigrant women are often identified as being particularly vulnerable to environmental exposures and health effects. The availability of biomonitoring data on newcomers is limited, thus, presenting a challenge to public health practitioners in the identification of priorities for intervention.

OBJECTIVES

In fulfillment of data needs, the purpose of this study was to characterize blood concentrations of cadmium (Cd) among newcomer women of reproductive age (19-45 years of age) living in the Greater Toronto Area (GTA), Canada and to assess potential sources of environmental exposures.

METHODS

A community-based model, engaging peer researchers from the communities of interest, was used for recruitment and follow-up purposes. Blood samples were taken from a total of 211 newcomer women from South and East Asia, representing primary, regional origins of immigrants to the GTA, and environmental exposure sources were assessed via telephone survey. Metal concentrations were measured in blood samples (diluted with 0.5% (v/v) ammonium hydroxide and 0.1% (v/v) octylphenol ethoxylate) using a quadrupole ICP-MS. Survey questions addressed a wide range of environmental exposure sources, including dietary and smoking patterns and use of nutritional supplements, herbal products and cosmetics.

RESULTS

A geometric mean (GM) blood Cd concentration of 0.39µg/L (SD:±2.07µg/L) was determined for study participants (min/max: <0.045µg/L (LOD)/2.36µg/L). Several variables including low educational attainment (Relative Ratio (RR) (adjusted)=1.50; 95% CI 1.17-1.91), milk consumption (RR (adjusted)=0.86; 95% CI 0.76-0.97), and use of zinc supplements (RR (adjusted)=0.76; 95% CI 0.64-0.95) were observed to be significantly associated with blood Cd concentrations in the adjusted regression model. The variable domains socioeconomic status (R²_adj=0.11) and country of origin (R²_adj=0.236) were the strongest predictors of blood Cd.

CONCLUSION

Blood Cd concentrations fell below those generally considered to be of human health concern. However, negative health effects cannot be entirely excluded, especially for those that fall in the upper percentile range of the distribution, given the mounting evidence for negative health outcomes at low environmental exposure concentrations.

Metal Concentrations in Newcomer Women and Environmental Exposures: A Scoping Review

Newcomer women from developing countries are recognized to be at risk for elevated exposures to environmental contaminants and associated negative health effects. As such, data on exposure sources and contaminant body burden concentrations is critical in the development of effective public health policies and interventions in support of newcomer health. We conducted a scoping review to gather evidence on important toxic metals of health concern, lead (Pb), mercury (Hg) and cadmium (Cd), and their concentrations and potential exposure sources among newcomer women. An initial 420 articles were identified through the databases MEDLINE, EMBASE and Scopus, many reporting by ethnicity rather than newcomer/immigrant status. Several articles reported metal concentrations for other biomarkers but did not include blood, nor stratify results. From the remainder, we selected a total of 10 articles for full textual review, which reported blood Pb, Hg or Cd levels for newcomer women and/or stratified blood metal results according to foreign birth or country of origin. Three of the articles reported higher Pb, Hg and Cd concentrations in newcomer women compared to their native-borne counterparts. Exposures identified as contributing to elevated Pb, Hg and Cd blood concentrations included: pica behaviour, the use of lead-glazed cookware or eye cosmetics, and fish/shellfish consumption. The review revealed a limited availability of data on metal body burden concentrations, exposure sources and routes among newcomer women specifically. More research is needed to better understand the extent to which newcomer women are disproportionately at risk of elevated metal exposures due to either country of origin or current exposures and to inform relevant, multi-national risk management strategies.

Lead Exposure and Oxidative Stress: A Systematic Review

Lead is an environmental toxicant that can induce oxidative stress (OS) via reactive oxygen species (ROS) generation, which has been reported as an important mechanism underlying lead toxicity (Gurer and Ercal 2000; Pande and Flora 2002; Kasperczyk et al. 2004a; Farmand et al. 2005; Verstraeten et al. 2008; Wang et al. 2009; Martinez-Haro et al. 2011). OS occurs when the generation of ROS exceeds the antioxidant system's ability to defend cells against oxidized molecules. ROS is a term generally used to refer to free radicals derived from O2 (e.g., superoxide anions [O2-] and hydroxyl radicals [OH-]) or to non-radical species (e.g. hydrogen peroxide [H2O2]) (Halliwell and Cross 1994).