You may have read that the lower your A1C level, the better. For best health, people with diabetes should aim for glucose as close to normal as possible. But some new research shows this may not be true for older people.
According to these studies, seniors could decide not to shoot for tight control of blood sugar or cholesterol. One study from Japan showed that lower HbA1c levels (a measure of average glucose control over the previous 2–3 months) were actually linked with an increased the risk of frailty in older adults. Frailty was measured in the study as how much help a person needs in living, and how poorly he or she recovers from an illness or injury.
Toshihiko Yanase, MD, PhD of Fukuoka University School of Medicine, Japan, reported, “The risk factors of metabolic syndrome, such as high blood glucose, obesity, high cholesterol, and hypertension, in middle age may shift from an unfavorable risk to favorable factors in old age.” The study was published in the Journal of Diabetes Investigation and reported by the online site Healio.com.
Yanase and colleagues analyzed data from 132 adults aged at least 65 years with Type 2 diabetes Average age was 78. The subjects had had diabetes for an average of 17 years and their mean A1C was 7.3%.
The subjects were categorized as frail or not on a 9-point clinical frailty scale (CFS). The CFS goes from 1 (very fit) to 9 (terminally ill). People who rated 5 or higher were classed as frail. Seventy-seven were not frail; 55 were. In those with higher frailty scores, HbA1c levels were found to be significantly lower.
The causes of frailty are not well understood. In men, frailty is strongly associated with loss of muscle mass. As you get weaker and thinner, you become more fragile. The same is probably true of women, although I haven’t seen those studies. Thinning bones also increase frailty and the risk of disabling fractures.
The American Diabetes Association (ADA) has long recommended looser control for people who are more frail. In these official guidelines, they recommend an A1C target of 7.5% for healthy people over 65, as compared to 7.0% for younger people. For people with other illnesses or impairments, their goal is 8.0%. For “complex patients in poor health,” the A1C goal is 8.5%
But why should older people do worse with tighter control? The ADA cites high treatment burden and increased risk of falls and hypoglycemia (low blood sugar) with tight control. If you have to take a bunch of drugs to get your glucose down, then there will be side effects and the danger of lows.
Episodes of low blood sugar are bad for you. In the Japanese study, about half the patients were on insulin or oral drugs that could cause lows.
But if people bring their glucose down with self-management behaviors like diet, exercise, and possibly plant medicines, that should be good, shouldn’t it?
It is possible that lower weight could have increased frailty, and that strict diabetes control might lead to undesirable weight loss. Researcher Mike Lustgarten, PhD, oultined a meta-analysis that found that a body-mass index (BMI) of 20–25 is associated with the longest life expectancy for younger people. For people over 65, though, the optimum BMI is about 27.5.
BMI is a measure that compares your weight with your height. If you know those numbers, you can calculate your own BMI here. An older 5’8″ person with a BMI of around 27.5 would weigh 180 pounds and would be classed as overweight, but he would have the longest life expectancy.
Dean Pomerleau, a practitioner of the Calorie Restriction diet, which generally advocates staying very thin as the key to long life, wrote “This late-life ‘obesity paradox’ might be a result of latent disease making people thin and more likely to die. Or it could simply be that heavier people have more metabolic reserves, which is important to enable the elderly to weather the ‘slings and arrows’ of aging, [for example,] falls and fractures, hospitalization, [other illnesses], loss of appetite, etc.”
Of course, everyone is different. If you want an A1C of 6 or less, and can work for that without dangerous side effects, and feel good doing it, go for it. But the point is not to live your life to reach a particular number on a lab test. Live the healthiest life you can, but realize that struggling for a strict glucose goal may not be the best way to do that when you’re older. Enjoy your life; share it with others. A little heavier and a little higher glucose level is OK.
Want to learn more about A1C? Read “Understanding Your HbA1c,” “What Does A1C Stand For? and “H-B-A-1-C: What It Is and Why It Matters.”
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