Chronic Diseases and Multimorbidity Among the Oldest Old: Prevalence, trends, and associations with self-rated health, functioning, long-term care admission, and mortality

Research output: Book/ReportDoctoral thesisCollection of Articles


Chronic diseases are one of the most significant public health concerns in aging societies, with major implications both for the organization of social and health care and for individuals’ quality of life, functioning, and care needs. Age is the single most important risk factor for many chronic diseases, and therefore the oldest old people who live to over 90 years are at an increased risk for developing chronic diseases based on their age alone. Multimorbidity, or the co-occurrence of two or more diseases, has become increasingly common in aging populations. Studies on morbidity among those living the longest lives can provide important insight into whether the increase in life expectancy is accompanied by better, worse, or unchanged health and into what is to be expected when increasing numbers of people live to very old age. There is still a scarcity of health research that addresses populations aged over 90; most former studies have concentrated on younger population segments. This study investigated the prevalence of chronic diseases and multimorbidity in a population aged over 90 and explored the associations of chronic diseases and multimorbidity with self-rated health and functioning, disability in mobility and activities of daily living (ADL), long-term care (LTC) admission, and mortality. In addition, the study assessed the reliability of self-reported survey information on chronic diseases by comparing it with national health register data.

The study used data from six repeated cross-sectional surveys conducted between 2001 and 2018 as part of the Vitality 90+ Study. The study population for each survey round consisted of all residents aged 90 and over in the city of Tampere. Response rates were close to 80% in each survey wave. Altogether the data comprised 5,441 respondents. Register data on LTC admission, mortality, hospital discharge information, and drug reimbursement were linked with the survey data. The study used several regression analysis methods in addition to agreement measures to address the research questions.

The level of multimorbidity was high in both women (82%) and men (77%). The most common chronic diseases were hypertension, heart disease, arthritis, and dementia. Multimorbidity was associated with poor self-rated health and poor selfrated functioning, ADL and mobility disability, and an increased risk for mortality. The number of diseases showed an increasing trend over time, with the biggest increases seen in the prevalence of hypertension, arthritis, and diabetes. The only condition that showed a decreasing trend across the years was depression. The prevalence of dementia was high (ca 41%) but it showed a slightly declining trend. The most common chronic conditions comorbid with dementia were hypertension, heart disease, arthritis, and depression. The disease that showed the strongest association with ADL and mobility disability and with LTC admission was dementia. The population attributable fraction (PAF) for mortality was highest for dementia. Most of the associations found were more pronounced in women than in men. Agreement between the survey data and health register data was almost perfect for Parkinson’s disease, substantial for diabetes and dementia, and moderate for heart disease and hypertension.

The study has two main conclusions: First, the morbidity profile of the oldest old people is characterized by a high level of dementia, depression, and multimorbidity as well as by an increasing number of chronic diseases over time. The findings reflect the advances that have been made in the diagnostics and treatment of chronic diseases even in very old age. Second, the results show that survey methods can be used in population-based health studies to acquire information on chronic diseases with acceptable reliability among the oldest old.

Dementia is a common condition among the oldest old. It is associated with lower functional ability and an increased need for LTC, and it is predictive of mortality. The growth of the oldest old population means that the number of people with chronic diseases is set to continue to increase. As age remains the most important risk factor for diseases, effective prevention among the oldest old is very difficult. New practices and models of care need to be developed to provide effective treatment for old people with multimorbidity. The main emphasis should be on improving the quality of life of people living with diseases. It is imperative to recognize the growing need for care posed by the increasing number of people with dementia and to make sure that adequate support and long-term care is available.
Original languageEnglish
Place of PublicationTampere
ISBN (Electronic)978-952-03-3246-4
Publication statusPublished - 2024
Publication typeG5 Doctoral dissertation (articles)

Publication series

NameTampere University Dissertations - Tampereen yliopiston väitöskirjat
ISSN (Print)2489-9860
ISSN (Electronic)2490-0028


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