On Christmas Day, Ncuti Gatwa made his full debut as Doctor Who in a special episode broadcast on BBC One.

A somewhat whimsical new study has found a curious statistical alignment between these Christmas specials and mortality rates across the UK the following year.

Since Doctor Who first aired in 1963, a new episode has been broadcast over the festive season (December 24 to January 1) a total of 31 times, including 14 episodes shown on Christmas Day itself.

Richard Riley, a biostatistician at the University of Birmingham in the UK, compared mortality rates for the years following a festive broadcast against the years without one – and found that Christmas Day episodes preceded an average of 4 fewer deaths per 10,000 person-years than would typically be expected in the UK.

The link was more pronounced from 2005 to 2019, when new episodes were consistently aired over the festive period. In these years, there were 6 fewer deaths per 10,000 person-years in the UK and 7 fewer deaths per 10,000 person-years if only England and Wales were considered.

Now, before we get too carried away, this study is far from proving cause and effect. The research is as much about an admiration of Doctor Who and health professionals as it is a serious statistical analysis. A rigorous set of models was used to crunch the data though, and attempt to rule out the more obvious statistical artifacts.

"This paper has two hearts," says Riley. "The first is about medical doctors, who work tirelessly to save lives and make others better, including over Christmas."

"The second is about the BBC TV series Doctor Who, which millions enjoy worldwide."

An accompanying editorial gets into the spirit of the study. It acknowledges the "impeccable mathematical models" used while arguing that a single television broadcast cannot affect an entire country's mortality rates.

"But in reality, releasing a melange of sound and vision on a midwinter holiday could never truly change the mortality rate of a population," state the two authors, University of York pediatric oncologist Bob Phillips and Leeds Teaching Hospitals nurse educator Nicola Mackenzie-Croft.

"This has to be a chance finding, drawn from luck, or the clustering of episodes airing, and I doubt that anyone who had undertaken the analysis with other "medical" shows (for example, Call the Midwife), would have attempted to publish."

These data patterns are almost certainly down to luck or other factors – but is it utterly inconceivable that seeing the Christmas adventures of a doctor intent on helping others might encourage people to go and check in with their own doctor earlier than they otherwise would? Or at least make some healthier lifestyle choices?

What's beyond doubt is the tremendous work done by healthcare teams across the world, even while many people take a break over Christmas and the New Year – work that can take its toll on doctors and nurses in the service of other people.

"Given the study findings, we should be even more grateful to health professionals working this festive season, and to the BBC and Disney Plus for broadcasting Doctor Who on Christmas Day," says Riley.

The research has been published in The BMJ.