Table 1.

Broad environmental DNA methylation regulators and references, by higher order classifications of toxicants.

	Factor (examples)	Observational Epidemiology Citations	Laboratory Toxicology Citations
Toxicant	Heavy metals (Pb, Cd, As, Ni)	[Pilsner et al. 2009] [Wright et al. 2010] [Marsit et al. 2006]	[Bihaqi et al. 2011]
	Air pollution (particulate matter)	[Madrigano et al. 2011] [Tarantini et al. 2009]	[Yauk et al. 2008]
	Persistent organo-pollutants	[Kim et al. 2010] [Rusiecki et al. 2008]	[Zama and Uzumcu 2009]
	Endocrine disrupting chemicals		[Bromer et al. 2010] [Anderson et al. 2012; Guerrero-Bosagna et al. 2008]
	Volatile organic compounds (benzene)	[Bollati et al. 2007; Seow et al. 2012]	[Ji et al. 2010; Tabish et al. 2012]
Nutrient	One-carbon metabolism	[Ba et al. 2011] [Hoyo et al. 2011] [Hirsch et al. 2008] [Fenech 2001a]	[Mehedint et al. 2010] [McKay et al. 2011]
	Micro-nutrients	[Fenech and Ferguson 2001] [Fenech 2001b]	[Davis and Uthus 2003] [Rowling et al. 2002]
	Caloric restriction	[Tobi et al. 2009]	[Hass et al. 1993]
	Nutraceuticals (EGCG, curcumin, piperine)	[Yuasa et al. 2009]	[Shi et al. 1994] [Fang et al. 2003]
Pharmaceutical		[Yang et al. 2006]	[Tryndyak et al. 2006]
Lifestyle and Demographic	Smoking	[Breitling et al. 2011] [Joubert et al. 2012]	[Belinsky et al. 2003]
	Socio-economic status	[Borghol et al. 2012] [McGuinness et al. 2012]
	Stress	[Essex et al. 2013] [Uddin et al. 2010]	[Murgatroyd et al. 2009] [Champagne et al. 2004]