OBJECTIVES- To determine the 1 0-yr incidence of impaired glucose tole
rance and NIDDM in families with a clustering of endogenous hypertrigl
yceridemia. RESEARCH DESIGN AND METHODS- The prospective population st
udy, where the oral glucose tolerance test and the measurement of seru
m lipids and lipoproteins were performed at the baseline examination a
nd after the 10-yr follow-up, was conducted on 56 subjects (17-60 yr o
f age at the baseline). The subjects were from six pedigrees with a cl
ustering of endogenous hypertriglyceridemia, and 47 of these subjects
attended the follow-up 10 yr later. RESULTS- in the study families, th
e prevalence of glucose intolerance and NIDDM increased from 15 to 49%
(P < 0.001) and from 2 to 21% (P < 0.001), respectively, over the 10-
yr period. When grouped according to the baseline serum triglyceride t
ertiles, 76% (P < 0.01) of the family members with highest serum trigl
ycerides were glucose intolerant (29% impaired glucose tolerance, 47%
NIDDM) at follow-up compared with 20% of those with lowest serum trigl
ycerides. In discriminant analysis, including age, body mass index, tr
eatment with thiazides and beta-blocking agents, and 2-h serum insulin
concentration, the baseline serum triglycerides still remained as an
independent predictor of development of impaired glucose tolerance and
NIDDM. CONCLUSIONS- Families with a clustering of hypertriglyceridemi
a are at increased risk of NIDDM, and in these families elevation of s
erum triglycerides serves as a risk marker of glucose intolerance and
NIDDM.