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

Abstract

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.

Transition to a market economy and chronic psychosocial stress in northern Laos: An exploratory study of urinary free cortisol in rural residents

“…We assumed that the three villages differed in terms of the degree of integration into the market economy. The characteristics of the study sites are also described by Mizuno et al (2022), who provide a map of the study area.…”

“…Occupation was categorized as “only farming,” “farming and other income‐generating activities,” or “only other income‐generating activities.” Other income‐generating activities included retail store management, peddling, wage labor, elementary school teaching, and handicrafts. Regarding roofing materials, building a concrete roof is expensive (>$1000 [US dollars]) and can thus be considered as an indicator of a substantial cash income (Mizuno et al, 2022). Other roofing materials include corrugated galvanized iron and wooden boards.…”

Impact of modernization on oxidative stress among indigenous populations in northern Laos

“…The limits of quantitation were 0.05 and 0.1 μg/L for 8-OHdG and 8-isoprostane, respectively; the detection rate was 100% for both. To adjust for the dilution effect, urine specific gravity and urinary creatinine concentration were measured (Mizuno et al, 2022).…”

“…The characteristics of the study population have been described elsewhere (Mizuno et al, 2022). In brief, the study was conducted in three villages in Oudomxay Province, northern Laos: Nam Nyon (the least modernized), Na Savang (somewhat modernized), and Na Lae (the most modernized).…”

Insights into the health status of the general population living near an electroplating industry zone: metal elevation and renal impairment

“…Except for blood Se, almost all the metal levels in our study were above those in the established literature, including domestic investigations in Wuhan(Wu et al. 2018, Zeng et al 2019) and Guangzhou (Huang et al 2022), as well as overseas surveys like the Canadian Health Measures Survey (2007-2019) (Haines et al 2017), the IMEPOGE study of Northern France (2008-2010) (Nisse et al 2017), the American National Health and Nutrition Examination Survey (Buser et al 2016, Yao et al 2021), and the exploration of Northern Laos(Mizuno et al 2022). Furthermore, we gained insight through studies on other polluted areas.…”