Table 2.

Quality assessment of the included studies

Author	Selection bias	Measurement bias		Confounding	Overall (0–4)a
		Retirement	Physical activity
Berger (2005)22	No	Yes	Yes	?	1
Brown (2009)23	Yes	No	No	Yes	2
Chung (2009)24	No	No	Yes	No	3
Evenson (2002)25	Yes	No	No	Yes	2
Fonseca (2004)26	Yes	No	Yes	Yes	1
Glamser (1985)27	Yes	No	Yes	Yes	1
Henkens (2008)28	Yes	No	Yes	?	1
Mein (2005)29	No	No	Yes	No	3
Midanik (1995)30	No	No	Yes	Yes	2
Parnes (1985)31	Yes	No	Yes	No	2
Patrick (1985)32	Yes	?	No	Yes	1
Slingerland (2007)33	Yes	No	Yes	No	2
Touvier (2010)34	Yes	No	No	Yes	2
Wells (1999)35	No	No	Yes	Yes	2
Wister (1996)36	No	No	Yes	?	2
Chung (2005)37	No	No	Yes	No	3
Nekuda (2007)38	?	?	Yes	No	1
Parise (2006)39	?	Yes	Yes	Yes	0
Zheng (2008)40	?	No	Yes	No	2

Note: ?, not reported; studies ordered by type (published articles followed by PhD theses) and then alphabetically by first author

^a0–1 indicates low quality; 2 indicates modest quality; 3–4 indicates high quality.