Understanding Physical and Cognitive Health Decline in the Oldest-Old Population
As the oldest-old population grows, there is little research about how demographics, socio-economic characteristics and one’s lifestyle affect changes in physical and cognitive health, whether there is a pattern to these changes and how physical or cognitive aspects affect transitions of the other dimensions. A study by researchers from the Interdisciplinary Centre on Population Dynamics (University of Southern Denmark) and University of Rome “La Sapienza”, Cosmo Strozza, Virginia Zarulli, and Viviana Egidi, analyse the 90+ population in Denmark to fill this gap in the research. They use data from the 1905 Danish Cohort survey, which was a longitudinal multi-assessment survey carried out between 1998 and 2005, focusing on the first and second waves when respondents were 93 and 95 years of age.
Good physical health was defined as being able to stand up from a chair with or without the use of assistance. If an individual could not stand up from a chair, even with the use of assistance, then he or she was considered to be in poor physical health. Mental health was measured using the Mini-Mental State Examination. Demographics, socio-economic characteristics and one’s lifestyle included sex, education, living conditions, physical activity and body mass index (BMI).
Based on their results, the authors found individuals had a higher chance of going from good to bad physical health within two years than dying. This was classified as a “one-step worsening pattern”. For cognitive health, there was a greater chance of dying within two years than having one’s cognitive health decline. Being a woman did not significantly affect transitioning from good to bad health, but it was associated with a lower chance of dying from both good and bad cognitive status and dying from a bad physical health condition. One’s level of education did not affect physical status, but higher education did decrease the chance of cognitive decline. Having a BMI over 22 resulted in lower chances of dying from either good or bad health status, while light to moderate physical activity reduced the chances of dying from poor physical or cognitive status. Living alone was found to decrease an individual’s chance of physical and cognitive decline, but a causal explanation could not be determined. Finally, the two health dimensions were dynamically related to each other: having a better physical or cognitive health condition lowered the chance of worsening one’s cognitive or physical status, respectively, and the probability of dying from a bad health condition.