Fasting ketonuria is inversely associated with coronary artery calcification in non-diabetic individuals

Background and aims: Increased levels of ketone bodies, an alternative fuel when glucose availability is low, may exert beneficial effects on cardiovascular disease (CVD) risk factors. Whether increased ketone bodies are associated with coronary artery calcium (CAC), a recognized and strong cardiovascular risk factor, remains unknown. We investigated the association of fasting ketonuria with CAC and its progression. Methods: Cross-sectional and longitudinal studies were conducted in adults without diabetes or CVD. Subjects underwent routine health examinations including cardiac computed tomography estimations of CAC scores. Logistic regression models were performed to compute the odds ratios (ORs), 95% confidence intervals (CIs), for prevalent CAC scores >0 according to fasting ketonuria categories (0, 1, and ≥2). Linear mixed models with random intercepts and random slopes were used to estimate CAC progression. Results: Of 144,346 subjects, 12.3% had CAC scores >0 at baseline. Overall, higher fasting ketonuria was associated with decreased prevalence of coronary calcification than no ketonuria. Multivariable-adjusted ORs (95% CIs) for prevalent CAC by comparing ketonuria categories 1 and ≥2 with no ketonuria, were 0.94 (0.84–1.06) and 0.82 (0.71–0.95), respectively. The associations did not differ according to clinically relevant subgroups. Ketonuria was associated with lower CAC progression over time; the multivariable adjusted ratio of progression rates comparing ketonuria ≥2 versus no ketonuria was 0.976 (0.965–0.995). Conclusions: We found an inverse association between fasting ketonuria and subclinical coronary atherosclerosis, in both prevalence and progression. The potentially protective role of increased ketone body formation in CVD requires further investigation.