Is borderline fasting hyperglycemia a risk factor for cardiovascular death?

Area of Science:

• Cardiology
• Endocrinology
• Epidemiology

Background:

• Previous studies on borderline hyperglycemia and cardiovascular disease often used post-challenge glucose, were limited to men, and showed inconsistent results.
• The predictive value of normal-range fasting plasma glucose (FPG) for mortality remains less understood.

Purpose of the Study:

• To investigate whether FPG levels within the normal range (<140 mg/dl) predict all-cause, cardiovascular, and ischemic heart disease mortality.
• To examine the association between FPG and common cardiovascular risk factors.

Main Methods:

• Prospective study of 3625 non-diabetic men and women aged 40-79 in Southern California.
• 9-year follow-up with analysis of FPG levels and mortality outcomes using proportional hazard models.
• Adjustment for major cardiovascular risk factors.

Main Results:

• FPG levels were significantly associated with most heart disease risk factors.
• In men, FPG was independently and significantly associated with all-cause, cardiovascular, and ischemic heart disease mortality.
• In women, only the highest FPG levels (130-139 mg/dl) showed a statistically significant association with all-cause mortality.

Conclusions:

• Fasting plasma glucose within the normal range is an independent predictor of cardiovascular mortality in men.
• Potential sex differences in the glucose-mortality association warrant further investigation.
• FPG may be a more reliable predictor than post-challenge glucose due to lower variability and misclassification bias.