Study Title: "Cardiovascular disease mortality attributable to monthly non-optimal temperature in the United States: a county-level analysis"
Conference: American College of Cardiology Scientific Sessions - Young Investigators Award Competition Finalist: "Outcomes Research" Presentation (Monday, March 30, 9:30 am CDT in New Orleans)
Journal: Journal of the American Journal of Preventative Cardiology (simultaneous publication)
Bottom line of the study: Colder temperatures are responsible for significantly more cardiovascular deaths from heart attacks, strokes, and coronary artery disease than milder months/warm temperatures in the United States. Heat consistently gets more attention as a cause for concern for heart patients; however, this study shows colder weather is the larger and more consistent risk.
Why this study is important: Most public health messaging focuses on heat waves, but this study's findings show that colder temperatures are associated with a substantially higher number of heart-related deaths each year. This highlights a major gap in awareness and prevention.
Why this study is unique: This research is the most comprehensive analysis of temperature-related trends to date across the United States. Previous studies have linked extreme temperatures with increased risk of cardiovascular death, but most have focused on other countries or smaller sections of the United States.
How the study was conducted: Researchers analyzed more than 14 million cardiovascular deaths of people over 25 years old across 819 counties in the United States (80 percent of the country's population) between 2000 and 2020. They linked mortality data with local temperature data and used statistical models to estimate how deviations from optimal temperatures were associated with cardiovascular death risk. They then quantified how many deaths were attributable to cold versus heat exposure.
Results: The researchers determined that the optimal temperature for heart health—the temperature at which the least mortality occurred—was 74 degrees Fahrenheit. Mortality risk rose asymmetrically when moving away from that point, with temperatures under 74 degrees Fahrenheit accounting for approximately 40,000 cardiovascular deaths each year of the study period (6.3 percent), while temperatures over 74 degrees accounted for about 2,000 cardiovascular deaths each year (.33 percent). In total, colder weather was linked to roughly 800,000 deaths over two decades, compared to 40,000 deaths due to warm weather.
Put differently, one in 16 cardiovascular deaths were linked to colder weather compared to one in 300 linked to heat.
