Asymptomatic Enteric Virus Infections and Association with the Gut Microbiome in Rural Residents of Northern Laos.

Viral gastrointestinal infections are an important public health concern, and the occurrence of asymptomatic enteric virus infections makes it difficult to prevent and control their spread. This study aimed to determine the prevalence of and factors associated with asymptomatic enteric virus infection in adults in northern Laos. Fecal samples were collected from apparently healthy participants who did not report diarrhea or high fever at the time of the survey in northern Laos, and enteric viruses were detected using polymerase chain reaction (PCR) and reverse transcription (RT)-PCR. Individual characteristics, including the gut microbiome, were compared between asymptomatic carriers and noncarriers of each enteric virus. Of the participants (N = 255), 12 (4.7%) were positive for norovirus genogroup I (GI), 8 (3.1%) for human adenovirus, and 1 (0.4%) for norovirus GII; prevalence tended to be higher in less-modernized villages. Gut microbial diversity (evaluated by the number of operational taxonomic units) was higher in asymptomatic carriers of norovirus GI or human adenovirus than in their noncarriers. Gut microbiome compositions differed significantly between asymptomatic carriers and noncarriers of norovirus GI or human adenovirus (permutational analysis of variance, P <0.05). These findings imply an association between asymptomatic enteric virus infection and modernization and/or the gut microbiome in northern Laos.

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

OBJECTIVES: The indigenous population in northern Laos has experienced a transition from self-sufficiency to a market-oriented economy, which may have brought about unprecedented chronic psychosocial stress. This study examined the association between the transition to a market economy and urinary free cortisol (UFC) concentration as a stress biomarker among rural residents of three villages with different degrees of integration into the market economy. METHODS: An interview survey and urine sample collection were conducted in August 2018 and March 2019. We measured the UFC concentration in spot urine samples collected in the morning from participants aged 20-60 years (n = 168) using an enzyme-linked immunosorbent assay. Multiple linear regression analysis was performed to examine differences in UFC concentrations among villages by sex, with time of arrival for the survey, age, and body mass index included as covariates. RESULTS: The UFC concentration was higher in men living in the village with the highest degree of integration into the market economy than in those in the two villages with a lower dependence on cash, possibly linking increased stress levels with a change in employment type. This trend was not observed in women. CONCLUSION: Socioeconomic changes incidental to a transition to a market economy may increase the stress levels of men in northern Laos.

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

OBJECTIVES: To explore the impact of modernization on oxidative stress during a momentous health transition process, we investigated differences in oxidative stress among the indigenous populations of villages in northern Laos with different levels of modernization. METHODS: We conducted a cross-sectional study of 380 adults in three villages with different levels of modernization. Three biomarkers related to oxidative stress were measured: urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-isoprostane concentrations (both measured by liquid chromatography-tandem mass spectrometry), and blood telomere length (measured with qPCR). We examined associations between village-level modernization and oxidative stress-related biomarkers in a multilevel analysis including a random effect and covariates. RESULTS: The geometric means of urinary 8-OHdG and 8-isoprostane concentrations were 2.92 and 0.700 µg/g creatinine, respectively, in our study population. Higher urinary 8-OHdG concentrations and shorter telomeres were observed in participants from the more modernized villages, whereas urinary 8-isoprostane concentrations did not differ significantly among villages. CONCLUSIONS: Our findings imply that modernization-induced changes in lifestyle may increase oxidative DNA damage. Baseline levels of oxidative lipid damage are expected to be high in the indigenous populations of northern Laos. Assessments of oxidative stress may provide valuable insights into the mechanisms of health transition in specific populations.

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.

Primary health care situations in remote rural villages of the Savannakhet province, Lao People's Democratic Republic.

BACKGROUND: To improve the health of the rural population in the Lao People's Democratic Republic (Lao PDR), the government has emphasized a primary health care approach in the Health Sector Reform Strategy by 2025. The objective of the present study was to describe the health-related situations of remote rural villages of the Lao PDR to inform strategies for promoting primary health care in such villages. METHODS: Ten remote rural villages were purposively selected from the catchment areas of two health centers in the Xepon district, Savannakhet province. The surveyors collected data by conducting a questionnaire-based interview with village health volunteers and by observing the village environment in 2018. The survey focused on village situations on the eight elements of primary health care (health education; food supply and nutrition; safe water and basic sanitation; maternal and child health care; immunization; prevention and control of locally endemic diseases; treatment of common diseases and injuries; and provision of essential drug). RESULTS: The common health problems were diarrhea, followed by malaria, and cough. The identified possible risk factors for the health problems were not washing hands with soap, open defecation, not boiling drinking water, not exclusively breastfeeding, presence of animal feces on the village ground, absence of garbage management system, not using a bed net when sleeping in the forest, and exposure to indoor cooking and tobacco smoke. In many villages, villagers were not able to eat enough food and did not eat protein-rich food and vegetables daily. CONCLUSIONS: Potential risk factors for the reported common health problems were often prevalent in the study villages. Villagers can address most of these risk factors, as interventions to address such risk factors do not require a large financial input. There is a need for intersectoral actions between the health and other sectors to address food shortages and indoor air pollution due to indoor cooking using biomass fuel.

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.

Is the place of birth related to the mother's satisfaction with childbirth? A cross-sectional study in a rural district of the Lao People's Democratic Republic (Lao PDR).

BACKGROUND: The place of birth has been rapidly changing from home to health facility in Lao People's Democratic Republic (Lao PDR) following the strategy to improve the maternal and neonatal mortality. This change in the place of birth might affect the mother's satisfaction with childbirth. The objective of this study was to assess whether the place of birth is related to the mother's satisfaction with childbirth in a rural district of the Lao PDR. METHODS: A community-based survey was implemented in 21 randomly selected hamlets in Xepon district, Savannakhet province, between February and March, 2016. Questionnaire-based interviews were conducted with mothers who experienced a normal vaginal birth in the past 2 years. Satisfaction with childbirth was measured by the Satisfaction with Childbirth Experience Questionnaire. Using the median, the outcome variable was dichotomized into "high satisfaction group" and "low satisfaction group". Logistic regression was performed to assess the association between place of birth and satisfaction with childbirth. Three models were examined: In Model 1, only the predictor of interest (i.e., place of birth) was included. In Model 2, the predictor of interest and the obstetrical predictors were included. In Model 3, in addition to these predictors, socio-demographic and economic predictors were included. A mixed-effects model was used to account for the hierarchical structure. RESULTS: Among the 226 mothers who were included in data analysis, 60.2% gave birth at the health facility and the remaining 39.8% gave birth at home. Logistic regression analysis showed that the mothers who gave birth at the health facility were significantly more likely to have a higher level of satisfaction compared to the mothers who gave birth at home (crude odds ratio: 5.44, 95% confidence interval: 3.03 to 9.75). This association remained even after adjusting for other predictors (adjusted odds ratio: 6.05, 95% confidence interval: 2.81 to 13.03). CONCLUSION: Facility-based birth was significantly associated with a higher level of satisfaction with childbirth among the mothers in the study district where maternal and neonatal mortalities are relatively high. The findings of the present study support the promotion of facility-based birth in a rural district of the Lao PDR.

Individual and household factors associated with incidences of village malaria in Xepon district, Savannakhet province, Lao PDR.

BACKGROUND: In the Lao PDR, the incidence of malaria greatly differs among villages even within a subdistrict, and the reasons for this difference are poorly understood. The objective of this study was to identify differences in villagers' behavior and the household environment between villages with high incidences and those with low incidences of malaria in a rural district of the Lao PDR. METHODS: A case-control study was conducted in Xepon district, Savannakhet province. Case villages were defined as those with a high incidence (> 10 cases per 1000 population per year), and control villages were those with a low incidence (0-10 cases per 1000 population per year). Data were collected from 178 households in the six case villages and six control villages between December 2016 and January 2017. The data collection consisted of an interview survey with the heads of households and an observational survey in and around the house. Logistic regression was used to assess the association between the case-control status and individual-level behavioral factors and household-level environmental factors adjusted for socio-demographic and economic factors. RESULTS: Compared to the household members in the control villages, household members in the case villages were significantly more likely to work at night in the forest (adjusted odds ratio 1.95; 95% confidence interval 1.28 to 2.98) and more likely to sleep overnight in the forest (adjusted odds ratio 1.94; 95% confidence interval 1.13 to 3.33). Additionally, compared to the households in the control villages, households in the case villages were significantly more likely to have an open space on the house surface (adjusted odds ratio 3.64; 95% confidence interval 1.68 to 7.84). CONCLUSIONS: There were significant differences in nighttime working and sleeping behaviors in the forest and the presence of an open space on the house surface in the case versus control villages. These differences can partly explain the difference in the incidences of malaria among the villages. The Lao National Malaria Control Program should recommend that villagers use personal protection when working and sleeping in the forest and to reduce any open space on the house surfaces.