The aim of this study is to determine the patterns of mortality from cardiac-cerebral vascular disease (CCVD) and how they relate to cosmophysical factors over a six-year span. The daily number of deaths recorded in Chengdu over 2192 consecutive days (2007-2012), together with several factors related to solar activity (SA), geomagnetic activity (GMA), and the interplanetary magnetic field, were analyzed by the extended cosinor to estimate the parameters of major cycles characterizing each variable. Estimates of their respective periods with a measure of uncertainty serve to find coperiodisms (i.e. shared rhythms). The results show that mortality of cardiovascular diseases (CVD) and CCVD on days of GMA in quiet level was relatively higher on days of GMA in unsettled level. Whereas mortality data are characterized by a one-year synchronized component, most GMA and SA indices have periods differing from precisely one year. A half-year cycle is shared by almost all SA, GMA, and mortality variables with 95% confidence interval of the period covering 0.5 year. A transyear cycle (about 1.3 years) is found for all mortality data and many of the environmental variables. A cis-half-year (about 0.43 year) is shared between mortality from CCVD and flow pressure, sunspot numbers and storm-time variation. These results suggest the presence of complex temporal relations between patterns of CCVD mortality and cosmophysical activity.
Bibliographical noteFunding Information:
The authors wish to acknowledge membership within and support from the National Nature Science Foundation of China [No. 41074131] to Zhengrong Wang.
- cardiac-cerebral vascular disease
- cosmophysical activity