The risk factors for type 1 diabetes differ from those for type 2 and gestational diabetes.
Type 1 diabetes
Risk factors include:
- Family history. This increases the chances that a person will have islet-cell antibodies which, in turn, increase the risk of developing type 1 diabetes. Islet cells are clusters of cells in the pancreas that sense blood-glucose levels, and which produce insulin accordingly. Some people’s bodies produce antibodies that attack these cells.
- Race. Type 1 diabetes is more common among certain ethnicities. For example, in the United States, Caucasian people have a greater risk for type 1 diabetes than African-Americans and Hispanic Americans.
- Autoimmune disease. Type 1 diabetes can occur along with other autoimmune diseases like Grave’s disease (where the thyroid gland produces too much thyroid hormone) or vitiligo (a condition in which skin pigment is lost).
- Environmental factors. The rising incidence of type 1 diabetes over the past 30 years has been linked to changes in the environment and lifestyle that have only been partially identified.
Type 2 diabetes
Risk factors such as genetics and lifestyle choices influence one’s chances of developing type 2 diabetes. While factors such as family history, age and ethnicity cannot be changed, we do have control over lifestyle risk factors related to diet, physical activity and weight.
The following factors can affect your chances of developing type 2 diabetes:
- Being 45 or older
- A family history of diabetes
- Ethnicity. Type 2 diabetes is up to six times more likely to occur in people of South Asian descent and up to three times more likely in African and Africa-Caribbean people. In the USA, black and Hispanic people are more likely to have diabetes than non-Hispanic whites.
- High blood pressure
- High cholesterol
- A history of gestational diabetes or giving birth to a baby weighing 4kg or more
- Physically inactivity
- A history of heart disease or stroke
- Polycystic ovarian syndrome (PCOS)
- Acanthosis nigricans (dark, thick, velvety skin around the neck, armpits or other skin folds)
Gestational diabetes is an increasingly common complication of pregnancy and a large percentage of women who develop it are overweight or obese. Therefore, trying to control your weight before and during pregnancy may help to lower your risk.
Other risk factors for gestational diabetes include:
- Pre-diabetes (higher-than-normal blood glucose levels)
- A history of gestational diabetes
- High blood pressure (hypertension)
- A family history of type 2 diabetes
- Hormone disorders such as polycystic ovary syndrome (PCOS)
- Being older than 25 (the risk is even higher if you’re older than 35)
- Ethnicity. The prevalence of gestational diabetes appears to be particularly high among women from South Asia and South East Asia compared to those who are Caucasian, African-American and Hispanic.
- Previously giving birth to a baby that weighed at least 4,5kg or who had a birth defect
- Previous unexplained stillbirth or miscarriage
- Early onset of menstruation. A study from Australia indicated that girls who get their first period at 11 years of age or younger are at a significantly greater risk of developing gestational diabetes during pregnancy.
- Short stature (<1.50m). In a study done in Brazil, women in the shortest quartile of height (151cm or shorter) had a 60% increased risk for gestational diabetes.
- Thyroid dysfunction during pregnancy. The very latest research shows that women with higher thyroid hormone levels in the first half of pregnancy face an increased risk of gestational diabetes.