Spatial variability in temperature exists within metropolitan areas but
very few studies have investigated intra-urban differentiation in the
temperature-mortality effects. We investigated whether local
characteristics of 42 Municipalities within the Greater Athens Area lead
to modified temperature effects on mortality and if effect modifiers can
be identified. Generalized Estimating Equations models were used to
assess the effect of high ambient temperature on the total and
cause-specific daily number of deaths and meta-regression to investigate
effect modification. We found significant effects of daily temperature
increases on all-cause, cardiovascular, and respiratory mortality (e.g.,
for all ages 4.16% (95% CI: 3.73,4.60%) per 1 degrees C increase in
daily temperature (lags 0-3). Heterogeneity in the effect estimates
between Municipalities was observed in several outcomes and
environmental and socio-economic effect modifying variables were
identified, such as % area coverage of buildings, length of
roads/km(2), population density, % unemployed, % born outside the EU
countries and mean daily temperature. To further examine the role of
temperature, we alternatively used modelled temperature per Municipality
and calculated the effects. We found that heterogeneity was reduced but
not eliminated. It appears that there are socioeconomic status and
environmental determinants of the magnitude of heat-related effects on
mortality, which are detected with some consistency and should be
further investigated