Table 3: Summary of Study Quality (with all scales used)

Reference Are the study design and sampling method appropria-te for the research question? Is the sampling frame appropri-ate? Is the sample size adequate? Are objective, suitable and standard criteria used for measure-ment of the health outcome? Is the health outcome measured in an unbiased fashion? Is the response rate adequate? Are the refusers described? Are the estimates of prevalence or incidence given with confidence intervals and in detail by subgroup, if appropriate? Are the study subjects and the setting described in detail and similar to those of interest to you? Score
(6) 1 1 ND 1 1 1 1 1 7
(10) 1 1 ND 1 1 1 1 1 7
(22) 1 1 ND 1 1 1 1 1 7
(24) 1 1 ND 1 1 1 1 1 7
(25) 1 1 ND 1 1 1 1 1 7
(34) 1 1 ND 1 1 1 1 1 7
(36) 1 1 ND 1 1 1 1 1 7
(37) 1 1 ND 1 1 1 1 1 7
(38) - - ND 1 1 1 - 1 5
(39) 1 1 ND 1 1 1 1 1 7
(40) 1 1 ND 1 1 1 1 1 7
(41) 1 1 ND 1 1 1 1 1 7
(42) 1 1 ND 1 1 1 1 1 7
(43) 1 1 ND 1 1 1 1 1 7
(44) 1 1 ND 1 1 1 1 1 7
(45) 1 1 ND 1 1 1 1 1 7
(46) 1 1 ND 1 1 1 1 1 7
Reference Representativeness of the exposed cohort Selection of the non exposed cohort Ascertainment of exposure Demonstration that outcome of interest was not present at start of study Comparability of cohorts on the basis of the design or analysis Assessment of outcome Was follow-up long enough for outcomes to occur Adequacy of follow-up of cohorts Newcastle - Ottawa Quality Assessment Scale Cohort Studies
(47) * * * * ** * * 8
Reference Is the case definition adequate? Representativeness of the cases Selection of the controls Definition of controls Comparability of cases and controls on the basis of the design or analysis Ascertainment of exposure Same method of ascertainment for cases and controls Same rate for both groups Non respondents described Rate different and no designation Total
(35) * * * * * * * 7*

ND = not determined