Table 3.
Critical appraisal of cross-sectional studies using Newcastle-Ottawa Scale
| Selection | Comparability | Outcomes | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 1 | 1 | 2 | ||||
| Paper | Representativeness of sample | Sample size | Non-respondents | Ascertainment of exposure | Total Selection Score/5 | Comparability of different groups | Total Comparability Score | Assessment of outcome | Statistical test | Total Outcomes Score/2 |
| Aggar 2012* [25] | (c) | (a)* | (a)* | (a)** | 4 | (a)* | 1 | (c) | (a)* | 1 |
| Comans 2011* [27] | (c) | (b) | (c) | (a)** | 2 | (a)* | 1 | (c) | (a)* | 1 |
| Cullen 1997 [28] | (b)* | (b) | (a)* | (a)** | 4 | (a)* | 1 | (c) | (a)* | 1 |
| Kim 2008 [30] | (a)* | (a)* | (c) | (b) | 2 | (a)* | 1 | (c) | (a)* | 1 |
*This publication represents the index study for a series of five papers by a single set of investigators [22–26]. As appraisal concerns not just study design and execution but also the way results are presented, it is based on a composite of these five papers. An explanation of the relationship between these articles appears in the “Results” section of the manuscript.
Selection
1. Representativeness of the sample
(a) Representative of the average in the target population (all subjects or random sampling) (*); (b) Somewhat representative (non-random sampling) (*); (c) Selected group of users; (d) Insufficient information
2. Sample size
(a) Justified and satisfactory (*); (b) Not justified
3. Non-respondents
(a) Comparability between respondents’ & nonrespondents’ characteristics established + response rate satisfactory (*); (b) Response rate unsatisfactory or comparability is unsatisfactory; (c) Insufficient information
4. Ascertainment of exposure (risk factor)
(a) Validated measurement tool (**); (b) Tool is described but is non-validated; (c) Insufficient information
Comparability
1. Subjects in different groups are comparable based on study design or analysis, and confounding factors are controlled
(a) Study controls for most important factor (*); (b) Study controls for any additional factor (*); (c) Insufficient information
Outcome
1. Assessment of outcome
(a) Independent blind assessment (**); (b) Record linkage (**); (c) Self-report (*); (d) Insufficient information
2. Statistical test
(a) Test used to analyze data is clearly described is appropriate, and measurement of association is presented including confidence intervals & probability (*); (b) Test not appropriate, not described, or incomplete