Life with a purpose rather than living for the sake of being healthy: the challenges and promises to reduce dementia risk in later life

In this issue of International Psychogeriatrics, Sutin et al. (2024) conducted a prospective study on the association between purpose in life and dementia. Purpose in life is gaining attention for reducing the risk of dementia. The modifiable risk factors for dementia include hearing impairment, hypertension, excessive alcohol consumption, and obesity in midlife. Smoking, depression, social isolation, physical inactivity, and diabetes are risk factors in later life (Livingston et al., 2020). A sense of purpose in life is the feeling that one’s life is goal-oriented and has direction (Ryff, 2014). This feeling may aid in recovering from stressful events and participating in activities such as exercise (Sutin et al., 2023a) and social engagement (Sutin et al., 2022a; 2023b), which may help reduce dementia risk.

Existing research suggests that individuals with a greater sense of purpose are less likely to develop Alzheimer’s disease and other dementias (Sutin et al., 2021). There is some evidence that it is also associated with cognitive function prior to impairment. A meta-analysis published in International Psychogeriatrics indicates a robust association between purpose and both verbal fluency and episodic memory (Sutin et al., 2022b). However, purpose measured during middle adulthood is not related to cognitive function in older adults (Nakanishi et al., 2019). A potential reason for this inconsistency could be the difference in when purpose in life was assessed, whether in midlife or later in life, among various study populations. To address these limitations, Sutin et al. (2024) used data from the Wisconsin Longitudinal Study of Aging (Herd et al., 2014) where purpose in life was measured at three-time points during middle and older adulthood. Having a sense of purpose in life during older adulthood was associated with a reduced risk of dementia, whereas purpose measured during midlife showed no significant association with dementia. These findings provide valuable insights into the impact of purpose in life on dementia risk as individuals age from midlife to later life. As noted in the Lancet Commission paper (Livingston et al., 2020), it is never too early and never too late in the life course for dementia prevention. Addressing modifiable risk factors in older adulthood could potentially reduce dementia risk, as these factors may still be changeable in later life.

However, translating the results into implications for interventions requires careful consideration of social contexts. Not all modifiable risk factors are equally easy to address (Wilson et al., 2023a). There is an emerging concern about ‘lifestyle’ stigma that would define people with dementia as those who have failed to employ a sustainable healthy lifestyle (Wilson et al., 2023b). This stigma can hinder people with dementia, their families, and those working to support them. Therefore, leveraging purpose in life should not be attributed solely to personal responsibility.

The association between a steeper decline in purpose and dementia risk found in this study may offer insight into the challenges of transitioning from middle to older adulthood. Transforming purposes alongside aging is challenging, especially in societies where work largely defines one’s social role and identity. Life changes often accompanying retirement can lead to a decrease in purpose (Lewis & Hill, 2020). A decline in physical health and the need for care, whether formal or informal, can also challenge one’s sense of purpose. Reliance on care may threaten an individual’s autonomy and integrity. A decrease in a person’s sense of purpose may occur before and after a diagnosis of dementia or cognitive decline (Sutin et al., 2023c). Another study published in International Psychogeriatrics underscored the emotional impact of the dementia diagnosis, as 15% of people around the time of diagnosis had recorded suicidal ideation (Naismith et al., 2022). Conversely, a strong sense of purpose can empower people with dementia to maintain their cognitive well-being (Boyle et al., 2012). Purpose in life can reflect one’s interpersonal relationships, connectedness, and sense of belonging. People with dementia can achieve their daily goals with the right support and self-help strategies. Other research in International Psychogeriatrics highlighted that people with dementia perceived social engagement as particularly important for everyday living activities rather than autonomous choice, personal growth, and keeping a routine (Wilkins et al., 2022). Care partners may harbor certain biases toward a sense of purpose in people with dementia (Wynn et al., 2021). Culture and society can either encourage or discourage older adults from redefining their purpose in life.

There may be tautology if older adults are recommended to maintain a sense of purpose to sustain their physical strength, function, and cognition. Nonetheless, many people wish to reduce morbidity, live independently, and be free from serious illness and disability until the very end of life (Fries, 2005), and health is not the final aim of life. Purpose in life itself is an important component of a meaningful life (Martela & Steger, 2016), and being healthy is a means to achieve this purpose. Barriers to establishing a sense of purpose should be explored in the context of the social determinants of health, systemic inequity, and cultural bias. Consequently, the role of purpose in reducing dementia risk across different life stages needs to be further examined in diverse populations and regions. It is particularly important to understand how social and cultural factors help older adults shape their purposes in later life. Furthermore, as dementia disproportionately affects women more than men, gender-related differences in such social determinants are worth exploring. Sutin et al. (2024) offered a significant step in advancing the evidence on living well and aging well.