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Diabetes Risk Factors & Prevention

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Aug 28, 2020.

Risk Factors

Risk factors are characteristics that can predispose you to developing a condition or disease. Just because you have one or more risk factors does not mean you will get diabetes. Risk factors for type 1 diabetes are not as clearly defined as for type 2 diabetes.

Type 1 diabetes risk factors include:

  • Family history of diabetes and genetics
  • Autoimmune disease, where the body mistakenly attacks the insulin-producing cells
  • Environmental factors
  • Geography: the incidence of type 1 diabetes tends to increase as you travel further away from the equator.

Type 2 diabetes risk factors include:

  • Age of 45 years or older
  • Weight Concerns: overweight (body mass index [BMI] ≥25 kg/m2) or obese (BMI ≥30 kg/m2).
  • Family history of diabetes, especially parent or sibling
  • A1C ≥5.7%, impaired glucose tolerance (IGT), impaired fasting glucose (IFG).
  • Diabetes during pregnancy (gestational diabetes)
  • High blood pressure or treatment; a history of vascular (vein) disease
  • History of polycystic ovary syndrome (PCOS)
  • Conditions linked with insulin resistance i.e., (acanthosis nigricans, severe obesity)
  • Lipid alterations: high blood levels of triglycerides (a type of fat molecule) >250 mg/dL; low HDL cholesterol <35 mg/dL, the “good” cholesterol.
  • Impaired glucose tolerance (IGT)
  • Sedentary, low physical activity
  • Native American, African American, Hispanic/Latino American, Asian American, or Pacific Islander heritage.

Type 1 diabetes is a result of an absolute deficiency of insulin due to autoimmune beta cell destruction in the pancreas, while type 2 diabetes results from an ongoing loss of insulin secretion coupled with insulin resistance. Insulin resistance is when the muscle, fat, and liver cells in a patient with type 2 diabetes does not respond to insulin in a normal fashion to effectively lower blood sugar.

How Can Diabetes Be Prevented?

  • Type 1 diabetes: There are no known methods to prevent type 1 diabetes.
  • Type 2 diabetes: Research studies have found that lifestyle changes can prevent or delay the onset of type 2 diabetes among high-risk adults; those identified with prediabetes.

Lifestyle interventions included diet and moderate-intensity physical activity (such as walking for at least 150 minutes each week). For both sexes and all age and racial and ethnic groups, the development of diabetes was reduced 40% to 60% during intensive blood glucose control studies that lasted 3 to 6 years.

Studies have also shown that medications such as metformin (brands include: Glumetza, Riomet, Riomet ER) have been successful in preventing diabetes in some population groups, although to a lesser degree than lifestyle intervention; the two should be used together.


The American Diabetes Association (ADA) recommends routine screening for type 2 diabetes beginning at age 45, especially if you're overweight. If the results are normal, repeat the test every three years. If the results are borderline or you have prediabetes, the test should be repeated at least yearly.

Screening is also recommended for people who are under 45 and overweight if there are other heart disease or diabetes risk factors present, such as a sedentary lifestyle, a family history of type 2 diabetes, a personal history of gestational diabetes or blood pressure above 140/90 millimeters of mercury (mm Hg).

Important Diabetes Prevention Studies

Several landmark studies in diabetes have been published. These studies proved the importance of intensive blood sugar control to prevent diabetes complications and prolong life.

Diabetes Control and Complications Trial (DCCT): Type 1 Diabetes

The landmark Diabetes Control and Complications Trial (DCCT) ran from 1983 to 1993 and set the standard for how diabetes is treated today. This important study showed that using intensive diabetes control with several shots of insulin (or a pump) and frequent glucose monitoring (at least 4 times per day) could reduce the occurrence of eye, kidney, and nerve disease compared to the lesser intense type 1 diabetes treatment at that time. The intensive group had an average A1C of 7%, while the conventional treatment group had an average A1C of 9%. However, a major side effect of intensive control was a 3-fold risk of hypoglycemia (low blood sugar). Weight gain was also a major side effect.

Participants in the intensive and early group had fewer diabetes-related health problems after 6.5 years, compared to people who used the conventional treatment. Health problems that were lowered include:

  • Diabetic eye disease was reduced by 76%
  • Diabetic kidney disease was reduced by 50%
  • Diabetic nerve disease was reduced by 60%

The Epidemiology of Diabetes Interventions and Complications (EDIC) study is an ongoing follow-up study to the DCCT trial. Over the last 20 years, EDIC has shown the long-term benefits of early, intensive blood glucose control to prevent diabetes complications, cardiovascular disease, and to prolong life.

Diabetes Prevention Study (DPS): Type 2 Diabetes

The Finnish Diabetes Prevention Study (DPS) conducted in Finland and published in 2003 in Diabetes Care involved 522 middle-aged, people who were overweight with impaired glucose tolerance (IGT). This was one of the first well-controlled and landmark studies to show that type 2 diabetes could be prevented with lifestyle changes. In the study, subjects were divided into two groups:

  • An intensive lifestyle intervention group who received individual counseling aiming to help them lose weight, reduce fat intake, and increase physical activity, at seven sessions in the first year and then every three months.
  • A control group who received general diet and exercise advice once a year.

After 1 and 3 years of follow-up, weight loss was 4.5 and 3.5 kg (9.9 and 7.7 lb) in the intervention group, and 1 and 0.9 kg (2.2 and 2 lb) in the control group, respectively. Measures of blood sugar and lipids improved more in the intervention group. After the subjects had been followed up for an average of 3.2 years, the incidence of diabetes was 58% lower in the intervention group than in the control group, a statistically significant effect.

A follow-up of this study published in Diabetologia showed that over the long-term, intervention in people at high risk of type 2 diabetes with ongoing lifestyle changes, such as weight reduction, dietary modification and increased physical activity can help to prevent progression to type 2 diabetes.

Diabetes Prevention Program (DPP): Type 2 Diabetes

The U.S. Diabetes Prevention Program (DPP), sponsored by The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) produced similar findings. This study involved 3,234 overweight people with impaired glucose tolerance (IGT) at increased risk of diabetes, 45% of whom were from an ethnic minority group. The study subjects were divided into three groups, who received:

  • General lifestyle advice once a year, plus metformin (daily)
  • General lifestyle advice once a year, plus placebo (daily)
  • Intensive lifestyle advice (16 sessions over 24 weeks) aiming to achieve weight loss and increased physical activity

The subjects were followed up for an average of 2.8 years. Compared to the placebo group, the incidence of diabetes was 58% lower in the group that had received intensive lifestyle advice (similar to the Diabetes Prevention Study), and 31% lower in the group who had received metformin. Treatment with metformin was most effective among younger, heavier people (those 25-40 years of age who were 50 to 80 pounds overweight) and less effective among older people and people who were not as overweight.

The DPP Outcomes Study (DPPOS) has continued to follow most DPP participants since 2002. The DPPOS has shown that patients in the DPP Lifestyle Change Program or who were taking metformin continue to delay type 2 diabetes by 27% and 18%, respectively, for at least 15 years compared to patients taking a placebo. After 15 years, about 55% of patients in each treatment group had developed type 2 diabetes compared to 62% in the placebo group.

At 15 years, researchers found no overall differences in small blood vessel problems such as those found in eyes, nerves, and kidneys between participants from the DPP Lifestyle Change Program and participants who continued to take metformin or took a placebo. 

How to Manage Diabetes

If you have a diagnosis of diabetes, you should closely control your blood sugars to help prevent complications in the long run.

Early and tight blood glucose control is the most important factor and is now the standard in delaying the onset of complications such as cardiovascular disease, kidney disease, blindness, nerve disease and amputations in both type 1 and type 2 diabetes. Attention to your blood pressure and cholesterol with diet and exercise can also help to protect your heart. This can give you many years of an active, healthy life.

If you have prediabetes, it's very important to take action to lower the risk of onset of type 2 diabetes. Weight loss, quitting smoking, and daily exercise are the most powerful changes you can make.

Blood Glucose Levels

Patients with diabetes need to monitor their blood glucose levels. They also need to know average blood glucose levels over time (over the previous 2 to 3 months), known as the glycosylated hemoglobin, HbA1C (or A1C). The A1C is a measurement of long-term blood glucose control. For this test, you can eat beforehand, unlike the fasting blood glucose test.

The normal A1C range in people who do not have diabetes is 4% to 5.6%. Based on ADA guidelines, an A1C level between 5.7% and 6.4% is considered prediabetes, where blood sugar levels are not high enough yet to diagnose diabetes. An A1C level of 6.5% or higher during two separate A1C tests typically results in a type 2 diabetes diagnosis. The rate of diabetes complications, such as nerve or eye damage, can be reduced for a patient who maintains an A1C of 7% or less.

Maintaining control of your blood sugars means keeping your blood glucose as close to normal as possible. The numbers you should aim for will be determined by your diabetes care team, but in general those blood glucose numbers range between 70 and 130 mg/dL before meals, and less than 180 mg/dL two hours after starting a meal, with an A1C level less than 7%.

Your doctor will determine what your goal A1C should be and it may be different from others. Your A1C goal may be higher based on factors specific for you, especially if you are at a greater risk for low blood sugar, which can be dangerous. For example, the American College of Physicians (ACP) recommends patient with type 2 diabetes be treated to achieve a hemoglobin A1C between 7% to 8% rather than the widely accepted range of 6.5% to 7%. Your doctor may also decide to adjust your medication or doses if your blood sugar is well-controlled.

Other Important Factors for Diabetes Control and Prevention

Involve yourself in diabetes education to learn how to best manage your blood sugar. Your care team will consist of doctors, nurses, dieticians, pharmacists and special diabetes educators who can help you. They will educate you on what your blood sugars should be and when, how to check for them, what and when to eat in relation to your medications, and how much insulin to use, if you need insulin. If you opt for a continuous glucose monitoring device, they will show you how to use it.

There are other actions to help prevent type 2 diabetes and complications. If you have prediabetes, these actions may help you avoid a full type 2 diabetes diagnosis.

  • If you smoke, speak to your health care provider about a smoking cessation plan. Smoking increases your risk of stroke, heart disease, cancer and other complications.
  • Develop a daily exercise routine (at least 30 minutes) in conjunction with your doctor, especially if you have not exercised in a while. However, even walking, swimming, and dancing count, so you don’t have to join an expensive gym. If you can't fit in 30 minutes, spread 10-minute or longer sessions throughout the day. Try to do this most days of the week.
  • Lose weight. Even losing 5% to 10% of your body weight, for example, 10 to 20 lb (4.5 to 9 kgs) if you weigh 200 lb (91 kg).
  • Be compliant with your medications. If you take high blood pressure, cholesterol, or other treatments be sure you taken them as directed. Keep your doctor appointments and lab checks to help monitor your progress. If your blood sugar levels indicate prediabetes, see your doctor at least once per year for a check up.
  • Eat healthful, whole foods, like fresh vegetables, fruits, low-fat dairy products, and lean cuts of meat. Eat plenty of fiber by choosing whole grain breads and pasta (not the “white” versions), and stay hydrated by choosing clean, fresh water, not high sugar juices or sodas.
  • Avoid alcohol which can raise your blood sugar and blood pressure.
  • Focus on making permanent changes to your eating and exercise habits.
  • Metformin (Glumetza, Riomet, Riomet ER) is a first-line oral diabetes medication and may help lower the risk of developing type 2 diabetes — but healthy lifestyle choices are still important and will boost the effect of metformin.

Know Your ABCs for Diabetes Control

The "ABCs" of diabetes is an easy way to remember items you need to focus on for diabetes control, although these are by no means the only items. Remember this acronym: "A" stands for A1C level, "B" stands for blood pressure, and "C" stands for cholesterol.

Lifestyle changes can help you with your ABCs. Each person's goals are unique, but, in general:

  • A1C levels should stay below 7%
  • Blood pressure should be below 120/80 to 140/90 in most cases; a blood pressure above 140/90 is considered hypertension (high blood pressure)
  • Cholesterol: the LDL or "bad" cholesterol level should be below 100.

More Information:

You can find an ADA Education Recognized Program at or by calling 1-800-DIABETES (800-342-2383).

See Also


  • Qaseem A, Wilt TJ, Kansagara D, et al. Hemoglobin A1c Targets for Glycemic Control With Pharmacologic Therapy for Nonpregnant Adults With Type 2 Diabetes Mellitus: A Guidance Statement Update From the American College of Physicians. Ann Intern Med. 2018;168(8):569-576. Accessed August 28, 2020 at doi:10.7326/M17-0939
  • American Diabetes Association (ADA). Standards of Medical Care in Diabetes - 2018. Diabetes Care 2018 Jan; 41(Supplement 1): S1-S2. Accessed August 28, 2020.
  • The Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 1993;329:977–986. Accessed August 28, 2020.
  • Epidemiology of Diabetes Interventions and Complications (EDIC) Research Group (authors). Epidemiology of Diabetes Interventions and Complications (EDIC): Design and implementation of a long-term follow-up of the Diabetes Control and Complications Trial cohort. Diabetes Care 1999;22:99–111. Accessed August 28, 2020,
  • Nathan D. and for the DCCT/EDIC Research Group. The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study at 30 Years: Overview. Diabetes Care. 2014 Jan; 37(1): 9–16. Accessed August 28, 2020.
  • Lindström J1, Peltonen M, Eriksson JG, et al. Improved lifestyle and decreased diabetes risk over 13 years: long-term follow-up of the randomised Finnish Diabetes Prevention Study (DPS). Diabetologia. 2013 Feb;56(2):284-93. Accessed August 28, 2020.
  • Lindström J, Louheranta A, Mannelin M, et al. The Finnish Diabetes Prevention Study (DPS). Diabetes Care 2003 Dec; 26(12): 3230-36. Accessed August 28, 2020.
  • The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diabetes Prevention Program (DPP). Accessed August 28, 2020.
  • The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Blood Glucose Control Studies for Type 1 Diabetes: DCCT and EDIC. Accessed August 28, 2020.
  • Up to Date. Patient education: The ABCs of diabetes (The Basics). Accessed August 28, 2020. 
  • The American Diabetes Association. Healthy ABCs. Accessed August 28, 2020 at
  • Up to Date. Patient education: Preventing type 2 diabetes (The Basics). Accessed August 28, 2020. 

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.