Table 3: Reporting of confounding bias in individual studies [23].

Van Asseldonk et al. (2006) [29]Mansfield et al. (2011) [10]Mansfield et al. (2012) [30]Marigold et al. (2004) [26]Marigold and Eng (2006) [25]Pereira et al. (2010) [27]Peurala et al. (2007) [28]Roerdink et al. (2009) [24]Sackley (1991) [8]Number of studies satisfied criteria

(1) Reporting of reasons why potential confounders are selected for analysis 0010100002
(2) Reporting of reasons to include confounders in final model 0010100002
(3) Reporting of characteristics of key confounders 0010000001
(4) Any method used to control for confounding 0011000103
(5) Reporting of both crude and adjusted effect estimate0010000001
(6) Comment on likelihood of unobserved confounding 1010110015
(7) Reporting of a qualitative statement on the direction of the potential effect of unobserved confounding 0010100002
(8) Sensitivity analysis used to estimate potential impact of unobserved confounding 0000000000

Total score107141011