Dyslipidemias among normoglycemic members of familial NIDDM pedigrees.

OBJECTIVE--To examine the hypothesis that hyperinsulinemia among relatives of NIDDM probands will increase the prevalence of DLPs, we measured insulin levels and examined the frequency of DLPs among NIDDM pedigree members. RESEARCH DESIGN AND METHODS--We performed 2-h 75-g OGTTs and measured lipid and insulin levels of 287 family members and 86 spouses from 16 large Utah pedigrees ascertained for greater than or equal to 2 siblings with NIDDM. RESULTS--One-hour insulin levels were higher among 206 family members with NGT than among 65 NGT spouses (483.3 vs. 361.7 pM, P = 0.05). Among the NGT family members, 32% had cholesterol levels at or above the age- and sex-specific 90th percentile level defined by the LRC studies, 33% had HDL levels less than or equal to 10th percentile, and 20% had triglyceride levels greater than or equal to 90th percentile. DLP (any of the three abnormalities) was found among 58% of NGT family members, which was significantly higher than the expected 27% (P less than 0.00001) and the prevalence among spouses of 45% (P less than 0.05). By NCEP criteria for hyperlipidemia, 40% of family members met criteria for diet and/or pharmacological therapy. CONCLUSIONS--Normoglycemic members of NIDDM pedigrees have a high prevalence of DLPs, which approaches the prevalence in patients with NIDDM. Our data suggest that members of NIDDM pedigrees should be screened carefully for lipid abnormalities.