## 3 Results  
### Study Selection  
A comprehensive search was conducted across PubMed, Web of Science, EMBASE, Google Scholar, and the Cochrane Library databases, yielding an initial 886 studies. After removing duplicates, 665 studies remained for screening. Abstracts were reviewed in detail, leading to the shortlisting of 8 articles for further evaluation (Figure 1). Following a thorough assessment using the JBI checklist for Analytical Cross-Sectional Studies and Cohort Studies, 4 studies were included in the final selection based on their study design and methodological quality (Table 1).  
Figure 1: The PRISMA flowchart.  
During the review, three studies authored by the same researcher were found to analyze overlapping populations. To avoid redundancy, these studies were combined into a single dataset before final inclusion. All selected studies met the criteria for providing adequate data for meta-analysis.  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & \multicolumn{2}{c}{**(a)**} \\ \hline Criteria & [PERSON] et al. (2021) [33] & [PERSON] et al. (2003) [45] \\ \hline Were the criteria for inclusion in the sample & & \\ clearly defined? & Yes & Yes \\ \hline Were the study subjects and the setting described & & \\ in detail? & Yes & Yes \\ \hline Was the exposure measured in a valid and & & \\ reliable way? & Yes & Yes \\ \hline Were objective, standard criteria used for & & \\ measurement of the condition? & Yes & Yes \\ \hline Were confounding factors identified? & Yes & Yes \\ \hline Were strategies to deal with confounding & & \\ factors stated? & Yes & Yes \\ \hline Were the outcomes measured in a valid and & & \\ reliable way? & Yes & Yes \\ \hline Was appropriate statistical analysis used? & Yes & Yes \\ \hline \multicolumn{2}{c}{**(b)**} \\ \hline JBI Checklist Items & [PERSON] and [PERSON]. (2003) [42] & [PERSON] et al. (2005) [34] \\ \hline
1. Were the two groups similar and recruited from & & \\ the same population? & Yes & Yes \\ \hline
2. Were the exposures measured similarly to assign & & \\ people to both exposed and unexposed groups? & & \\ \hline
3. Was the exposure measured in a valid and & & \\ reliable way? & & \\ \hline
4. Were confounding factors identified? & Yes & Yes \\ \hline
5. Were strategies to deal with confounding & & \\ factors stated? & Yes & Yes \\ \hline
6. Were the groups/ participants free of the & & \\ outcome at the start of the study (or at the moment & & \\ of exposure)? & & \\ \hline
7. Were the outcomes measured in a valid and & & \\ reliable way? & & \\ \hline
8. Was the follow-up time reported and sufficient & & \\ to be long enough for outcomes to occur? & & \\ \hline
9. Was follow-up complete, and if not, were the & & \\ reasons for loss to follow-up described & & \\ and explored? & & \\ \hline
10. Were strategies to address incomplete & & \\ follow-up utilized? & & \\ \hline
11. Was appropriate statistical analysis used? & Yes & Yes \\ \hline \hline \end{tabular}  
* Each study was evaluated using the appropriate JBI Checklist for its design: the JBI Checklist for Cohort Studies or the JBI Checklist for Analytical Cross-Sectional Studies. These assessments considered key methodological criteria, including the validity and reliability of findings. Partial fulfillment indicates areas where additional clarity or rigor could improve the study’s methodological robustness.  
\end{table}
Table 1: Quality Assessment of Included Studies Using the JBI Checklist. **(a)** JBI checklist for Cross-sectional study. **(b)** JBI checklist for Cohort study.