Diabetes & Heart Disease

What is diabetes?

Diabetes is a serious, lifelong condition in which the body can’t properly control the level of sugar in the blood. Insulin is a hormone that regulates sugar (glucose) levels in the blood. In people with diabetes, the body doesn’t make enough insulin or can’t use insulin as well as it should.

During digestion, carbohydrates from food are broken down into sugar, which is then absorbed into the bloodstream. In response to this absorption, the pancreas secretes insulin, allowing sugar to be absorbed from the blood into cells and tissues. Cells and tissues then use the sugar for energy. When you have diabetes, sugar builds up in your blood instead of being used for energy.

Diabetes increases your risk for early death, heart disease, heart attack, and stroke, as well as kidney, nerve, and eye damage.

What are the different types of diabetes?

There are three major types of diabetes:

  • Type 1 diabetes, also known as juvenile-onset or insulin-dependent diabetes mellitus (IDDM)
  • Type 2 diabetes, also known as adult-onset or non-insulin-dependent diabetes mellitus (NIDDM)
  • Gestational diabetes

What is type 1 diabetes?

Type 1 diabetes is usually diagnosed in children and young adults. Between 5% and 10% percent of people with diabetes have type 1 diabetes. Type 1 diabetes is an autoimmune disease – a disease in which the body’s natural defenses turn against itself. In type 1 diabetes, the immune system kills the cells in the pancreas that make insulin. Since the body cannot make enough insulin, cells can’t take up sugar in the blood. People with type 1 diabetes need daily injections of insulin for their entire life, and must follow a strict diet and monitor their blood sugar levels every day.

What is type 2 diabetes?

Type 2 diabetes is the most common form of diabetes. About 90% of people with diabetes have type 2 diabetes. This form of diabetes usually develops in adults older than 40 years of age, most commonly those aged 55 and older. About 80% of people with type 2 diabetes are overweight.

In type 2 diabetes, the pancreas usually produces enough insulin, but the body cannot use the insulin effectively – a condition called insulin resistance. Because insulin resistance runs in families, we know that genes are partially responsible, but other factors such as obesity and lack of exercise also contribute to the development of insulin resistance. Over time, the pancreas produces less and less insulin. The end result is the same as type 1 diabetes – an unhealthy buildup of sugar in the blood.

What is gestational diabetes?

Gestational diabetes is high blood sugar that develops during pregnancy in women who have never had diabetes before. It occurs in 2% to 9% of pregnancies and usually disappears once the baby is born. Gestational diabetes can be harmful to the baby, but it does not carry the same risks (e.g., early death, heart disease, stroke) to the mother as type 1 or type 2 diabetes. However, women who have gestational diabetes are at increased risk for developing type 2 diabetes later in life.

What is prediabetes?

Prediabetes is a condition in which you have more sugar in your blood than normal, but not enough to be considered diabetic. People who have prediabetes are more likely to develop diabetes in the future. In addition, some long-term damage to the body, especially to the heart and blood vessels, may occur during prediabetes. Prediabetes may be more dangerous for women than men.

If you have prediabetes, you can prevent it from progressing to type 2 diabetes by taking the proper steps to manage your blood sugar level.

How common is diabetes?

About 10 million American women have diabetes; 3 million of them are not even aware they have the disease. Another 6 million women have prediabetes.

Diabetes is nearly twice as common in African Americans and Mexican Americans as in whites, and women of these races are more likely to have diabetes than men of these races. In whites, men are slightly more likely to have diabetes than women. In women older than 20 years, almost 13% of African Americans and over 11% of Mexican Americans have physician-diagnosed diabetes, compared with about 5% of white women.

What are the signs and symptoms of diabetes?

Many people with type 2 diabetes have no signs or symptoms, or symptoms that are so mild they do not notice them. People with type 1 diabetes tend to have more severe symptoms that appear more suddenly. The following symptoms are a sign of diabetes:

  • Increased thirst or hunger
  • Increased urination (especially at night)
  • Nausea, vomiting, or stomach pain
  • Losing weight without trying
  • Feeling very tired
  • Very dry, itchy skin
  • Slow healing sores
  • More infections than usual (including vaginal yeast and bladder infections in women)
  • Tingling or numbness in the feet or hands
  • Blurred vision

Diabetes Testing

Who should be tested for diabetes?

Everyone 45 years or older should be tested for diabetes. People younger than 45 should be tested if they are overweight and have one or more risk factors for diabetes, particularly high blood pressure or high cholesterol. If your test results are normal, you should be tested again every 3 years. If you have prediabetes, you should be checked every 1 to 2 years after your diagnosis.

What is a fasting plasma glucose test?

A Fasting plasma glucose (FPG) test is the preferred test for diagnosing type 1 and type 2 diabetes. It is a simple blood test that measures blood sugar after you have fasted for at least 8 hours. Blood sugar is measured in milligrams (mg) per deciliter (dL) of blood. An FPG value of 126 mg/dL or greater means that you have diabetes. An FPG value of 110 mg/dL to 125 mg/dL means that you have prediabetes.

Fasting Plasma Glucose Level (mg/dL)
Normal blood glucose

less than 110




126 or higher

What is a nonfasting blood glucose test?

A Nonfasting (casual) blood glucose test, used to diagnose type 1 or 2 diabetes, is done regardless of when you had your last meal. You will be diagnosed with diabetes if the casual level of sugar in your blood is 200 mg/dL or more and you have symptoms of diabetes.

What is an oral glucose tolerance test?

An oral glucose tolerance test (OGTT) measures the amount of sugar in your blood 2 hours after you drink a glucose syrup. This test can tell how well your body processes the sugar. You will be asked to follow a diet, containing at least 150 grams of carbohydrates per day, for 3 days before this test. Then you will fast for 8 hours immediately before the test. A blood sample is taken at the end of the fast, then again 1 to 3 hours after you drink the glucose syrup. This test can diagnose diabetes, prediabetes, and gestational diabetes. Because it is cumbersome, this test is not routinely used except for diagnosing gestational diabetes.

100-Gram Oral Glucose Tolerance Test for Gestational Diabetes (mg/dL)*

95 or higher

1 hour after

180 or higher

2 hours after

155 or higher

3 hours after

140 or higher

*Gestational diabetes is diagnosed when measurements at 2 or more of the time points are too high.

Heart Risk of Diabetes

Does diabetes increase my risk of heart disease?

Both type 1 and type 2 diabetes increase your risk for heart disease. Women with diabetes are 2 to 5 times more likely to die of heart disease than women without diabetes. Heart disease is the leading cause of death in people with diabetes – 3 out of 4 people with diabetes die from heart disease or stroke. People with diabetes have the same risk of dying from heart disease as people without diabetes who have already had a heart attack. Women who have heart disease and have had diabetes for over 15 years are 30 times more likely to die early than women with neither condition. After a heart attack, people with diabetes are more likely to die than heart attack patients who don’t have diabetes.

Women with diabetes have 3- to 7-fold increased risk of developing heart disease than women without diabetes. In men diabetes increases the risk of heart disease 2- to 3-fold. The reason for this gender difference is not fully understood, but diabetes may have a greater effect on risk factors for heart disease in women than in men

How does diabetes affect the heart?

Diabetes increases your risk for heart disease because the excess sugar in your blood causes blood vessel problems, making you more likely to have high blood pressure and atherosclerosis (hardening of the arteries). In addition, diabetes can increase the risk of blood clots, which can cause heart attack or stroke.

Treatment & Prevention

What are the risk factors for diabetes?

Family history is the main risk factor for type 1 diabetes. Many risk factors for type 2 diabetes are also risk factors for heart disease. Risk factors for type 2 diabetes include:

  • Older age
  • Obesity
  • Carrying body fat around the belly (“apple-shaped”)
  • Family history of diabetes
  • Lack of exercise (fewer than 3 times a week)
  • Impaired glucose tolerance in an earlier diabetes test
  • Delivering a baby weighing more than 9 pounds or history of gestational diabetes
  • High blood pressure
  • Low HDL (good) cholesterol or high LDL (bad) cholesterol
  • Polycystic ovary syndrome
  • Certain ethnicities, including African American, Native American/Alaska Native, Asian American, Hispanic/Latino, and Native Hawaiian/Pacific Islander

How can I prevent type 1 diabetes?

There are no known ways to prevent type 1 diabetes. A nationwide study called the Diabetes Prevention Trial Type 1 (DPT-1) found that insulin injections or pills failed to prevent type 1 diabetes from developing. Studies are underway to find a way to prevent type 1 diabetes in people who have close relatives with the disease, and therefore a higher risk of developing it.

How can I prevent type 2 diabetes?

Weight and blood sugar control through diet and exercise are the best ways to prevent type 2 diabetes. If you have prediabetes, you are more likely to develop diabetes, but you can take steps to delay or prevent it. In the Diabetes Prevention Program, losing 7% of body weight and exercising for 150 minutes per week (30 minutes a day most days) more than halved the risk of diabetes in men and women of all races with prediabetes. For people over 60 years of age, these healthy habits lowered the risk of diabetes by 71%.

How is diabetes treated?

The main goal of treating diabetes is to prevent the problems that diabetes can cause, including heart disease. If you have diabetes, controlling your blood sugar level through diet and exercise (and medications or insulin shots if necessary) will reduce your chances of having complications of diabetes. Among adults with diabetes, 12% take both insulin and oral blood sugar-lowering medications, 19% take insulin only, 53% take oral medications only, and 15% take neither.

What are the ABC’s of diabetes management?

There are three major treatment goals to keep your diabetes under control: the ABCs of diabetes management. Following the ABCs of diabetes management lowers your risk of death due to diabetes and having complications of diabetes, especially heart disease. Ask your doctor what your numbers are, what your individual goals should be, and what you need to do to reach and maintain them.

  • A is for A1C test (short for hemoglobin A1C). This simple blood test measures your average blood sugar over the last 3 months, and you should have it done at least twice a year. Aim to have an A1C level less than 7%.
  • B is for blood pressure. You should aim for a blood pressure less than 130/80. Have your blood pressure checked at every doctor’s visit.
  • C is for cholesterol. Aim to have your LDL (bad) cholesterol less than 100 mg/dL. Have your cholesterol checked at least once a year.

Your healthcare provider can help you develop a plan for things you should do every day to take care of your diabetes, including following a healthy eating plan (eat your meals and snacks around the same time each day) and being physically active for a total of 30 minutes most days. If you have diabetes, you are at higher risk for many other diseases and problems. In addition to treating the diabetes itself, it’s important to reduce other risk factors you have and to keep an eye out for other conditions (such as vision or foot problems).

African Americans & Diabetes

Is diabetes common in African-American women?

Diabetes is particularly widespread in African-American women. One in four African-American women older than 55 years of age has diabetes, nearly twice the rate of white women. African Americans experience higher rates of complications and medical visits due to diabetes compared with white women.

Several factors contribute to the higher rate of diabetes in African-American women. Research suggests that many African Americans carry a gene that predisposes them toward impaired glucose tolerance, one of the risk factors for diabetes. African-American women are also more likely to be obese, another risk factor for diabetes. African-American women between the ages of 25 and 74 are more overweight compared to white women of the same age group. The location of body fat also plays a role. Women who have most of their body fat around the belly (“apple-shaped”) are at higher risk for diabetes than women who carry their weight on their hips and buttocks (“pear-shaped”). African-American women are more likely than white women to be apple-shaped. Another risk factor is lack of physical activity. In the government’s National Health Interview Survey, 73% of black women reported that they participated in no vigorous leisure time physical activity, compared with 60% of white women.

Is diabetes treated any differently in African Americans?

Treatment and prevention of diabetes are no different for African-American women than for women of other races beginning with diet and exercise. African-American women should find reasonable ways to exercise, including walking, jogging, community sports, or in-home exercise videos. These life changes are critical to avoid the potentially devastating side effects of this disease.

Low Blood Sugar

What is hypoglycemia?

Hypoglycemia (low blood sugar) occurs when glucose levels in the blood drop too low to fuel the body’s activity. It can occur as a side effect of diabetes medications, especially in people with type 1 diabetes. It can also happen because of other medications or diseases. In severe cases, hypoglycemia can cause loss of consciousness or a coma.

In people taking blood sugar-lowering medications, low blood sugar can be brought on by:

  • Skipping or delaying meals or snacks
  • Increased exercise
  • Excessive doses of insulin or diabetes medications
  • Excessive alcohol

Signs of low blood sugar include weakness, drowsiness, confusion, dizziness, headache, irritability, trembling, sweating, a fast heartbeat, and a cold, clammy feeling.

How can I prevent low blood sugar?

Low blood sugar can be prevented by measuring your blood glucose level regularly, sticking to your diet and exercise plans, and avoiding excess alcohol. Hypoglycemia is usually mild and can be relieved by eating or drinking something containing carbohydrates. People who have severe hypoglycemia may need an injection (glucagon) to raise their blood sugar.


Should all pregnant women be tested for diabetes?

Nearly all pregnant women should be tested for gestational diabetes during the 24th to 28th weeks of pregnancy. The only women who do not need to be tested are low-risk women who meet all of the following criteria:

  • Under 25 years of age
  • Normal body weight before pregnancy (body mass index [BMI] )
  • No family history of diabetes
  • Not a member of a high-risk ethnic group (such as African Americans)

Is it safe for women with diabetes to become pregnant?

In women with type 1 or type 2 diabetes who become pregnant, there is a higher risk of birth defects or death for the baby. The higher the mother’s blood glucose, the greater the risk of these complications. The good news is that proper care can greatly reduce the risk of problems for the baby, so if you have diabetes and are planning to become pregnant, it is extremely important to discuss it with your doctor. Taking part in a program to understand and control your diabetes before you become pregnant can reduce the risk of your baby having major birth defects. In one study, only 1% to 2% of infants born to women who participated in such a program had birth defects compared with as many as 11% of infants whose mothers did not participate.

What if a woman develops diabetes during pregnancy?

Gestational diabetes is when a woman who has never had diabetes develops high blood sugar during pregnancy. Hormones from the placenta (which supports the baby as it grows) can block the action of insulin in the mother’s body, forcing the mother to produce up to 3 times as much insulin as normal. When the body cannot produce this extra insulin, gestational diabetes occurs and causes a buildup of sugar in the blood just like regular diabetes. Gestational diabetes occurs in about 4% of pregnancies.

Gestational diabetes can cause certain problems for the baby. The high blood sugar in the mother crosses into the baby, and since the baby is getting more energy than it needs to grow, the extra sugar is stored as fat and can lead to big babies (macrosomia) who weigh more than 4000 g to 4500 g (nearly 10 pounds) at birth. Babies with macrosomia can have shoulder injuries during birth, are at risk for breathing problems, and have a higher risk of developing obesity and type 2 diabetes later in life than babies of normal birth weight.

How is gestational diabetes treated?

Treatment for gestational diabetes aims to keep the mother’s blood sugar at a normal level, and includes special meal and exercise plans and glucose testing. Some women may also need insulin injections to keep their blood sugar under control during pregnancy. For more information on treatment of gestational diabetes, including information on diet and physical activity, see the National Institute of Child Health & Human Development publication Managing Gestational Diabetes: A Patient’s Guide to a Healthy Pregnancy.


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