When you look at official statistics on the causes of death in old age and how they have changed over time, it is worth remembering that the underlying records are of terrible quality for more advanced ages, even in wealthier regions of the world. A great deal of work must take place to make anything of them, and all sorts of varying assumptions are baked into that work. In some cases the data simply isn't there, obscured by the tradition of marking the cause of death as 'old age' rather than any more specific item if known.
The researchers extracted information about the place and cause of death of centenarians in England between 2001 and 2010 from the ONS death registration database, linked these data with area level information on deprivation and care-home bed capacity, and analyzed the data statistically. Over the 10-year study period, 35,867 centenarians (mainly women, average age 101 years) died in England. The annual number of centenarian deaths increased from 2,823 in 2001 to 4,393 in 2010.
[The] findings suggest that many centenarians have outlived death from the chronic diseases that are the common causes of death among younger groups of elderly people and that dying in the hospital is often associated with pneumonia. Overall, these findings suggest that centenarians are a group of people living with a risk of death from increasing frailty that is exacerbated by acute lung infection. The accuracy of these findings is likely to be affected by the quality of UK death certification data. Although this is generally high, the strength of some of the reported associations may be affected, for example, by the tendency of clinicians to record the cause of death in the very elderly as "old age" to provide some comfort to surviving relatives.
'Old age' was the most common cause of certifying death (28%), followed by pneumonia (18%) and other respiratory diseases (6%); stroke (10%); heart disease (9%) and other circulatory diseases (10%); dementia and Alzheimer's disease (6%); and cancer (4%). Pneumonia accounted for the largest group of hospital deaths, while across non-hospital settings 'old age' formed the largest category followed by pneumonia. Overall, three-quarters of centenarian death certificates stated 'old age' as either an underlying cause (28%) or contributing cause (47%). The main causes of death changed with increasing age. In the group aged 80-85 years, heart disease was stated on 19% of death certificates, with 'old age' on only one per cent of certificates.