Table 2. Cluster details of keywords.

Cluster ID	Cluster size	Silhouette	Median (year)	Cluster name	LLR (top three keywords)
LLR, log-likelihood rate; IGF1, insulin-like growth factor 1; GH, growth hormone.
0#	38	0.915	2001	Breast cancer	Breast cancer, circadian rhythms, mortality
1#	38	0.897	2009	NF-κB	NF-κB, aging, safety
2#	30	0.874	2003	Pineal gland	Pineal gland, hormone, DNA
3#	30	0.863	2014	Cell cycle	Cell cycle, cellular senescence, cancer risk factors
4#	28	0.890	2004	Dihydropyrimidine dehydrogenase	Dihydropyrimidine dehydrogenase, 5-fluorouracil, pharmacokinetics
5#	28	0.896	1999	Breast neoplasms	Breast neoplasms, electromagnetic fields, night work
6#	27	0.856	2015	Calorie restriction	Calorie restriction, night-shift work, aryl hydrocarbon receptor
7#	26	0.932	2008	Period	Period, bone formation, genes
8#	26	0.897	2012	IGF1	IGF1, GH, actigraphy
9#	24	0.768	2004	Transcription	Transcription, liver, in vivo