Diabetes Prevention Guide
En español | There’s a reason nearly 90 percent of people with prediabetes don’t realize they even have it: Symptoms can be hard to spot when your blood sugar is higher than it should be but not high enough for a diabetes diagnosis. Some people in this precursor stage experience increased thirst, frequent urination, fatigue or blurred vision — which are also signs of full-fledged diabetes. But more often than not, there are no clear signs. That’s why it’s important to be aware of the major risk factors for prediabetes and diabetes.
Almost nine in 10 adults in the U.S. with diagnosed diabetes are overweight or obese, according to the Centers for Disease Control and Prevention (CDC). Research suggests why: One large study of more than 77,000 people with prediabetes, published in The Permanente Journal, found that the raises your risk for diabetes increased with increasing blood sugar levels and body mass index (BMI).
So it was no surprise when the U.S. Preventive Services Task Force, a panel of experts in disease prevention and evidence-based medicine, last week tweaked its recommendation on screening for diabetes: People who are overweight (meaning a BMI between 25 and 30) or obese (a BMI of 30 or more) should be screened for type 2 diabetes and abnormally high blood sugar levels beginning at age 35, rather than age 40, which was its previous recommendation.
The revised guidelines, reported in the Journal of the American Medical Association, suggested that health care providers consider screening overweight and obese patients at an even earlier age if they also have a family history of diabetes, a personal history of conditions like gestational diabetes, or if they are Black, Hispanic, Native American, Alaska Native or Asian American.
(For more on the link between diabetes and ethnicity, see “How Race Factors In.”)
One recent study, published in the journal Diabetologia, suggests that a high body mass index raises your risk for diabetes regardless of whether you have a genetic predisposition. Compared with people of normal weight, study participants who were overweight (meaning their BMI was between 25 and 30) were almost two and a half times more likely to develop diabetes. Obese participants (a BMI of 30 or more) were six times as likely.
“Although COVID-19 is a pandemic, overweight/obesity is becoming the most common chronic disease ‘pandemic’ in the world,” says Robert Eckel, professor of medicine emeritus at the University of Colorado School of Medicine Anschutz Medical Campus and immediate past president of the American Diabetes Association (ADA). “Obesity is the most important predictor of new onset type 2 diabetes.”
But it isn’t just BMI that figures in; where you carry your weight also makes a difference. “Fat around the waist — an apple shape — is uniquely dangerous for developing diabetes and other chronic illnesses such as heart disease and kidney failure,” says Mercedes Carnethon, professor and vice chair of the Department of Preventive Medicine at the Northwestern University Feinberg School of Medicine. “Fat in the waist region is described by scientists and doctors as being ‘metabolically active’ — meaning that central fat releases hormones and other biological substances that target and damage the organs and blood vessels that contribute to diabetes and other chronic illnesses.”
The good news? Research clearly shows that losing weight can delay the progression of prediabetes to diabetes.
You’re 45 or older
The ADA, as well as the American Association of Clinical Endocrinology, recommends screening for diabetes every year beginning at age 45 — or even younger if you have other major risk factors. “The chances of developing diabetes are significantly higher with age,” says Marwan Hamaty, an endocrinologist at the Cleveland Clinic. “As we get older, there are declines in the function and number of cells secreting insulin.” Without the right amount of insulin, the glucose that normally powers cells gets stuck in the bloodstream, with potentially serious health effects. “Early detection is essential for successful treatment,” Hamaty adds.
You have a parent or sibling with diabetes
Having a first-degree relative such as a parent or sibling with diabetes doubles, maybe even triples, your own risk of developing the disease. But having what’s considered a “family history” of diabetes is about more than just shared genes. “Some proportion of family history is due to the environment that a family shares,” says Carnethon. “That shared environment can include family meals and other behaviors that predispose [people] to diabetes.” If, for instance, you grew up in a physically inactive family that sat down to large meals on a daily basis, you’re likely to do so into adulthood.
Although you can’t do anything about your genetic makeup, you can alter your lifestyle. “Your genes don’t have to define your destiny, since genes interact with the environment to promote, or prevent, disease,” Carnethon says. “Knowing that a family member has diabetes should encourage other members of the family to adhere to healthy behaviors to prevent the onset of diabetes.” Those behaviors will include regular exercise and a healthy diet.
You lead a sedentary life
We all sit too much. In fact, research suggests the majority of us spend more than half of each day sitting. That alone dramatically ups the risk for diabetes — and not only because physical inactivity contributes to weight gain. A sedentary lifestyle also exacerbates insulin resistance, experts say. A large review of studies published in the journal Medicine and Sport Science suggests a 112 percent greater relative risk for type 2 diabetes associated with a sedentary lifestyle.
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To prevent diabetes — especially if you have prediabetes — the ADA recommends at least 150 minutes per week of moderate-intensity aerobic activity (like brisk walking) and two to three strength-training sessions each week. But here’s the rub: You can meet the ADA’s recommendation for exercise and still be at risk for diabetes if you don’t break up prolonged bouts of sitting throughout the day. That’s why the ADA also suggests getting up every half hour and doing some form of activity for a few minutes, whether it’s stretching, jumping rope or walking in place.
You’ve had gestational diabetes
Up to 10 percent of women in the U.S. are affected by gestational diabetes, a type of diabetes that can occur during pregnancy. Even if a woman’s blood sugar levels go down after giving birth, she’s still at higher risk for type 2 diabetes later in life. (For that matter, so is her baby.)
“The hormonal changes during pregnancy serve as a ‘stress test’ to the cells making insulin,” Hamaty says. “The demands for insulin increase significantly, and if they aren’t met, gestational diabetes develops.” About 50 percent of women with gestational diabetes go on to develop type 2, according to the CDC.
You’re part of a high-risk ethnic group
African Americans, Latino/Hispanic Americans, Native Americans and Alaska Natives are all at higher risk for diabetes than Caucasians. So, too, are some Pacific Islanders and Asian Americans. Although family history plays a role, environment is believed to play an equal role in contributing to the greatest risk factor — obesity. “The risk factors for obesity are shared among lower-income groups,” Carnethon says. “Lower-income communities have less access to healthy foods and safe spaces for physical activity, which can each drive obesity.”
What’s behind the greater diabetes risk for certain groups
You’ve heard — maybe even heeded — the warning: If you don’t watch what you eat and exercise regularly, you’re raising your risk for diabetes. What you may not hear as much about is the role ethnicity plays. African Americans, Latino/Hispanic Americans,, American Indians, and some Pacific Islanders and Asian Americans are all at higher risk for diabetes than Caucasians.
According to the 2020 National Diabetes Statistics Report from the Centers for Disease Control and Prevention, new diabetes cases were highest among Hispanics, followed closely by non-Hispanic Blacks. That’s why the U.S. Preventive Services Task Force now recommends that health care workers consider screening overweight and obese patients in these populations beginning no later than age 35.
Not only are racial and ethnic minorities disproportionately affected by the disease, they’re also more likely to experience complications — such as blindness, kidney disease and amputations — than their white counterparts.
For a long time, researchers couldn’t make sense of why certain ethnic groups were hardest hit. They believed that genes were to blame — meaning more people of certain races were simply destined to develop diabetes. But research suggests that’s not the case. A study published in 2017 in the Journal of the American Medical Association set out to understand why Black adults in the U.S. are nearly twice as likely as white adults to develop type 2 diabetes. The researchers found that both groups actually have the same biological risk. The reason for the disparity has to do with a familiar culprit: obesity.
“Far and away, the leading factor for type 2 diabetes appears to be obesity,” says study co-author Mercedes Carnethon of the Northwestern University Feinberg School of Medicine. “Factors we collectively refer to as the social determinants of health — our financial resources, access to health care, level of education and the neighborhoods we live in — all of these contribute to the development of obesity and common complications of being overweight, such as diabetes.”
Consider the consequences of living in a community that doesn’t have easy access to health care, nutritious foods or spaces that lend themselves to physical activity. “These things lead people to make choices that result in a higher risk of obesity,” Carnethon says. “That’s really what drives the disparities in the development of diabetes among ethnic groups.”