Cross-sectional association of equol producing status with aortic calcification in Japanese men aged 40-79 years

Equol is an isoflavone (ISF)-derived metabolite by the gut microbiome in certain individuals termed equol-producers (EP). Equol might be the critical anti-atherogenic component of ISFs. In a population-based study of 979 Japanese men aged 40-79 without cardiovascular (CVD) or chronic kidney disease, we measured the urinary levels of equol and ISFs. Aortic calcification (AC) in the entire aorta was assessed by electron-beam or multi-detector-row computed tomography. Subjects with log10 (urinary equol to daidzein concentration) > - 1.5 were classified as EP. EP was further classified as person with low- and high-equol. We analyzed the association between equol-producing status and AC presence, defined as AC score > 0, by the logistic regressions. We found that EP (50% of the sample) had significantly lower odds of AC presence (odds ratio (OR): 0.62, 95% confidence interval (CI): 0.39, 0.98) compared to non-EP. This association was independent of CVD risk factors. For the dose-response association, compared to non-EP, subjects with low and high levels of equol had ORs of 0.51 (95% CI 0.30, 0.84) and 0.67 (95% CI 0.39, 1.14) after adjusting for major CVD risk factors (p for trend = 0.06). ISFs concentrations were not significantly associated with AC presence (OR: 1.18, 95% CI: 0.82, 1.69). In conclusion, EP had a significantly lower burden of AC than non-EP, while ISFs were not associated with AC presence in Japanese men aged 40-79 years.