CHICAGO – Aging-related decline in physical functioning has emerged as a previously unrecognized independent risk factor for new-onset diabetes, according to investigators at the Centers for Disease Control and Prevention.
In a multivariate analysis involving 22,876 subjects over age 50 years at baseline in the longitudinal, prospective Health and Retirement Study, those who had mild or moderate functional decline at enrollment or who developed it during an average 8.7 years of follow-up had a 17% increased risk of subsequently being diagnosed with new-onset diabetes, compared with subjects who did not have prevalent or incident functional decline or physical disability, Barbara H. Bardenheier, Ph.D., reported at the annual scientific sessions of the American Diabetes Association.
Subjects who had severe functional decline at baseline or developed it during follow-up had a 12% excess risk of subsequent diabetes. Like mild-to-moderate functional decline, severe functional decline was also a statistically significant risk factor for later diagnosis of diabetes in a multivariate analysis adjusted for age, race, education, baseline body mass index, and socioeconomic factors. The excess diabetes risk in individuals with prevalent or incident severe functional decline would have been higher but for the fact that they also had a 2.3-fold increased risk of mortality, compared with participants without aging-related functional decline, observed Dr. Bardenheier of the CDC in Atlanta.
It has been shown consistently in longitudinal and cross-sectional studies that diabetes is associated with an increased risk of subsequent physical disability, but this analysis of the Health and Retirement Study is the first to show the converse: that aging-related functional decline and physical disability or frailty place an individual at increased risk for subsequent diabetes, she added.
The definitions of aging-related functional decline employed in this study were based on difficulty expected to last longer than 3 months in performing specific mobility measures. Five mobility measures were used: walking one block; walking several blocks; stooping, crouching, or kneeling; climbing one flight of stairs, and pushing or pulling a large object.
Mild functional decline was defined as difficulty in stooping and walking several blocks or difficulty in any two mobility measures other than stair-climbing. Moderate functional decline required either difficulty in climbing a single flight of stairs or difficulty with any three of the other mobility measures. Severe decline was defined as difficulty with at least four mobility measures.
Among the 13,143 study participants who did not have aging-related functional decline at baseline, those who developed mild functional decline during follow-up had an adjusted 19% excess risk of being diagnosed with diabetes afterward. Those who developed moderate decline had a 30% excess risk of subsequent diabetes, while those with incident severe functional decline had a 16% increased risk of diabetes along with a 2.4-fold increased mortality risk. During follow-up, 18.8% of subjects without baseline aging-related functional decline developed moderate or severe decline.
Of note, 77% of participants reported some level of functional decline during the study period. During follow-up, 15.5% of subjects developed diabetes and 25.6% of subjects died.
The clinical relevance of this new observation that aging-related functional decline is a risk factor for subsequent diabetes lies in the fact that prior studies have shown functional decline is potentially modifiable. For example, physical exercise programs geared for older patients with moderate physical frailty have been shown to be protective against further disability, according to Dr. Bardenheier.
The Health and Retirement Study is sponsored by the National Institute on Aging. Dr. Bardenheier’s analysis was funded by the CDC. She reported having no conflicts of interest.