Bifidobacterium genus abundance decreases significantly with age. The association of Bifidobacterium abundance with disease status and clinical metadata (including age) was determined to be significant in these data using a sparse general linear model. Clade abundances were transformed with the arcsine square-root transformation for proportional data (y-axis). Size of effect, standard deviation, P-value (p) and Benjamini and Hochberg false discovery rate (q) are shown in parentheses, and the line of best fit in green.