The characteristics of the microbiome in regard to developmental and postnatal exposure to environmental chemicals and the possible associations with markers of glucose metabolism abnormalities will be examined in >500 young adults, who are members of a unique birth cohort established in 1986-1987 at the Faroe Islands, a community with an unusually wide range of exposures to environmental chemicals. Cohort members will be invited at age 28 years for clinical examination, and a fecal sample will be obtained. Data on past chemical exposures, diet, medical history and other covariates were obtained at birth and at previous clinical examinations at ages 7, 14, and 22 years, in which 84%-90% of the cohort (N = 1,000) participated. The data include exposures to methylmercury, PCBs, DDE, and perfluorinated compounds. The clinical examination will include glucose tolerance test. The structure and function of the gut microbiome of these subjects will be assessed in a two-stage process. The microbes present in every sample will be determined by 16S rRNA gene sequencing, followed by deep metagenomic and metatranscriptomic sequencing on a subset of samples chosen to be maximally biologically informative. In combination with downstream statistical biomarker discovery, this will allow the determination of microbial clades, genes, pathways, or transcripts associated with early life chemical exposure and subsequent adult glucose tolerance.
Recent insights and data on the role of the human microbiome in health and disease have strongly suggested its sensitivity to environmental chemical exposures early in life. The principal investigators will thus examine the microbiome in young adult members of a Faroese cohort followed since birth with dietary, medical and exposure information. At a clinical examination at age 28 years, where glucose metabolism will be characterized, they will obtain a suitable fecal sample from at least 500 cohort members to ascertain key characteristics of the microbiome in regard to exposures and clinical data. This study will thus contribute to our understanding of the microbiome's potential impact on glucose metabolism as a key health parameter and its sensitivity to environmental chemical exposures during early postnatal life and later in life.