Prevention or delay of type 2 diabetes
Numerous clinical trials have shown that in high-risk subjects (particularly those with impaired glucose tolerance), type 2 diabetes can be prevented or delayed by lifestyle interventions or by various classes of medications. These trials primarily enrolled middle-aged participants. In the DPP, which is the largest trial to date, ∼20% of participants were aged ≥60 years at enrollment. These participants seemed to have more efficacy from the lifestyle intervention than younger participants, but did not appear to benefit from metformin (13,18). Follow-up of the DPP cohort for 10 years after randomization showed ongoing greater impact of the original lifestyle intervention in older participants (49% risk reduction in those aged ≥60 years at randomization vs. 34% for the total cohort) (19) and additional benefits of the lifestyle intervention that might impact older adults, such as reduction in urinary incontinence (20), improvement in several quality-of-life domains (21), and improvements in cardiovascular risk factors (22). Although these results suggest that diabetes prevention through lifestyle intervention be pursued in relatively healthy older adults, the DPP did not enroll significant numbers over the age of 70 years or those with functional or cognitive impairments. Preventive strategies that can be efficiently implemented in clinical settings and in the community have been developed and evaluated (23), but as yet there has been little focus on older adults in these translational studies.