LEP and metabolic syndrome: This cluster primarily focuses on terms related to the circadian rhythm, metabolism, insulin-resistance, high-fat diet, rev-erb-alpha, oxidative stress, adipose-tissue, clock genes, gene-expression, inflammation, etc. Followed by the cluster 2 (green), with 204 keywords, including food-intake, weight, leptin, suprachiasmatic nucleus, insulin, glucose, fat, resistance, receptor, stress, etc. With 196 terms, cluster 3 (blue) includes obesity, metabolic syndrome, sleep, shift work, association, body-mass index, risk, physical-activity, prevalence, cardiovascular-disease and impact.