Temporal distribution of death among oncology patients: environmental links.

BACKGROUND

The natural history of terminal oncologic disease is death from cardiopulmonary arrest. The goal of this study was to determine whether the temporal distribution of death among oncology patients is related to levels of environmental physical activity-solar, geomagnetic, and cosmic rays and high energy space proton flux, as previously shown for other situations like accidents, suicide, and the occurrence of acute myocardial infarction.

METHODS

Deaths of oncology patients, n = 102604, in 168 consecutive months were compared with-monthly indices of solar, geomagnetic, cosmic rays activity (sunspot number, solar flux, Ap, Cp, Am), and indices of magnetic and cosmic rays activity according to neutron monitor data). In addition, oncology patients monthly death numbers were compared with numbers of deaths from ischemic heart disease (IHD), stroke, sudden cardiac death (SCD), accidents, road accidents, non cardiovascular death (total deaths - [IHD + stroke]). The National Data of the Republic of Lithuania was used, excluding SCD and myocardial infarction in Kaunas--the second largest city in Lithuania Monica study register was used for SCD at age 25-64, and all data of AMI. Pearson correlation coefficients and their probabilities were obtained between the numbers of oncology patient monthly deaths and (1) cosmo-physical indices and (2) the number of deaths from other causes and the occurrence of AMI.

RESULTS

The number of oncology patient deaths was inversely correlated with solar and geomagnetic activity indices and positively correlated with cosmic rays activity. The number of oncology patient deaths was correlated with monthly number of deaths from non-cardiovascular courses, stroke, suicide, at trend level with SCD, but not with deaths from IHD, accidents, road accidents. Oncology patient deaths showed a significant correlation with the number of AMI.

CONCLUSIONS

The monthly death number of oncology patients is significantly related with environmental physical activity and shows similarity with deaths distribution by time of some other groups of death--stroke, SCD, suicide, and occurrence of AMI. The inverse correlation with solar and geomagnetic activity and positive links with cosmic rays activity level are remarkable.