Information on the family history may be helpful for prognosis, diagnosis, and public health. The incidence of type 2 diabetes can be predicted more accurately based on family history of the disease than it can by genetic and environmental factors alone. According to a study, the likelihood of developing diabetes is significantly influenced by a family history of the disease. Another study confirms that having a parent with diabetes is a risk factor for developing the disease.
However, the association becomes weaker in men free of cardiovascular disease. Moreover, the association is much higher in 45–54 years old men compared to 55–68 years old men. Furthermore, the prevalence of type 2 diabetes is stronger in men than women. This indicates that parental history of diabetes, combined with other risk factors such as aging, gender, and cardiovascular diseases, increases the risk of incidence of type 2 diabetes.
Researchers found that a family history of diabetes in the first degree of relative (parents, offspring, and siblings) is a strong and independent risk factor for the prevalence of impaired fasting glucose (prediabetes) in children and adolescents. This is in the absence of obesity. The findings reveal that it is essential to consider the parental history of diabetes while screening for diabetes in children and adolescents. This is because only obesity-based screening could lead to underestimation. One study also found that the prevalence of type 2 diabetes is significantly influenced by the presence of diabetes in at least two first-degree relatives or one first-degree relative and at least two second-degree relatives.
However, it is undeniable that having a family history of diabetes might strengthen the link between obesity and diabetes. Given a BMI⩾35, an individual with a family history of diabetes is at a higher risk of incidence of diabetes compared to one without a family history of diabetes. Furthermore, ethnicity is also considered an essential factor in an obese individual with a family history of diabetes.
An individual having a family history of diabetes can have an early onset of diabetes compared to the ones without a family history. However, it is hard to conclude which among the maternal, paternal, and both maternal and paternal family history of diabetes is more significant for incidence/prevalence of type 2 diabetes as the results in the literature are inconsistent.