FIG 1.

Gut microbiota richness is nonlinearly associated with age and differs between women and men in multiple populations: United States (n = 2,588) (A), United Kingdom (n = 936) (B), Colombia (n = 437) (C), and China (n = 4,963) (D). (Left) Sequence variant (SV) richness in adults ages 20 to 69 years (the age of the Colombians ranged from 20 to 62 years); lines indicate the relationship of richness with age after Loess smoothing for women and men separately. (Right) SV richness in young (age, 20 to 45 years) and middle-aged (age, 46 to 69 years) adults; lines indicate the linear regression fit for women and men separately.