SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
"This paper examines two aspects of hierarchical urban models: the variations of total urban population and that of the urbanization ratio, in function of the number of hierarchical levels. Both variations are analysed through four categories of models. The complexity of the results suggests two approximations in order to make the analysis more tractable."
"This paper has three aims. The first is to examine the reliability of the data base for the statistics which are used as the basis for commenting on urban change in 'the Third World'. The second is to explore whether valid generalisations about urban change can be made for the Third World. And the third is to examine the validity of United Nations projections for the Third World's urban future."
AIMS: To assess the influence of socioeconomic status on the prevalence of the metabolic syndrome in an urban south Indian population in Chennai. METHODS: The Chennai Urban Population Study is an epidemiological study involving two residential colonies in Chennai (formerly Madras) in south India representing the middle and lower income groups. All individuals > or = 20 years of age living in the colonies were invited to participate in the study. Of the total 1399 eligible subjects, 1262 individuals (479 belonging the middle income group colony and 783 from the low income group colony) participated in the study. The overall response rate was 90.2%. The main outcome measures were the prevalence rates of the various components of the metabolic syndrome. RESULTS: There were significant differences in the socioeconomic status and lifestyle of the inhabitants of the two areas. The mean monthly income of the Tirumangalam (middle income) group (Rs8075 +/- 3859) was significantly higher than the T. Nagar (low income) group (Rs1399 +/- 916). The dietary profile of the middle income group showed higher intake of calories, fat and sugar compared to low income group (P < 0.001). The age-standardized prevalence rates of the various components of the metabolic syndrome were significantly higher in the middle compared to the low income group - diabetes (12.4 vs. 6.5%), impaired glucose tolerance (7.5 vs. 2.9%), hypertension (14.9 vs. 8.4%), obesity (males 38 vs. 13.4%, females 33.1 vs. 24.2%), hypercholesterolaemia (24.2 vs. 14.2%) and hyperinsulinaemia (16.7 vs. 6.6%) P < 0.001). Although the prevalence of coronary artery disease and hypertriglyceridaemia were higher in the middle income group, the differences did not reach statistical significance. The relative odds ratio for diabetes and impaired glucose tolerance increased significantly with increase in income while hypercholesterolaemia, hypertriglyceridaemia, hypertension and coronary artery disease showed no significant changes. Logistic regression analysis revealed that geographical area (higher social class) had a strong association with the components of the metabolic syndrome even after inclusion of other risk factors like age and body mass index in the model. CONCLUSIONS: Significant differences exist in the prevalence of various components of the metabolic syndrome even within an urban environment and this appears to be influenced by socioeconomic status.
The authors present evidence that "urbanisation in the GDR [German Democratic Republic] has considerably increased within the last 30 years though statistically the urban population has only slightly grown. Urbanisation is seen as a socio-economic process, as a stage-by-stage transition from the rural to the urban way of life. The socialist changes led to a spread and consolidation of the urban way of life. With the population trend stagnant, there are long-term regional concentration processes apparent, marked by the further development and a more equal distribution of large and medium towns." (SUMMARY IN ENG, RUS)
Like other persistent organic pollutants (POPs), polychlorinated biphenyls (PCBs) are still present in the environment despite their almost worldwide prohibition. A study was conducted over 1 year in Switzerland to analyze the source and load of PCBs in urban stormwater and their importance in urban water systems. The mean PCB concentrations of 89 rain events were determined in five different strictly separate drainage systems (three in Lausanne and two in Geneva). The mean concentrations of PCBs in stormwater ranged from values below the detection limit (0.11-0.24 ng/l) to 403 ng/l. A model for the wet and dry deposition of PCBs based on these results estimates that their concentration in rainwater has remained practically constant (35 ng/l) over a period of 12 years. A mass balance of Swiss levels estimates a total input load of PCBs in the urban water systems at 110-125 kg/year. The contribution of stormwater is 75-94 kg/year in combined sewer systems and 23-34 kg in separate sewer systems. This mass balance illustrates that a major part of the PCB load in the environment or in WWTP sludges originates from urban stormwater. This result was confirmed by a fingerprint of PCB congeners in stormwater, which showed a pattern identical to that found in sewage sludge in combined sewer systems.
A multimedia model has been developed to estimate the dynamics of semivolatile organic compounds (SOCs) in urban areas. The model is based on a Level III fugacity model of Mackay and consists of six compartments: air, surface water, sediment, soil, vegetation, and an organic film that coats impervious surfaces. The model was used to illustrate the effect of impervious surfaces in urban areas by parametrization for downtown, Toronto, Canada, and modification of the same area to simulate forested conditions. With illustrative emissions of PCB homologues to air, the model indicates that most chemicals are lost by advection, with the remainder undergoing air-to-surface (organic film or vegetation) transfer. Under urban conditions chemicals with Log[K(OA)] < 7.5 volatilize from the film into air where they are susceptible to advection and photolytic degradation. Chemicals with Log[K(OA)] > 7.5 are washed off the film to surface waters where they may undergo volatilization, advection, sedimentation, and degradation. Both loss mechanisms from the film increase the overall mobility of SOCs in the urban relative to the forested environment. In forested areas, vegetation more efficiently accumulates gas- and particle-phase SOCs and subsequently transfers them to surface soils, the greatest chemical reservoir, where they are relatively immobile.
Platelet fatty acids, platelet aggregations, and coagulation factors were measured in 27 rural blacks, 27 urban blacks and 39 urban whites. Platelets were significantly less aggregable to collagen and arachidonic acid in in both black groups as compared to whites (p less than 0.01), but there were no significant differences in ADP or epinephrine aggregation between these groups. Factor VIII coagulant activity was much higher in rural and urban blacks than whites (p less than 0.001), and the partial thromboplastin times were shorter (p less than 0.005). Platelet arachidonic acid showed a marked difference between the groups, being 16.4 +/- 5.4% of total platelet fatty acids in the rural blacks, 19.9 +/- 4.2% in the urban blacks and 22.6 +/- 3.3% in the whites (p less than 0.001). Whites had higher LDL and lower HDL cholesterol than blacks (p less than 0.005). These findings suggest that in addition to the well known association of raised LDL cholesterol and acute myocardial infarction, platelet aggregation patterns and platelet arachidonic acid levels may be associated risk factors in coronary thrombosis.
Five schools were chosen in different districts of Brazzaville where the intensity of malaria transmission, determined in a previous study, is representative of the very varied conditions observed in this town in relation to urbanization. The parasitological and serological results found in schoolchildren are analysed according to the level of transmission to which they are exposed, and compared with the results of a longitudinal survey carried out in the rural area of the Brazzaville region. In the urban area malaria prevalences in schoolchildren aged from 5 to 9 years and from 10 to 14 years vary considerably according to the districts. They are, respectively, 78.9% and 84% in Massina, 58.8% and 71.7% in Talangai, 32.3% and 46.9% in Bacongo and 5.6% and 12.6% in Moungali. In Poto-Poto, no positive thick films were found in a representative sample of 62 schoolchildren aged 6 and 7 years who have always lived in this district, and the malaria prevalence is only 6.9% in schoolchildren aged 14 and 15. In the rural area, the malaria prevalence is 76.4% in schoolchildren aged 5 to 9 and 82% in those aged from 10 to 14. According to standard immunofluorescent technique, 63% of children aged 6 and 7 years living since birth in the central part of the Poto-Poto and Moungali districts have no detectable antibodies. In the rural area, all children over 4 years of age are seropositive. These results show that the decrease in vectorial density which accompanies urbanization has considerable parasitological repercussions.(ABSTRACT TRUNCATED AT 250 WORDS)
Fundamental to primary health care is the need to provide adequate environmental health services to the population. Such services constitute primary prevention, and, under some circumstances, may have a greater impact on health than the provision of personal health services. This study aimed to assess the availability of environmental health services among blacks living in urban and peri-urban areas of South Africa. A stratified random sample of 800 households was selected. After discussions with the Urban Foundation, it was felt that the proportion of informal dwellings obtained (20%) underestimated the true figure, which was closer to 50%. For that reason estimates are presented for a range of values (20-50% informal dwellings). For environmental health services the percentage availability was 30-45% for reticulated water in the home; 18-29% for an inside flush toilet; and 48-62% for possession of a personal refuse receptacle. Data obtained on domestic fuel use indicated that 41-61% of households had electricity. General indicators of social class showed that 62% of households had a monthly income less than R400, and that 22-30% of mothers with children under 5 years of age had an educational level of less than Standard 5. All of the measures were substantially worse among people living in informal dwellings. The data indicate that urgent attention should be given to improving the foundations of primary health care, particularly by providing and giving attention to equity, intersectoral co-ordination and community participation in the provision of essential environmental health services.
OBJECTIVE: The aim of this study was to determine the mortality rate in diabetic and non-diabetic subjects in urban south India. METHODS: The Chennai Urban Population Study is an ongoing epidemiological study in Chennai [formerly Madras, in south India]. All individuals > or = 20 years of age living in two residential colonies in Chennai were invited to participate in the study. Of the total 1399 eligible subjects, 1262 individuals responded [90.2%] at baseline, and of these, 1140 individuals [90.3%] could be followed annually from 1997 to 2003-04. Mortality rates and causes of death were the main outcome measures. RESULTS: The median follow up period was six years. The overall mortality rate was higher in diabetic compared to non-diabetic subjects [18.9 vs.5.3 per 1000 person-years, p=0.004]. Mortality due to cardiovascular [diabetic subjects, 52.9%; non-diabetic subjects, 24.2%,p=0.042] and renal causes[diabetic subjects, 23.5%; non-diabetic subjects, 6.1%,p=0.072] was higher among diabetic subjects whereas mortality due to gastrointestinal 112.1%], respiratory [9.1%], lifestyle related [6.1%] and unnatural causes [18.2%] were observed only among non-diabetic subjects. Hazards ratio [HR] for all cause mortality for diabetes was 3.6, [95% Confidence Interval [CI]: 2.02-6.53, p<0.001] and this remained significant even after adjusting for age [HR:1.9, 95% CI:1.04-3.45, p=0.038]. Light grade physical activity was associated with higher mortality rate [p=0.008], but the significance disappeared when adjusted for age. Smoking was also associated with increased mortality. CONCLUSIONS: In urban India, mortality rates are two fold higher in people with diabetes compared to nondiabetic subjects. Cardiovascular and renal diseases are the commonest causes of death among diabetic subjects.
Once located in time and place the beginning of urbanization process, the mechanisms of adaptation to urban ecosystem and of dissemination by human conveyances are studied for two domestic mosquitoes: Aedes aegypti and Culex pipiens fatigans (= quinque-fasciatus). Then epidemiological consequences are discussed. Ae. aegypti pullulation constitutes a potential risk of urban yellow fever outbreak and the main factor of dengue haemorrhagic fever appearance; the increase of C. p. fatigans populations involves a slow rise of bancroftian filariasis. Future prospects for these diseases are discussed with regards to data concerning recent evolution of their own epidemiological features.
"We use Tanzanian data to test a recently proposed hypothesis that rural-to-urban migrants have an incentive to supply greater work effort than native urban workers, because of the migrants' positive probability of returning to the low-wage rural areas. We treat the choice between public- and private-sector employment as endogenous and, for theoretical and empirical reasons, distinguish migrants with access to rural land from those without access. Our results show that migrants in both sectors face lower initial wage offers than native urban workers. But, the wage gap is eliminated within a decade or less, and thereafter, migrants surpass the wage offers of native workers."
AIMS: To estimate the prevalence of opiate or benzodiazepine misuse in the Grampian Health Board area, Scotland and illustrate the use of the capture-recapture method in both rural and urban settings. DESIGN: Capture-recapture analyses on six distinct sources of data with unequal coverage of the geographical area. SETTING: Grampian Health Board area, including the City of Aberdeen. PARTICIPANTS: Data were collated from the Police, Social Work Departments, GPs contributing to the Scottish Drug Misuse Database, statutory drug agencies, a voluntary sector drug agency and a needle/syringe exchange. MEASUREMENTS: In total 1770 individuals were identified as misusing opiates or benzodiazepines and residing in the Grampian Health Board area; 1129 individuals were resident in the City of Aberdeen. FINDINGS: The total number of opiate or benzodiazepine misusers in the City of Aberdeen was estimated to be 2519 (95% CI 2048-3200). This figure corresponds to 2.0% (1.6-2.5%) of the population aged 15-54 years. In a town to the north of Aberdeenshire where high levels of heroin use had previously been reported in the media, 2.5% of the population aged 15-54 (1.8-3.8%) were estimated to be misusing opiates or benzodiazepines. CONCLUSIONS: Although there may be difficulties in applying capture-recapture methods in all settings, the methodology can give valuable information on the extent of drug misuse in both urban and non-urban areas. This information is particularly important to assess the spread of drug misuse from cities to rural areas.
The authors provide background on the poor health and economic status of the residents of East Baltimore, Maryland--the neighborhood surrounding a significant part of Johns Hopkins University, including the School of Medicine, the School of Nursing, the Bloomberg School of Public Health, and the Johns Hopkins Hospital. The president of the Johns Hopkins University established a council on urban health, consisting of a broad array of individuals from across the university and the community to develop a recommended course of action to help deal with these conditions. Based on the recommendations of the council, the Johns Hopkins Urban Health Institute was established with the mission to marshall the resources of the university and external groups to improve the health and well-being of the residents of East Baltimore and to promote evidence-based interventions to solve urban health problems nationwide. After becoming fully operational in 2001, the institute established three major goals: (1) strengthen research and learning, (2) reduce disparities in health and health care for East Baltimore residents, and (3) promote economic growth in East Baltimore. The article describes the institute's major activities, including community-based participatory research projects, the Journal of Community-Based Participatory Research, and programs for research fellows to promote research and learning; HIV/AIDS counseling and testing centers and a primary care clinic for the uninsured to reduce health disparities; and a technology resource center providing training and job opportunities to promote economic growth. The authors conclude by outlining the next steps planned for the institute.
BACKGROUND: A previous study in an inner city emergency department (ED) in Baltimore, Maryland, showed a high prevalence of gonorrhea and chlamydia infection among ED patients. GOAL: The goal was to compare results from an inner city ED to results from an urban ED in Baltimore, in terms of study population and setting, risks for infection, and factors associated with nonparticipation in the study. METHODS: This was a cross-sectional study of patients aged 14 to 44 years at two EDs. Outcomes for multivariate logistic regression analyses were (1). positive for gonorrhea or chlamydia by urine ligase chain reaction assay and (2). nonparticipation in the study. Comparative analyses were limited to patients aged 18 to 31 years. RESULTS: Patients differed significantly between EDs by participation rate, distribution of race/ethnicity, healthcare access, and behavioral risks, although the prevalence of infection did not differ. Risks for infection at the inner city ED were younger age, history of STD, and recent number of sex partners. Risks for infection at the urban ED were female gender and recent number of sex partners. At both EDs, being African American was associated with increased chance of participating, whereas lack of any genitourinary complaint was associated with nonparticipation. At the urban ED, women and patients approached for study enrollment during the day were also less likely to participate. CONCLUSION: ED-based screening for STDs can be an effective intervention for unrecognized infections. However, assessing population characteristics is necessary to develop targeted screening methods and clinical algorithms and to improve participation of patients and program sustainability.
PURPOSE: To assess the prevalence of diabetic retinopathy (DR) in type 2 diabetic subjects in urban India using four-field stereo color photography. METHODS: The Chennai Urban Rural Epidemiology Study (CURES) is a population-based study conducted on a representative population of Chennai (formerly Madras) city in South India. Individuals > or =20 years in age (n = 26,001) were screened for diabetes. Of the 1529 known diabetic subjects, 1382 (90.4%) participated in the study. Subjects with newly detected diabetes (n = 354) by the oral glucose tolerance test (OGTT) also consented to participate in the study. All the subjects underwent four-field stereo color photography, and retinopathy was graded in the color fundus photographs according to Early Treatment Diabetic Retinopathy Study (ETDRS) criteria. RESULTS: The overall prevalence of DR in the population was 17.6% (95% confidence interval [CI]: 15.8-19.5), which included 20.8% (95% CI: 18.7-23.1) in known diabetic subjects and 5.1% (95% CI: 3.1-8.0) in subjects with newly detected diabetes. The prevalence of DR was significantly higher in men than in women (21.3% vs. 14.6%; P < 0.0001) and among subjects with proteinuria (P = 0.002). Logistic regression analysis showed that for every 5-year increase in the duration of diabetes, the risk for DR increased 1.89-fold (95% CI: 1.679-2.135; P < 0.0001). For every 2% elevation of glycated hemoglobin (HbA1c), the risk for DR increased by a factor of 1.7 (95% CI: 1.545-1.980; P < 0.0001). CONCLUSIONS: This study shows that the prevalence of diabetic retinopathy is lower in urban South Indians than in other ethnic groups. However, due to the large number of diabetic subjects, DR is likely to pose a public health burden in India; hence, routine retinal examination is mandatory to detect DR in the early stages.
BACKGROUND: Currently, there is a significant lack of knowledge concerning urban malaria patterns in general and in Abidjan in particular. The prevalence of malaria, its distribution in the city and the fractions of fevers attributable to malaria in the health facilities have not been previously investigated. METHODS: A health facility-based survey and health care system evaluation was carried out in a peripheral municipality of Abidjan (Yopougon) during the rainy season of 2002, applying a standardized Rapid Urban Malaria Appraisal (RUMA) methodology. RESULTS: According to national statistics, approximately 240,000 malaria cases (both clinical cases and laboratory confirmed cases) were reported by health facilities in the whole of Abidjan in 2001. They accounted for 40% of all consultations. In the health facilities of the Yopougon municipality, the malaria infection rates in fever cases for different age groups were 22.1% (under one year-olds), 42.8% (one to five years-olds), 42.0% (> five to 15 years-olds) and 26.8% (over 15 years-olds), while those in the control group were 13.0%. 26.7%, 21.8% and 14.6%, respectively. The fractions of malaria-attributable fever were 0.12, 0.22, 0.27 and 0.13 in the same age groups. Parasitaemia was homogenously detected in different areas of Yopougon. Among all children, 10.1% used a mosquito net (treated or not) the night before the survey and this was protective (OR = 0.52, 95% CI 0.29-0.97). Travel to rural areas within the last three months was frequent (31% of all respondents) and associated with a malaria infection (OR = 1.75, 95% CI 1.25-2.45). CONCLUSION: Rapid urbanization has changed malaria epidemiology in Abidjan and endemicity was found to be moderate in Yopougon. Routine health statistics are not fully reliable to assess the burden of disease, and the low level of the fractions of malaria-attributable fevers indicated substantial over-treatment of malaria.
BACKGROUND: The thinking behind malaria research and control strategies stems largely from experience gained in rural areas and needs to be adapted to the urban environment. METHODS: A rapid assessment of urban malaria was conducted in Dar es Salaam in June-August, 2003 using a standard Rapid Urban Malaria Appraisal (RUMA) methodology. This study was part of a multi-site study in sub-Saharan Africa supported by the Roll Back Malaria Partnership. RESULTS: Overall, around one million cases of malaria are reported every year by health facilities. However, school surveys in Dar es Salaam during a dry spell in 2003 showed that the prevalence of malaria parasites was low: 0.8%, 1.4%, 2.7% and 3.7% in the centre, intermediate, periphery and surrounding rural areas, respectively. Health facilities surveys showed that only 37/717 (5.2%) of presenting fever cases and 22/781 (2.8%) of non-fever cases were positive by blood slide. As a result, malaria-attributable fractions for fever episodes were low in all age groups and there was an important over-reporting of malaria cases. Increased malarial infection rates were seen in persons who travelled to rural areas within the past three months. A remarkably high coverage of insecticide-treated nets and a corresponding reduction in malarial infection risk were found. CONCLUSION: The number of clinical malaria cases was much lower than routine reporting suggested. Improved malaria diagnosis and re-defined clinical guidelines are urgently required to avoid over-treatment with antimalarials.