Winter mortality index - WMCA

Directly age-standardised registration rate for oral cancer (ICD-10 C00-C14), in persons of all ages, per 100,000 2013 European Standard PopulationRationaleThe purpose of the winter mortality measure is to compare the number of deaths that occurred in the winter period (December to March) with the average of the non winter periods (August to November and April to July). Winter mortality is not solely a reflection of temperature, but of other factors as well. These include respiratory diseases and pressure on services, which have been more intense than usual during and following the height of the pandemic (1).It is an important measure as it allows users to assess whether policies are having an impact on mortality risks during the winter period (2). (1) Office for National Statistics (ONS), released 19 January 2023, ONS website, statistical bulletin, Winter mortality in England and Wales: 2021 to 2022 (provisional) and 2020 to 2021 (final). (2) Office for National Statistics (ONS), released 19 January 2023, ONS website, QMI, Winter mortality in England and Wales QMI: 19 January 2023Definition of numeratorTotal number of winter deaths for all ages in defined year 20xx/20xx+1 (number of deaths occurring in December in year 20xx and January to March in 20xx plus 1) minus half the number of deaths in the non winter months (preceding August to November in year 20xx and following April to July in year 20xx plus 1) and registered by 31 December 20xx plus 1.Definition of denominatorThe average number of deaths for all ages ( in defined year 20xx/20xx plus 1) occurring in the non winter months, i.e. the total number of deaths occurring in the preceding August to November in year 20xx and the following April to July in year 20xx plus 1 divided by two and registered by 31 December 20xx plus 1.CaveatsIn 2020, the coronavirus (COVID 19) pandemic led to a large increase of deaths mostly in the non-winter months of April to July 2020. This has impacted the WMI for 2019 to 2020. Because we rely on using the difference between deaths occurring in the winter and the average of non winter months; specifically, the scale of COVID 19 deaths during non winter months has fundamentally disturbed the data time series and so data for 2019 to 2020 should be interpreted with caution.The Office for National Statistics (ONS) Annual Births and Mortality Extract is based on registered deaths (Date of registration) and the Winter deaths compared to non winter deaths and WMI calculations are based on the date of death occurrences (Date of death). It is possible that a number of deaths might not have been registered when the data were released and this could vary between areas. This indicator only includes deaths which are registered by the end of the calendar year 20xx plus 1.Data published in the PHOF will differ from published ONS results which uses an extract of mortality data taken approximately five months after the annual ONS mortality extract is taken, in order to give more time for late registrations (for example, deaths that were referred to a coroner) to appear in the data.The WMI will be partly dependent on the proportion of older people in the population as most winter deaths effect older people (there is no standardisation in this calculation by age or any other factor).This winter period was selected as they are the months which over the last 50 years have displayed above average monthly mortality. However, if mortality starts to increase prior to this, for example in November, the number of deaths in the non winter period will increase, which in turn will decrease the estimate of winter deaths compared to non winter deaths.The counts are presented rounded to the nearest 10, in line with how data is presented by the ONS.

直接按年龄标准化的人口登记率（ICD-10 C00-C14，口腔癌），针对所有年龄段，每10万人中的比例，基于2013年欧洲标准人口。理由：冬季死亡率指标旨在将冬季（12月至3月）期间发生的死亡人数与非冬季时期（8月至11月和4月至7月）的平均死亡人数进行比较。冬季死亡率并不仅仅反映温度，还涉及其他因素，例如呼吸系统疾病和服务压力，这些因素在疫情期间及其高峰期后通常更为严重（1）。这是一项重要的指标，因为它使用户能够评估政策是否对冬季期间的死亡率风险产生影响（2）。
（1）国家统计局（ONS）发布于2023年1月19日，ONS网站，统计公报，英格兰和威尔士冬季死亡率：2021至2022年（临时）和2020至2021年（最终）。
（2）国家统计局（ONS）发布于2023年1月19日，ONS网站，季度指标，英格兰和威尔士冬季死亡率季度指标：2023年1月19日。
定义分子：特定年份20xx/20xx+1中所有年龄段冬季死亡的总数（20xx年12月的死亡人数加上20xx+1年1月至3月的死亡人数）减去非冬季月份（20xx年中前8月至11月和20xx+1年4月至7月之后）死亡人数的一半，并在20xx+1年12月31日前登记。
定义分母：特定年份20xx/20xx+1中所有年龄段非冬季月份的平均死亡人数，即20xx年中前8月至11月和20xx+1年4月至7月之后死亡人数的总数，除以2，并在20xx+1年12月31日前登记。
注意事项：在2020年，新冠病毒（COVID-19）大流行导致4月至7月非冬季月份的死亡人数大幅增加，这影响了2019至2020年的WMI。由于我们依赖于冬季和平均非冬季月份死亡人数之间的差异；特别是，非冬季月份COVID-19死亡规模的根本性扰乱了数据时间序列，因此对于2019至2020年的数据应谨慎解读。国家统计局（ONS）年度出生与死亡率提取基于已登记的死亡（登记日期）和冬季死亡与非冬季死亡以及WMI的计算基于死亡日期。可能存在一些死亡人数在数据发布时未登记的情况，并且这可能在各地区之间存在差异。本指标仅包括在20xx+1年年底前登记的死亡。
PHOF中发布的数据将与ONS发布的数据存在差异，ONS使用的数据提取是从年度ONS死亡率提取大约五个月后进行的，以便为晚些时候的登记提供更多时间（例如，被转介给验尸官的死亡）。
WMI将部分取决于人口中老年人的比例，因为大多数冬季死亡都影响老年人（在此计算中没有按年龄或其他因素进行标准化）。本冬季时期被选中，因为这些月份在过去的50年中表现出每月死亡率高于平均水平。然而，如果在这些月份之前死亡率开始增加，例如在11月，非冬季期间的死亡人数将会增加，这反过来又会导致冬季死亡与非冬季死亡估计值的减少。
数据计数以最接近的10进行四舍五入，符合ONS的数据展示方式。