Table 3.
Quality of studies
| Study quality and score based on NOS for cohort studies | |||||||||
| Author, cohort studies | Selection | Comparability | Outcomes and associated statistical analysis | ||||||
| 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 (★) | Overall quality | |
| Ahmed et al22 | ★ | – | – | ★ | ★ | ★ | ★ | – | Sat |
| Adesunkanmi et al21 | ★ | – | ★ | ★ | – | ★ | ★ | – | Poor |
| Begoihn et al28 | ★ | – | ★ | -★ | ★ | ★ | -★ | – | Sat |
| Chu et al31 | ★ | – | ★ | ★ | ★ | ★ | ★ | – | Sat |
| Freeman et al36 | ★ | – | ★ | ★ | ★ | ★ | ★ | – | Sat |
| Eze et al23 | ★ | – | ★ | ★ | – | ★ | – | – | Poor |
| Antel et al32 | ★ | – | ★ | ★ | ★ | ★ | ★ | – | Sat |
| Study quality and score based on NOS adapted for cross-sectional studies | ||||||||
| Author, cross-sectional studies | Representativeness of the sample (★) | Justification of sample size (★) | Non-respondents (★) | Ascertainment of exposure (★★) | Comparability of subjects (★★) | Assessment of outcome (★★) | Statistical test (★) | Overall quality |
| Jemebere27 | ★ | – | ★ | ★ | – | ★ | – | Poor |
| Ezeome19 | ★ | – | – | ★ | – | ★ | – | Poor |
| Mlange et al34 | ★ | – | ★ | ★ | ★ | ★ | ★ | Sat |
| Alatise et al24 | ★ | – | – | ★ | – | ★ | – | Poor |
| Afungchwi et al33 | ★ | – | – | ★ | – | ★ | – | Poor |
| Brown et al25 | ★ | – | – | ★ | ★ | – | – | Poor |
| Njuguna et al35 | ★ | – | ★ | ★ | ★ | ★ | – | Sat |
| Study quality and scores based on the JBI Checklist for Qualitative Research | |||||||||
| Authors, qualitative studies | Congruity between stated philosophical perspective and the research methodology? | Congruity between research method and the research question or objectives? | Congruity between research method and the methods used to collect data? | Congruity between research method and representation and analysis of data? | Congruity between method and interpretation of results? | Statement locating the researcher culturally or theoretically? | Influence of the researcher on the research, and vice versa, addressed? | Participants’ voices adequately represented? | Evidence of ethical approval? |
| Dye et al26 | Unclear | Yes | Yes | Yes | Yes | Unclear | No | Yes | Yes |
| Pruitt et al20 | Unclear | Yes | Yes | Yes | Yes | Unclear | No | Yes | Yes |
| Aziato and Clegg-Lamptey29 | Unclear | Yes | Yes | Yes | Yes | Unclear | No | Yes | Yes |
| Agbokey et al30 | Unclear | Yes | Unclear | Yes | Yes | Unclear | No | Yes | Yes |
JBI, Joanna Briggs Institute; NOS, Newcastle-Ottawa Quality Assessment Scale; Sat, satisfactory-quality paper.