Individual wealth rank, community wealth inequality, and self-reported adult poor health: a test of hypotheses with panel data (2002-2006) from native Amazonians, Bolivia

Growing evidence suggests that economic inequality in a community harms the health of a person. Using panel data from a small-scale, preindustrial rural society, we test whether individual wealth rank and village wealth inequality affects self-reported poor health in a foraging-farming native Amazonian society. A person's wealth rank was negatively but weakly associated with self-reported morbidity. Each step up/year in the village wealth hierarchy reduced total self-reported days ill by 0.4 percent. The Gini coefficient of village wealth inequality bore a positive association with self-reported poor health that was large in size, but not statistically significant. We found small village wealth inequality, and evidence that individual economic rank did not change. The modest effects may have to do with having used subjective rather than objective measures of health, having small village wealth inequality, and with the possibly true modest effect of a person's wealth rank on health in a small-scale, kin-based society. Finally, we also found that an increase in mean individual wealth by village was related to worse self-reported health. As the Tsimane' integrate into the market economy, their possibilities of wealth accumulation rise, which may affect their well-being. Our work contributes to recent efforts in biocultural anthropology to link the study of social inequalities, human biology, and human-environment interactions.     

Kinship,Family, and Gender Effects in the Ultimatum Game

Kinship and reciprocity are two main predictors of altruism. The ultimatum game has been used to study altruism in many small-scale societies. We used the ultimatum game to examine effects of individuals’ family and kin relations on altruistic behavior in a kin-based horticultural community in rural Dominica. Results show sex-specific effects of kin on ultimatum game play. Average coefficient of relatedness to the village was negatively associated with women’s ultimatum game proposals and had little effect on men’s proposals. Number of brothers in the village was positively associated with men’s ultimatum game proposals and negatively associated with women’s proposals. Similarly, presence of father in the village was associated with higher proposals by men and lower proposals by women. We interpret the effect of brothers on men’s proposals as a consequence of local competition among brothers. We speculate that daughter-biased parental care in this community creates a sense of entitlement among women with brothers, which may explain the inverse relation between number of brothers and women’s ultimatum game proposals. The pattern of results may be consistent with how matrifocality affects cultural models of fairness differently along gender and family lines.     

Cultural Consonance and Psychological Well-Being. Estimates Using Longitudinal Data from an Amazonian Society

Researchers have hypothesized that the degree to which an individual’s actual behavior approximates the culturally valued lifestyle encoded in the dominant cultural model has consequences for physical and mental health. We contribute to this line of research by analyzing data from a longitudinal study composed of five annual surveys (2002–2006 inclusive) of 791 adults in one society of foragers-farmers in the Bolivian Amazon, the Tsimane’. We estimate the association between a standard measure of individual achievement of the cultural model and (a) four indicators of psychological well-being (sadness, anger, fear and happiness) and (b) consumption of four potentially addictive substances (alcohol, cigarette, coca leaves and home-brewed beer) as indicators of stress behavior. After controlling for individual fixed effects, we found a negative association between individual achievement of the cultural model and psychological distress and a positive association between individual achievement of the cultural model and psychological well-being. Only the consumption of commercial alcohol bears the expected negative association with cultural consonance in material lifestyle, probably because the other substances analyzed have cultural values attached. Our work contributes to research on psychological health disparities by showing that a locally defined and culturally specific measure of lifestyle success is associated with psychological health.     

A new approach to decision making in primary health care

The village health worker has two basic tasks: (1) to prevent health problems; (2) to identify and provide effective management of illness in the village. The village health worker has limited education and the length of basic health training is usually 12 weeks. This training can only be considered appropriate if it enables the village health worker to practise effectively within the cultural, social, economic and educational constraints of the village. How far does the training help this worker to work with other members of the village community to prevent illness? These others include mothers, children, school teachers, village leaders, religious leaders, traditional birth attendants, and traditional healers; training needs to be problem-oriented. The management decisions that have to be made in situations of shortage of resources are complex to analyse. A W.H.O. research project has been undertaken to determine the feasibility of developing and using flow charts to provide alternative and more appropriate methods to help the village health worker to provide optimal management in suboptimal situations. Some examples of these new methods are presented.     

Leadership solves collective action problems in small-scale societies

Observation of leadership in small-scale societies offers unique insights into the evolution of human collective action and the origins of sociopolitical complexity. Using behavioural data from the Tsimane forager-horticulturalists of Bolivia and Nyangatom nomadic pastoralists of Ethiopia, we evaluate the traits of leaders and the contexts in which leadership becomes more institutional. We find that leaders tend to have more capital, in the form of age-related knowledge, body size or social connections. These attributes can reduce the costs leaders incur and increase the efficacy of leadership. Leadership becomes more institutional in domains of collective action, such as resolution of intragroup conflict, where collective action failure threatens group integrity. Together these data support the hypothesis that leadership is an important means by which collective action problems are overcome in small-scale societies.     

Do Markets Worsen Economic Inequalities? Kuznets in the Bush

Integration into a market economy or economic development can erode the quality of life of indigenous people by, for example, increasing income inequalities. The Kuznets hypothesis predicts that the link between income inequality and income (a proxy for economic development) resembles an inverted U. We test the hypothesis using a survey of 511 households from 59 villages of Tsimane' Amerindians, a horticultural-foraging society in the tropical rain forest of Bolivia. We measure village inequalities of three economic outcomes: income, imputed annual value of rice production, and wealth. We used three indices of inequality: the coefficient of variation, the standard deviation of the logarithm, and the Gini coefficient. Explanatory variables include either income and income squared, wealth and wealth squared, or imputed annual rice production and production squared. We used village-to-town distance as a control. We find little evidence that integration to the market increases inequalities of economic outcomes, with two exceptions: Wealth bore the predicted inverted U-shaped relation with wealth inequalities, and imputed rice production bore a U-shaped relation to inequality, but only when (a) using adult equivalents to express household size and (b) the Gini coefficient and the coefficient of variation to measure inequality; in no case were results robust to different econometric specifications. We advance several explanations for why economic development might not accentuate economic inequalities among relatively autarkic rural economies.     

On a tendency in health economics to dwell on income inequality and underestimate social stress

Social stress can cause physical and mental harm. It is therefore not surprising that public health policy makers have sought to identify and implement policies aimed at tackling this social ill. A frequently prescribed remedy is to reduce social stress by reducing income inequality, which is typically measured by the Gini coefficient. Decomposing the coefficient into a measure of a population’s social stress and a population’s income makes it possible to show that steps taken to lower the coefficient can actually exacerbate social stress. We formulate conditions under which lowering the Gini coefficient coincides with increasing social stress. If the aim of public policy is to improve public health and increase social welfare, and if social welfare is reduced by social stress, then lowering the Gini coefficient may not be the right course of action.     

Status competition,inequality, and fertility: implications for the demographic transition

The role that social status plays in small-scale societies suggests that status may be important for understanding the evolution of human fertility decisions, and for understanding how such decisions play out in modern contexts. This paper explores whether modelling competition for status—in the sense of relative rank within a society—can help shed light on fertility decline and the demographic transition. We develop a model of how levels of inequality and status competition affect optimal investment by parents in the embodied capital (health, strength, and skills) and social status of offspring, focusing on feedbacks between individual decisions and socio-ecological conditions. We find that conditions similar to those in demographic transition societies yield increased investment in both embodied capital and social status, generating substantial decreases in fertility, particularly under conditions of high inequality and intense status competition. We suggest that a complete explanation for both fertility variation in small-scale societies and modern fertility decline will take into account the effects of status competition and inequality.     

Inflammation and Infection Do Not Promote Arterial Aging and Cardiovascular Disease Risk Factors among Lean Horticulturalists

Background

Arterial aging is well characterized in industrial populations, but scantly described in populations with little access to modern medicine. Here we characterize health and aging among the Tsimane, Amazonian forager-horticulturalists with short life expectancy, high infectious loads and inflammation, but low adiposity and robust physical fitness. Inflammation has been implicated in all stages of arterial aging, atherogenesis and hypertension, and so we test whether greater inflammation associates with atherosclerosis and CVD risk. In contrast, moderate to vigorous daily activity, minimal obesity, and low fat intake predict minimal CVD risk among older Tsimane.

Methods and Findings

Peripheral arterial disease (PAD), based on the Ankle-Brachial Index (ABI), and hypertension were measured in Tsimane adults, and compared with rates from industrialized populations. No cases of PAD were found among Tsimane and hypertension was comparatively low (prevalence: 3.5%, 40+; 23%, 70+). Markers of infection and inflammation were much higher among Tsimane than among U.S. adults, whereas HDL was substantially lower. Regression models examine associations of ABI and BP with biomarkers of energy balance and metabolism and of inflammation and infection. Among Tsimane, obesity, blood lipids, and disease history were not significantly associated with ABI. Unlike the Tsimane case, higher cholesterol, C-reactive protein, leukocytes, cigarette smoking and systolic pressure among North Americans are all significantly associated with lower ABI.

Conclusions

Inflammation may not always be a risk factor for arterial degeneration and CVD, but instead may be offset by other factors: healthy metabolism, active lifestyle, favorable body mass, lean diet, low blood lipids and cardiorespiratory health. Other possibilities, including genetic susceptibility and the role of helminth infections, are discussed. The absence of PAD and CVD among Tsimane parallels anecdotal reports from other small-scale subsistence populations and suggests that chronic vascular disease had little impact on adult mortality throughout most of human evolutionary history.     

Income distribution and mortality: cross sectional ecological study of the Robin Hood index in the United States.

OBJECTIVE--To determine the effect of income inequality as measured by the Robin Hood index and the Gini coefficient on all cause and cause specific mortality in the United States. DESIGN--Cross sectional ecological study. SETTING--Households in the United States. MAIN OUTCOME MEASURES--Disease specific mortality, income, household size, poverty, and smoking rates for each state. RESULTS--The Robin Hood index was positively correlated with total mortality adjusted for age (r = 0.54; P < 0.05). This association remained after adjustment for poverty (P < 0.007), where each percentage increase in the index was associated with'' an increase in the total mortality of 21.68 deaths per 100,000. Effects of the index were also found for infant mortality (P = 0.013); coronary heart disease (P = 0.004); malignant neoplasms (P = 0.023); and homicide (P < 0.001). Strong associations were also found between the index and causes of death amenable to medical intervention. The Gini coefficient showed very little correlation with any of the causes of death. CONCLUSION--Variations between states in the inequality of income were associated with increased mortality from several causes. The size of the gap between the wealthy and less well off--as distinct from the absolute standard of living enjoyed by the poor--seems to matter in its own right. The findings suggest that policies that deal with the growing inequities in income distribution may have an important impact on the health of the population.     

Differential visibility of treponemal disease in pre‐Columbian stratified societies: Does rank matter?

Treponemal disease is known to be associated with the compromised community health of permanent village settlement. This association explains its high visibility in the village‐based, arguably chiefdom level, agriculturalist societies of late prehistoric (AD 1300–1600) North America. Within chiefdom‐level societies, health differences have often been demonstrated between mortuary‐defined “elite” and “nonelite” individuals. This theoretically should predict status‐based differences in treponemal disease visibility. The prediction is tested in a five‐site osteological sample (N = 650) from the Dallas phase (AD 1300–1550), a simple mortuary‐defined two‐tiered presumptive chiefdom level maize agriculturalist socioeconomic context from lower east Tennessee. The Dallas phase results affirm a general pre‐Colombian North American pattern of no sex differences and display comparable adult to subadult frequencies. The study also reveals that given a sufficient sample size, “elites” do indeed exhibit a significantly lower frequency of tertiary stage treponemal disease. This can be attributed to better baseline health, which has been previously demonstrated in this sample. It may also be affected by the mortuary inclusion of achieved status individuals whose good health may have facilitated sociopolitical advancement. Another pattern that emerged is an apparent young adult age bias in disease visibility. This suggests that tertiary treponemal disease morbidity may either directly or synergistically factor in early adult age at death. Future research will address the veracity of this association. Am J Phys Anthropol, 2011. © 2010 Wiley‐Liss, Inc.     

The spread of inequality

The causes of socioeconomic inequality have been debated since the time of Plato. Many reasons for the development of stratification have been proposed, from the need for hierarchical control over large-scale irrigation systems to the accumulation of small differences in wealth over time via inheritance processes. However, none of these explains how unequal societies came to completely displace egalitarian cultural norms over time. Our study models demographic consequences associated with the unequal distribution of resources in stratified societies. Agent-based simulation results show that in constant environments, unequal access to resources can be demographically destabilizing, resulting in the outward migration and spread of such societies even when population size is relatively small. In variable environments, stratified societies spread more and are also better able to survive resource shortages by sequestering mortality in the lower classes. The predictions of our simulation are provided modest support by a range of existing empirical studies. In short, the fact that stratified societies today vastly outnumber egalitarian societies may not be due to the transformation of egalitarian norms and structures, but may instead reflect the more rapid migration of stratified societies and consequent conquest or displacement of egalitarian societies over time.     

林木个体大小不一致性指标对人工林间伐方式的即时性响应

以广西14年生杉木和马尾松人工林为对象,设同一疏伐强度的下层疏伐、上层疏伐、机械疏伐和干扰树间伐4种处理,分别用标准差、变异系数、偏度、Gini系数、库兹涅茨系数和洛伦茨不对称系数6种指标对4种间伐方式下采伐前后林木个体大小差异进行评价.结果表明: 与间伐前相比,马尾松和杉木人工林下层疏伐或上层疏伐后,林木个体材积的标准差、变异系数、Gini系数和库兹涅茨系数均变小,偏度变大;干扰树间伐后标准差、变异系数、Gini系数和库兹涅茨系数均变大,偏度则不一定.马尾松林和杉木林下层疏伐后洛伦茨不对称系数变大,上层疏伐或干扰树间伐后则变小.机械疏伐后各指标无明显变化规律.干扰树间伐后林木个体大小差异性增加,上层疏伐和下层疏伐后林木个体大小差异性减小.洛伦茨曲线、Gini系数和洛伦茨不对称系数均能较好地反映林木个体大小不一致性,可以进行不同林分间个体差异程度静态和动态比较,较好地反映不同间伐方式引起的林木个体差异.洛伦茨不对称系数可以判断林木个体大小不一致性的来源是大树还是小树.近自然森林经营中干扰树间伐措施可以在减小目标树竞争压力的同时拉大林木个体大小差距,有助于保持目标树在林分中的优势地位.
     

Comparison of skewness coefficient,coefficient of variation,and Gini coefficient as inequality measures within populations

Summary The moment skewness coefficient, coefficient of variation and Gini coefficient are contrasted as statistical measures of inequality among members of plant populations. Constructed examples, real data examples, and distributional considerations are used to illustrate pertinent properties of these statistics to assess inequality. All three statistics possess some undesirable properties but these properties are shown to be often unimportant with real data. If the underlying distribution of the variable follows the often assumed two-parameter lognormal model, it is shown that all three statistics are likely to be highly and positively correlated. In contrast, for distributions which are not two-parameter lognormally distributed, and when the distribution is not concentrated near zero, the coefficient of variation and Gini coefficient, which are sensitive to small shifts in the mean, are often of little practical use in ordering the equality of populations. The coefficent of variation is more sensitive to individuals in the right-hand tail of a distribution than is the Gini coefficient. Therefore, the coefficient of variation may often be recommended over the Gini coefficient if a measure of relative precision is selected to assess inequality. The skewness coeficient is suggested when the distribution is either three-parameter lognormally distributed (or close to such), or when a measure of relative precision is not indicated.Scientific Paper no 7830. College of Agriculture and Home Economics Research Center, Washington State University     

Evidence of traditional knowledge loss among a contemporary indigenous society

As biological and linguistic diversity, the world’s cultural diversity is on decline. However, to date there are no estimates of the rate at which the specific cultural traits of a group disappear, mainly because we lack empirical data to assess how the cultural traits of a given population change over time. Here we estimate changes in cultural traits associated to the traditional knowledge of wild plant uses among an Amazonian indigenous society. We collected data among 1151 Tsimane’ Amerindians at two periods of time. Results show that between 2000 and 2009, Tsimane’ adults experienced a net decrease in the report of plant uses ranging from 9% (for the female subsample) to 26% (for the subsample of people living close to towns), equivalent to 1% to 3% per year. Results from a Monte Carlo simulation show that the observed changes were not the result of randomness. Changes were more acute for men than for women and for informants living in villages close to market towns than for informants settled in remote villages. The Tsimane’ could be abandoning their traditional knowledge as they perceive that this form of knowledge does not equip them well to deal with the new socio-economic and cultural conditions they face nowadays.     

Signaling by consumption in a native Amazonian society

People signal status by producing, distributing, or consuming goods. Behavioral ecologists working with foragers stress signaling by production (e.g., supply of wildlife), whereas economists working in industrial economies stress signaling by individual consumption or expenditures. As foraging economies experience economic transformations, one expects greater reliance on individual consumption compared with production to signal status. We test two hypotheses: if people signal by individual consumption, they will allocate a higher share of their monetary expenditures to luxuries or to visible durable goods (Hypothesis 1) and the propensity to signal by individual consumption will be more salient among people closer to market towns (Hypothesis 2). To test the hypotheses, we draw on data from a native Amazonian society of foragers and slash-and-burn farmers in Bolivia (Tsimane') undergoing increasing exposure to the market economy. The sample included 161 women and 257 men 16+ years of age in 13 villages. The dependent variable was the share of total monetary expenditures allocated to different types of durable goods (e.g., clothing, luxuries, highly visible and less visible goods) during the previous year. Separate OLS regressions were used for women and men. We found support for Hypothesis 1. Higher levels of total monetary expenditures bore a positive association with the share of expenditures allocated to luxury goods and a negative association with expenditures allocated to less visible durable goods. Only among women did we find a positive association between total expenditures and the share of expenditures allocated to highly visible goods. We found no support for Hypothesis 2.     

我国城乡地区卫生人力资源分布的公平性分析

目的:了解我国卫生人力资源的配置现状及其变化趋势,尤其是卫生人力资源在城乡地区的分布状况,评价我国城乡卫生人力资源配置的公平性。方法:对2004-2011年的相关数据进行统计描述,用基尼系数测量卫生资源配置的公平程度及其变化。结果:农村地区卫生人力资源在数量上仍然处于极大的劣势,卫生人力构成以中专为主,中专及以下学历人员占大多数,人员素质相对城市有较大差距,提供卫生服务的能力相对薄弱。我国2004年到2011年我国卫生人力资源量逐年增加,各项指标较2004年的增幅都达到了10%以上,每千人口卫生技术人员数稳步上升,但是城镇和乡村上升速度相差巨大。卫生人力资源基尼系数按地理分布在0.13~0.25之间,连续5年一直上升。结论:我国卫生人力资源配置总体上均衡,但是公平性在下降,医师的公平性优于护士,城乡差距较大,应该重点加强农村经济发展,改善医疗卫生条件,建立健全农村卫生人才队伍培养机制。     

Socio-economic determinants of health and physical fitness in southern Ethiopia

The dependence of health and physical fitness on the socio-economic factors of rural families in southern Ethiopia is investigated, with particular emphasis on the role of inequality. This paper contributes to our knowledge of the effect of inequality on health in several ways: it compares the results of objective and subjective health measures, it distinguishes between wealth inequality and nutrition inequality, and it evaluates the impact of nutrition inequality both at the village level and at the household level. The subjective health measures are the number of days respondents were ill during the last month, their ability to walk distances, their ability to carry heavy loads, and their ability to work in the field. The objective health measure is having Body Mass Index (BMI) lower than 18.5. Males are healthier than females. Height has a positive and significant effect on health and fitness and the same is true for per-capita wealth measured at the village level. Availability of satisfactory health facilities has a negative effect on morbidity. Per-capita wealth inequality is positively associated with morbidity and with a low BMI. Within-household nutrition inequality has a complex effect on health and physical fitness: the effect is negative, but only for household members whose nutritional status is above the household mean. The results indicate a clear positive effect of economic well-being on health and physical fitness. The role of inequality is less clear, and certainly deserves further analyses at both the theoretical and empirical levels.     

Income Inequality,Economic Growth and Stroke Mortality in Brazil: Longitudinal and Regional Analysis 2002-2009

Background and Purpose

Stroke accounts for more than 10% of all deaths globally and most of it occurs in low- and middle-income countries (LMIC). Income inequality and gross domestic product (GDP) per capita has been associated to stroke mortality in developed countries. In LMIC, GDP per capita is considered to be a more relevant health determinant than income inequality. This study aims to investigate if income inequality is associated to stroke mortality in Brazil at large, but also on regional and state levels, and whether GDP per capita modulates the impact of this association.

Methods

Stroke mortality rates, Gini index and GDP per capita data were pooled for the 2002 to 2009 period from public available databases. Random effects models were fitted, controlling for GDP per capita and other covariates.

Results

Income inequality was independently associated to stroke mortality rates, even after controlling for GDP per capita and other covariates. GDP per capita reduced only partially the impact of income inequality on stroke mortality. A decrease in 10 points in the Gini index was associated with 18% decrease in the stroke mortality rate in Brazil.

Conclusions

Income inequality was independently associated to stroke mortality in Brazil.     

Egocentric social network structure, health, and pro-social behaviors in a national panel study of Americans

Using a population-based, panel survey, we study how egocentric social networks change over time, and the relationship between egocentric network properties and health and pro-social behaviors. We find that the number of prosocial activities is strongly positively associated with having more friends, or an increase in degree, with approximately 0.04 more prosocial behaviors expected for every friend added. Moreover, having more friends is associated with an improvement in health, while being healthy and prosocial is associated with closer relationships. Specifically, a unit increase in health is associated with an expected 0.45 percentage-point increase in average closeness, while adding a prosocial activity is associated with a 0.46 percentage-point increase in the closeness of one's relationships. Furthermore, a tradeoff between degree and closeness of social contacts was observed. As the number of close social contacts increases by one, the estimated average closeness of each individual contact decreases by approximately three percentage-points. The increased awareness of the importance of spillover effects in health and health care makes the ascertainment of egocentric social networks a valuable complement to investigations of the relationship between socioeconomic factors and health.