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In 2014, the prevalence of diabetes in the United States in all age groups was 29.1 million people, or 9.3% of the population (1). However, 25.9% of US adults (11.2 million) aged 65 years or older have dia- betes, and the aging of the overall population is a sig- nificant driver of the diabetes epidemic. In addition, another one-third of US older adults have undiagnosed diabetes. In 2001, only 18.4% of US adults aged 65 years or older had diabetes (2). The percentage of adults with diabetes also differs by race/ethnicity: non-Hispanic whites 7.6%, Asian Americans 9%, Hispanics 12.8%, non-Hispanic blacks 13.2%, and American Indians/Alaska Natives 15.9% (1). Of great concern are the estimated 86 million Americans (51% of adults 60 years or older and 37% of adults 20 years or older) with prediabetes, based on fasting glucose or hemoglobin A1c (HbA1c) levels. Of interest is that the percentage of adults with prediabetes is similar for non-Hispanic whites (35%), non-Hispanic blacks (39%), and Hispanics (28%) (1). All are at high risk for conversion to type 2 diabetes and cardiovascu- lar disease (CVD) if lifestyle prevention strategies are not implemented. Type 2 diabetes accounts for 90% to 95% of all diagnosed cases of diabetes; the risk for developing type 2 diabetes is associated with older age, obesity, family history of diabetes, history of gestational diabe- tes, impaired glucose tolerance, physical inactivity, and race/ethnicity. However, type 2 diabetes is becoming increasingly more common in children, adolescents, and younger adults (1).

AGING AND DIABETES

Diabetes in older adults is linked to higher mortality, reduced functional status, and increased risk of institu- tionalization, as well as being at substantial risk for both acute and chronic microvascular and cardiovascu- lar complications of the disease (3). However, the rec- ognition of diabetes in older adults is often delayed.

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Nutritional Aspects of Diabetes

Typical symptoms of excess thirst, fatigue, and weight changes may not be reported by older adults. Polydipsia may be absent because decreased thirst is ignored or is associated with advanced age. Fatigue is a common complaint in this population and may not warrant concern. Weight changes may not be perceived as unusual to many older adults. The renal threshold for glucose increases with advanced age; therefore, glycosuria is not seen at usual levels. Dehydration is often more common with hyperglycemia because of older adults’ altered thirst perception and delayed fluid supplementation (4).

Older adults are more likely to be diagnosed with type 2 diabetes, but type 1 diabetes can occur at any age, even in the eighth and ninth decades of life (1). Insulin resistance combined with age-related decreas- ing insulin production is considered to be the most common etiology of type 2 diabetes in older adults (3). Age-related insulin resistance is primarily associated with adiposity, sarcopenia, and physical inactivity. In the presence of insulin resistance, greater amounts of insulin must be provided to compensate for the loss of tissue sensitivity to insulin. Even though insulin levels may be relatively high, they are still inadequate to com- pensate for the high glucose levels that result from decreased glucose uptake by muscle and other insu- lin-sensitive tissues. With increasing severity over time, beta cells of the pancreas may fail to meet the additional needs for insulin in response to hyperglycemia, particu- larly in those who are obese. Therefore, as the disease progresses, insulin deficiency becomes the prominent defect.

Insulin release occurs in two phases—an initial

surge in postprandial insulin in response to rapidly rising blood glucose and a second-phase insulin release. Insulin deficiency in older adults includes loss of the first-phase insulin release. Deficient first-phase insulin release results in elevations of glucose that are much greater after meals than when fasting. This