A spatial analysis of community level overweight and obesity.

BACKGROUND: Rates of overweight and obesity are now considered to be epidemic. Few studies have examined the spatial distribution of overweight and obesity at the community level, an area of geography recommended for prevention and intervention. Therefore, the present study aimed to examine the spatial variation of overweight and obesity using community geographic boundaries. METHODS: A cross-sectional secondary spatial data analysis was conducted using three combined cycles of Canadian Community Health Survey data for the province of Nova Scotia with community level boundaries. Descriptive rates were calculated using standardised incidence ratio values and spatial analysis was carried out using Global and Local Moran's I and the GetisOrdGi* statistic for cluster identification. RESULTS: Maps illustrating local cluster analysis showed a significant degree of similarity between neighbouring communities in urban areas more so than rural communities. Hot spot analysis maps showed communities clustering together in the urban centre tended to have lower incidence of overweight and obesity ('cool spots'), whereas clustered communities in a more rural area had a higher incidence of overweight and obesity ('hot spots). CONCLUSIONS: The present study showed that there was geographical variation in overweight and obesity between urban and rural communities, and also there was a tendency for communities to cluster based on the incidence of overweight and obesity. This highlights the importance of understanding community level obesity rates and associated behavioural determinants, such as diet and physical activity, as well as the role that urbanisation or rurality may play in intervention initiatives for these behavioural determinants. Specifically, public health nutrition efforts for community level food environments in rural areas should ensure an individualised approach is used, whereas urban areas may be amenable to more general approaches aiming to support healthy weight status among the broader population.

Beating the heat: development and evaluation of a Canadian hot weather health-response plan.

An increasing number of cities subject to hazardous summer weather in the United States and Canada have begun to develop and implement hot weather response plans to prevent heat-related illnesses and deaths. In this study we focus on heat-mortality relationships in Toronto, Ontario, between 1980 and 1996 and evaluate the potential effectiveness of the city's interim hot weather-health response plan. Using two heat stress indexes--humidex and apparent temperature--we identified excess mortality associated with hot and humid weather and then estimated excess deaths for hot and cool summers. Mortality rates for all ages and for > 64 years age groups rose with increasing humidex and apparent temperature, with no significant increase for the population < 65 years. Excess mortality occurred as low as the 30-35 degrees C humidex range, which is below the 40 degrees C humidex used to issue a heat warning under Toronto's interim hot weather response plan. During a hot summer (such as 1988 or 1995), 32 excess deaths would be expected, whereas 34 fewer deaths than baseline levels would be expected during a cool summer like 1982 or 1992. Days with high humidex levels occur infrequently in Toronto, and thus exposure is limited under current climatic conditions. In the event of a warming climate, more days with dangerously high humidex levels are likely to occur, and summer deaths are expected to increase. Toronto's hot weather health-response plan is an important early step for adaptation to climate change.

Heat-stress-related mortality in five cities in Southern Ontario: 1980-1996.

The Toronto-Windsor corridor of Southern Ontario, Canada, experiences hot and humid weather conditions in summer, thus exposing the population to heat stress and a greater risk of mortality. In the event of a climate change, heat-stress conditions may become more frequent and severe in Southern Ontario. To assess the impact of summer weather on health, we analyzed heat-related mortality in the elderly (older than 64 years) in the metropolitan areas of Windsor, London, Kitchener-Waterloo-Cambridge, Hamilton, and Toronto for a 17-year period. Demographic, socioeconomic, and housing factors were also evaluated to assess their effect on the potential of the population to adapt and their vulnerability to heat stress. Heat-stress days were defined as those with an apparent temperature (heat index) above 32 degrees C. Mortality among the elderly was significantly higher on heat-stress days than on non-heat-stress days in all cities except Windsor. The strongest relationships occurred in Toronto and London, followed by Hamilton. Cities with the greatest heat-related mortality have relatively high levels of urbanization and high costs of living. Even without the warming induced by a climate change, (1) vulnerability is likely to increase as the population ages, and (2) ongoing urban development and sprawl are expected to intensify heat-stress conditions in Southern Ontario. Actions should be taken to reduce vulnerability to heat stress conditions, and to develop a comprehensive hot weather watch/warning system for the region.