Urbanisation and the incidence of eating disorders. (73/350)

The link between degree of urbanisation and a number of mental disorders is well established. Schizophrenia, psychosis and depression are known to occur more frequently in urban areas. In our primary care-based study of eating disorders, the incidence of bulimia nervosa showed a dose-response relation with degree of urbanisation and was five times higher in cities than in rural areas. Remarkably, anorexia nervosa showed no association with urbanisation. We conclude that urban life is a potential environmental risk factor for bulimia nervosa but not for anorexia nervosa. These findings provide a promising avenue for further research into the aetiology of eating disorders.  (+info)

Animal communication: city birds have changed their tune. (74/350)

Birds adjust their songs to make themselves heard in the presence of ambient noise. New research comparing songs of great tits across Europe shows how animals adapt their signals to the urban din.  (+info)

Cities change the songs of birds. (75/350)

Worldwide urbanization and the ongoing rise of urban noise levels form a major threat to living conditions in and around cities. Urban environments typically homogenize animal communities, and this results, for example, in the same few bird species' being found everywhere. Insight into the behavioral strategies of the urban survivors may explain the sensitivity of other species to urban selection pressures. Here, we show that songs that are important to mate attraction and territory defense have significantly diverged in great tits (Parus major), a very successful urban species. Urban songs were shorter and sung faster than songs in forests, and often concerned atypical song types. Furthermore, we found consistently higher minimum frequencies in ten out of ten city-forest comparisons from London to Prague and from Amsterdam to Paris. Anthropogenic noise is most likely a dominant factor driving these dramatic changes. These data provide the most consistent evidence supporting the acoustic-adaptation hypothesis since it was postulated in the early seventies. At the same time, they reveal a behavioral plasticity that may be key to urban success and the lack of which may explain detrimental effects on bird communities that live in noisy urbanized areas or along highways.  (+info)

The relationship between parity and overweight varies with household wealth and national development. (76/350)

BACKGROUND: Recent studies support a positive relationship between parity and overweight among women of developing countries; however, it is unclear whether these effects vary by household wealth and national development. Our objective was to determine whether the association between parity and overweight [body mass index (BMI) > or =25 kg/m(2)] in women living in developing countries varies with levels of national human development and/or household wealth. METHODS: We used data from 28 nationally representative, cross-sectional surveys conducted between 1996 and 2003 (n = 275 704 women, 15-49 years). The relationship between parity and overweight was modelled using logistic regression, controlling for several biological and sociodemographic factors and national development, as reflected by the United Nations' Human Development Index. We also modelled the interaction between parity and national development, and the three-way interaction between parity, household wealth and national development. RESULTS: Parity had a weak, positive association with overweight, which varied by household wealth and national development. Among the poorest women and women in the second tertile of household wealth, parity was positively related to overweight only in the most developed countries. Among the wealthiest women, parity was positively related to overweight regardless of the level of national development. CONCLUSIONS: As development increases, the burden of parity-related overweight shifts to include poor as well as wealthy women. In the least-developed countries, programmes to prevent parity-related overweight should target wealthy women, whereas such programmes should be provided to all women in more developed countries.  (+info)

Impact of urbanisation on bionomics and distribution of malaria vectors in Lagos, southwestern Nigeria. (77/350)

BACKGROUND & OBJECTIVES: The patterns of annual, rainfall as well as average daily temperature have not changed drastically in the study area since 1960 when detailed baseline entomological surveys were carried out. However, the increase in human population from 1.2 to 10 million has resulted in both expansion of land and tremendous ecological and environmental change. This has led to drastic changes in vectors' densities as well as species' composition while the preferred larval habitat of malaria vectors has shifted to water reservoirs. A longitudinal study was carried out to investigate the impact of urbanisation on bionomics and distribution of malaria vectors in Lagos, a mega city in Nigeria. METHODS: Mosquitoes were collected indoors and outdoors using WHO standard techniques in the selected areas between January and December 2000. Specimens were identified using the morphological keys and PCR assays. ELISA tests were used for Plasmodium falciparum sporozoite infection. RESULTS: The Anopheles gambiae species-specific PCR identified 56% (435/777) of the An. gambiae s.1. as An. gambiae s.s. and 44% (342/777) as An. arabiensis. The molecular M and S forms represented 35.3 and 64.7% of the An. gambiae s.s. population, respectively. The An. funestus species-specific PCR identified 60% (239/401) of the An. funestus group as An. funestus s.s. and 40% (162/401) as An. rivulorum. The biting activity of An. funestus s.s. both indoors and outdoors attained a peak at 0200 and 2200 hrs, respectively, with a significant increase in the "pre-bed time" collections indoors (Chi2 = 6.15, df = 1, p < 0.05) and outdoors (Chi2 = 6.28, df = 1, p < 0.05). The overall outdoor collection was significantly higher (Chi2 = 28.23, df =3, p < 0.05) than that recorded indoors. The overall sporozoite rates for An. gambiae s.s., An. arabiensis and An. funestus were significantly different in both localities (Chi2 = 0.58, df = 2, p < 0.01). Infection rates in both indoor and outdoor collections were also different statistically (Chi2 = 0.67, df = 2, p < 0.01). INTERPRETATION & CONCLUSION: Large number and species of anopheline mosquitoes collected in the study area may be associated with the availability of aquatic breeding sites. A phenomenon leading to an increase in man-vector contact and a high level of risk to the crowded urban population is observed.  (+info)

Illness-related behaviour and utilization of oral health services among adult city-dwellers in Burkina Faso: evidence from a household survey. (78/350)

BACKGROUND: In sub-Saharan Africa, the availability and accessibility of oral health services are seriously constrained and the provision of essential oral care is limited. Reports from the region show a very low utilization of oral health care services, and visits to dental-care facilities are mostly undertaken for symptomatic reasons. The objectives of the present study were to describe the prevalence of oral symptoms among adults in Ouagadougou, capital city of Burkina Faso and the use of oral health services and self-medication in response to these symptoms and to measure the associations between predisposing, enabling and needs factors and decisions to seek oral health care. METHODS: The conceptual design of the study was derived from both the Andersen-Newman model of health care utilization and the conceptual framework of the WHO International Collaborative Study of Oral Health Outcomes. Data were obtained by two-stage stratified sampling through four areas representative of different stages of urbanization of Ouagadougou. The final study population comprised 3030 adults aged 15 years or over and the response rate was 65%. RESULTS: Overall, 28% of the respondents had experienced an oral health problem during the past 12 months; a high proportion (62%) reported pain or acute discomfort affecting daily life. In response to symptoms, only 28% used oral health facilities, 48% used self-medication and 24% sought no treatment at all. Multivariate analyses revealed that several socio-economic and socio-cultural factors such as religious affiliation, material living conditions and participation in a social network were significantly associated with the use of oral health care services by adults who had experienced oral health problems during the previous year. CONCLUSION: The proportion of people who have obtained oral health care is alarmingly low in Ouagadougou and self-medication appears to be an important alternative source of care for adult city-dwellers. Decision-makers in sub-Saharan countries must seek to ensure that access to essential oral health care is improved.  (+info)

Chagas disease and globalization of the Amazon. (79/350)

The increasing number of autochthonous cases of Chagas disease in the Amazon since the 1970s has led to fear that the disease may become a new public health problem in the region. This transformation in the disease's epidemiological pattern in the Amazon can be explained by environmental and social changes in the last 30 years. The current article draws on the sociological theory of perverse effects to explain these changes as the unwanted result of the shift from the "inward" development model prevailing until the 1970s to the "outward" model that we know as globalization, oriented by industrial forces and international trade. The current article highlights the implementation of five new patterns in agriculture, cattle-raising, mining, lumbering, and urban occupation that have generated changes in the environment and the traditional indigenous habitat and have led to migratory flows, deforestation, sedentary living, the presence of domestic animals, and changes in the habitat that facilitate colonization of human dwellings by vectors and the domestic and work-related transmission of the disease. The expansion of Chagas disease is thus a perverse effect of the globalization process in the Amazon.  (+info)

Urban physiology: city ants possess high heat tolerance. (80/350)

Urbanization has caused regional increases in temperature that exceed those measured on a global scale, leading to urban heat islands as much as 12 degrees C hotter than their surroundings. Optimality models predict ectotherms in urban areas should tolerate heat better and cold worse than ectotherms in rural areas. We tested these predications by measuring heat and cold tolerances of leaf-cutter ants from South America's largest city (Sao Paulo, Brazil). Specifically, we compared thermal tolerances of ants from inside and outside of the city. Knock-down resistance and chill-coma recovery were used as indicators of heat and cold tolerances, respectively. Ants from within the city took 20% longer to lose mobility at 42 degrees C than ants from outside the city. Interestingly, greater heat tolerance came at no obvious expense of cold tolerance; hence, our observations only partially support current theory. Our results indicate that thermal tolerances of some organisms can respond to rapid changes in climate. Predictive models should account for acclimatory and evolutionary responses during climate change.  (+info)