Table 1.
Definitions of low education used in studies with categorical and dichotomous operationalisations of education.
| Author | Year | Country | Definition of low education |
|---|---|---|---|
| Categorical operationalisations | |||
| Bermejo-Pareja | 2008 | Spain | illiterate |
| Lobo | 2011 | Spain | illiterate |
| Harmanci | 2003 | Turkey | no schooling |
| Ojagbemi | 2016 | Nigeria | 0 years |
| Zhang | 1998 | China | 0 years |
| Nitrini | 2004 | Brazil | 0 years illiterate |
| DiCarlo | 2002 | Italy | 0–5 years |
| Yuan | 2016 | China | <1 year |
| Ravaglia | 2005 | Italy | <3 years |
| Chen | 2011 | China | primary school or less |
| deBruijn | 2015 | Netherlands | < primary or lower vocational |
| vanOijen | 2007 | Netherlands | primary |
| Dekhtyar | 2015 | Sweden | elementary or less |
| AlHazzouri Zeki | 2013 | USA | <6 |
| McDowell | 2007 | Canada | <6 years |
| Schmand | 1997 | Netherlands | <6 years |
| Nakahori | 2018 | Japan | ≤6 years |
| Then | 2016 | Germany | < elementary or basic vocational |
| Letenneur | 2000 | Denmark, France, Netherlands, UK | ≤7 years |
| Dekhtyar | 2016 | Sweden | <8 years |
| DeDeyn | 2011 | Belgium | <9 years |
| Roberts | 2012 | USA | <9 years |
| Kukull | 2002 | USA | <12 years |
| Fitzpatrick | 2004 | USA | <high school |
| Sullivan | 2018 | USA | <high school |
| Cadar | 2018 | England | no qualification |
| Valenzuela | 2011 | United Kingdom | Unclear |
| Dichotomous operationalisations | |||
| Prince | 2012 | Cuba, Dominican Republic, Venezuela, Peru, Mexico, China | illiterate |
| Lee | 2008 | Korea | illiterate |
| He | 2000 | China | illiterate |
| Noale | 2013 | Italy | <3 years |
| Marengoni | 2011 | Italy | ≤3 |
| Geerlings | 1999 | Netherlands | <6 years |
| Yoshitake | 1995 | Japan | <6 years |
| Letenneur | 1999 | France | <primary school |
| Bickel | 1994 | Germany | <=elementary or less |
| Luukinen | 2005 | Finland | <grade school |
| Scarmeas | 2001 | USA | <8 years |
| Stern | 1994 | USA | <8 years |
| Karp | 2009 | Sweden | <8 years |
| Schmand | 1997 | Netherlands | Assume <8 years |
| Beard | 1992 | USA | <9 years |
| Kaup | 2014 | USA | <9th grade reading level literacy |
| Shadlen | 2006 | USA | <10 years |
| Then | 2016 | Germany | <10 years |
| Borenstein | 2005 | USA | <11 years |
| Kotaki | 2019 | Japan | finished school before age 16 |
| Lopez | 2003 | USA | <=high school |
| Moceri | 2000 | USA | <=high school |