Bayesian spatial modelling of environmental and health data with applications in Brazilian Amazonia:linking environment and health in disadvantaged groups

Impacts of climate change on human health are a major concern for public health. Increase in frequency and intensity of extreme hydro-climatic events (floods and droughts) is one of the main characteristics of climate change. The occurrence of these events can drastically affect the lives of the population through different pathways. For example, by affecting accessibility to sufficient, safe and nutritious food (food security), increasing levels of malnutrition or increasing disease incidence. We hypothesize that nutrition might be a relevant pathway through which extreme hydro-climatic events affect human health and that the impacts are worse for vulnerable groups where they exacerbate existing vulnerabilities. Then, to understand and evaluate the effects of extreme hydro-climatic events on human health, we developed three studies. First, we propose a model-based standardized index to identify and quantify extreme temporal events and compared it against the classical standardized precipitation index (SPI). We found that our index holds the properties of the SPI, but improves on the methodology by tackling some of its limitations. Second, we used the model-based standardized index to evaluate the effects of exposure to extreme hydro-climatic events during pregnancy on birth weight. We controlled for other social and placed-based factors that could influence birth weight and found out that floods could significantly reduce birth weight. We also detected characteristics of vulnerable groups where birthweight is expected to be lower. Finally, we proposed our denominated spatial item factor analysis to model and predict spatially structured latent factors. With our application on predicting food insecurity in a roadless city of the Brazilian Amazonia, we discover that severely food insecure areas were related to flood-prone, poor and marginalized neighbourhoods. In general, our results highlight the importance of policies to reduce the effects of extreme hydro-climatic events on vulnerable populations of the Brazilian Amazonia. Although our methods were motivated by the study of the impacts of extreme hydro-climatic events, they can be applied in more general cases

Rainfall variability and adverse birth outcomes in Amazonia

Amazonian populations are increasingly exposed to climatic shocks yet knowledge of related health impacts is limited. Understanding how health risks are co-produced by local climatic variability, place and social inequities is vital for improving decision-making, particularly in decentralized contexts. We assess the impacts of rainfall variability and multi-scale vulnerabilities on birth-weight, which has life-long health consequences. We focus on highly river-dependent areas in Amazonia, using urban and rural birth registrations during 2006-2017. We find a strong but spatially-differentiated relationship between local rainfall and subsequent river-level anomalies. Using Bayesian models we disentangle the impacts of rainfall shocks of different magnitudes, municipal characteristics, social inequities and seasonality. Prenatal exposure to extremely intense rainfall is associated with preterm birth, restricted intra-uterine growth and lower mean birth-weight (≤-183g). Adverse birth outcomes also follow non-extreme intense rainfall (40% higher odds of low birth-weight), drier than seasonal averages (-39g mean birth-weight) and conception in the rising-water season (-13g mean birth-weight). Babies experience penalties totalling 646g when born to adolescent, Amerindian, unmarried mothers that received no formal education, antenatal or obstetric healthcare. Rainfall variability confers inter-generational disadvantage, especially for socially-marginalized Amazonians in forgotten places. Structural changes are required to reduce inequities, foster citizen empowerment, and improve the social accountability of public institutions

Urban Amazonians use fishing as a strategy for coping with food insecurity

Fishing provides livelihoods and food for millions of people in the Global South yet inland fisheries are under-researched and neglected in food and nutrition policy. This paper goes beyond the rural focus of existing research and examines how urban households may use fishing as a livelihood strategy for coping with food insecurity. Our study in Brazilian Amazonia is based on a random sample of households (n=798) in four remote riverine towns. We quantitatively examine the inter-connections between fishing and food insecurity, and find that fishing is a widespread coping strategy among disadvantaged, food insecure households. Fisher households tend to be highly-dependent on eating fish, and for these households, consuming fish more often is associated with a modest reduction in food insecurity risks. Fishing provides monthly non-monetary income worth ≤USD54 (equivalent to ~12% of mean monetary income), potentially reducing food insecurity risks almost as much as the conditional cash transfer Bolsa Família. We estimate that nearly half a million inhabitants of the region’s remote, riverine urban centres are directly dependent on a household member catching fish, a nutritious and culturally-preferred food. Consequently, small-scale urban fishers must be recognized in policy debates around food and nutrition security and management of natural resources

Wildmeat consumption and child health in Amazonia

Consuming wildmeat may protect against iron-deficiency anemia, a serious public health problem globally. Contributing to debates on the linkages between wildmeat and the health of forest-proximate people, we investigate whether wildmeat consumption is associated with hemoglobin concentration in rural and urban children (< 5 years old) in central Brazilian Amazonia. Because dietary practices mediate the potential nutritional benefits of wildmeat, we also examined whether its introduction into children’s diets is influenced by rural/urban location or household socio-economic characteristics. Sampling 610 children, we found that wildmeat consumption is associated with higher hemoglobin concentration among the rural children most vulnerable to poverty, but not in the least vulnerable rural, or urban children. Rural caregivers share wildmeat with children earlier-in-life than urban caregivers, potentially because of cultural differences, lower access to domesticated meat, and higher wildmeat consumption by rural households (four times the urban average). If wildmeat becomes unavailable through stricter regulations or over-harvesting, we predict a ~ 10% increased prevalence of anemia among extremely poor rural children. This modest protective effect indicates that ensuring wildmeat access is, alone, insufficient to control anemia. Sustainable wildlife management could enhance the nutritional benefits of wildlife for vulnerable Amazonians, but reducing multidimensional poverty and improving access to quality healthcare are paramount