Extreme cold kills more people than leukemia, homicide and liver disease

The bitter chill isn't just an inconvenience. It could kill you. A 2007 study by Olivier Deschenes and Enrico Moretti found that "the number of annual deaths attributable to cold temperature is 27,940 or 1.3% of total deaths in the US."

Extreme cold turns out to be deadlier  than extreme heat. Hot weather kills, but digging deep into the data, Deschenes and Moretti find that it mostly kills people who were already close to death. After the heat wave ends, the death rate drops so sharply that it totally offsets the weather-related spike. "The only effect of the weather shock is to change the timing of mortality, but not the number of deaths," they write.

Periods of extreme cold are also associated with an immediate spike in deaths. But unlike extreme heat, there's no offsetting decline in expected mortality in the weeks following cold snaps. The result is that "the cumulative effect of 1 day of extreme cold temperature during a 30-day window is an increase in daily mortality by as much as 10%." In total, the authors calculate, the cold is responsible for more annual deaths than "leukemia, homicide, and chronic liver disease."

This is particularly true in low-income communities. "The effect for counties in the bottom income decile is 66% larger than the effect for counties the top income decile." One reason, of course, is that low-income communities have more people who lack adequate shelter. Dan Diamond has written a useful post on how to help the homeless during the cold, and his list of hypothermia hotlines in major American cities is particularly helpful:

• Atlanta: 404-447-3678 for the Metro Atlanta Task Force for the Homeless
• Baltimore: 311
• Birmingham, Ala.: 205-252-9571 for the Firehouse Shelter
• Boston: 617-534-2526 for Friends of Boston’s Homeless or dial 311
• Chicago: 311
• Denver: 720-944-1007 for Denver’s Road Home (during business hours)
• Detroit: 1-800-274-3583 and 1-800-343-4427
• Fort Collins, Colo.: 719-632-1822 for Springs Rescue Mission and 970-484-5010 for Catholic Charities-Larimer County
• Kansas City, Mo.: 816-474-4599
• Las Vegas: 702-369-4357 for HELP of Southern Nevada (from 7 a.m. to 4 p.m., Monday through Thursday)
• Minneapolis: 612-879-7624 for St. Stephen’s street outreach team
• New York City: 311
• Philadelphia: 215-232-1984 for the Project HOME Homeless Outreach Hotline
• San Francisco: 311
• St. Louis: 314-802-5444 for the Housing Resource Center hotline (between 8 a.m. and 8 p.m., Mon-Friday)
• Thunder Bay, Ontario: 807-620-7678 for the SOS team (operates between 2 p.m. and 2 a.m.)
• Toronto: 311
• Washington, D.C.: 1-800-535-7252 for the Hypothermia Hotline

Deschenes and Moretti find that Americans are quietly implementing a longer-term solution, too. In recent decades, there's been a large and continuous migration from cold Northeastern states to warm Southwestern states. The authors find that each year, 5,400 deaths are being delayed by this movement -- and they're being delayed for, on average, more than nine years each. The aggregate effect of that is huge: "our estimates indicate that 8%-15% of the gains in longevity experienced by the US population over the past three decades are due to the secular movement toward warmer states in the West and the South, away from the colder states in the North."

Oh, and cold is a bigger killer among the elderly than among anyone else. So your parents have good reason to be moving to Florida.

Study via Tyler Cowen.