Autor: |
Chen, Kai, Wolf, Kathrin, Hampel, Regina, Stafoggia, Massimo, Breitner, Susanne, Cyrys, Josef, Samoli, Evangelia, Andersen, Zorana Jovanovic, Bedada, Getahun Bero, Bellander, Tom, Jacquemin, Bénéédicte, Pekkanen, Juha, Peters, Annette, Schneider, Alexandra |
Zdroj: |
Occupational and Environmental Medicine; 2018, Vol. 75 Issue: Supplement 1 pA14-A14, 1p |
Abstrakt: |
Background/aimRecent epidemiological studies investigating the modifying effect of air temperature in ozone-mortality associations lack consensus as how to adjust for nonlinear temperature effect in addition to including an interaction term.MethodsWe evaluated the influence of temperature confounding control on temperature-stratified ozone-mortality risks in a time-series setting in eight European cities and 86 U.S. cities, respectively. To investigate potential residual confounding, we additionally incorporated next day’s ozone in models with differing temperature control.ResultsUsing only a categorical variable for temperature or only controlling nonlinear effect of low temperatures yielded highly significant ozone effects at high temperatures, but also significant residual confounding in both regions. Adjustment for a nonlinear effect of temperature, especially high temperatures, substantially reduced ozone effects at high temperatures and residual confounding. For example, when using a distributed lag nonliner temperature term, risk estimates at low, medium, and high temperatures were 0.23% (95% CI: −0.09% to 0.55%), 0.23% (95% CI: −0.06% to 0.53%), and 0.36% (95% CI: 0.04% to 0.68%) in European cities, and 0.11% (95% CI: −0.31% to 0.54%), 0.17% (95% CI: −0.07% to 0.41%), and 0.59% (95% CI: 0.32% to 0.85%) in U.S. cities.ConclusionInadequate control for confounding by air temperature leads to residual confounding and an overestimation of the temperature modifying effect in studies of ozone-related mortality. |
Databáze: |
Supplemental Index |
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