MYOCARDIAL-INFARCTION AND GEOMAGNETIC DISTURBANCES - AN ANALYSIS OF MORBIDITY AND MORTALITY DATA

Relationships between different parameters of the geomagnetic activity and medical statistical data on myocardial infarction were investigat ed anew, because previous results in this field have been often incons istent. The data are daily numbers of myocardial infarction incidence rates (15,543 cases) and number of deaths for infarction (3,065 cases) , abstracted from registries of the 14 biggest hospitals of St. Peters burg (1989-1990). The analysis showed a statistically significant incr ease in myocardial infarction rate during big geomagnetic disturbances , defined by the days of the descending phase of cosmic ray Forbush de creases. An overall estimation of the average increase in infarction i ncidence rate during big geomagnetic storms, (10.5+/-1.2)%, has been c omputed by taking into account previous results [1-3]. In contrast, mo rbidity data did not show any significant correlation with geomagnetic disturbances. It was found also that the infarction incidence rate ap pears to be rather constant from Monday; to Friday and to decrease sha rply by a factor similar to 1.25 on Saturday-Sunday and mid-week festi vities. This. effect is associated with different exposure during work days and week-ends to man-made magnetic field environment mainly prod uced by electrified transport. Such effect was not observed in mortali ty data. The results and their methodological aspects are placed in th e context of studies on possible health effects of low frequency magne tic fields both natural and man-made origin.