Background/Introduction

Global warming and heat events in particular are increasingly acknowledged as independent health risks. Moreover, low ambient air quality is a major environmental risk factor for health. However, only a limited number of studies have explored interactive effects so far. Recent evidence points to an exacerbation of the adverse effects of heat on cardiovascular health by air pollution. Of particular concern is the exposure of susceptible subgroups of the population to temperature extremes in combination with air pollution. In patients with pre-existing atherosclerotic cardiovascular diseases (ASCVD) in Bavaria, evidence for the effects of environmental triggers on the incidence of acute myocardial infarction (AMI) is still scarce.

Purpose

To explore the effects of high air temperature and heat days and their interactive effects with air pollutants on AMI events in patients with pre-existing ASCVD in Bavaria.

Methods and Results

This study is based on data of more than 1.2 million individuals insured in Bavaria with pre-existing ASCVD. For all individuals, exact diagnoses (ICD-10 based) and cardiovascular related acute hospital admissions are available over nine years (2010-2018) on a monthly basis. The number of incident events (AMI denoted ICD-I21) was 132.432, a limitation being that ICD-10 codes are not validated by procedural codes and the number of “invasively treated MI” is unclear. Daily averages of environmental data [air temperature, particulate matter (PM)₁₀, PM_2.5, Nitrogen dioxide (NO₂), Ozone (O₃)] obtained from spatiotemporal models were used for calculating monthly averages for each postal code area. We will follow a two-stage modeling approach of postal code area-specific and then pooled estimates of health effects. We will apply Quasi-Poisson regression models allowing for over-dispersion for each postal code area, and will use cubic regression splines to model the impact of temperature and adjust for non-linear confounding and long-term/seasonal variations. Effect modifiers such as age and sex, and meta-regressors such as vegetation and socio-economic variables, will be considered. Moreover, we will explore the modification of our temperature effects by different air pollutants. In a second step, data will be analyzed separately by two periods [period from 2010-2014 (14 heat days >30°C) versus period from 2014-2018 (29 heat days >30°C] to investigate possible adaptation effects of the population to higher ambient temperatures over time. Results will be reported at the meeting.

Conclusions

The heat-related impact on cardiovascular health is expected to increase globally; however, understanding the intricate connection between air pollution, rise in temperature, and its impact on cardiovascular health additionally depends on local factors. In this regard, local studies are essential for understanding the potential synergistic effects of environmental risk factors and consequently developing actionable heat-health plans. In conclusion, our analyses are likely to additionally support the needed large-scale and long-term economic investments in sustainable environments to protect susceptible population subgroups and, specifically, individuals living with pre-existing ASCVD in Bavaria.