Relationship between urinary phytoestrogen metabolites and telomere length: a cross-sectional study from the National Health and Nutrition Examination Survey

-1) × 100 %. Of the 2607 participants, 48·52 % were male. A 1-sd increase in urinary equol was associated with a 1·50 % (95 % CI 0·51, 2·50) increase in TL, and TL was 4·26 % (95 % CI 1·07, 7·56) longer in the highest quintile of equol compared with the lowest. Similarly, a 1-sd increase in the equol:daidzein ratio was linked to a 1·87 % (95 % CI 0·91, 2·84) rise in TL, and TL was 4·83 % (95 % CI 1·71, 8·05) longer in the highest quintile of the equol:daidzein ratio compared with the lowest. No significant association of urinary daidzein, genistein, O-demethylangolensin, enterodiol and enterolactone with TL was observed. Our findings suggested that higher levels of urinary equol and its ratio with daidzein were associated with longer leukocyte TL, highlighting the need for further research into their relationship with ageing.