Summary: Sugar, Insulin, and the Aging Body
Diabetes as the Disease That Accelerates Everything Else
Nearly 29% of Americans over 65 have diabetes. Another 52% have prediabetes. If you are reading this, there is roughly an 80% chance one of those numbers applies to you.
Type 2 diabetes after 60 is not a single disease. It is a metabolic accelerant. Elevated glucose and insulin resistance damage blood vessels, nerves, and organs through overlapping pathways. Cardiovascular risk roughly doubles. Chronic kidney disease progresses faster. Peripheral neuropathy affects more than half of people with longstanding diabetes and contributes to falls. And a growing body of evidence confirms that diabetes significantly increases dementia risk, including Alzheimer’s, through vascular damage, chronic inflammation, and insulin resistance in the brain itself.
GLP-1 drugs (semaglutide, tirzepatide) have transformed diabetes treatment, with strong evidence across cardiovascular, renal, and metabolic outcomes. Large observational studies found 42 to 45% reductions in dementia risk among diabetes patients taking GLP-1 drugs. But two large Phase 3 trials testing oral semaglutide in people who already had early Alzheimer’s showed it did not slow cognitive decline. The distinction matters: these drugs appear to protect against developing dementia but cannot reverse it once established. Prevention and treatment are different problems.
The cost and access problem is real. Medicare’s BALANCE model, launching mid-2026, will offer qualifying beneficiaries GLP-1 access at $50 per month. Whether the communities with the highest diabetes prevalence actually gain access depends entirely on implementation. Prescribing disparities persist: Black and Hispanic Americans have substantially higher diabetes rates but lower GLP-1 prescription rates.
The most effective interventions are not primarily pharmaceutical. Diet and exercise can reduce the risk of progressing from prediabetes to diabetes by nearly 60%. But prescribing exercise is not like prescribing metformin. There is no pharmacy that fills it. Medicare limits physical therapy visits. The infrastructure for the most effective intervention barely exists.
Metabolic health can improve at any age. Insulin sensitivity improves with exercise at every age tested. The body after 60 is not done responding. It is waiting to be asked.