Diabetes is a complex condition with several types and no clear cause. If there is a history of a type of diabetes in a person’s family, they may have a higher risk of developing the same condition.
Genetic factors can make some people more vulnerable to some types of diabetes. However, a person may not inherit the condition, and there may be ways to reduce the risk. Knowing how type 2 diabetes affects family members, for example, can encourage a person to take steps to prevent it.
Also, an awareness of family history may help with getting an early diagnosis. This, in turn, may help a person prevent some complications.
The role of genetic factors varies among types of diabetes. In type 2, for example, lifestyle factors appear to be more influential than genetics.
Knowing how genes, lifestyle, and the environment affect diabetes can encourage a person to minimize their risk of developing the condition and its complications.
Type 1 diabetes is an autoimmune disease. It occurs when the body’s immune system mistakenly attacks healthy cells. This type often appears during adolescence, but a person can develop it at any age.
In the past, doctors believed that type 1 diabetes was wholly genetic. However, not everyone with type 1 diabetes has a family history of it.
Genetics Home Reference suggests that some genetic features may make type 1 diabetes more likely to develop under certain circumstances.
In people with this type of diabetes, scientists have found changes in the genes that produce certain proteins. These proteins play a key role in the immune system.
These genetic features make a person susceptible to developing type 1 diabetes, and certain factors can trigger the condition. Once a person develops type 1 diabetes, they will have it for life.
According to the American Diabetes Association, possible risk factors include:
Cold weather: Type 1 diabetes is more likely to appear in winter than in summer. It is also more common in cooler climates.
Early diet: Being breastfed as a baby may lower the chance of developing type 1 diabetes later in life.
People with type 1 diabetes may have autoimmune antibodies in their blood for many years before showing symptoms.
The condition may develop over time, or something may have to activate the autoimmune antibodies before symptoms appear. After this triggering, symptoms tend to appear quickly, within days or weeks.
Type 2 diabetes It is the most common type, accounting for about 90–95 percent of all diabetes cases in the United States, according to the Centers for Disease Control and Prevention (CDC).
As with type 1 diabetes, people with type 2 often have a close family member with the condition.
However, while genetic factors may play a role, experts believe that lifestyle factors, including diet and exercise, have the most significant impact.
Apart from family history, other factors increase the risk of developing type 2 diabetes, including:
- an age of 45 years or older
- excess weight, a high body mass index (BMI), or obesity
- a sedentary lifestyle that involves limited physical activity
- high levels of fat and cholesterol in the blood
- high blood pressure
- polycystic ovary syndrome, which many know as PCOS
- a history of gestational diabetes, which occurs during pregnancy
- a history of cardiovascular disease
Certain groups of people also have a higher risk of developing type 2 diabetes. These include African-Americans, Alaska Natives, American Indians, Asian-Americans, Hispanic-Americans, Native Hawaiians, and Pacific Islanders.
A person’s race, ethnicity, or both may also affect the BMI at which the risk of type 2 diabetes begins, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
For white, Hispanic, and African Americans, the added risk begins with a BMI of 25. For Asian Americans, this involves a BMI of 23. For Pacific Islanders, the risk begins with a BMI of 26.
People with two or more risk factors have a higher chance of developing type 2 diabetes.
Gestational diabetes occurs during up to 14 percent of all pregnancies in the U.S. There are not usually any symptoms, but it can increase the risk of delivery complications and other problems.
Gestational diabetes usually passes after delivery, but type 2 diabetes may then develop, sometimes soon after the pregnancy is over or several years later.
Doctors are unsure why it happens, and there is no clear inheritance pattern. However, a woman with gestational diabetes often has a family member with diabetes, usually type 2.
Diabetes insipidus is a completely different condition from type 1 or type 2 diabetes. These are both types of diabetes mellitus, and they affect either the production of the hormone insulin in the pancreas or the body’s ability to use that insulin.
Diabetes insipidus, however, does not affect insulin or the way that the body uses blood sugar. Instead, it results from a malfunction in the pituitary gland and affects the production of the hormone vasopressin. This changes the balance of water in the body.
There are two types of diabetes insipidus:
Nephrogenic diabetes insipidus, a genetic condition that develops after a parent has passed on a genetic mutation.
Neurohypophyseal diabetes insipidus, which is partly hereditary and genetic, but it can also stem from other factors, such as an injury or a tumor.
A person with diabetes insipidus can become dehydrated very easily. They will need to drink lots of water and urinate frequently. In someone with the condition, dehydration can lead to confusion, low blood pressure, seizures, and a coma.
Researchers have yet to discover all the genetic risk factors for diabetes, and it is not yet possible for everyone to have genetic testing to determine their risk.
However, people who know that they are more likely to develop the condition can often take steps to reduce their risk.
Genetic testing can predict type 1 diabetes and distinguish between types 1 and 2 in some people.
Researchers are still working on genetic tests that can predict type 1 and type 2 diabetes.
Anyone who is interested should ask their doctor about these tests.
Type 1 diabetes
It is not possible to prevent type 1 diabetes, but the following may help lower the risk:
- breastfeeding infants until the age of 6 months
- minimizing exposure to infections during childhood by receiving recommended vaccinations on time and practicing good hygiene, such as handwashing
Type 2 diabetes
Doctors believe that, in many cases, it is possible to prevent type 2 diabetes by making certain lifestyle changes.
The American Diabetes Association recommend starting routine screening from the age of 45.
However, people with risk factors beyond age, such as obesity, may need to start screening earlier. A doctor can advise about the best strategy for each person.
Sometimes screening shows that a person has prediabetes. This means that blood glucose is high, but not high enough for a diagnosis of type 2 diabetes. At this stage, it is often possible to prevent the onset of the condition by making changes to the diet and to activity levels.
Many of the lifestyle modifications that help manage the symptoms of diabetes can also:
- lower the risk of type 2 diabetes developing
- reduce the likelihood of type 1 or type 2 diabetes complications worsening
These strategies include:
Maintaining a healthy body weight: People with excess weight or obesity may be able to reduce their risk of diabetes by losing 5–7 percent of their starting weight.
Keeping physically active: For adults, current guidelines recommend getting at least 150 minutes of moderate-intensity aerobic exercise or 75 minutes of vigorous exercise each week.
Eating healthful, balanced meals: A diet that focuses on fresh fruits and vegetables, fiber, and whole grains can help with maintaining a healthy weight and preventing blood sugar spikes.
Click here to learn more about how to reduce the risk factors and manage different types of diabetes.
Anyone with a family history of any type of diabetes should be aware of the symptoms of high blood sugar, which include exhaustion and excessive thirst and urination.
If these appear suddenly, they can indicate type 1 diabetes. Symptoms of type 2 can take longer to show, and complications, such as cardiovascular disease, may already be present.
People with a family history of type 2 diabetes, or with risk factors such as obesity, should maintain a healthful diet and a healthy weight. They should also get plenty of exercise and speak to a doctor about screening.