Determinants of oxidative stress among indigenous populations in Northern Laos: Trace element exposures and dietary patterns.

OBJECTIVES: To investigate determinants of oxidative stress in an indigenous population, we examined associations of trace element exposures and dietary patterns with three oxidative stress-related biomarkers among indigenous populations in Northern Laos. METHODS: This cross-sectional study included 341 adults from three villages with different levels of modernization. We used three oxidative stress-related biomarkers: urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-isoprostane concentrations, which were measured using liquid chromatography-tandem mass spectrometry, and blood telomere lengths, which were measured using a quantitative polymerase chain reaction method. We used multilevel analysis to examine associations of urinary arsenic, cadmium, and selenium concentrations, their interaction terms, and wild-plant-food scores (principal component scores calculated from food consumption frequencies) with oxidative stress-related biomarkers. RESULTS: Urinary arsenic and cadmium concentrations were positively associated with urinary 8-isoprostane concentrations. Urinary selenium concentrations were positively associated with urinary 8-OHdG concentrations. Interaction terms ([arsenic or cadmium] × selenium) showed negative associations with urinary 8-OHdG and 8-isoprostane concentrations, respectively. Urinary cadmium concentrations were negatively associated with telomere lengths. Wild-plant-food scores did not exhibit associations with oxidative stress-related biomarkers. CONCLUSION: Our findings imply that exposure to arsenic and cadmium is associated with greater oxidative lipid damage, whereas selenium may attenuate arsenic-induced oxidative DNA damage and cadmium-induced oxidative lipid damage. Cadmium exposure may accelerate telomere attrition. Trace element exposure may be a determinant of oxidative stress among indigenous populations in Northern Laos.

Impact of modernization on urinary concentrations of arsenic, cadmium, lead, and selenium in rural residents of Northern Laos.

OBJECTIVES: The impacts of modernization on toxic heavy metal exposure and essential trace element intake in indigenous populations of subsistence societies are unknown. We assessed urinary trace element concentrations in rural residents of Northern Laos and examined associations with levels of modernization. METHODS: A cross-sectional study was conducted comprising 380 residents of three villages in Northern Laos with different levels of modernization. We surveyed general characteristics and measured the weight and height of 341 participants. Arsenic, cadmium, lead, and selenium concentrations were measured in spot urine samples by inductively coupled plasma mass spectrometry. We examined associations between urinary trace element concentrations and variables related to modernization (village, roofing material, possessions index [total number of possessions], and body mass index [BMI]) using multilevel analyses with household as a random effect, after adjusting for sex, age, and smoking status. RESULTS: Urinary concentrations of arsenic and cadmium were high, while those of lead and selenium were low in comparison to previous reports of populations in non-contaminated regions or without excess/deficiency. We observed associations between urinary trace element concentrations and village-level modernization: lead and selenium concentrations were higher in more modernized villages and cadmium concentration was highest in the least modernized village. Urinary arsenic concentration was not predicted by the modernization level of a village, although we observed significant differences among villages. In addition, urinary selenium concentration was higher in participants inhabiting more modernized houses. CONCLUSION: Modernization of villages may impact toxic heavy metal exposure and selenium intake in rural residents of Northern Laos.

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.

Protective role of selenium in the shortening of telomere length in newborns induced by in utero heavy metal exposure.

The effects of toxic heavy metals, such as arsenic (As), cadmium (Cd), and lead (Pb), on telomere length (TL) have been reported previously. Although selenium (Se) is considered as an anti-oxidant which may detoxify the effects, there are no data on whether Se could protect against the TL-shortening effects of heavy metals. Thus, the aim of this study was to evaluate the protective role of Se against heavy metal-induced TL shortening. A birth cohort study was conducted in Myanmar in 2016, including 408 mother-infant pairs. First, pregnant women in the third trimester were interviewed concerning their socioeconomic, and pregnancy and birth characteristics using a pre-validated questionnaire. Maternal spot urine samples were collected after the interview. During the follow-up period (1-3 months), blood samples were collected from the umbilical cord at birth by local health workers. Metal concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). TL was measured by quantitative real-time polymerase chain reaction (PCR). Relative TL was calculated as the ratio of telomere genes to single-copy genes. To evaluate the effect of Se on TL shortening, molar ratios were calculated. Linear regression analyses were performed to examine the associations between heavy metals and TL, individually and after adjustment for Se level. The effects of As, Cd, and Pb exposure on TL were smaller after adjustment for the Se level, especially for Pb (unadjusted ß = -0.10; 95% CI: 0.18, -0.01; adjusted ß = -0.03; 95% CI: 0.13, 0.05). On stratifying the data by Se concentration, there was no significant association between Cd or Pb exposure and TL in the high-Se group. Our study indicated a protective effect of Se against the TL shortening induced by heavy metal exposure, where the effect sizes were smaller after adjusting for the Se level, compared to individual metal exposure.

Prevalence of non-communicable disease risk factors in three sites across Papua New Guinea: a cross-sectional study.

Papua New Guinea (PNG) is a culturally, environmentally and ethnically diverse country of 7.3 million people experiencing rapid economic development and social change. Such development is typically associated with an increase in non-communicable disease (NCD) risk factors. AIM: To establish the prevalence of NCD risk factors in three different regions across PNG in order to guide appropriate prevention and control measures. METHODS: A cross-sectional survey was undertaken with randomly selected adults (15-65 years), stratified by age and sex recruited from the general population of integrated Health and Demographic Surveillance Sites in West Hiri (periurban), Asaro (rural highland) and Karkar Island (rural island), PNG. A modified WHO STEPS risk factor survey was administered along with anthropometric and biochemical measures on study participants. RESULTS: The prevalence of NCD risk factors was markedly different across the three sites. For example, the prevalences of current alcohol consumption at 43% (95% CI 35 to 52), stress at 46% (95% CI 40 to 52), obesity at 22% (95% CI 18 to 28), hypertension at 22% (95% CI 17 to 28), elevated levels of cholesterol at 24% (95% CI 19 to 29) and haemoglobin A1c at 34% (95% CI 29 to 41) were highest in West Hiri relative to the rural areas. However, central obesity at 90% (95% CI 86 to 93) and prehypertension at 55% (95% CI 42 to 62) were most common in Asaro whereas prevalences of smoking, physical inactivity and low high-density lipoprotein-cholesterol levels at 52% (95% CI 45 to 59), 34% (95% CI 26 to 42) and 62% (95% CI 56 to 68), respectively, were highest in Karkar Island. CONCLUSION: Adult residents in the three different communities are at high risk of developing NCDs, especially the West Hiri periurban population. There is an urgent need for appropriate multisectoral preventive interventions and improved health services. Improved monitoring and control of NCD risk factors is also needed in all regions across PNG.

Medical Pluralism and Traditional/Complementary and Alternative Medicine Use Among Older People: a Cross-Sectional Study in a Rural Mountainous Village in Japan.

Given current concerns about the rapidly aging population in Japan, we investigated medical pluralism and health-seeking behaviors among individuals aged 50 years or older living in a rural mountain village in Japan. In total, 76 participants were interviewed about the methods they used to treat 11 common medical conditions. We found that all the respondents used at least two types of treatment for their medical conditions and nearly 90% used four or five types of treatment. The factors affecting health-seeking behaviors were age, education, car use, and the characteristics of the medical condition. Our results show that the older individuals in this community used both formal and traditional/complementary and alternative medicine (TM/CAM) treatments and did not view issues related to medical care as involving a dualistic choice between formal healthcare services and TM/CAM; however, the relationship between different types of TM/CAM and conventional healthcare varied.

Urinary concentrations of toxic and essential trace elements among rural residents in Hainan Island, China.

BACKGROUND: Toxic element exposure and essential trace element consumption may have changed after the Chinese economy transformed to a market-oriented system. The objectives of this study were to measure urinary concentrations of toxic (arsenic, cadmium, lead) and essential trace (selenium, zinc, copper) elements among rural residents in Hainan, China and to examine if variations in economic development are linked to differences in toxic and trace element exposure. METHODS: We conducted a questionnaire-based survey and undertook anthropometric measurements of residents aged ≥20 years (n = 599). Urinary samples were collected and analyzed using inductively coupled plasma mass spectrometry. RESULTS: The median (µg/g creatinine) element concentrations were: arsenic, 73.2; cadmium, 1.8; lead, 3.1; selenium, 36.5; zinc, 371; and copper, 11.0. Intra-community variation in element concentrations was explained by age (arsenic, cadmium, zinc and copper), sex (arsenic, cadmium and selenium: higher in females; zinc: higher in males), body mass index (cadmium) and individual involvement in the market economy as indexed by agrochemical use (lead and selenium). The degree of community-level economic development, which was determined by the proportion of people living in better housing among the study communities, was positively associated with cadmium concentration. CONCLUSIONS: The degree of community-level economic development was positively associated with urinary cadmium concentration while individual involvement in the market economy was positively associated with lead and selenium.

Cord blood levels of toxic and essential trace elements and their determinants in the Terai region of Nepal: a birth cohort study.

The purpose of this study is to evaluate the cord blood level of toxic and trace elements and to identify their determinants in Terai, Nepal. One hundred pregnant women were recruited from one hospital in Chitwan, Nepal in 2008. The cord blood levels of toxic [lead (Pb), arsenic (As), and cadmium (Cd)], essential trace elements [zinc (Zn), selenium (Se), and copper (Cu)], demographic, socioeconomic, and behavioral variables were measured. The mean values of Pb, As, Cd, Zn, Se, and Cu in cord blood level were found as 31.7, 1.46, 0.39, 2,286, 175, and 667 µg/L, respectively. In the multivariate regression model, cord blood As levels from less educated mothers were higher than those from educated mothers (coefficient = -0.01, 95% confidence interval [CI] = -0.02-0.00). The maternal age was positively associated with the cord blood Cd level (coefficient = 0.02, 95% CI = 0.01-0.03), while it was negatively associated with the cord blood As level (coefficient = -0.01, 95% CI = -0.03--0.01). Cord blood levels of Pb, Zn, Se, and Cu were not associated with maternal age, socioeconomic status, living environment, and smoking status. As and Cd levels were relatively lower than those reported in previous studies in Asia, while the levels of Pb and the trace elements were similar. Less educated mothers are more likely to become a higher in utero As source to their fetus, and fetuses of older mothers were more likely to have higher in utero Cd exposure in Terai, Nepal.

Energy and nutrient intake of Tongan adults estimated by 24-hour recall: the importance of local food items.

Tongan adults show one of the highest prevalences of obesity in the world. The present study aims to estimate Tongans' energy and nutrient intakes and food sources using a 24-hour recall survey for 14 days targeting 15 men and 19 women. The mean (SD) daily energy intake was 12.2 (2.3) MJ for men and 10.6 (2.2) MJ for women. Imported foods accounted for about half of their energy and macronutrient intakes, but for much less of their micronutrients. Some local food items, specifically pork, kava, and sea hare, contributed significantly to their vitamin, Fe, and Ca intakes, respectively. These findings suggest that heavy reliance on imported foods can lead not only to a high prevalence of obesity, but also to micronutrient deficiencies.