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PubMed2005

Particle size distributions of polycyclic aromatic hydrocarbons in rural and urban atmosphere of Tianjin, China.

The size distributions of 16 polycyclic aromatic hydrocarbons (PAHs) and particle mass less than 10 microm in aerodynamic diameter (Dp) were measured using a nine-stage low-volume cascade impactor at rural and urban sites in Tianjin, China in the winter of 2003-2004. The particles exhibited the trimodal distribution with the major peaks occurring at 0.43-2.1 and 9.0-10.0 microm for both urban and rural sites. The concentrations of the total PAH (sum of 16 PAH compound) at rural site were generally less than those of urban site. Mean fraction of 76.5% and 63.9% of the total PAH were associated with particles of 0.43-2.1 microm at rural and urban sites, respectively. Precipitation, temperature, wind speed and direction were the important meteorological factors influencing the concentration of PAHs in rural and urban sites. The distributions of PAHs concentration with respect to particle size were similar for rural and urban samples. The PAHs concentrations at the height of 40 m were higher than both of 20 and 60 m at urban site, but the mass median diameter (MMD) of total PAH increased with the increasing height. The mid-high molecular weight (278 >or= MW >or= 202) PAHs were mainly associated with fine particles (Dp or=MW >or=178) PAHs were distributed in both of fine and coarse particle. The fraction of PAHs associated with coarse particles (Dp>2.1 microm) decreased with increasing molecular weight. The relatively consistent distribution of PAHs seemed to indicate the similar combustion source of PAHs at both of rural and urban sites. The fine differences of concentration and distribution of PAHs at different levels at urban site suggested that the different source and transportation path of particulate PAHs.

Air↗

PubMed2005

Microbial indicators of heavy metal contamination in urban and rural soils.

Urban soils and especially their microbiology have been a neglected area of study. In this paper, we report on microbial properties of urban soils compared to rural soils of similar lithogenic origin in the vicinity of Aberdeen city. Significant differences in basal respiration rates, microbial biomass and ecophysiological parameters were found in urban soils compared to rural soils. Analysis of community level physiological profiles (CLPP) of micro-organisms showed they consumed C sources faster in urban soils to maintain the same level activity as those in rural soils. Cu, Pb, Zn and Ni were the principal elements that had accumulated in urban soils compared with their rural counterparts with Pb being the most significant metal to distinguish urban soils from rural soils. Sequential extraction showed the final residue after extraction was normally the highest proportion except for Pb, for which the hydroxylamine-hydrochloride extractable Pb was the largest part. Acetic acid extractable fraction of Cd, Cu, Ni, Pb and Zn were higher in urban soils and aqua regia extractable fraction were lower suggesting an elevated availability of heavy metals in urban soils. Correlation analyses between different microbial indicators (basal respiration, biomass-C, and sole C source tests) and heavy metal fractions indicated that basal respiration was negatively correlated with soil Cd, Cu, Ni and Zn inputs while soil microbial biomass was only significantly correlated with Pb. However, both exchangeable and iron- and manganese-bound Ni fractions were mostly responsible for shift of the soil microbial community level physiological profiles (sole C source tests). These data suggest soil microbial indicators can be useful indicators of pollutant heavy metal stress on the health of urban soils.

Biological Availability↗

PubMed1999

The potential contribution of urban runoff to surface sediments of the Passaic River: sources and chemical characteristics.

Urban runoff has been reported as the second most frequent cause of surface water pollution in the United States. Due to the incidence of runoff in urban areas, it was of interest to estimate the impact runoff may have to recent sediment quality within the lower reaches of the Passaic River. Study objectives included i) review of recent urban runoff studies to determine the occurrence and pattern of distribution of chemicals in runoff; ii)comparison of the "fingerprints" from urban runoff studies to the contaminant distributions in surface sediments from the River; and iii) estimation of mass loadings to the surface sediments using surrogate data. The analyses showed that metals and PAH distributions in the sediments were similar to those observed in runoff from diverse locations, suggesting that urban runoff composition within the Passaic watershed is similar to other urban areas. Mass loading calculations demonstrated that urban runoff is a significant source of the metals observed in the sediments, and that PAH and DDT sediment loadings could, in some cases, be accounted for by urban runoff. Observed sediment loads for PCBs, however, were significantly higher than were estimated from urban runoff.

Fresh Water↗

PubMed2003

Prevalence of antibodies to Neospora caninum in dogs of rural or urban origin in central New Zealand.

AIM: To investigate the seroprevalence of Neospora caninum infection in populations of dogs from dairy farms, sheep/beef farms and urban areas in the central part of New Zealand. It was postulated seroprevalence would be higher for farm dogs than urban dogs if the life-cycle of this parasite involves transmission between dogs and cattle. METHODS: Serum samples were obtained from dogs that lived on dairy farms (n=161), sheep/beef farms (n=154) and in urban situations (n=150). The relative risk of detecting antibodies to N. caninum using an immunofluorescent antibody test (IFAT) was compared between farm and urban dogs. RESULTS: The relative risk of having a titre of > or = 1:200 to N. caninum was 2.43 (95% CI=1.88-3.14) for dairy-farm dogs and 3.16 (95% CI=2.48-4.02) for sheep/beef-farm dogs, compared with urban dogs. At this titre, which is currently used in New Zealand to indicate seropositivity, seroprevalence of N. caninum infection was 30.7% in urban dogs, 74.5% in dairy-farm dogs and 96.8% in sheep/beef-farm dogs. CONCLUSION: This observation is consistent with a cycling of this disease between cattle and dogs on farms in New Zealand and with higher exposure of dogs to N. caninum on farms than occurs in urban environments. The prevalence of antibodies in all three groups of dogs tested in this study (dairy-farm dogs, sheep/beef-farm dogs and urban dogs) is higher than has generally been reported elsewhere. New Zealand farm dogs have a higher serological prevalence of N. caninum infection than urban dogs. CLINICAL RELEVANCE: Management and disease control practices that break the life-cycle of transmission between cattle and dogs should assist in controlling cattle abortion due to N. caninum.

Journal Article↗

PubMed2004

Linking optimal foraging behavior to bird community structure in an urban-desert landscape: field experiments with artificial food patches.

Urban bird communities exhibit high population densities and low species diversity, yet mechanisms behind these patterns remain largely untested. We present results from experimental studies of behavioral mechanisms underlying these patterns and provide a test of foraging theory applied to urban bird communities. We measured foraging decisions at artificial food patches to assess how urban habitats differ from wildlands in predation risk, missed-opportunity cost, competition, and metabolic cost. By manipulating seed trays, we compared leftover seed (giving-up density) in urban and desert habitats in Arizona. Deserts exhibited higher predation risk than urban habitats. Only desert birds quit patches earlier when increasing the missed-opportunity cost. House finches and house sparrows coexist by trading off travel cost against foraging efficiency. In exclusion experiments, urban doves were more efficient foragers than passerines. Providing water decreased digestive costs only in the desert. At the population level, reduced predation and higher resource abundance drive the increased densities in cities. At the community level, the decline in diversity may involve exclusion of native species by highly efficient urban specialists. Competitive interactions play significant roles in structuring urban bird communities. Our results indicate the importance and potential of mechanistic approaches for future urban bird community studies.

Animals↗

PubMed2000

Are the elderly in Pakistan getting their due share in health services? Results from a survey done in the peri-urban communities of Karachi.

OBJECTIVE: To assess the health, activity and social status of the elderly. METHODS: This Cross-sectional study with qualitative and quantitative designs was conducted in two areas of Karachi; one was a peri-urban squatter settlement and other a middle income community. The students of second year at Jinnah Medical College were trained to collect data, which was then entered on database IV and analyzed on the SPSS statistical package. RESULTS: The average age of peri-urban respondents was 66 and urban was 69 years. Majority of the senior citizens were independent and 69% had active daily life (ADL), power of decision making for adults was related to their status in the family (p < 0.000), majority were alert, happy and satisfied with life with no difference between urban and peri-urban residents. Fifty-three percent of peri-urban and 25% of the urban residents wanted to be employed and 13% of peri-urban and 22% of the urban wanted to continue working at the time of retirement. Fifty-two percent were suffering from hypertension and out of these 81% were on medication and of these 33% could not take drugs due to economic reasons. Their ailments included diabetes (15.6%), difficulty in walking (46.7%), vision disturbances (71.3%) and hearing loss. Seventy-three percent said that the health care services are present, but insufficient to deal with geriatric care (50%) and unsatisfactory (53%). There was a total lack of social services for elderly in the community. CONCLUSION: In the present cultural set up of Pakistan although the elderly are taken care of by their families but the majority want to continue working and be more independent. Most of the study population had one or the other form of ailment related to ageing which impaired their ADL indicator. There is extreme deficiency of health and social care services for the elderly hence the health care providers should start allocating and improvising for the specialized needs of the elderly. The social structure for elderly should be developed and jobs should also be created for the ones willing to continue working.

Activities of Daily Living↗

PubMed2000

[Study on the mortality of injury in Chinese population in urban and rural areas from 1990 to 1997].

OBJECTIVE: To describe the characteristics and trend of injuries among urban and rural Chinese population. METHODS: Data from annual Chinese national health statistics (1990 - 1997) were analyzed. RESULTS: The overall mortality of injury in China increased from 36.8/10(6) to 76.7/10(6) from 1990 to 1997. Injury was the forth leading causes of death in urban areas and the fifth in rural areas. The death rate of injury declined in the urban while increasing in the rural areas. The rural death rate of injury was about two times of that in urban and the difference was increasing over time. The death rate of men was higher than that of women and the ratio was 1.3 - 1.9. Children below 4 years old and people above 60 years old showed the highest rates. The first three leading causes of death of injuries in urban areas were traffic accident, suicide and fall, while in rural areas were suicide, traffic accident and drowning. The death rate caused by suicide was 6.5/10(6) - 27.1/10(6) and the rate in rural areas was 2.7 to 4.0 times of that in urban areas. The mortality of suicide declined in urban while increased in rural areas. The mortality of traffic accidents had a tendency of increase in both urban and rural areas. CONCLUSION: Injury has been one of the leading cause of death but without effectively control programs for population in Urban and Rural areas in China, special in rural areas.

Accidents, Traffic↗

PubMed1964

TRAFFIC DEATHS. A PRELIMINARY STUDY OF URBAN AND RURAL FATALITIES IN CALIFORNIA.

An analysis by the California Department of Public Health of California Highway Patrol reports for 1961 showed that traffic accidents injured one and one-half times as many people per 1,000 population in rural California counties (under 50,000 people) as in urban counties (over 500,000 people), also persons injured in rural counties were almost four times as likely to die of their injuries as those injured in urban counties.A death certificate study was undertaken of 782 traffic deaths (excluding pedestrians) occurring in rural and urban California counties during 1961. Accidents occurring in rural counties tended to be single vehicle accidents which resulted in less severe injuries, while those in urban counties tended to be two vehicle and multiple vehicle accidents resulting in more serious injuries. The anatomic distribution of injuries was the same for both urban and rural accidents. However, people dying in rural accidents more frequently died at the scene of the accident, died sooner after injury, and died of less serious injuries than did those injured in urban accidents. For injuries where theoretically few lives should be salvaged by prompt emergency care, the time between injury and death was about the same in urban as in rural counties. Where such care should delay or prevent death because the injury was possibly or probably salvageable, those injured in rural counties died more quickly.Thirty-two per cent of fatalities in rural counties happened to urban and out-of-state residents, while only 12 per cent of fatalities in urban counties were to rural or out-of-state residents, suggesting that traffic accidents to non-residents may place an excessive load upon medical care resources in rural areas.

Accidents↗

PubMed1981

Urbanization in Taiwan, 1964-1975.

"This paper examines levels and rates of urbanization in Taiwan and its ability to absorb a growing labor supply in its urban centers. Urban growth is concentrated in the Northern region and in large urban places. By 1975, half of Taiwan's population was located in places of 50,000 or more and 80 percent of the total population growth between 1964 and 1975 occurred in urban areas. Despite substantial urban growth and an even more rapid labor force growth, workers were absorbed into 'urban' industries and occupations. Based on this ability to absorb, Taiwan does not appear to be overurbanized and seems to fit the Western model." This paper was originally presented at the 1980 Annual Meeting of the Population Association of America (see Population Index, Vol. 46, No. 3, Fall 1980, p. 373). (summary in CHI)

Asia↗

PubMed2005

Perspectives on urban conditions and population health.

The majority of the world's population will live in cities in the next few years and the pace of urbanization worldwide will continue to accelerate over the coming decades. While the number of megacities is projected to increase, the largest population growth is expected to be in cities of less than one million people. Such a dramatic demographic shift can be expected to have an impact on population health. Although there has been historic interest in how city living affects health, a cogent framework that enables systematic study of urban health across time and place has yet to emerge. Four alternate but complementary approaches to the study of urban health today are presented (urban health penalty, urban health advantage, urban sprawl, and an integrative urban conditions model) followed by three key questions that may help guide the study and practice of urban health in coming decades.

Cities↗

PubMed1986

A model of urbanization with nonlinear migration flows.

"This paper seeks an appropriate specification of the migration exchange between rural and urban areas so that the implied evolution of the degree of urbanization agrees with its commonly observed S-shape. After demonstrating that the gross migration flows between rural and urban areas should be specified as nonlinear functions of the population in the origin sector, the paper introduces a model in which such flows are represented by gravity-type functional forms....[The model] can be used to give insights into the time paths of three basic urbanization variables: the urban-rural growth rate differential, the rural net outmigration rate, and the urban net immigration rate. All take on a zero value at the two extremes of the urbanization process and evolve in between according to a bell-shaped curve. These findings are illustrated by applying the model to data from the United States for the period 1790-1980."

Americas↗

PubMed1998

Homicide rates among US teenagers and young adults: differences by mechanism, level of urbanization, race, and sex, 1987 through 1995.

CONTEXT: Homicide rates for persons 15 through 24 years old began to decline between 1993 and 1994, but recent trends in homicide rates by mechanism of homicide and urbanization group have not been described. OBJECTIVE: To examine homicide trends from 1987 through 1995 for persons 15 through 24 years old by urbanization level. DESIGN: Homicide rates by urbanization level were analyzed using the Compressed Mortality File, a county-level mortality and population database maintained by the National Center for Health Statistics, Centers for Disease Control and Prevention, and the rural-urban continuum codes developed by the Economic Research Service, US Department of Agriculture. SETTING: United States, 1987 through 1995, according to 5 urbanization strata: core, counties with the primary central city of a metropolitan statistical area (MSA) of 1 million or more; fringe, remaining counties within an MSA of 1 million or more; medium, counties within an MSA of 250000 to 999999; small, counties in an MSA of less than 250000; and nonmetropolitan, counties not in an MSA. SUBJECTS: All persons 15 through 24 years old by race whose cause of death was homicide (International Classification of Diseases, Ninth Revision codes E960-E969). MAIN OUTCOME MEASURES: Firearm and nonfirearm homicide rates and average annual percentage changes by 5 urbanization levels, race, and sex. RESULTS: From 1987 through 1991, the average annual firearm homicide rates among persons 15 through 24 years old among all 5 urbanization strata increased between 10.7% in small counties and 19.8% in fringe counties. From 1991 through 1993, the rates increased between 3.3% in core counties and 11.7% in small counties. From 1993 through 1995, the rates declined between 4.4% in fringe counties and 15.3% in medium counties. By 1995, firearm homicide rates among persons 15 through 24 years old ranged from 6.5 and 7.3 per 100000 in the nonmetropolitan and small counties, respectively, to 9.6 and 13.3 per 100000 in the fringe and medium strata, respectively, to 33.5 per 100000 in the core stratum. During 1987 through 1990, nonfirearm homicide rates either were stable or increased, and from 1990 through 1995, nonfirearm homicide rates declined in all 5 strata, on average 3.7% to 8.0% per year, with rates in 1995 ranging from 2.1 to 4.7 per 100000 across the strata. CONCLUSIONS: After increasing since 1987, firearm and nonfirearm homicide rates began declining between 1993 and 1995 among persons 15 through 24 years old. These declines are taking place across all urbanization strata and among white and black males and females.

Adolescent↗

PubMed2026

Genetic Diversity and Population Structure of Urban and Rural Goshawks.

Urbanization poses a growing threat to biodiversity with potential impacts on species' genetic diversity and population structure. The Eurasian goshawk (Astur gentilis) is traditionally a forest-dwelling raptor that has recently established breeding populations in urban environments such as Helsinki, Finland. Here, we investigated genetic diversity and population structure across urban, suburban, and rural goshawk populations in Finland using 10 microsatellite markers and 72 individuals sampled between 1990 and 2020. Genetic diversity, measured by heterozygosity and allelic richness, was similar among populations. Genetic differentiation was low to moderate (F ST = 0.022-0.074) and statistically non-significant. Despite urbanization, contemporary urban goshawks showed genetic similarity to adjacent contemporary non-urban goshawks, while greater differentiation was observed between temporally separated populations. Consistent with this pattern, clustering supported K = 2 as the primary level of genetic structure, separating the contemporary urban and surrounding populations from the earlier surrounding and rural populations. Given the limited marker set and sample sizes, these findings are interpreted as broad-scale patterns rather than definitive evidence of fine-scale population structure. Further studies using larger sample sizes and genome-wide markers are needed to resolve population connectivity and the longer-term genetic effects of urbanization.

Astur gentilis↗

PubMed2005

Depressive symptoms, chronic medical conditions and functional status: a comparison of urban and rural elders in Taiwan.

BACKGROUND AND PURPOSE: The associations of depression, chronic condition and functional disability have not been studied well in Taiwan. The present study hypothesized that strong relations between chronic medical conditions, functional status, and the manifestation of depression would be evident; the interrelationships of the interested measures would differ in urban and rural populations METHODS: The study sample was recruited in a community survey in 2001 that included urban and rural elderly dwelling in southern Taiwan. The Chinese-version Geriatric Depression Scale (GDS) was used for data collection on depressive symptoms. Univariate and multivariate logistic regression analyses were performed to identify the predictors for depressive symptoms in urban and rural samples RESULTS: There were 20.1% of urban elders and 12.8% of rural samples classified with depressive symptoms. While controlling for socio-demographics, the prevalence of chronic disease and ADL summary scores were consistently associated with depressive symptoms for urban and rural samples. Cardiovascular disease and hip fracture were significantly predictive of depression for the urban sample, whereas the influence of stroke history was found to be predictive of depression in the rural sample. By individual PADL/IADL items, toileting problems and shopping difficulties were significant predictors of depression for both elderly samples CONCLUSION: The present findings confirm urban-rural differences in the reporting of associations between depressive symptoms, chronic medical conditions, and functional disability. For developing prevention programs on geriatric depression, it is critical to call more attention to chronic medical conditions, functional status, and social support of urban and rural elderly.

Activities of Daily Living↗

PubMed1996

Exposure to urban and rural air pollution: DNA and protein adducts and effect of glutathione-S-transferase genotype on adduct levels.

Ambient air in urban areas is polluted by agents suspected of causing cancer in humans. A number of epidemiological studies have revealed an increased cancer risk in urban communities, especially in lung cancer. The relative risk have been estimated to be in the order of 1.5. The objective of this study was to evaluate differences in genotoxic exposure through air pollution in urban and rural areas using DNA and protein adducts as biomarkers. Another objective was to investigate whether the GSTM1 genotype has any effect on adduct level. The analyses included 32P postlabelling of DNA adducts in lymphocytes, enzyme-linked immunosorbent assay for measuring benzo[a]pyrene protein adducts and polymerase chain reaction amplification of the GSTM1 genotype. The study was a cross-sectional study of non-smoking, healthy males from rural and urban Danish areas and from Athens, Greece. All individuals in the study were healthy, non-smoking males. The Danish urban group included 74 university students, the rural group 29 students from agricultural colleges and the Greek group 17 individuals. Adduct levels differed significantly in the three groups with median levels of 0.152 fmol/micrograms DNA (rural), 0.205 fmol/micrograms (urban) and 0.285 fmol/micrograms (Athens). The adduct patterns showed some identical spots, but also specific adducts. Here we report increasing DNA adduct levels comparing residents in rural, small urban and large urban residential areas; we found no influence of GSTM1 genotype on DNA or protein adduct levels in non-smokers exposed to low levels of air pollution.

Adult↗

PubMed1995

A comparison of health status between rural and urban adults.

The objective of the study was to examine and compare health status between rural and urban adults. The data are from a 1993 statewide probability-based telephone survey of adult Kentuckians (n = 662). Metropolitan Statistical Area (MSA) residents (n = 264) and nonMSA residents (n = 398) were compared using the Medical Outcomes Study, Short Form Health Survey (SF-20). Self-perceived urban (n = 406) and rural (n = 256) residents were also compared. Additional analyses were stratified by the age categories of 18-44, 45-64, and > or = 65 years of age. Few differences in health status existed between rural and urban adults. However, rural elders (> or = 65 years) had significantly poorer health status than urban elders. After controlling for demographic variables in multiple regressions, rural elders had significantly poorer functioning (all p < .05) than urban elders as measured by the SF-20 subscales of a) physical functioning, b) role functioning, c) social functioning, d) general mental health, and e) general health perceptions. No differences between rural and urban residents were noted for the pain subscale. Although the health status of rural and urban adults is generally similar, the rural elderly have significantly worse health status than their urban counterparts.

Adult↗

PubMed1997

Prevalence of NIDDM and impaired glucose tolerance in a rural and an urban population in Cameroon.

The adoption of Western lifestyles is known to lead to increasing prevalence of non-insulin-dependent diabetes mellitus in Africa, yet epidemiological studies using standardised methods are rare. The prevalence of diabetes and impaired glucose tolerance was determined in a rural and an urban community in Cameroon using the 75-g oral glucose tolerance test and the World Health Organization diagnostic criteria in 719 rural (292 men, 427 women) and 1048 urban (458 men, 590 women) subjects aged 24-74 years. The response rate was 95 and 91% for the rural and urban population, respectively. The age-standardized prevalence of diabetes in the rural and urban population was respectively 0.9% (95% confidence interval (0.2-2.7)) and 0.8% (0.2-1.8) for men and 0.5% (0.1-1.6) and 1.6% (0.7-3.1) for women, and that of impaired glucose tolerance was 5.8% (3.3-9.4) and 1.8% (0.9-3.2) for men, and for women, 2.2% (1.0-4.0) and 2.0% (0.6-4.5). Although for both men and women the body mass index was higher at all ages in the urban than in the rural area, the 2-h plasma glucose, even after adjustment for age and body mass index, was significantly higher in the rural than in the urban area (p < 0.005, p < 0.002 for men and women, respectively). There was a female excess of diabetes in the urban area and an equal sex distribution in the rural area. In the rural area 67% (4 of 6) of diabetic subjects were unknown before the survey, compared with 57% (8 of 14) in the urban area. These data indicate a low prevalence of diabetes in Cameroon; however, the prevalence of impaired glucose tolerance suggests an early stage of a diabetes epidemic.

Adult↗

PubMed2003

Doctors perceptions of the influences on their prescribing: a comparison of general practitioners based in rural and urban Australia.

OBJECTIVES: To compare and contrast the influences on prescribing perceived by general practitioners in an urban area of Queensland, Australia, to those perceived by general practitioners in rural Queensland. METHOD: An investigation was undertaken with a group of general practitioners in urban and rural locations of Australia. A self-administered questionnaire requested the doctors' demographic details and their opinions on statements about prescribing. They also reported their prescribing of six recently marketed drugs. RESULTS: One hundred and forty-two general practitioners from rural areas of Queensland (55% of the eligible population of these doctors) and one hundred and thirty-seven from the urban area (54% response) returned the surveys. The urban group were older and had more experience as general practitioners. Similarities and differences were detected between the two groups. The urban group considered that continuing medical education had a lesser influence on their prescribing than the rural group. The rural general practitioners were more likely than the urban doctors to agree that their information needs on prescribing were not being met in their practice, that their practice location had an effect on their prescribing (and also an effect on their prescribing of new drugs) as well as the remoteness of the patient's address having an effect. The rural doctors agreed more than the urban doctors that they try to avoid drugs requiring a significant amount of monitoring, reinforced by their agreement that they would be more likely to prescribe a newly marketed drug requiring less monitoring. When relating to whether the doctors in the two groups had reported initiating a supply of specific newly marketed drugs, independent of a specialist, rural general practitioners had initiated fewer of these selected new medicines. CONCLUSION: This study has highlighted some of the differences in perceptions of doctors on the influences on prescribing in rural relative to urban areas of Australia. An understanding of these perceptions will allow targeting and development of location-relevant prescribing interventions and messages.

Adult↗