However, it is possible that although coded as the underlying cause, some of these deaths were precipitated by another condition such as influenza or CVD (Ho and Hendi, 2018). For example, in England and Wales, over a third of all deaths with an underlying cause of dementia or Alzheimer’s disease are reported to also have a respiratory disease mentioned on the death certificate (ONS, 2016a). Although the reasons for the seasonal pattern in deaths from dementia and Alzheimer's disease are not clear, it may be related to the greater vulnerability of people with these conditions to respiratory diseases.