Time spent within specific glycemic ranges may be associated with metabolic health even in individuals without diabetes. A cross-sectional and longitudinal analysis published in Diabetes Care evaluated continuous glucose monitoring (CGM) metrics and their associations with metabolic parameters in adults without diabetes.

The analysis included 8,687 adults aged 40-70 years, of whom 54% were women, from the Human Phenotype Project. Each participant contributed 1,149 ± 279 glucose readings using FreeStyle Libre Pro sensors. Age- and sex-adjusted correlations assessed associations between time-in-range metrics and 45 clinical phenotypes, including adiposity, vascular measures, liver markers, sleep indices, and nutrition. Cox proportional hazards models evaluated associations between time above glycemic thresholds and incident metabolic disease over a mean follow-up of 2.6 ± 1.3 years.

Participants spent a median of 93.0% (interquartile range [IQR] 91.8-98.2) of time within 70–140 mg/dL and 95.2% (IQR 95.1-99.8) within 70-180 mg/dL. Time below 140 mg/dL and 180 mg/dL was 97.7% (IQR 97.6-97.8) and 99.9% (IQR 99.9-99.9), respectively. Less time below 140 mg/dL was correlated with higher waist circumference, visceral fat, triglycerides, blood pressure, serum alanine aminotransferase (ALT), and liver attenuation, along with lower high-density lipoprotein (HDL) cholesterol and mean nocturnal oxygen saturation. These associations were attenuated when using the <180 mg/dL threshold.

In longitudinal analyses, less time below 180 mg/dL and below 140 mg/dL was associated with a higher risk of incident metabolic disease, with hazard ratios of 1.21 (95% CI 1.15-1.26) and 1.34 (95% CI 1.26-1.42), respectively. These findings provide population-level reference data for glycemic ranges in adults without diabetes and indicate that lower time within tighter glycemic thresholds is associated with less favorable metabolic profiles.