Heart-related Deaths More Likely to Occur in Winter, but Cold Weather Not a Major Factor

According to study results presented at the American Heart Association Scientific Sessions 2012 in Los Angeles, California, most heart issue-related deaths occur during the winter months, no matter what climate the patient lives in.

For the study, researchers from the Good Samaritan Hospital in Los Angeles, California looked at the total number of deaths and the number of cardiac-related deaths that occurred from January 1, 2005, to December 31, 2008, in seven regions of the US with different climates. They obtained and analyzed daily death certificate data from local health departments in Los Angeles county, California; Texas; Arizona; Georgia; Washington; Pennsylvania; and Massachusetts.

The average seasonal values for each day of the year were obtained by calculating a 19-day centered moving average and taking the average values of the four-year curves. Analysis of the data revealed that all-cause and cardiovascular deaths increased greatly during the winter months as compared to spring, fall, and summer.

The death certificate assessment revealed that fatal heart attacks, heart failure, cardiovascular disease, and stroke peaked during the winter months in all of the locations. Overall, circulatory deaths rose on average from 26% to 36% from the summer months to the winter months over four years. The death rates at all of the examined sites were clustered closely together, and no site was statistically different.

Although the study was not designed to determine cause of death, the researchers offered several possible explanations. “People generally don’t live as healthy in winter as they do summer,” said lead author Bryan Schwartz, MD, a fellow at the University of New Mexico in Albuquerque. “This was surprising because climate was thought to be the primary determinant of seasonal variation in death rates,” he said. Schwartz also said that he believes that colder weather might increase vessel constriction and raise blood pressure.

“People should be extra aware that maintaining healthy behaviors is important in the winter,” said Schwartz.