Increased Winter Mortality (Excess Winter Deaths)
The Increased Winter Mortality (Excess Winter Deaths) figure for Scotland in 2017/18 was 4,800.
Increased Winter Mortality or Excess Winter Deaths are recorded by the National Records of Scotland (NRS).
There is no single cause of 'additional' deaths in winter. Very few are caused by hypothermia. Most are from respiratory and circulatory diseases such as pneumonia, coronary heart disease and stroke. In only a small proportion of deaths is influenza recorded as the underlying cause.
The seasonal increase in mortality in the winter has been defined as the difference between the number of deaths in the four 'winter' months (December to March) and the average of the numbers of deaths in the two four month periods which precede winter (August to November) and follow winter (April to July).
Statistics of the seasonal increase in mortality in the winter inform public debate and the development of government policy on matters such as the health of the elderly population, fuel poverty and whether there is a need to improve the housing stock in terms of central heating and thermal insulation.
The annual statistics are available here from the NRS. The increased winter mortality (Excess Winter Deaths) figure for Scotland in 2017/18 was 4,800.
The archive on increased winter mortality is available here.
The Occasional Paper (published in April 2002) on "The Raised Incidence of Winter Deaths" is here
- There were 23,137 deaths registered in Scotland in the four months of winter 2017/18 (December to March), compared with 20,946 in winter 2016/17. It was the largest number since the 23,379 deaths registered in winter 1999/2000.
- Comparing the number of deaths in the four winter months with the average for the two adjacent four-month periods, the seasonal increase in mortality in winter 2017/18 was 4,800. This was 2,070 more than the corresponding value of 2,730 for the previous winter, and the largest value since winter 1999/2000, when the seasonal increase in mortality was 5,190.
- The seasonal increase in mortality has been calculated for every winter from 1951/52. The seasonal increase of 4,800 in winter 2017/18 was larger than in most of the previous 66 winters, and exceeded the level seen in all of the previous ten winters, and in 19 of the previous 20 winters.
- The long-term trend in the seasonal increase in mortality in the winter has clearly been downward, but it can fluctuate greatly from winter to winter. There have been unusually large figures in some years (including, latterly, 4,060 for winter 2014/15 and 4,800 for winter 2017/18, which had the largest value since winter 1999/2000). However, the height of the peaks has generally been falling.
- The five year moving average, which smooths out much of the year to year fluctuation, had tended to decline, but has risen recently (due, for example, to winters 2014/15 and 2017/18 entering the calculation). While the latest value (3,208) is the twenty third lowest ever, it is greater than all of the previous ten values, greater than 15 of the previous 20 values, and clearly above the level that had applied since the early 2000s. However, it is too early to say whether there has been a change in the long-term trend: the recent rise in the 5 year moving average could just be a short-term one, like that which was seen around the middle of the 1990s, after which the 5-year moving average fell for several years.
- The latest 18 winters have had 7 out of the 10 lowest seasonal increases in mortality ever recorded. Over the 67 years covered by these statistics, the lowest seasonal increase in mortality was for winter 2011/12 (1,420), the second lowest was for winter 2013/14 (1,600), the third lowest was for winter 2005/06 (1,780), the fourth lowest was for winter 2001/02 (1,840), and the fifth lowest was for winter 2012/13 (2,000). The eighth and ninth lowest seasonal increases in mortality were for winter 2007/08 (2,180) and winter 2000/01 (2,220).
A separate document, Increased Winter Mortality - Background Note, published in October 2010 (available on the NRS website), gives information about some of the medical causes of the seasonal increase in mortality in the winter, describes some research studies' findings on factors that influence it, reports on a comparison of the figures for a number of European countries, mentions previous publications on this topic, and provides references to the sources of the material.
The main points to note are:
- high cold-related mortality is associated with low indoor temperatures, and with people not wearing appropriate clothing when outdoors in cold weather;
- increased winter mortality was at the same level in Scotland as the overall mean for the 14 European countries covered by a comparative study; and
- the seasonal increase in mortality in the winter is higher in countries with a warmer winter climate, probably because their homes tend to be poorly insulated and their populations tend not to dress well for cold weather.