Continuous glucose monitoring uncovers metabolic risk in adults without diabetes

A cross-sectional study of 62,122 free-living adults on the Levels digital-health platform found that average glucose measured by continuous glucose monitoring tracked insulin resistance, triglycerides, HDL cholesterol, uric acid and C-reactive protein more closely than HbA1c in the 7,930 participants without diabetes who had laboratory data, explaining nearly three times more variance in fasting insulin (R² 0.131 vs 0.048). With a normal HbA1c, occult hyperinsulinemia (fasting insulin ≥10 µIU/mL) was twice as common at average glucose ≥110 mg/dL (27.5% vs 12.6%), and at the same average glucose, spike width rather than height or frequency tracked insulin resistance, triglycerides and C-reactive protein. Average glucose was the most reliable metric across weeks (intraclass correlation 0.747), and the authors propose a framework for interpreting CGM in adults without diabetes; the analysis was conducted independently by Precision Longevity Consultants, whose principals P.G. and M.L. consult for and hold equity in Levels Health.

Abstract Whether continuous glucose monitoring CGM provides actionable information in adults without diabetes is contested, as its metrics were designed for diabetes and screening relies on HbA1c. In this cross-sectional study of 62,122 free-living adults on the Levels digital-health platform, average glucose was the most reliable measure across weeks intraclass correlation 0.747 . Among 7,930 participants without diabetes with laboratory data, it tracked insulin resistance, triglycerides, HDL cholesterol, uric acid, and C-reactive protein more closely than HbA1c, explaining nearly three times more variance in fasting insulin R² 0.131 vs 0.048 . With a normal HbA1c, occult hyperinsulinemia fasting insulin ≥10 µIU/mL was twice as common at average glucose ≥110 mg/dL 27.5% vs 12.6% . Counterintuitively, at the same average glucose, spike width, not height or frequency, tracked insulin resistance, triglycerides, and C-reactive protein; carbohydrate sensitivity, although reliable, did not track insulin resistance. This analysis suggests a framework for interpreting CGM in adults without diabetes. Competing Interest Statement P.G. and M.L. are the principals of Precision Longevity Consultants, PLLC PLC , an independent applied clinical AI research laboratory and practice. Both are consultants to Levels Health, Inc. and hold equity in the company. This analysis was conducted independently by PLC. Levels Health reviewed the manuscript and provided feedback but had no right to approve, delay, or prevent its publication. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Advarra Institutional Review Board approved the protocol LH-001; Pro00058897 . Adult US members provided electronic informed consent, including HIPAA authorization; the analysis used a de-identified research export. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone e.g., hospital staff, patients or participants themselves outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance . Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist s and other pertinent material, if applicable. Yes CC-BY-NC-ND 4.0 International license http://creativecommons.org/licenses/by-nc-nd/4.0/ .