Tuberculosis in Brazil: construction of a territorially based surveillance system

OBJECTIVE: To analyze the occurrence of tuberculosis and to identify variables that define situations of collective risk that determine the spatial distribution of the disease, as backing for implementing a territory-based surveillance system for tuberculosis control. METHODS: This was an ecological study performed in Olinda, a municipality in the metropolitan region of Recife, State of Pernambuco, between 1996 and 2000. The median number of notified tuberculosis cases in each census tract served as the cutoff point for characterizing areas of high and low transmission. A logistic regression model using this response variable allowed odds ratios for some socioeconomic variables from the 2000 demographic census and other covariates related to the transmission of the disease to be estimated. RESULTS: Tuberculosis in Olinda presented high incidence rates during the study period (average of 111 cases per 100,000 inhabitants). Significant associations with the occurrence of tuberculosis were found for the variables of average number of inhabitants per household (OR=2.2; 95% CI: 1.3; 3.6); existence of families with more than one case during the study period (OR=5.1; 95% CI: 2.3; 11.3); and presence of cases of retreatment (OR=6.8; 95% CI: 2.7; 17.1). The census tract where the latter two events occurred accounted for 45% of the total number of cases during the study period, while representing only 28% of the population of Olinda. CONCLUSIONS: The two explanatory covariates that were strongly associated with higher incidence rates of the disease are events that need to be carefully monitored at a local level by the tuberculosis surveillance system. Simply by mapping out retreatment cases and households with more than one case, attention could be focused on small areas with high priority for intensive intervention, thus facing up to the tuberculosis problem.     

Estimation of risk areas for hepatitis A

This study estimated hepatitis A risk areas in a region of Duque de Caxias, Rio de Janeiro State, Brazil. A cross-sectional study consisting of a hepatitis A serological survey and a household survey were conducted in 19 census tracts. Of these, 11 tracts were selected and 1,298 children from one to ten years of age were included in the study. Geostatistical techniques allowed modeling the spatial continuity of hepatitis A, non-use of filtered drinking water, time since installation of running water, and number of water taps per household and their spatial estimation through ordinary and indicator kriging. Adjusted models for the outcome and socioeconomic variables were isotropic; risk maps were constructed; cross-validation of the four models was satisfactory. Spatial estimation using the kriging method detected areas with increased risk of hepatitis A, independently of the urban administrative area in which the census tracts were located.     

A spatial analysis of social and economic determinants of tuberculosis in Brazil

We investigated the spatial distribution, and social and economic correlates, of tuberculosis in Brazil between 2002 and 2009 using municipality-level age/sex-standardized tuberculosis notification data. Rates were very strongly spatially autocorrelated, being notably high in urban areas on the eastern seaboard and in the west of the country. Non-spatial ecological regression analyses found higher rates associated with urbanicity, population density, poor economic conditions, household crowding, non-white population and worse health and healthcare indicators. These associations remained in spatial conditional autoregressive models, although the effect of poverty appeared partially confounded by urbanicity, race and spatial autocorrelation, and partially mediated by household crowding. Our analysis highlights both the multiple relationships between socioeconomic factors and tuberculosis in Brazil, and the importance of accounting for spatial factors in analysing socioeconomic determinants of tuberculosis.     

Hard Times and Common Mental Health Disorders in Developing Countries: Insights from Urban Ghana

Over the past century, the world has rapidly become urbanized, meaning more people now live in urban areas and cities than in rural areas. The mass movement of the rural poor to urban centers and cities has also changed the dynamics of poverty. Scarce employment opportunities, lack of assets, and sudden changes in economic conditions have been proposed as increasing the stress level for most urban residents, especially the poorer ones. Using a face-to-face household survey that included a six-item non-specific psychometric instrument, the data revealed how psychological distress may be patterned by socioeconomic status among urban residents in Ghana during difficult times characterized by food and fuel price hikes. The data collected in interviews of 1,158 adults (49% males and 51% females) who were 18 years and above were analyzed using multinomial logit regressions. The results confirmed previous findings and showed negative links between socioeconomic status, adverse life events, and psychological distress. Specifically, low income, low level of education, large household size, undesirable life events and being employed in agriculture was found to be associated with psychological disorders. The outcomes of this research project are consistent with previous findings—that people in lower socioeconomic strata and those who have suffered adverse events are more likely to suffer psychological distress. The implications of these results for behavioral health are discussed.     

浙江省2011-2015年发热伴血小板减少综合征发病空间预测

目的 了解浙江省发热伴血小板减少综合征（SFTS）发病空间分布特征,预测发病区域及聚集性疫情发生概率。方法 收集2011-2015年浙江省SFTS发病个案数据,使用ArcGIS 10.0软件进行空间分析,利用Moran''s I和G统计量探索空间自相关;采用趋势面分析发病趋势;以Kriging插值进行预测。结果 2011-2015年浙江省报告SFTS发病数逐年上升,报告发病地区扩大,发病时间和人群特征与既往研究结果相似;SFTS发病具有地区聚集性（P<0.001）,全省发病自东北向西南方向呈下降趋势;采用Kriging预测精度较好,预测发病区域较为广泛,以安吉、岱山、天台县发生聚集性病例概率相对更高,内部地区预测误差小于边缘地区。结论 Kriging插值预测SFTS发病较为准确,浙江省SFTS病例发生区域和水平均高于目前报告水平,以安吉、岱山、宁海、天台、三门、临海等地区发生聚集性疫情风险较高。     

Socioeconomic inequalities in coronary heart disease in Italy: a multilevel population-based study

This longitudinal study evaluates the role of individual and contextual socioeconomic determinants in the socioeconomic inequalities in incidence and mortality for coronary events in Turin, Italy, using hierarchical models. All residents aged 35-74 at the start of 1997 were included in the study population. We considered as outcomes all incident cases and deaths that occurred in the study population in the period 1997-2002. The socioeconomic indicators were educational level, job status and median income per census tract. A neighbourhood deprivation index was also used, which combines, in an aggregated measure, a series of poor individual socioeconomic conditions. The analyses were performed using hierarchical Poisson models, with individuals (n = 523,755) considered as level I units and neighbourhoods (n = 23) as level II units. Among men, we observed an inverse gradient in incidence by educational level and an excess risk for persons who were not actively employed. More marked excesses were found for mortality (RR: 1.63; 95% CI: 1.05-2.55, for unemployed persons compared to employed persons). Among women, greater socioeconomic differences were observed for both incidence and mortality; all of the individual indicators contributed to these differences. The differentials in mortality were particularly great for the retired and for housewives (RR: 1.98; 95% CI: 1.40-2.81). Slight excesses in incidence were observed among men for the most deprived areas. The results of this study reveal that job status is the most important individual factor explaining socioeconomic inequalities for coronary events, whereas context seems to play a marginal role.     

Access to iodized salt in 11 low- and lower-middle-income countries: 2000 and 2010

Objective

To describe changes in household access to iodized salt in relation to socioeconomic factors.

Methods

We extracted data on iodized household salt from Multiple Indicator Cluster Surveys conducted in 2000 and 2010. As part of the surveys, household salt samples were tested for iodization by standardized rapid-test kits that yield results to indicate whether salt is not iodized, inadequately iodized, (less than 15 parts per million, ppm), or adequately iodized (more than 15 ppm). We calculated indices of household salt iodization in 2000 and 2010, taking into account survey sampling weights. We explored associations between these indices and socioeconomic variables, both within and between countries.

Findings

We analysed data from 105 162 households in 2000 and 144 018 households in 2010. Between 2000 and 2010, household coverage of adequately iodized salt increased by 6.1% (from 46.3% to 52.4%) on average, but with regional differences: coverage fell by 13.0% (from 77.5% to 64.5%) in the Central African Republic but improved by 40.4% (from 22.2% to 62.6%) in Sierra Leone. Improvements in coverage were higher in rural areas and among the poorest households, but within-country socioeconomic disparities remained. There were weak associations between changes in salt iodization and national level socioeconomic indicators.

Conclusion

Overall, the coverage of adequately iodized household salt increased over the last decade. However, the changes varied widely among countries. The goal of universal salt iodization is still distant for many countries and requires renewed efforts by governments, bilateral and multilateral agencies and civil society.     

The Chilean infant mortality decline: improvement for whom? Socioeconomic and geographic inequalities in infant mortality, 1990–2005

OBJECTIVE: To measure socioeconomic inequalities and differential risk in infant mortality on national and regional levels in Chile from 1990 to 2005, and propose new policy targets. METHODS: The study analysed Chilean vital events registries from 1990 to 2005 for infant mortality by maternal education, head of household occupational status, cause, age and location of death. Annual infant mortality rates and relative risk were calculated by maternal education and head of household occupational status for each cause and age of death. Socioeconomic inequalities were then mapped to 29 regional health services. FINDINGS: Reductions in the national infant mortality rate were driven by reductions among highly educated mothers, while recent stagnation in the national rate is caused by high levels of infant mortality among uneducated mothers. These vulnerable households are particularly prone to infant mortality risk due to infectious disease and trauma. We also identify clustering of high socioeconomic inequalities in infant mortality throughout the poorer north, indigenous south and densely populated metropolitan centre of Santiago. Finally, we report large inequities in vital statistics coverage, with infant deaths among vulnerable households much more likely to be inadequately defined than in the remaining population. CONCLUSION: These results indicate that the socioeconomically disadvantaged in Chile are at a significantly higher risk for infant mortality by infectious diseases and trauma during the first month of life. Efforts to reduce national infant mortality in Chile and other countries must involve policies that target child survival for at-risk populations for specific diseases, ages and locations.     

Relation of socioeconomic position to the case fatality, prognosis and treatment of myocardial infarction events; the FINMONICA MI Register Study

OBJECTIVE: To examine socioeconomic differences in case fatality and prognosis of myocardial infarction (MI) events, and to estimate the contributions of incidence and case fatality to socioeconomic differences in coronary heart disease (CHD) mortality. DESIGN: A population-based MI register study. METHODS: The FINMONICA MI Register recorded all MI events among persons aged 35-64 years in three areas of Finland during 1983-1992. A record linkage of the MI Register data with the files of Statistics Finland was performed to obtain information on socioeconomic indicators for each individual registered. First MI events (n=8427) were included in the analyses. MAIN RESULTS: The adjusted risk ratio of prehospital coronary death was 2.11 (95% CI 1.82, 2.46) among men and 1.68 (1.14, 2.48) among women with low income compared with those with high income. Even among persons hospitalised alive the risk of death during the next 12 months was markedly higher in the low income group than in the high income group. Case fatality explained 51% of the CHD mortality difference between the low and the high income groups among men and 38% among women. Incidence contributed 49% and 62%, respectively. CONCLUSIONS: Considerable socioeconomic differences were observed in the case fatality of first coronary events both before hospitalisation and among patients hospitalised alive. Case fatality explained a half of the CHD mortality difference between the low and the high income groups among men and more than a third among women.     

Neighbourhood socioeconomic inequalities in incidence of acute myocardial infarction: a cohort study quantifying age- and gender-specific differences in relative and absolute terms

ABSTRACT: BACKGROUND: Socioeconomic status has a profound effect on the risk of having a first acute myocardial infarction (AMI). Information on socioeconomic inequalities in AMI incidence across age- gender-groups is lacking. Our objective was to examine socioeconomic inequalities in the incidence of AMI considering both relative and absolute measures of risk differences, with a particular focus on age and gender. METHODS: We identified all patients with a first AMI from 1997 to 2007 through linked hospital discharge and death records covering the Dutch population. Relative risks (RR) of AMI incidence were estimated by mean equivalent household income at neighbourhood-level for strata of age and gender using Poisson regression models. Socioeconomic inequalities were also shown within the stratified age-gender groups by calculating the total number of events attributable to socioeconomic disadvantage. RESULTS: Between 1997 and 2007, 317,564 people had a first AMI. When comparing the most deprived socioeconomic quintile with the most affluent quintile, the overall RR for AMI was 1.34 (95% confidence interval (CI): 1.32 - 1.36) in men and 1.44 (95% CI: 1.42 - 1.47) in women. The socioeconomic gradient decreased with age. Relative socioeconomic inequalities were most apparent in men under 35 years and in women under 65 years. The largest number of events attributable to socioeconomic inequalities was found in men aged 45-74 years and in women aged 65-84 years. The total proportion of AMIs that was attributable to socioeconomic inequalities in the Dutch population of 1997 to 2007 was 14% in men and 18% in women. CONCLUSIONS: Neighbourhood socioeconomic inequalities were observed in AMI incidence in the Netherlands, but the magnitude across age-gender groups depended on whether inequality was expressed in relative or absolute terms. Relative socioeconomic inequalities were high in young persons and women, where the absolute burden of AMI was low. Absolute socioeconomic inequalities in AMI were highest in the age-gender groups of middle-aged men and elderly women, where the number of cases was largest.     

Are clinical criteria just proxies for socioeconomic status? A study of low birth weight in Jamaica.

OBJECTIVE: To determine if the clinical risk factors for low birth weight are independent of socioeconomic risk factors in a population based sample from a developing country. DESIGN: Survey data from patient reported socioeconomic measures and their most recent pregnancy history. SETTING: A national sample of randomly selected households in Jamaica. SUBJECTS: All women aged 14-50 in the household who had a pregnancy lasting seven months in the past five years (n = 952). MAIN OUTCOME MEASURE: Birth weight. RESULTS: Clinical risk factors for low birth weight, such as parity age, are independent of socioeconomic determinants, such as consumption and where a mother lives. Women who are nulliparous, 35 or older, poor, or living in certain areas are more likely to have lower birth weight children than those that do not have these characteristics (t statistics > 2.0). The addition of socioeconomic factors to the multiple regression does not alter the estimates for the clinical risk factors for low birth weight. Thus, the effect of being nulliparous can be offset by being in the highest consumption quintile and, conversely, the risk of being older will be compounded if women are poor. CONCLUSIONS: Both clinical and socioeconomic risk factors should be used to target women at risk. In terms of the quality of care, this study links clinical and socioeconomic risk factors to poor outcomes. Further studies are needed, however, to link the quality of care at various locations to these outcomes.     

Spatial clusters detection of violent deaths in Porto Alegre, Rio Grande do Sul, Brazil, 1996]

Violence is of major importance in the health profile of Brazilian metropolitan areas and should be treated as a public health problem. Spatial analysis methods can be highly useful for the surveillance and prevention of violence. This paper analyzes the spatial distribution of victims' place of residence in relation to the main causes of violent death in Porto Alegre (1996) in order to identify vulnerable areas. For motor vehicle accidents, homicides, and suicide, the victim's place of residence was pinpointed using the municipal Geographic Information System. The point patterns of health events and population density were analyzed using a Kernel smoother, visually compared. Some areas with higher concentration of events are similar to population distribution but differ from each other in the remaining high concentration areas, thus indicating specific micro-areas at risk. Areas of higher homicide risk are mainly located on the periphery of the more urbanized area, with worse socioeconomic conditions. Motor vehicle accidents are concentrated in areas that are simultaneously commercial and residential and are traversed by streets with heavy traffic. Suicide deaths are more evenly distributed over the territory. Identification of risk areas provides meaningful information for developing preventive and health promotion measures focusing on the events for which health policies may play a central role.     

基于核密度和地理探测器的南宁市手足口病空间聚集及影响因素

  目的  分析2008-2015年南宁市手足口病(hand, foot and mouth disease, HFMD)空间聚集及影响因素,为南宁市防控HFMD提供参考。  方法  收集南宁市2008-2015年HFMD疫情数据,通过核密度方法分析空间聚集,通过地理探测器分析气象因素与社会经济因素对发病的影响。  结果  2008-2015年南宁市累计报告HFMD 326 785例,年均发病率为505.24/10万,发病高峰主要集中在4-7月。核密度分析显示HFMD存在明显的空间聚集,其中8年均出现聚集的地区是兴宁区、青秀区、江南区、良庆区和西乡塘区五个区的交界处及马山县的部分地区;地理探测器分析发现气象因素的影响大于社会经济因素的影响,且因素间的交互作用大于它们的单独作用。气温和相对湿度的单独作用及交互作用均是最强的,交互作用最大q值可达0.71(P＜0.001)。  结论  2008-2015年南宁市HFMD受气象因素影响较大,社会经济因素的影响可能存在双向作用,中心城区和部分基层地区是防控的关注点。     

Tuberculosis in Bissau: incidence and risk factors in an urban community in sub-Saharan Africa

BACKGROUND: Despite the long history of tuberculosis (TB) research, population-based studies from developing countries are rare. METHODS: In a prospective community study in Bissau, the capital of Guinea-Bissau, we assessed the impact of demographic, socioeconomic and cultural risk factors on active TB. A surveillance system in four districts of the capital identified 247 adult (>or=15 years) cases of intrathoracic TB between May 1996 and June 1998. Risk factors were evaluated comparing cases with the 25,189 adults living in the area in May 1997. RESULTS: The incidence of intrathoracic TB in the adult population was 471 per 100 000 person-years. Significant risk factors in a multivariate analysis were increasing age (P < 0.0001), male sex (odds ratio [OR] = 2.58, 95% CI: 1.85, 3.60), ethnic group other than the largest group (Pepel) (OR = 1.64, 95% CI: 1.20, 2.22), adult crowding (OR = 1.68, 95% CI: 1.18, 2.39 for >2 adults in household), and poor quality of housing (OR = 1.66, 95% CI: 1.24, 2.22). Household type was important; adults living alone or with adults of their own sex only, had a higher risk of developing TB than households with husband and wife present, the adjusted OR being 1.76 (95% CI: 1.11, 2.78) for male households and 3.80 (95% CI: 1.69, 8.56) for female households. In a multivariate analysis excluding household type, child crowding was a protective factor, the OR being 0.68 (95% CI: 0.51, 0.90) for households with >2 children per household. CONCLUSIONS: Bissau has a very high incidence of intrathoracic TB. Human immunodeficiency virus (HIV), increasing age, male sex, ethnicity, adult crowding, family structure, and poor housing conditions were independent risk factors for TB. Apart from HIV prevention, TB control programmes need to emphasize risk factors such as socioeconomic inequality, ethnic differences, crowding, and gender.     

Socioeconomic status of very small areas and stroke incidence in the Netherlands

OBJECTIVE: To examine whether characteristics of very small living areas can be used to predict disease incidence and to use these characteristics to assess socioeconomic differences in stroke incidence in the Netherlands. DESIGN: Characteristics of postcode areas of stroke patients are compared with characteristics of postcode areas of all individual people in the study region, using Poisson regression analysis. SETTING: Six provinces of the Netherlands, covering about half of the country. PATIENTS: 760 patients who in 1991 or 1992 were consecutively admitted because of stroke to 23 Dutch hospitals. Main results: Stroke incidence is significantly higher among people living in postcode areas with below average socioeconomic status (relative risk=1.27; 95% confidence intervals 1.08 to 1.51) and among people living in postcode areas with predominantly older inhabitants (RR=3.17; 95% CI=2.29 to 4.39). It is also significantly increased in more urbanised areas compared with the countryside, the highest incidence being found in the large cities (RR=1.78; 95% CI=1.31 to 2.44). CONCLUSIONS: A clear socioeconomic gradient in stroke incidence in the Netherlands is observed, with people living in detailed postcode areas with below average socioeconomic status experiencing a significantly higher risk of stroke. The analysis also confirms that characteristics of detailed postcode areas can effectively be used to differentiate between areas with and areas without stroke patients.     

Self-reported economic difficulties and coronary events in men: evidence from the Whitehall II study

BACKGROUND: Numerous studies have demonstrated social inequalities in coronary heart disease using a variety of measures of social position. In this study we examine associations between persistent economic difficulties and serious coronary events. Our aim is to assess whether these associations are (i) explained by other measures of socioeconomic status, and (ii) mediated by psychosocial, behavioural and biological factors. METHODS: The data come from 5021 middle-aged, white-collar men in the Whitehall II study. Self-reported household financial problems, measured at baseline (1985-88) and Phase 3 (1991-93), were used to construct a five-category score of persistent economic difficulties. Associations between economic difficulties and incident coronary events were determined over an average follow-up of 7 years. Other socioeconomic, psychosocial, behavioural and biological explanatory variables were obtained from the Phase 3 questionnaire and clinical examination. RESULTS: Age-adjusted Cox regression analyses demonstrated steep gradients in the incidence of coronary events with economic difficulties. The relative hazard between the bottom and the top of the difficulties hierarchy was 2.5 (95% confidence intervals (CI) 1.2-5.2) for fatal and non-fatal myocardial infarction (MI), 2.1 (1.3-3.6) for MI plus definite angina and 2.8 (1.9-4.2) for total coronary events. Adjustment for other markers of socioeconomic position, early life factors, psychosocial work environment characteristics and health-related behaviours had little effect, while adjustment for the biological factors reduced the association between difficulties and coronary events by 16-24%. CONCLUSION: We have demonstrated an economic difficulties gradient in coronary events in men that is independent of other markers of socioeconomic position and appears to be only partially mediated by well-known risk factors in mid-life.     

Area-based socioeconomic environment, obesity risk behaviours, area facilities and childhood overweight and obesity: socioeconomic environment and childhood overweight

Objective

The objective of this study is to evaluate whether the relation between area-based socioeconomic environment and childhood obesity can be explained by household socioeconomic position, obesity-related risk behaviours and area facilities.

Methods

Two indicators of socioeconomic environment based on wealth and deprivation were estimated in a sample of 4529 Spanish children and adolescents in 2006. Multilevel logit models were used to calculate the relation between each indicator and obesity.

Results

After adjusting for socioeconomic position and risk behaviours, no relation was observed between wealth and overweight; however, obesity prevalence was 1.45 times higher in subjects living in areas with lower wealth than in those living in areas with higher wealth. After adjusting for these variables, the prevalence of overweight and obesity in subjects living in deprived areas was, respectively, 1.26 and 1.63 higher than in those living in non-deprived areas. There was a graded association between number of sports facilities and prevalence of physical inactivity, but no relation was found between the price of fruits and vegetables and frequency of consumption.

Conclusion

The relation of socioeconomic environment with childhood obesity could not be explained by household socioeconomic position or obesity-related risk behaviours. Availability of sport facilities may mediate this relation.     

Effect of deep tube well use on childhood diarrhoea in Bangladesh

Objective

To determine whether the installation of deep tube wells to reduce exposure to groundwater arsenic in rural Bangladesh had an effect on the incidence of childhood diarrhoeal disease.

Methods

Episodes of diarrhoeal disease in children aged under 5 years that occurred on one specified day each month between 2005 and 2006 were reported to community health workers for six rural villages. A geographical information system containing details of household water use and sanitation in the villages was built using data obtained by a global positioning system survey. The information system also included health, spatial and demographic data. A field survey was carried out to determine whether households obtained drinking water from deep tube wells installed in 2005. The effect of deep tube well use on the incidence of childhood diarrhoea was assessed using a random effects negative binomial regression model.

Findings

The risk of childhood diarrhoea was 46% lower in the 179 households that used a deep tube well than in the 364 that used a shallow tube well (P = 0.032). Neither socioeconomic status, latrine density, population density nor study year had a significant influence on disease risk. The incidence of childhood diarrhoea declined dramatically between 2005 and 2006, irrespective of water source.

Conclusion

The introduction of deep tube wells to reduce arsenic in drinking water in rural Bangladesh had the additional benefit of lowering the incidence of diarrhoea among young children.     

Neighborhood socioeconomic context, individual income and myocardial infarction

BACKGROUND: The incidence of myocardial infarction (MI) varies among socioeconomic groups, and geographic differences in incidence rates are observed within most urban regions. Whether spatial social differentiation gives rise to social contexts detrimental to health is still an open question. In this study, we evaluate 2 aspects of the neighborhood context as contributory factors in MI: level of economic resources and degree of socioeconomic homogeneity. We adopt a multilevel approach to analyze potential mechanisms, which involve individual social characteristics. METHODS: We analyzed data from the SHEEP study, a population-based case-control study of first events of acute MI in Stockholm County in 1992-1994. Data on socioeconomic characteristics in neighborhoods came from total population registers of income and social circumstances. RESULTS: The level of neighborhood socioeconomic resources had a contextual effect on the relative risk of MI after adjustment for individual social characteristics. The incidence rate ratio (IRR) in low-income, compared with high-income, neighborhoods was 1.88 for women and 1.52 for men. Although the degree of socioeconomic homogeneity in neighborhoods has less impact on MI, the IRR for men in homogenous low-income areas compared with men living in heterogeneous high-income areas was 2.65. For men, the combined exposure to low-personal disposable income and low-income level in the neighborhood seemed to have an additive effect but for women, a synergistic (supra-additive) effect was found. CONCLUSION: The socioeconomic context of neighborhoods has an effect on cardiovascular outcomes.     

Spatial modeling using mixed models: an ecologic study of visceral leishmaniasis in Teresina,Piauí State,Brazil

Most ecologic studies use geographical areas as units of observation. Because data from areas close to one another tend to be more alike than those from distant areas, estimation of effect size and confidence intervals should consider spatial autocorrelation of measurements. In this report we demonstrate a method for modeling spatial autocorrelation within a mixed model framework, using data on environmental and socioeconomic determinants of the incidence of visceral leishmaniasis (VL) in the city of Teresina, Piauí, Brazil. A model with a spherical covariance structure indicated significant spatial autocorrelation in the data and yielded a better fit than one assuming independent observations. While both models showed a positive association between VL incidence and residence in a favela (slum) or in areas with green vegetation, values for the fixed effects and standard errors differed substantially between the models. Exploration of the data's spatial correlation structure through the semivariogram should precede the use of these models. Our findings support the hypothesis of spatial dependence of VL rates and indicate that it might be useful to model spatial correlation in order to obtain more accurate point and standard error estimates.