A new study looking at risks for immediate family members of people with type I diabetes found that age and a positive islet cell autoantibodies (ICA) test are larger risk factors than specific family relationship.
The study, which appeared in the December 1995 Journal of Clinical Endocrinology and Metabolism, reported that if a person has a relative with diabetes and receives a positive ICA test before the age of ten, that person has a 66 percent chance of developing type I diabetes. This number drops progressively as the person gets older, the study found, with only a 16 percent chance if the person is over 40, has an immediate family member with diabetes, and receives a positive ICA test.
The study was conducted by following 5,851 non-diabetic relatives of 2,742 people with diabetes from 1979-1994. Family members were contacted once a year to see if they had developed diabetes.
Among immediate families of people with diabetes, ICA positive or not, the study found that around three percent of fellow siblings developed diabetes, around 1.5 percent of offspring developed diabetes, and less than one percent of parents developed diabetes.
For ICA positive family members of someone with diabetes the numbers jumped to around 50 percent of siblings, 28 percent of offspring, and around 25 percent of parents.
The researchers who performed the study hope the information can be used to determine who will be likely candidates for early intervention trials.