Acute myocardial infarction (AMI) (n-11026) on days of zero geomagnetic activity (GMA) and the following week: Differences at months of maximal and minimal solar activity (SA) in solar cycles 23 and 24

Background: Acute myocardial infarction (AMI) is one of most common cardiovascular pathologies in the industrial world. In addition to known risk factors, environmental physical activity factors such as solar activity (SA), geomagnetic activity (GMA), and cosmic ray activity (CRA) could be also involved in the timing of AMI. The aim of this study was to study AMI admissions at days of zero GMA, accompanied by high CRA, and the following week in the higher and lowest parts of solar cycles 23 and 24. Methods: Patients admitted for AMI (n = 11,026, 59.5 % men) in years 2000 - 2009 at the Department of zardiology of Lithuanian University of Medical Sciences were studied for all periods and separately for the higher part of the 11-year solar activity in cycles 23 and 24 (2000 - 2007) and its lowest part (2008 - 2009). Admissions at day of zero GMA as well as 1, 2, 6, and 7 days after zero-GMA day were compared. Results: At high SA, zero-GMA days were rare and isolated (36 in years 2000 - 2007). They have been followed by significant increase in admissions on the following days. In the two lowest years of SA 2008 - 2009, there were 57 days of zero GMA, many of which were consecutive and in groups. For the whole solar cycle, there was a more gradual increase in AMI from 1 to 2 days after zero-GMA day, and there were significantly higher AMI admissions at 6 days after the first zero-GMA day (p = 0.018). Conclusions: Zero-GMA/high-neutron activity is followed by increase in AMI admissions at the days that follow. The effects are different at high and low parts of the 11-year solar cycle.