Comprehensive profiling of skin microbiome diversity and major determinants in a multi-regional Chinese population

The human skin microbiome is essential for health and is shaped by both host and environmental factors. To establish a nationwide baseline, we profile the skin microbiome of 1,029 Chinese individuals across three body sites (hand, axilla, and foot), four geographic regions, and four ethnic groups using 16S rRNA gene sequencing. Within each skin site, we identify two cutotypes, one of which is consistently dominated by Staphylococcus. Microbial diversity and community composition vary across body sites, geography, ethnicity, gender, and age, with geographic location emerging as the strongest source of variation and enabling accurate classification by Random Forest models. Notably, Han and minority populations within the same region exhibit greater similarity than the same ethnic group across different regions. Aging-related shifts differ by both body site and geography, reflecting interactions between physiological and environmental influences. This population-scale study provides a comprehensive reference for the Chinese skin microbiome and reveals how host and environmental factors jointly structure skin microbial communities.