You may think you already know the signs of diabetes: You're thirsty all the time, you feel exhausted 24/7 and/or you're constantly running to the bathroom. Yet a surprising number of Americans have abnormally high blood-sugar (glucose) levels but don't know it. The signs can be so subtle—or altogether absent—that the problem goes undetected, yet it increases the risk for heart disease and other serious health problems. As more and more of us pack on extra pounds, the incidence of diabetes and its recently defined precursor, pre-diabetes, is soaring in the United States.
What it is
Diabetes is a disease in which levels of blood glucose, also called blood sugar, are above normal. People with diabetes have problems converting food to energy. Normally, after a meal, the body breaks food down into glucose, which the blood carries to cells throughout the body. Cells use insulin, a hormone made in the pancreas, to help them convert blood glucose into energy.
People develop diabetes because the pancreas does not manufacture enough insulin or because the cells in the muscles, liver, and fat do not use insulin properly, or both. As a result, the amount of glucose in the blood increases while the cells are starved of energy. Over the years, high blood glucose, also called hyperglycemia, damages nerves and blood vessels, which can lead to complications such as heart disease, stroke, kidney disease, blindness, nerve problems, gum infections, and amputation.
Types of Diabetes
There are many different types of diabetes. The two main ones are called type 1 and type 2. A third form of diabetes is called gestational diabetes.
- Type 1 diabetes, formerly called juvenile diabetes, is usually first diagnosed in children, teenagers, and young adults. In this form of diabetes, the pancreas no longer makes insulin because the body's immune system has attacked and destroyed the pancreatic cells specialized to make insulin. These insulin-producing cells are called beta cells.
- Type 2 diabetes, formerly called adult-onset diabetes, is the most common form. People can develop type 2 diabetes at any age, even during childhood. This form of diabetes usually begins with insulin resistance, a condition in which muscle, liver, and fat cells do not use insulin properly. As a result, the body needs more insulin to help glucose enter cells to be used for energy. At first, the pancreas keeps up with the added demand by producing more insulin. In time, however, the pancreas loses its ability to secrete enough insulin in response to meals. . People who are overweight and inactive are more likely to develop type 2 diabetes.
- Gestational diabetes is diabetes that first occurs during pregnancy. When women are pregnant, their need for insulin appears to increase, and many can develop gestational diabetes during the late stages of pregnancy. Although this form of diabetes usually goes away after the baby is born, a woman who has had it is more likely to develop type 2 diabetes later in life.
Who is at risk?
Approximately 18 million Americans have diabetes, either type 1 or type 2, and about 5 million of these diabetics are unaware they have the condition, according to the American Diabetes Association (ADA). An estimated 186,300 young people under 20 years of age have diabetes. As obesity rates in children continue to soar, type 2 diabetes, a disease that used to be seen primarily in adults over age 45, is becoming more common in young people.
What's even more worrisome is that more than 24 million additional Americans have pre-diabetes, in which a person's blood-sugar levels are higher than normal, but not quite high enough to be classified as diabetic. Research has found that the majority of people with pre-diabetes develop type 2 diabetes within 10 years. More alarming, pre-diabetes, by itself, carries a 50 percent increased risk of cardiovascular disease. Yet, because it is often symptomless, most people who have it are blissfully unaware of the danger.
In addition to being overweight or obese, risk factors include:
- being physically inactive
- having a parent, brother, or sister with diabetes
- having a family background that is African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, or Pacific Islander
- giving birth to a baby weighing more than 9 pounds or being diagnosed with gestational diabetes
- having high blood pressure—140/90 mmHg or above—or being treated for high blood pressure
- having an HDL, or "good," cholesterol level below 35 mg/dL or a triglyceride level above 250 mg/dL
- having polycystic ovary syndrome, also called PCOS
- having IFG or IGT on previous testing
- having a condition called acanthosis nigricans, characterized by a dark, velvety rash around the neck or armpits
- having a history of cardiovascular disease—disease affecting the heart and blood vessels
Symptoms of type 2 diabetes
More than 6 million people in the United States have type 2 diabetes and do not know it. Many have no signs or symptoms. Symptoms can also be so mild that you might not even notice them. Some people have symptoms but do not suspect diabetes. Symptoms include:
- increased thirst
- increased hunger
- increased urination, especially at night
- weight loss
- blurred vision
- sores that do not heal
Many people do not find out they have the disease until they have diabetes complications, such as blurry vision or heart trouble. If you find out early that you have diabetes, then you can get treatment to prevent damage to the body.
Anyone 45 years old or older should consider getting tested for diabetes. If you are 45 or older and overweight getting tested is strongly recommended. If you are younger than 45, overweight, and have one or more risk factors, you should consider getting tested. Ask your doctor for a fasting blood glucose test or an oral glucose tolerance test. Your doctor will tell you if you have normal blood glucose, pre-diabetes, or diabetes.
The following tests are used for diagnosis:
- A fasting plasma glucose (FPG) test measures blood glucose in a person who has not eaten anything for at least 8 hours. This test is used to detect diabetes and pre-diabetes.
- An oral glucose tolerance test (OGTT) measures blood glucose after a person fasts at least 8 hours and 2 hours after the person drinks a glucose-containing beverage. This test can be used to diagnose diabetes and pre-diabetes.
- A random plasma glucose test, also called a casual plasma glucose test, measures blood glucose without regard to when the person being tested last ate. This test, along with an assessment of symptoms, is used to diagnose diabetes but not pre-diabetes.
Test results indicating that a person has diabetes should be confirmed with a second test on a different day.
The FPG test is the preferred test for diagnosing diabetes because of its convenience and low cost. However, it will miss some diabetes or pre-diabetes that can be found with the OGTT. The FPG test is most reliable when done in the morning. People with a fasting glucose level of 100 to 125 milligrams per deciliter (mg/dL) have a form of pre-diabetes called impaired fasting glucose (IFG). Having IFG means a person has an increased risk of developing type 2 diabetes but does not have it yet. A level of 126 mg/dL or above, confirmed by repeating the test on another day, means a person has diabetes.
Research has shown that the OGTT is more sensitive than the FPG test for diagnosing pre-diabetes, but it is less convenient to administer. The OGTT requires fasting for at least 8 hours before the test. The plasma glucose level is measured immediately before and 2 hours after a person drinks a liquid containing 75 grams of glucose dissolved in water. If the blood glucose level is between 140 and 199 mg/dL 2 hours after drinking the liquid, the person has a form of pre-diabetes called impaired glucose tolerance (IGT). Having IGT, like having IFG, means a person has an increased risk of developing type 2 diabetes but does not have it yet. A 2-hour glucose level of 200 mg/dL or above, confirmed by repeating the test on another day, means a person has diabetes.
Gestational diabetes is also diagnosed based on plasma glucose values measured during the OGTT, preferably by using 100 grams of glucose in liquid for the test. Blood glucose levels are checked four times during the test. If blood glucose levels are above normal at least twice during the test, the woman has gestational diabetes.
Random Plasma Glucose Test
A random, or casual, blood glucose level of 200 mg/dL or higher, plus the presence of the following symptoms, can mean a person has diabetes:
- increased urination
- increased thirst
- unexplained weight loss
If results of testing are normal, testing should be repeated at least every 3 years. Doctors may recommend more frequent testing depending on initial results and risk status. People whose test results indicate they have pre-diabetes should have their blood glucose checked again in 1 to 2 years and take steps to prevent type 2 diabetes.
When a woman is pregnant, the doctor will assess her risk for developing gestational diabetes at her first prenatal visit and order testing as needed during the pregnancy. Women who develop gestational diabetes should also have follow-up testing 6 to 12 weeks after the baby is born.
Since type 2 diabetes has become more common in children and teens than in the past, those at high risk for developing diabetes should be tested every 2 years. Testing should begin at age 10 or at puberty, whichever occurs first.
Body Mass Index (BMI)
BMI is a measurement of body weight relative to height that can help you determine if your weight places you at risk for diabetes. To note: The BMI has certain limitations. It may overestimate body fat in athletes and others who have a muscular build and underestimate body fat in older adults and others who have lost muscle.
BMI for children and teens must be determined based on age, height, weight, and sex. The Centers for Disease Control and Prevention (CDC) has information about BMI in children and teens, including a BMI calculator, at www.cdc.gov/nccdphp/dnpa/bmi. The CDC website also has a BMI calculator for adults.
Over time, high levels of blood glucose, also called blood sugar, can cause health problems. These problems include heart disease, heart attacks, strokes, kidney disease, nerve damage, digestive problems, eye disease, and tooth and gum problems. You can help prevent health problems by keeping your blood glucose levels on target.
Everyone with diabetes needs to choose foods wisely and be physically active. If you can't reach your target blood glucose levels with wise food choices and physical activity, you may need medication. The kind of medicine you take depends on your type of diabetes, your schedule, and your other health conditions.
Diabetes medicines help keep your blood glucose in your target range. The target range is suggested by diabetes experts and your doctor or diabetes educator.
Treatment for type 1 diabetes includes taking insulin shots or using an insulin pump, making wise food choices, exercising regularly, controlling blood pressure and cholesterol, and taking aspirin daily—for some.
Treatment includes taking diabetes medicines, making wise food choices, exercising regularly, controlling blood pressure and cholesterol, and taking aspirin daily—for some.
Recommended targets for blood glucose levels
Blood glucose levels go up and down throughout the day and night in people with diabetes. High blood glucose levels over time can result in heart disease and other health problems. Low blood glucose levels can make you feel shaky or pass out. But you can learn how to make sure your blood glucose levels stay on target—not too high and not too low.
The National Diabetes Education Program uses blood glucose targets set by the American Diabetes Association (ADA) for most people with diabetes. To learn your daily blood glucose numbers, you'll check your blood glucose levels on your own using a blood glucose meter. Target blood glucose levels for most people with diabetes: Before meals 70 to 130 mg/dL; one to two hours after the start of a meal less than 180 mg/dL.
Also, you should ask your doctor for a blood test called the A1C at least twice a year. The A1C will give you your average blood glucose for the past 3 months and should be less than 7 percent. Ask your doctor what's right for you.
The results of your A1C test and your daily blood glucose checks can help you and your doctor make decisions about your diabetes medicines, food choices, and physical activity.
Types of diabetes medicines
Diabetes medicines come in several forms.
If your body no longer makes enough insulin, you'll need to take it. Insulin is used for all types of diabetes. It helps keep blood glucose levels on target by moving glucose from the blood into your body's cells. Your cells then use glucose for energy. In people who don't have diabetes, the body makes the right amount of insulin on its own. But when you have diabetes, you and your doctor must decide how much insulin you need throughout the day and night and which way of taking it is best for you.
- Injections. This involves giving yourself shots using a needle and syringe. The syringe is a hollow tube with a plunger which you fill with your dose of insulin. Some people use an insulin pen, which has a needle for its point.
- Insulin pump. An insulin pump is a small machine about the size of a cell phone, worn outside of your body on a belt or in a pocket or pouch. The pump connects to a small plastic tube and a very small needle. The needle is inserted under the skin where it stays in for several days. Insulin is pumped from the machine through the tube into your body.
- Insulin jet injector. The jet injector, which looks like a large pen, sends a fine spray of insulin through the skin with high-pressure air instead of a needle.
Some people with diabetes who use insulin need to take it two, three, or four times a day to reach their blood glucose targets. Others can take a single shot. Each type of insulin works at a different speed. For example, rapid-acting insulin starts to work right after you take it. Long-acting insulin works for many hours. Most people need two or more types of insulin to reach their blood glucose targets.
Possible side effects include: low blood glucose and weight gain.
Along with meal planning and physical activity, diabetes pills help people with type 2 diabetes or gestational diabetes keep their blood glucose levels on target. Several kinds of pills are available. Each works in a different way. Many people take two or three kinds of pills. Some people take combination pills that contain two kinds of diabetes medicine in one tablet. Some people take pills and insulin.
If your doctor suggests that you take insulin or another injected medicine, it doesn't mean your diabetes is getting worse. Instead, it means you need insulin or another type of medicine to reach your blood glucose targets. Everyone is different. What works best for you depends on your usual daily routine, eating habits, and activities, and your other health conditions.
Injections other than insulin
In addition to insulin, two other types of injected medicines are now available. Both work with insulin—either the body's own or injected—to help keep your blood glucose from going too high after you eat. Neither is a substitute for insulin.
How to reduce your risk
You can do a lot to lower your chances of getting diabetes. Exercising regularly, reducing fat and calorie intake, and reaching and maintaining a healthy weight can help you reduce your risk of developing type 2 diabetes. Lowering blood pressure and cholesterol levels also helps you stay healthy.
What you eat has a big impact on your health. By making wise food choices, you can help control your body weight, blood pressure, and cholesterol.
- Take a look at the serving sizes of the foods you eat. Reduce serving sizes of main courses such as meat, desserts, and foods high in fat. Increase the amount of fruits and vegetables.
- Limit your fat intake to about 25 percent of your total calories. For example, if your food choices add up to about 2,000 calories a day, try to eat no more than 56 grams of fat. Your doctor or a dietitian can help you figure out how much fat to have. You can also check food labels for fat content.
- Limit your sodium intake to less than 2,300 mg—about 1 teaspoon of salt—each day.
- Talk with your doctor about whether you may drink alcoholic beverages. If you choose to drink alcoholic beverages, limit your intake to one drink—for women—or two drinks—for men—per day.
- You may also wish to reduce the number of calories you have each day. Your doctor or dietitian can help you with a meal plan that emphasizes weight loss.
- Keep a food and exercise log. Write down what you eat, how much you exercise—anything that helps keep you on track.
- When you meet your goal, reward yourself with a nonfood item or activity, like watching a movie.
Research has demonstrated that people at risk for type 2 diabetes can prevent or delay developing type 2 diabetes by losing a little weight. The results of the Diabetes Prevention Program (DPP) showed that moderate diet changes and physical activity can delay and prevent type 2 diabetes. Participants in this federally funded study of 3,234 people at high risk for diabetes experienced a 5- to 7-percent weight loss.
Study participants were overweight and had higher than normal levels of blood glucose—pre-diabetes, also called impaired glucose tolerance. Both pre-diabetes and obesity are strong risk factors for type 2 diabetes. Because of the high risk for diabetes among some minority groups, about half of the DPP participants were African American, American Indian, Asian American, Pacific Islander, or Hispanic/Latino.
DPP participants also included others at high risk for developing type 2 diabetes, such as women with a history of gestational diabetes and individuals aged 60 and older.
The DPP tested two approaches to preventing diabetes: lifestyle change—a program of healthy eating and exercise—and the diabetes drug metformin. People in the lifestyle change group exercised about 30 minutes a day 5 days a week, usually by walking, and lowered their intake of fat and calories. Those who took the diabetes drug metformin received information on exercise and diet. A third group only received information on exercise and diet.
The results showed that people in the lifestyle change group reduced their risk of getting type 2 diabetes by 58 percent. In the first year of the study, people lost an average of 15 pounds. Lifestyle change was even more effective in those aged 60 and older. They reduced their risk by 71 percent. People receiving metformin reduced their risk by 31 percent.
Prevention: 8 simple steps
The good news is that there is a lot you can do now to lower your risk of developing both pre-diabetes and type 2 diabetes. The latest research suggests that more than half of new cases of diabetes could be prevented through lifestyle changes. Here are six steps that can greatly reduce your odds.
1. Lose excess weight. Extra body fat prevents insulin from working properly in the body, thereby laying the groundwork for type 2 diabetes— sometimes as early as childhood. In fact, being overweight or obese is the biggest risk factor for type 2 diabetes. Abdominal obesity seems to be worse than the pear-shaped pattern. The fat that's contained within the abdominal cavity gets broken down into fatty acids, is released more easily into the bloodstream and interferes with the way insulin works. For most overweight and obese people, losing as little as 7 percent of their current body weight would substantially lower their risk of developing diabetes.
2. Swap carbohydrates. It's smart to cut back on your overall intake of refined carbs such as cookies, cake and the like because they raise blood sugar, which can make you eat more. Increase the amount of fiber-rich whole grains, fruits, nuts, legumes and vegetables. A recent study at the University of Helsinki in Finland found that a reasonably high intake of dietary fiber —the median intake for women in the study was 17 grams a day and included both the soluble and insoluble kinds—seems to increase the body's ability to respond to and use insulin, and may help prevent type 2 diabetes. Aim to get 25 grams daily from a variety of foods.
3. Cut back on fat. Particularly harmful fats include saturated fat, cholesterol and trans fatty acids; research has found that all of these can increase insulin resistance, in which the body doesn't use insulin efficiently. Polyunsaturated or monounsaturated fats —found in seafood and vegetable oils, respectively —are associated with a lower risk of developing diabetes. Even if you trade bad fats for good ones, keep an eye on your overall intake. In a study at the University of Auckland in New Zealand, researchers found that when people who had blood-sugar abnormalities reduced their total fat intake by 34 grams per day, their ability to metabolize carbohydrates (what's called glucose tolerance) improved, and a lower percentage developed type 2 diabetes a year later than those who didn't slash fat. Total fat intake should not exceed 25-30 percent of your daily calories.
4. Exercise regularly. Data suggest that even 30-40 minutes of brisk walking, five times a week, can decrease your risk by up to 40 percent. Why? When you exercise, your muscles take sugar out of the bloodstream and use it, which causes blood-sugar levels to decline. Add weight loss to the equation and your risk drops even further: Research at the National Institute of Diabetes and Digestive and Kidney Diseases found that when overweight people lost 7-10 percent of their body weight and began taking half-hour walks five days a week, they cut their odds of developing diabetes by 58 percent. And it's likely that the lower your blood-sugar levels, the lower your risk for heart disease.
5. Watch your alcohol intake. Among healthy women, moderate drinking (defined as about a glass and a half of wine per day) may reduce the risk of developing type 2 diabetes, according to a recent study at Karolinska Institute in Stockholm, Sweden. More than that, however, appears to increase the risk in lean women, though not in those who are overweight. Because the research has been mixed as far as alcohol goes, it's important not to overindulge. If you do drink, have food with your alcohol. Abstain if you're starting medication for diabetes or pre-diabetes, or if you have a strong family history of diabetes.
6. Have your blood-sugar level tested. Fasting blood sugar (a measure of your blood-sugar level after you haven't eaten for eight to 12 hours) is considered normal if below 100 milligrams per deciliter, but a person with pre-diabetes has a fasting blood-sugar level between 100 and 125 mg/dl, and someone with full-fledged diabetes has blood sugar measuring 126 mg/dl or above. If you do have a pre-diabetic condition, know that it can be reversed. Once you get diabetes, however, reversing it is a lot harder.
7. Be physically active every day. Regular exercise tackles several risk factors at once. It helps you lose weight, keeps your cholesterol and blood pressure under control, and helps your body use insulin. If you are not very active, you should start slowly. Talk with your doctor first about what kinds of exercise would be safe for you. Make a plan to increase your activity level toward the goal of being active at least 30 minutes a day most days of the week.
Choose activities you enjoy. Some ways to work extra activity into your daily routine include the following:
- Take the stairs rather than an elevator or escalator.
- Park at the far end of the parking lot and walk.
- Get off the bus a few stops early and walk the rest of the way.
- Walk or bicycle whenever you can.
8. Take your prescribed medications. Some people need medication to help control their blood pressure or cholesterol levels. If you do, take your medicines as directed. Ask your doctor about medicines to prevent type 2 diabetes.
Adapted from the National Institute of Diabetes and Digestive and Kidney Diseases (www.niddk.nih.gov)