In this regular column, Club Vita's longevity experts will help you visualise the often abstract world of longevity risk by introducing their own personal favourite charts.

17 December 2019

In this edition of Top Charts International, Richard Brown, Erik Pickett and Daniel Reddy discuss whether more people die in the winter than in the summer.

Question:

Do more people die in the winter than the summer?

Answer:

For Canada, the UK and the US, the short answer is yes. How many more depends on the location.

The bar chart shows the ratio of winter deaths to summer deaths in the UK, Canada and the US. Surprisingly, the UK sees the largest ratio of winter deaths to summer deaths over the period we have measured, despite having the least variation in temperatures¹.

_Source:_{Winter is defined as the beginning of December in the previous year to the end of February. Summer is defined as the beginning of June to the end of August. The 2013-2017 period was chosen as the most recent 5 year period where data was available for all locations.}

_{Data sources:}

_{England and Wales: ONS Deaths registered monthly in England and Wales}

_{Scotland: NRS Monthly Data on Births and Deaths Registered in Scotland}

_{Northern Ireland: NISRA Monthly Deaths}

_{Canada StatCan Monthly death data by province/territory}

_US:_{CDC State monthly death data}

But what happens if we zoom in closer?

The maps below show the ratios of winter deaths to summer deaths for the US, Canada and the UK, split by state for the US, province for Canada and by Scotland, Northern Ireland, England, and Wales for the UK.

_{Source: as previous chart}

Key takeaways

There is not much variation across Canada, apart from in Québec. Québec is a significant outlier, with a far higher proportion of winter deaths than the rest of the country. Just as high as the UK!
In the US, we see a much lower proportion of winter deaths in Alaska (where we’d expect people to be better equipped to deal with the cold) and Hawaii and Florida (whose winters are much less severe than the rest of the country). Apart from that, there is some variation between states, but not much of a visible pattern.
There is little variation across the UK. The high ratio of winter to summer deaths is seen across Scotland, Northern Ireland, England and Wales. However, our team in Glasgow would like it highlighted that they have a slight win in terms of Scotland dealing with winter conditions better than England.

The key questions we have are:

Why is the ratio of winter deaths to summer deaths so much higher in the UK and Québec?
Were the winters in 2013-2017 relatively harsh in the UK compared to North America?
Why has Québec experienced such high levels of excess winter deaths compared to other Canadian provinces?

What do you think?

Please post your questions in our Friends of Club Vita discussion group on LinkedIn.

_{[1] The range of average historical monthly high and low UK temperatures is 33°F (18°C) compared to 52°F (29°C) for the US and 69°F (38°C) for Canada (Source: www.weatherbase.com)}