Older Americans with diabetes living longer without disability, US study shows

The study examined trends in disabled years of life among a national sample of US adults born in the 1940s compared with the 1930s. They found that adults with diabetes born in the 1940s generally become disabled later and were living more years without disability by the age of 70, than those born in the 1930s. The study did not differentiate between people with type 1 and type 2 diabetes.

"Over the past two decades, we have seen an increase in the length of good disability-free years of life in older Americans aged 50-70 both with and without diabetes," explains lead author Dr. Barbara Bardenheier from the US Centers for Disease Control & Prevention. "Our findings suggest that efforts to promote healthy lifestyles, advancements in the management of diabetes and other chronic conditions such as heart disease, and the increasing popularity of procedures such as hip and knee replacements have been successful in 'compressing disability' -- reducing the number of years with disability into later years, up to age 70."

However, the authors warn that the trend seen among this older generation may not continue with an aging population more likely to develop type 2 diabetes and increased rates of obesity, unhealthy diets, alcohol, and physical inactivity meaning that diabetes is becoming more common. In the USA, the incidence and prevalence of type 2 diabetes has more than doubled over the last 20 years, and over 21 million Americans are now living with diabetes. With the vast majority of cases of type 2 diabetes in adults over 65 being preventable, the authors say that efforts to prevent the onset of diabetes will continue to have the greatest impact on improving health.

Substantial reductions in mortality mean that people with diabetes are living longer and, although yearly rates of several diabetes-related complications like heart attack, stroke, and amputations have fallen substantially over the last 20 years in the USA, it remains unclear whether these extra years of life with diabetes are lived with or without disability.

In this study, a team of US researchers analysed data on adults aged between 50 and 70 both with (1367) and without (11414) diabetes from the Health and Retirement Study, which surveys a nationally representative sample of more than 20000 older Americans every 2 years. They compared three types of disability including impaired mobility, less ability to perform activities of daily living such as bathing or eating, and impaired ability to carry out instrumental activities of daily living such as using the phone, shopping, and preparing meals, as well as recovery from disability, and death between two cohorts. Cohort 1 was born in the 1930s and followed 1992 to 2002, and cohort 2 was born in the 1940s and followed 2002 to 2012. Modeling was used to estimate and compare the number of years lived with and without disability by age 70 in people with and without diabetes.

Gains in disability-free life years and compression of disability were seen in adults with and without diabetes and across the three types of disability. However, from age 50, adults living with diabetes in both cohorts had reduced life expectancy before age 70 and higher numbers of years living with disability compared to people without diabetes.

Adults living with diabetes who were born in the 1940s experienced a delay in all types of disability and a greater increase in disability-free years of life compared with adults living with diabetes born in the 1930s as well as living more years without disability prior to age 70. For example, a 50-year-old man living with diabetes born in the 1940s experienced a delay in the average age of disability onset for all three disability types (0.8 to 2.3 years later) compared with those born a decade earlier, while living 1.3 years longer and fewer years with a disability (0.4 to 1.0 fewer) prior to age 70. The findings were similar in women living with diabetes.

The authors note that their research was limited by a lack of data beyond age 70, restricting their analyses to fairly early disability, rather than more common age-related disability that occurs later in life. What's more, the model did not assess factors such as obesity, high blood pressure physical activity, education, and depression which could explain many of the differences seen between those with and without diabetes.

According to co-author Dr Edward Gregg at CDC, "We don't know whether this compression of disability in those with and without diabetes will continue. The chances of succumbing to type 2 diabetes are strongly connected to lifestyle. Smoking, an unhealthy diet, alcohol, and physical inactivity can all take their toll. Ultimately, prevention will play an important role in achieving more years of healthy life free of disability."

Writing in a linked Comment, Dr Evelyn Wong from Deakin University, Melbourne, Australia says, "This study is important as it highlights the success and advancements in the management of chronic conditions in the postponement of disability...[However] future studies on the cost of this postponement of disability in light of the increasing prevalence of diabetes needs to be considered...As populations age and policies regarding retirement ages and eligibility for pensions become an increasingly important debate, future studies aimed at ascertaining compression or expansion of disability should focus on differences across social gradients. Programs to promote compression of disability may need to target the more socially disadvantaged groups specifically to decrease the health disparities across social stratum."