Although a strong genetic susceptibility has been established for NIDDM and a maternal transmission of the disease predominates in some populations, a relationship between parental diabetes status and metabolic abnormalities in nondiabetic offspring has not been shown in humans. To address this question, we studied 2,152 first-degree relatives of patients with NIDDM (FH+) and 528 age- and weight-matched spouses without a family history of NIDDM (FH−) in Western Finland (the Botnia study). A subset of the subjects underwent a euglycemic insulin clamp combined with indirect calorimetry to measure insulin sensitivity and energy expenditure. Despite similar amounts of total body fat, persons with a family history of NIDDM had a greater waist-to-hip ratio (WHR) than spouses without a family history of diabetes (P &amp;lt; 0.003). They also had a decreased resting metabolic rate (P = 0.005), but this difference disappeared when adjusted for the difference in WHR. Insulin-stimulated glucose metabolism (P = 0.002), particularly nonoxidative glucose metabolism (P = 0.009), was reduced in FH+ compared with FH− subjects, and this difference remained after adjustment for WHR. A parental history of NIDDM influenced the insulin response to the oral glucose load, with male offspring of diabetic mothers showing the lowest insulin values (P = 0.011). Moreover, a parental effect was also observed on HDL and HDL2 cholesterol concentrations with female offspring of diabetic mothers showing lower values than female offspring of diabetic fathers (both P &amp;lt; 0.002). We conclude that abdominal obesity, insulin resistance, and decreased resting metabolic rate are characteristic features of first-degree relatives of patients with NIDDM and that the decrease in resting metabolic rate is partially related to the degree of abdominal obesity. A sex-specific paternal effect was observed on insulin and HDL cholesterol concentrations. Therefore, one has to consider the possibility of unprecedented maternal or paternal inheritance of different NIDDM phenotypes.

Metabolic Consequences of a Family History of NIDDM (The Botnia Study): Evidence for Sex-Specific Parental Effects