This is a cohort study to understand the role of the human metagenome, and associated metabolites, in health and in various diseased states, in particular obesity as well as sarcopenia.

Recruited participants will have their fecal, salivary, urine, serum, and in certain instances, mucosal samples taken, for metagenomic sequencing and metabolite testing.

We hope to uncover various differences and signatures in the metagenome and metabolome in various diseased states, with potential future therapeutic applications in personalised medicine.

The human metagenome comprises all nucleotide sequences isolated from all organisms living on and within an individual and has been shown to have significant alterations in relation to certain diseased states related to chronic inflammation, such as obesity and sarcopenia.

The gut bacteriome, and more recently the virome, has been shown to be significantly correlated with the obese phenotype, while gut microbiome dysbiosis is known to occur in individuals with sarcopenia. Clinically, there is an unmet clinical need to better personalize the treatment of patients with metabolic disorders such as obesity and metabolic syndrome, and patients suffering from sarcopenia and frailty as a result of aging. However, the literature regarding the metagenomic signatures associated with these disorders, in particular the non-bacteriome species, bacterial metabolites, and their relationship with host metabolism, were scarce.

Thus we hypothesize, that the human metagenome and metabolome, may play a role in influencing chronic inflammatory disorders related to metabolic disorders, such as obesity and diseases related to aging like sarcopenia and aging.

This is a cohort study, involving metagenomic sequencing and metabolomic analysis, of patients metagenome and metabolome, in various diseased states. A cohort of healthy control patients without obesity or sarcopenia will also be recruited.

Samples collected will include fecal, salivary, serum, urine, mucosal samples for metagenomic sequencing and metabolomic testing.

Inclusion Criteria (obese cohort):

• Obese (BMI>27.5kg/m2)

Inclusion Criteria (sarcopenic cohort):

• Sarcopenic patients, defined as 1) low handgrip strength (<26 for males; <18kg for females), AND/OR low gait speed (<0.8m/s) AND low muscle mass (<7.0kg/m2 for males; <5.7kg/m2 for females)

Inclusion Criteria (control cohort):

- Healthy subjects without sarcopenia, and not obese (BMI<27.5kg/m2)

Exclusion Criteria:

• No informed consent
• Presence of intestinal stoma, hence inability to collect fecal samples

Obese and sarcopenic patients will be recruited from patients from Sengkang General Hospital, opportunistically found during their management to be sarcopenic. Obese patients will be recruited from patients who are seen in the Sengkang General Hospital Weight Management Clinic.

Controls are recruited from patients who are on follow-up for other non-related conditions found opportunistically to fit the inclusion criteria, as well as healthy volunteers.

Undecided at the moment. Deidentified data can potentially be shared following institutional review board and hospital permission.