Contents
Main Points
- There were 21,983 deaths registered in Scotland in the four months of winter 2023/24 (December 2023 to March 2024). This is 10 per cent fewer than the previous winter when the highest number of winter deaths in over thirty years was recorded.
- The number of winter deaths has fluctuated over the last ten years but has generally been increasing. This follows a decrease over the longer term.
- The seasonal increase in mortality of 1,796 for winter 2023/24 is much lower than the previous winter (4,137).
- There has been a long-term downward trend in the seasonal increase in mortality. In the 1950s and 60s, there was an average seasonal increase of over 5,200 deaths in winter, whereas over the most recent decade it has averaged around 2,900.
- The causes of death with the largest seasonal increase in winter 2023/24 were dementia and Alzheimer’s disease (380 additional deaths), Influenza (240 deaths), chronic lower respiratory disease (210 additional deaths), coronary (ischaemic) heart disease (180 additional deaths), other respiratory system diseases (140 additional deaths), cerebrovascular disease (140 additional deaths) and pneumonia (130 additional deaths). Very few deaths are directly due to cold weather (e.g. hypothermia); in each full calendar year since 2019 there have been fewer than ten deaths from ‘exposure to excessive natural cold’.
- Older age groups are consistently affected most by the seasonal increase in mortality in winter. In winter 2023/24, for people aged 85 and over there were 11 per cent more deaths compared to the months before and after winter. In the under 65 age group there were 7 per cent more deaths in winter.
Introduction
This publication provides statistics on mortality in Scotland during winter 2023/24. This includes trends since 1951/52, as well as breakdowns by age, sex, cause of death, areas of Scotland and other factors.
Winter months generally see more deaths than other times of the year. This report examines the seasonal increase in mortality in winter - the difference between deaths registered over winter (December to March) and the average number of deaths in the adjacent four-month periods (before and after). This definition is also used by other organisations like the Office for National Statistics (ONS) and the World Health Organisation (WHO) to measure winter mortality. For more information on this definition, see the box below.
The seasonal increase in mortality is calculated using data from death registration records. The latest year’s figures are provisional until the 2024 mortality data are finalised in summer 2025, but any revisions are usually small.
Winter mortality in Scotland
There were 21,983 deaths registered in Scotland in the four months of winter 2023/24 (December 2023 to March 2024). This is 10 per cent lower than the previous winter.
It is generally expected that more deaths will be registered in the four winter months (December to March), than in either the four months before (August to November) or the four months after (April to July). There has been only one exception in 70 years: because of the
coronavirus (COVID-19) pandemic, more deaths were registered from April 2020 to July 2020 than were registered in winter 2019/20 (December 2019 to March 2020).
What is Winter Mortality?
The seasonal increase in mortality in the winter is defined as the difference between the number of deaths registered in the four-month winter period (December to March, inclusive) and the average number of deaths in the two four-month periods which precede winter (August to November) and follow winter (April to July).
The seasonal increase represents the number of additional deaths in winter.
To account for differences in population size, seasonal increases for different areas of Scotland are better compared using the Increased Winter Mortality Index (IWMI). This is defined as the number of additional winter deaths divided by the average number of deaths in a four month non-winter period, expressed as a percentage.
Winter 2023/24 saw a seasonal increase in mortality of 1,796 compared to the surrounding non-winter periods. This is a considerably smaller increase than the previous winter. There has been a lot of variation in the seasonal increase over the past decade with increases ranging from 550 to 4,813.
The four month period before winter saw a small decrease in deaths (4%) while the period after saw a similar sized increase (3%) in the number of deaths. Both were high compared to the general trend.
Figure 1: Figures for the most recent years suggest a departure from the long-term downward trend in the number of deaths
Deaths registered in the Winter and in the Preceding and Following periods, Scotland, 1951/52 to 2023/24
Comparing the number of deaths in winter with the surrounding non-winter periods shows that the number of additional winter deaths can change from winter to winter and over time. In the 1950s and 60s, there was an average seasonal increase in winter of over 5,200 deaths, whereas over the most recent decade it has averaged around 2,900.
The Increased Winter Mortality Index has also fallen over time – from an average winter increase of 27% in the 1950s and 60s to an average of 15% over the last decade. The Increased Winter Mortality Index value for 2023/24 is 8.9 – the winter period had around 9% more deaths than the surrounding non-winter periods.
Figure 2: The Increased Winter Mortality Index has also generally fallen over time
Seasonal Increase in Mortality in the Winter, Scotland, 1951/52 to 2023/24
The seasonal increase in mortality in the winter by age-group
Older age groups are affected most by the seasonal increase in mortality in winter.
In winter 2023/24, for people aged 85 and over there were 11 per cent more deaths, compared to 7 per cent more for those aged under 65.
The figures fluctuate from year to year, but on the whole, the oldest age groups tend to have a greater seasonal increase in winter than the younger age groups.
Figure 3: Older people are affected most by the seasonal increase in mortality in winter
Increased Winter Mortality Index, by age-group. Scotland, 2012/2013 to 2023/24
The seasonal increase in mortality in the winter by sex
For most of the past 30 years, the number of additional deaths in winter – and the Increased Winter Mortality Index - has been greater for females than for males. This is largely explained by the fact that females live longer than males, and therefore account for a larger proportion of the population in older age groups. For females, in winter 2023/24 there were 11 per cent
more deaths and for males there were 7 percent more than in the surrounding non-winter periods.
Figure 4: The seasonal increase in mortality in winter is greater for females than for males
Increased Winter Mortality Index by sex, Scotland, 1990/91 to 2023/24
The seasonal increase in mortality in the winter by deprivation
There is no clear evidence of any consistent difference in the seasonal increase in mortality in winter between the most deprived and least deprived parts of Scotland.
In winter 2023/24 the Increased Winter Mortality Index was greatest in the middle deprivation quintile (12%). The most deprived quintile had an increase of 10% compared to other times of the year. As Figure 5 shows, the pattern has not been consistent over time.
Deprivation quintiles are based on the Scottish Index of Multiple Deprivation (SIMD). This is an area-based measure of deprivation. Quintiles are allocated according to the deceased’s usual place of residence.
Figure 5: There is no clear pattern linking deprivation with the seasonal increase in mortality
Increased Winter Mortality Index by SIMD quintile 2010/11 to 2023/24
The seasonal increase in mortality in the winter across areas in Scotland
There is no clear evidence of any consistent difference in the seasonal increase in mortality in winter across areas of Scotland. The Health Boards and Local Authority areas with the highest and lowest increased winter mortality indexes tend to fluctuate from year to year.
Tables 5 and 6 show the number of deaths in winter in each Local Authority and NHS Board area, along with the seasonal increases in each area.
The in the winter by cause of death
The causes of death with the largest seasonal increase in winter 2023/24 were dementia and Alzheimer’s disease (380 additional deaths), Influenza (240 deaths), chronic lower respiratory disease (210 additional deaths), coronary (ischaemic) heart disease (180 additional deaths), other respiratory system diseases (140 additional deaths), cerebrovascular disease (140 additional deaths) and pneumonia (130 additional deaths). Very few deaths are directly due to cold weather (e.g. hypothermia); in each full year since 2019 there have been fewer than ten deaths from ‘exposure to excessive natural cold’.
Figure 6: The seasonal increase in mortality is seen more acutely for specific causes of death
Seasonal Increase in Mortality in Winter 2023/24 (rounded) : main underlying causes
The underlying cause of death is defined as the disease or injury which initiated the chain of morbid events leading directly to death, or the accident/act which produced the fatal injury. Statistics are normally produced on this basis because every death has just one underlying cause, and so will be counted only once.
For additional information on this research and an explanation on some of the causes of increased mortality in winter, see the background note.
Links to related statistics
Notes on statistical publications
Accredited Official Statistics
These official statistics were independently reviewed by the Office for Statistics Regulation. They comply with the standards of trustworthiness, quality and value in the Code of Practice for Statistics and should be labelled ‘accredited official statistics’.
In June 2024 The Office for Statistics Regulation introduced the new accredited official statistics badge, to denote official statistics that have been independently reviewed by the Office for Statistics Regulation (OSR) and judged to meet the standards in the Code of Practice for Statistics. The new badge replaces the current National Statistics badge, though the meaning is the same. Accredited official statistics are called National Statistics in the Statistics and Registration Service Act 2007.
It is National Records of Scotland’s responsibility to maintain compliance with the standards expected of accredited official statistics. If we become concerned about whether these statistics are still meeting the appropriate standards, we will discuss any concerns with the Office for Statistics Regulation promptly. Accredited official statistics status can be removed at any point when the highest standards are not maintained, and reinstated when standards are restored.
Information on background and source data
Further details on data source(s), timeframe of data and timeliness, continuity of data, accuracy can be found in the ‘About this Publication’ document that is published alongside this publication on the NRS website.
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