You get a sort of wave of death that ebbs in the late summer months, rises sharply through December, and hits a peak exactly on Jan. 1 before subsiding more gradually through the beginning of the year.
The general contours of this wave are well known — you can plot it yourself year-over-year from 1999 using the Centers for Disease Control and Prevention's WONDER database. Lately, a typical January has seen 40,000 to 60,000 more fatalities than the typical August or September. Here's what that looks like:
The burning question: Why? Does it have something to do with suicides or car crashes or drinking around the holidays? Nope: "This pattern turns up in every natural cause of death, but not for external causes like auto accidents," Phillips said in an interview. "It's hard to understand why that would be."
In other words, the deaths are being driven generally by illness, disease and old age, rather than by accidents or homicides or any other non-health-related cause.
Not only do we not know what's driving the seasonality, we're not even trying to figure it out as far as Phillips is concerned. Nobody he's aware of is doing any research into it. "It's not only a mystery, but a mystery that people haven't even tried to engage with," he said.
Phillips's research has turned up some limited but tantalizing clues. When he restricted his 57 million death certificates to only people who had died in an emergency room, the spikes on Christmas and New Year's Day became hugely exaggerated. "There are more emergency department deaths on Christmas, the day after Christmas, and New Year’s Day than on any other day of the year," he wrote. And those jumps in fatality were much higher than what you'd expect simply because of the general seasonality of death.
So he started looking for causes. It doesn't seem to have anything to do with the weather, or with people being indoors more, because the holiday spikes are even bigger in Southern states, where it's warmer. The spikes are just as big if you exclude people who died from alcohol or drugs, or people who died from pneumonia or the flu.
He did come up with a couple of hypotheses that he wasn't able to eliminate completely: There has been some research showing that "people postpone going into the ER around the holidays because they want to be with their family," he said. In situations where minutes or seconds can mean the difference between life and death, some folks may be, say, feeling a twinge of chest pain at the start of dinner but not telling anybody about it until afterward.
"In the case of some serious illness, that's a very foolish thing to do," Phillips says.
Another potential reason is that hospitals may be understaffed around the holidays, and their most experienced workers may be taking time off. That could lead to reduced performance and reduced ability to save lives.
Phillips stresses that his numbers don't necessarily prove that either of these scenarios are actually happening — only that he couldn't rule either one out, and that a lot more research is needed.
"The next step is for hospitals to look at much smaller data sets and to gather much more detail," he said. "If you did that, then you could see if indeed there was an association between seniority of staff and the number of staff and the jump in fatalities."
As for the typical consumer like you and me, "if you've got pains in your chest, don't say I'm gonna wait until after the holidays to get it looked at," Phillips said.
* Correction: The author of this story misattributed a line from T.S. Eliot to Chaucer. He is deeply ashamed and embarrassed.