How can older adults combat diabetes to achieve a longer and healthier life?

Type 2 diabetes (hereafter, diabetes) and prediabetes are very common in older adults and constitute a great health concern for this population. The objective of this project is to investigate the impact of prediabetes and diabetes on health and survival among older adults, and to identify modifiable factors that may attenuate the risk of diabetes on disability and mortality to prolong survival with independence. Data used in this project were derived from the ongoing population-based Swedish National study on Aging and Care in Kungsholmen (SNAC-K).

Study I described the natural history of prediabetes and identified prognostic factors related to different outcomes of prediabetes. We found that among 918 participants with prediabetes at baseline, 204 (22%) reverted back to normoglycemia, 119 (13%) developed diabetes, and 215 (23%) died during the 12-year follow-up. Lower systolic blood pressure, and weight loss, and the absence of heart diseases were associated with the reversion of prediabetes to normoglycemia, whereas obesity was related to its progression to diabetes. Study II examined the association of prediabetes and diabetes with the risk of stroke and subsequent dementia. Among 2,655 dementia-free participants at baseline, a stroke-free cohort and a prevalent stroke cohort were identified based on prevalent stroke. In the stroke-free cohort, 236 participants developed ischemic stroke and 47 developed post-stroke dementia. Diabetes was associated with a higher risk of ischemic stroke and post-stroke dementia. In the prevalent stroke cohort, diabetes was also related to dementia risk. We did not find a significant association between prediabetes and stroke or post-stroke dementia. Study III assessed the association of prediabetes and diabetes with physical function decline and disability progression and explored whether cardiovascular diseases (CVDs) mediate these associations. During a 12-year follow-up, prediabetes accelerated the deterioration in chair stand performance, walking speed, and disability progression, independent of the future development of diabetes. Diabetes led to a faster decline than prediabetes, especially among those with uncontrolled diabetes. CVDs mediated 7.1%, 7.8%, and 20.9% of the associations between prediabetes and chair stand performance, walking speed, and disability progression, respectively. Study IV examined the association of prediabetes and diabetes on a composite outcome of disability or death and further identified modifiable factors that may prolong disability-free survival. Diabetes, but not prediabetes, was associated with a higher risk of disability or death. Compared to diabetes-free participants with a favorable lifestyle profile including the presence of at least one of the healthy behaviours, active leisure activities, or moderate-to-rich social network, those with diabetes and an unfavorable profile had 2.46 times higher risk of the outcomes. However, among participants with diabetes, the risk of the outcome was attenuated (HR 1.19, 95% CI 0.93 to 1.53) in those with a favorable profile, which prolonged disability-free survival by 3 years compared to those with an unfavorable profile.

Conclusions: In addition to its associations with stroke and cardiovascular diseases, diabetes could increase the risk of dementia secondary to stroke and accelerate decline in physical function. This decline in physical function might start already during prediabetes. Yet, one out of five older adults with prediabetes could revert back to normoglycemia with lifestyle modifications such as weight management. Diabetes is related to the risk of disability or death among older adults, but a healthy and socially active lifestyle may attenuate this risk and prolong disability-free survival.

List of scientific papers

I. Shang Y, Marseglia A, Wang HX, Wang R, Welmer AK, Fratiglioni L, Xu W. Natural history of prediabetes in older adults from a population-based longitudinal study. J Intern Med. 2019;286(3):326-340.
https://doi.org/10.1111/joim.12920

II. Shang Y, Fratiglioni L, Marseglia A, Plym A, Welmer AK, Wang HX, Wang R, Xu W. Association of diabetes with stroke and post-stroke dementia: A population-based cohort study. Alzheimers Dement. 2020;16(7):1003-1012.
https://doi.org/10.1002/alz.12101

III. Shang Y, Fratiglioni L, Vetrano D, Dove A, Welmer AK, Xu W. Not only diabetes but also prediabetes leads to functional decline and disability in older adults. Diabetes Care. 2021;44(3):690-698.
https://doi.org/10.2337/dc20-2232

IV. Shang Y, Wu W, Dove A, Guo J, Welmer AK, Rizzuto D, Fratiglioni L, Xu W. Healthy behaviours, leisure activities, and social network prolong disability-free survival in older adults with diabetes. [Manuscript]