Older adults with slightly elevated blood sugar, sometimes called "prediabetes," usually don't develop full-blown diabetes, a Swedish study suggests.
Researchers followed 2,575 men and women aged 60 and older without diabetes for up to 12 years. At the start of the study, 918 people, or 36 percent of the group, did have higher-than-normal blood sugar levels that were still below the threshold for diabetes.
Only 119 people, 13 percent of those who started out with elevated blood sugar, went on to develop diabetes. Another 204, or 22 percent, had blood sugar levels drop enough to no longer be considered prediabetic.
"Progressing to diabetes is not the only destination," said lead study author Ying Shang of the Aging Research Center at the Karolinska Institute in Stockholm.
"In fact, the chance to stay prediabetic or even revert back to (normal blood sugar) is actually pretty high (64 percent), without taking medication," Shang said by email. "Lifestyle changes such as weight management or blood pressure control may help stop prediabetes from progressing."
Average blood sugar levels over the course of about three months can be estimated by measuring a form of hemoglobin that binds to glucose in blood, known as A1c. Hemoglobin A1c levels of 6.5percent or above signal diabetes.
Levels between 5.7 percent and 6.4 percent are considered elevated, though not yet diabetic, while 5.7 percent or less is considered normal.
Worldwide, about 352 million adults have elevated blood sugar that's not high enough to warrant a diabetes diagnosis, the study team notes in the Journal of Internal Medicine. By 2045, that's projected to rise to 587 million, or 8.3 percent of adults worldwide.
People in the study with prediabetes were more likely to return to healthy blood sugar levels if they lost weight, were free of heart disease and had low blood pressure.
Obese adults with prediabetes were more likely to progress to full-blown diabetes.
The study wasn't designed to determine why people with prediabetes might progress to full-blown disease or return to healthy blood sugar levels.
One limitation of the study is that it had too few people with prediabetes to draw broad conclusions about how the condition might progress for millions of people worldwide. Researchers also lacked data on what lifestyle changes, such as shifts in eating or exercise habits, people might have used to try to reverse prediabetes.
"Larger studies will be needed to confirm these findings, and more treatment and lifestyle information would be needed to better understand why less people became diabetic than anticipated," said Dr R Brandon Stacey of Wake Forest University School of Medicine in Winston-Salem, North Carolina.
"By having more lifestyle and treatment information, it may be possible to better identify patterns that enabled patients to successfully lose weight or lower their blood pressure to potentially reduce the risk of diabetes," Stacey, who wasn't involved in the study, said by email.
Even so, the results suggest that a diagnosis of prediabetes should motivate patients to make lifestyle changes, said Dr Ron Ruby, co-director of the cardiometabolic centre at Providence Little Company of Mary Medical Center in Torrance, California.
"Optimise the things you can control; weight loss, diet, exercise, and sleep," Ruby, who wasn't involved in the study, said by email.
"This approach, though challenging to maintain for the long term, may be sufficient to prevent the progression to diabetes."