Population Demographics and Heat-Related Mortality
Hattis, D., Ogneva-Himmelberger, Y. and Ratick, S. 2012. The spatial variability of heat-related mortality in Massachusetts. Applied Geography 33: 45-52.
In examining the data, Hattis et al. report that average state-wide mortality anomalies were 5.11, 6.26 and 7.26 deaths on days exceeding the 85th, 90th and 95th percentiles of apparent temperature, respectively, which days they classified as hot, very hot and extremely hot, respectively. However, they write that these results "may be overstated," because "previous studies indicate that high apparent temperatures are associated with pollution episodes, which also impact mortality," citing Kovats and Hajat (2008), while further reporting that "a study of Mexico City found that controlling for air pollution and respiratory epidemics decreased the impact of apparent temperature on mortality by 50%," citing O'Neil et al. (2005). In addition, they found that a linear stepwise regression showed that the percent African-American population and the percent elderly population (those above the age of 65) were positively associated with an MG's mortality anomaly on days exceeding the 85th percentile of apparent temperature. And, last of all, they determined that "in spite of the urban heat island effect," their measure of urbanization "was not associated with higher rates of heat-related mortality."
In light of their several findings, the three researchers conclude that "at least in Massachusetts, an area's demographics may be more important to its heat-related mortality than its level of urbanization."
Kovats, R.S. and Hajat, S. 2008. Heat stress and public health; a critical review. Annual Review of Public Health 29: 41-55.
O'Neil, M., Hajat, S., Zanobetti, A., Ramirez-Aguilar, M. and Schwartz, J. 2005. Impact of control for air pollution and respiratory epidemics on the estimated associations of temperature and daily mortality. International Journal of Biometeorology 50: 121-129.