BackgroundAverage profiles of salivary progesterone in women vary significantly at the inter- and intrapopulation level as a function of age and acute energetic conditions related to energy intake, energy expenditure, or a combination of both. In addition to acute stressors, baseline progesterone levels differ among populations. The causes of such chronic differences are not well understood, but it has been hypothesised that they may result from varying tempos of growth and maturation and, by implication, from diverse environmental conditions encountered during childhood and adolescence.Methods and FindingsTo test this hypothesis, we conducted a migrant study among first- and second-generation Bangladeshi women aged 19–39 who migrated to London, UK at different points in the life-course, women still resident in Bangladesh, and women of European descent living in neighbourhoods similar to those of the migrants in London (total n = 227). Data collected included saliva samples for radioimmunoassay of progesterone, anthropometrics, and information from questionnaires on diet, lifestyle, and health. Results from multiple linear regression, controlled for anthropometric and reproductive variables, show that women who spend their childhood in conditions of low energy expenditure, stable energy intake, good sanitation, low immune challenges, and good health care in the UK have up to 103% higher levels of salivary progesterone and an earlier maturation than women who develop in less optimal conditions in Sylhet, Bangladesh (F 9,178 = 5.05, p < 0.001, standard error of the mean = 0.32; adjusted R 2 = 0.16). Our results point to the period prior to puberty as a sensitive phase when changes in environmental conditions positively impact developmental tempos such as menarcheal age (F 2,81 = 3.21, p = 0.03) and patterns of ovarian function as measured using salivary progesterone (F 2,81 = 3.14, p = 0.04).ConclusionsThis research demonstrates that human females use an extended period of the life cycle prior to reproductive maturation to monitor their environment and to modulate reproductive steroid levels in accordance with projected conditions they might encounter as adults. Given the prolonged investment of human pregnancy and lactation, such plasticity (extending beyond any intrauterine programming) enables a more flexible and finely tuned adjustment to the potential constraints or opportunities of the later adult environment. This research is the first, to our knowledge, to demonstrate a postuterine developmental component to variation in reproductive steroid levels in women.

Petrol has been extracted from Achuar territory in the Northern Peruvian Amazon since the 1970s. In spite of early identification of negative impacts on the environment and repeated attempts by the Achuar to improve conditions, very little research has been done on specific environmental and health impacts. Some recent governmental studies have shown extremely high blood lead and cadmium levels in Achuar communities. In this paper we apply an environmental justice framework to review the evidence of pollution and health status available in existing studies, as well as government and operating company actions over the last 30 years. We identify gaps in our knowledge which hamper efforts to respond to the environmental and health situation, as well as negligent actions on the part of the State and petrol companies.

Women living in energetically stressful conditions have significantly lower baseline salivary steroid levels compared to those in affluent environments. Developmental hypotheses suggest that interpopulation variation in ovarian function results from contrasting environments experienced during growth. We use a migrant study of Bangladeshi women to test this hypothesis. We compared middle-class women (19-39 years) who migrated to London, UK, at different life-stages (pre and postmenarche), with Bangladeshi sedentees, second-generation British-Bangladeshis, and white British women living in similar London neighborhoods (total n = 227). We analyzed levels of salivary estradiol for one menstrual cycle, together with data on anthropometry, diet, lifestyle, and migration and reproductive histories. Results from multiple linear regression models, controlling for anthropometric and reproductive variables, show no significant differences in baseline estradiol levels between groups whether all cycles or just ovulatory cycles are analyzed. We also found no correlation between age at migration or time since migration on estradiol levels, nor between adult estradiol levels and age at menarche. Our results differ from previous reports of significantly lower salivary estradiol levels in populations living in more extreme ecological settings. They also contrast with our previous findings of significant intergroup differences in baseline levels of salivary progesterone. However, women who spent their childhood in Sylhet have a lower proportion of ovulatory cycles compared to women who developed in Britain. These group differences in ovulation frequency indicate more qualitative effects of contrasting developmental environments. We discuss possible explanations for differences in response between progesterone and estradiol, as well as broader implications of our findings.

SummaryOver the past 50 years, there have been considerable changes both in how medical anthropologists view their relationship to topical public health and in how tropical public health professionals view the role of anthropologists. In particular, in recent decades critical currents have emerged from an anthropology of medicine, calling for an examination of biomedicine and its conceptualisation of public health. There are parallel debates in public health about a narrow disease-focused or broader socio-cultural approach to improving population health. Based on a review of the literature and a qualitative study of the views of public health professionals and anthropologists working in tropical public health, the data presented in this paper suggest that public health professionals remain unaware of many of the contributions anthropology could make to tropical public health theory and practice. However, the objectives of a critical social science are not dissimilar to those of the broader concept of public health. We suggest that there are grounds for optimism. For those of us concerned not just with disease but also with inequities in health, the challenge is to work towards a critical tropical public health which draws as much from social science as from biomedicine, in theory and practice.keywords anthropology, tropical public health, inequities in health

Many small groups of indigenous peoples in the Amazon basin avoid and resist direct encounters with outsiders. As far as we know, they do so because of appalling experiences in earlier encounters with national society. When contacted today, they are extremely vulnerable to introduced diseases and exploitation. In this paper we draw on our experience in the Kugapakori Nahua Reserve for isolated peoples in SE Peru to discuss some of the current debates about whether isolated peoples should be contacted and how best to respect their right to life, health, autonomy and territory.The remote headwater regions where isolated peoples sought refuge during the last century are increasingly sought after for resource extraction. In particular, the extraction of oil and gas is increasing throughout the Peruvian Amazon. In the second part of the paper we give some examples of how oil/gas companies and the energy sector in Peru have affected the well-being of the peoples in this reserve in the 21st century. If this trend is not reversed the impacts for isolated peoples will be irreparable.