Diabetes Prevention (Type 2 Diabetes)

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Type 2 Diabetes Warning Signs

Type 2 diabetes prevention tips and facts

  • While genetics plays an important role in the development of diabetes, an individual still has the ability to influence their health to prevent type 2 diabetes.
  • There is no known way to prevent type 1 diabetes. This article focuses on ways to control risk factors for type 2 diabetes.
  • Obesity and a sedentary lifestyle are the biggest diabetes risk factors that are controllable.
  • People should watch their weight and exercise on a regular basis to help reverse prediabetes, and prevent the development of type 2 diabetes.
  • Diet is important because it helps with weight loss. Some foods such as nuts in small amounts provide health benefits in blood sugar regulation.
  • There is no single recommended diabetes prevention diet, but following a sound nutrition plan and maintaining a healthy weight are important steps in preventing the disease.
  • Exercise is beneficial even without weight loss in the prevention of type 2 diabetes.
  • Exercise is even more beneficial with weight loss in the prevention of type 2 diabetes.
  • Smoking is harmful in many ways including increasing the risk of cancer and heart disease. It also increases the risk of developing type 2 diabetes.
  • There are medications available that have been shown in large trials to delay or prevent the onset of overt diabetes. Metformin (Glucophage) is recommended by the American Diabetes Association for prevention of diabetes in high-risk people.
  • The coming years will be very exciting regarding the advances in the field of prevention of diabetes. However, the cornerstone of therapy will likely remain a healthy lifestyle.

What is type 2 diabetes?

There are two major forms of diabetes - type 1 and type 2. This article focuses specifically on the prevention of type 2 diabetes since there is no know way to prevent type 1 diabetes. This form of diabetes is virtually a pandemic in the United States. This information reviews the risk factors for developing type 2 diabetes and reviews key points regarding prediction of those at risk for type 2 diabetes. It also is a review of what they can do about it.

While diabetes is characterized by high blood sugar values, type 2 diabetes is also associated with a condition known as insulin resistance. Even though there is an element of impaired insulin secretion from the beta cells of the pancreas, especially when toxic levels of glucose occur (when blood sugars are constantly very high), the major defect in type 2 diabetes is the body's inability to respond properly to insulin.

Eventually, even though the pancreas is working at its best to produce more and more insulin, the body tissues (for example, muscle and fat cells) do not respond and become insensitive to the insulin. At this point, overt diabetes occurs as the body is no longer able to effectively use its insulin to maintain normal blood sugar levels. Over time, these high levels of sugar result in the complications we see all too often in patients with diabetes.

Quick GuideBlood Sugar Swings: Tips for Managing Diabetes & Glucose Levels

Blood Sugar Swings: Tips for Managing Diabetes & Glucose Levels

Pre-Diabetes? Could You Have It?

About 41 million Americans between the ages of 40 and 74 have "pre-diabetes." Prediabetes is a condition that, as the name implies, can be considered an early, potentially reversible, stage in the development of Type II diabetes. Pre-diabetes is sometimes called impaired glucose tolerance or Impaired Fasting Glucose (IGT/IFG). In pre-diabetes, a person's blood sugar(glucose) levels are slightly higher than the normal range, but not high enough for a true diagnosis of diabetes. People with pre-diabetes have a significant risk of developing full-blown diabetes.

What are symptoms of prediabetes?

In general, prediabetes is not associated with any specific symptoms. However, there may be indicators of problems in blood sugar metabolism that can be seen years before the development of overt diabetes. Health-care professionals in the field of endocrinology are now routinely looking at these indicators in patients who are high risk for developing diabetes.

Irregular menses (menstruation) and premenstrual syndrome

There is an association between the lengthening of the menstrual cycle and the risk for developing diabetes, particularly in obese women. In a national study of nurses, those who had a cycle length of greater than 40 days were twice as likely to develop diabetes then those who cycled every 26 to 31 days. The association is thought to be related to polycystic ovary syndrome (PCOS), which also is known to be associated with insulin resistance. Insulin resistance may be a precursor for type 2 diabetes.

Impaired fasting glucose

By definition, diabetes is associated with a fasting blood sugar of greater than 126 mg/dl. There is another group that has been identified and referred to as having impaired fasting glucose or prediabetes. These people have a fasting blood sugar value of between 110-125mg/dl. The main concern with this group is that they have an increased potential to develop type 2 diabetes when compared to the normal population. The actual percent increase varies depending on ethnicity, weight, etc.; but it is significantly higher, regardless of absolute numbers. In addition, it is known that people with impaired fasting glucose also are at increased risk for heart disease and stroke.

Inflammatory markers

The role of inflammation is an area of extreme interest in regard to disease development. For example, we have begun to understand the importance of inflammation and heart disease. We now know that inflammation may play an important role in the development of diabetes as well. An inflammation marker known as C-reactive protein (CRP) has been shown to be increased in women at risk for developing the metabolic syndrome, and in both men and women at risk for developing type 2 diabetes. Recent studies have shown shifts in the blood levels of a number of markers for inflammation during the progression from no disease, to prediabetes, and then to full-blown diabetes. This research highlights the importance of inflammation as part of the mechanism of diabetes development.

Other risks for type 2 diabetes

Other risks for the development of diabetes include endothelial dysfunction (abnormal response of the inner lining of blood vessels) and retinal artery narrowing (narrowing of the tiny blood vessels in the back of the eye).

Is there a diet to prevent getting type 2 diabetes?

Diet becomes a critical issue when dealing with disease processes. When exploring dietary factors as a contributor to disease processes, one must take a number of things into account, for example, is it the specific food itself or the weight gain associated with its consumption that causes the risk? Is it the food, or the age/lifestyle of those consuming it that causes the risk? While cinnamon, coffee, and fenugreek seeds are among the many food products that some feel are associated with development/prevention of diabetes, none of these claims have truly been fully scientifically evaluated.

Rather than following a specific diabetes prevention diet, the greatest impact in prevention has occurred with weight reduction. Consequently, there is no single recommended diabetes prevention diet. The American Diabetes Association recommends goals of modest weight loss (5%-10% of body weight) and moderate exercise as primary interventions for preventing type 2 diabetes.

A "Western" diet vs. a "healthy" diet

In a study of over 42,000 men, diets high in red meat, processed meat, high fat dairy products, and sweets were associated with an increased risk of diabetes by almost two times that of those eating a "healthy" diet without high levels of these foods. Again, this is independent of weight gain and other factors mentioned previously.

Dairy foods

The data on dairy products seems to vary. In a study of over 289,000 health professionals, Harvard researchers showed that consumption of yogurt, in contrast to other dairy products, was associated with a reduced risk for diabetes. In a pooled analysis of 17 studies about dairy products and diabetes risk, those who consumed more dairy products had a lower risk than those who consumed few dairy products, A Swedish study found that high-fat dairy products, but not low-fat dairy products, lowered the risk for type 2 diabetes.

Sugar

Sugar consumption alone has not been associated with the development of type 2 diabetes. There is of course, weight gain associated with sugar consumption. However, after adjusting for weight gain and other variables, there appears to be a relationship between drinking sugar-laden beverages and the development of type 2 diabetes. Women who drink one or more of these drinks a day have almost twice the risk of developing diabetes than women who drink one a month or less.

Quick GuideBlood Sugar Swings: Tips for Managing Diabetes & Glucose Levels

Blood Sugar Swings: Tips for Managing Diabetes & Glucose Levels

What are the risk factors for developing diabetes?

The risk factors for developing diabetes actually vary depending on where a person lives. This is in part due to the environment the person lives in, and in part due to the genetic makeup of the family. In the United States, it is estimated that one in three males and two out of every five females born in the year 2000 will develop diabetes (the lifetime risk). It has also been calculated that for those diagnosed with diabetes before the age of 40, the average life expectancy is reduced by 12 years for men, and 19 years for women.

The risk for developing diabetes increases in certain cases such as the following.

  • Genetics: People with a close relative with type 2 diabetes are at higher risk.
  • Ethnic background: For example, the actual prevalence of diabetes in the Caucasian population of the US is about 7.1% while in the African American population; it increases to about 12.6%. Approximately 8.4% of Asian Americans and 11.6% of Hispanic Americans are affected. In a well-studied group of Native Americans, the Pima Indians, the prevalence increases to almost 35%.
  • Birth weight: There is a relationship between birth weight and developing diabetes, and it's the opposite of what one might intuitively think. The lower the birth weight, the higher the risk of type 2 diabetes. At the other end of the spectrum, a very high birth weight (over 8.8 pounds or 4 kg) also is associated with an increased risk. Additionally, mothers of infants who had a higher birth weight (over 9 pounds) are at increased risk for developing diabetes.
  • Metabolic syndrome: People who have the metabolic syndrome are at especially high risk for developing diabetes.
  • Obesity: Obesity is probably the most impressive risk factor and in most situations the most controllable. This is in part due to the fact that obesity increases the body's resistance to insulin. Studies have shown that reversal of obesity through weight reduction improves insulin sensitivity and regulation of blood sugar. However, the distribution of fat is important. The classic "pear" shaped person (smaller waist than hips) has a lower risk of developing diabetes than the "apple" shaped person (larger around the waist). The exact reason for this difference is unknown, but it is thought to have something to do with the metabolic activity of the fat tissue in different areas of the body.
  • Gestational diabetes: Women who have gestational diabetes during pregnancy have a greater risk for developing type 2 diabetes later in life.

Is gestational diabetes a risk for developing type 2 diabetes later in life?

The simple answer is yes. The risk for type 2 diabetes is higher in women who have had gestational diabetes (diabetes of pregnancy). In general, type 2 diabetes will occur in about 40% of women with gestational diabetes over the following 10 years. This number increases to the 50% range in obese women.

There are efforts underway to see if treating women with gestational diabetes (using lifestyle, and medications such as thiazolidinediones) can change the course of development of type 2 diabetes. The results appear promising, and further work is being done to identify who will potentially respond to treatment.

How can type 2 diabetes be prevented?

One of the most important factors in the development of diabetes is genetics (over which we have no control). However, there are things in our environment and lifestyle we can control to lower our personal risk of developing diabetes, including exercise and weight loss.

Exercise

When adjusted for family history, the benefits of exercise can be evaluated based on previous studies. Of note, for every 500 kcal burned weekly through exercise, there is a 6% decrease in relative risk for the development of diabetes. This data is from a study done in men who were followed over a period of 10 years. The study also notes a greater benefit in men who were heavier at baseline. There have been similar reports on the effects of exercise in women.

Exercise is thought to be a major determinant of insulin sensitivity in muscle tissue. By increasing exercise, the body uses insulin more efficiently, for up to 70 hours after the exercise period has occurred. Thus exercising three to four times per week would be beneficial in most people.

The same benefits are seen when looking specifically at people with impaired prediabetes (glucose tolerance/impaired fasting glucose). When diet and exercise are used as tools in this population over a six year study and compared to a control group, glucose tolerance improves by about 76% compared to deterioration in 67% of the control group. The exercise group also had a lesser rate of progression to type 2 diabetes.

It should be noted that a lot of the benefit of exercise occurs independent of weight loss. However, when combined with weight loss, the benefits increase substantially.

Weight Loss

In people at risk for diabetes, weight loss can improve insulin sensitivity as well as delay, and even prevent progression to type 2 diabetes. In patients with overt diabetes, weight loss can play a tremendous role in improving blood sugar control.

Two large studies - one in Finland and the other one U.S. (the Diabetes Prevention Program- DPP) have shown the benefit of weight loss in diabetes prevention. In the Finnish study, more than 500 men and women with impaired glucose tolerance were assigned to a control group or an exercise/weight loss group. By the end of the study, the weight loss group had lost about 8 pounds, and the control group about 2 pounds. The weight loss group had significantly less participants develop diabetes than the control group.

The DPP study showed a similar result. In this study, there was also a group taking metformin (Glucophage) as a preventative measure. At the end of the study, the lifestyle group actually did better at prevention of diabetes than those taking metformin. In fact, the study was stopped early, because the benefit of weight loss (the weight loss group lost about 15 pounds on average and kept it off) was so dramatic.

Smoking

Smoking 16 to 20 cigarettes a day or more can increase a person's risk of developing diabetes to more than three times that of nonsmokers. The exact reason for this isn't well understood. It may be that smoking directly decreases the body's ability to utilize insulin. Moreover, it has been observed that after smoking, blood sugar levels increase. Finally, there is also an association between smoking and body fat distribution, smoking tends to encourage the "apple" shape, which is a risk factor for diabetes.

Nuts

In as study of over 83,000 women consuming nuts (and peanut butter) seemed to show some protective effect against the development of diabetes. Women who have more than five one-ounce servings of nuts a week lowered their risk of developing diabetes compared to women who consumed no nuts at all.

Quick GuideBlood Sugar Swings: Tips for Managing Diabetes & Glucose Levels

Blood Sugar Swings: Tips for Managing Diabetes & Glucose Levels

Are there medications that can help to prevent type 2 diabetes?

  • As described previously, metformin (Glucophage) has been shown in the DPP trial to prevent the development of diabetes in those with impaired glucose tolerance. While not quite as effective as intensive lifestyle change, metformin decreased the rate of progression from 29% in the placebo group to 22%.
  • The American Diabetes Association has recommended metformin for the prevention of diabetes in very high-risk individuals.
    • High-risk individuals are those under 60 years of age or who are obese, or women with a history of gestational diabetes who have impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or hemoglobin A1C levels of 5.7% to 6.4%, in whom lifestyle interventions fail to improve control of glucose levels.
  • Acarbose (Precose), a drug designed to reduce small intestinal absorption of carbohydrates has been used with some success as well and is licensed for diabetes prevention in some countries. The STOP NIDDM trial showed that in about 1400 patients with impaired glucose tolerance, acarbose significantly reduced progression to diabetes compared to placebo. However, the occurrence of gastrointestinal side effects have limited the use of this drug for some people.

REFERENCES:

American Diabetes Association, Diabetes Care. Effects of Diet and Exercise in Preventing NIDDM in People With Impaired Glucose Tolerance: The Da Qing IGT and Diabetes Study.

American Diabetes Association, Diabetes Care. The Finnish Diabetes Prevention Study (DPS).

American Diabetes Association, Diabetes Care. The Diabetes Prevention Program (DPP): description of lifestyle intervention.

CDC.gov. Diabetes Facts.

FDA Prescribing Information for Avandia.

Harvard School of Public Health. Study Links Western Dietary Pattern with a Greater Risk for Type 2 Diabetes in Men.

Harvard School of Public Health. Simple Steps to Preventing Diabetes.

Medscape. Metformin underused in patients with prediabetes. May 01, 2015
<http://www.medscape.com/viewarticle/844072>

Medscape. Inflammatory marker profile shifts as type 2 diabetes develops. May 01, 2015.
<http://www.medscape.com/viewarticle/844081>

Last Editorial Review: 8/29/2016

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Reviewed on 8/29/2016
References
REFERENCES:

American Diabetes Association, Diabetes Care. Effects of Diet and Exercise in Preventing NIDDM in People With Impaired Glucose Tolerance: The Da Qing IGT and Diabetes Study.

American Diabetes Association, Diabetes Care. The Finnish Diabetes Prevention Study (DPS).

American Diabetes Association, Diabetes Care. The Diabetes Prevention Program (DPP): description of lifestyle intervention.

CDC.gov. Diabetes Facts.

FDA Prescribing Information for Avandia.

Harvard School of Public Health. Study Links Western Dietary Pattern with a Greater Risk for Type 2 Diabetes in Men.

Harvard School of Public Health. Simple Steps to Preventing Diabetes.

Medscape. Metformin underused in patients with prediabetes. May 01, 2015
<http://www.medscape.com/viewarticle/844072>

Medscape. Inflammatory marker profile shifts as type 2 diabetes develops. May 01, 2015.
<http://www.medscape.com/viewarticle/844081>

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