Abstract
It has been reported that, in Caucasians, the prevalence of a family history of diabetes in noninsulin-dependent diabetics is higher than in insulin-dependent diabetics. In Japan, few studies of family histories of diabetes by types have been undertaken among diabetics with juvenile onset and identical duration of the disease. We examined family histories of diabetes among first degree relatives. One hundred and forty-eight probands were selected from among diabetics treated at the Diabetes Center of Tokyo Women's Medical College. The probands in this study experienced the onset of diabetes before the age of 20, their present age was between 20 and 40, and the duration of their diabetes was three years or longer.
Seventy-five patients were classified as insulin-dependent diabetes mellitus (IDDM) cases and 73 as non-insulin-dependent diabetes mellitus (NIDDM) cases. Among diabetics in whom the onset was before the age of 15, the prevalence of insulin-dependent diabetics was higher than that of non-insulindependent diabetics; the rate of non-insulin-dependent diabetics increased when the onset was afte the age of 15. Six of the 75 probands with IDDM had parents with NIDDM and two had siblings with IDDM; 36 of the 73 probands with NIDDM had parents with NIDDM, 12 had siblings with NIDDM and nine had parents and siblings with NIDDM. In other words, 39 of the 73 probands with NIDDM had positive family histories for NIDDM alone, while only four of 75 non-diabetics had positive family histories.
