Table 1.
Baseline features of selected studies.
| First author | Year | Country | Age (case/control) | Sample size (case/control) | Oral microbiota assessment | Oral sample | Collection time |
|---|---|---|---|---|---|---|---|
| Tianyu Chang | 2024 | China | 57.40 ± 7.10/56.00 ± 8.60 | 30/30 | 16S rRNA sequencing (V3-V4) | Saliva | 3d |
| Zhiyan Huang | 2024 | China | 65.00 ± 11.70/63.00 ± 13.00 | 100/31 | 16S rRNA sequencing (V1-V9) | Mucosal swab | 24 h |
| Mengjia Yang | 2022 | China | 54.20 ± 8.80/56.70 ± 3.20 | 52/26 | 16S rRNA sequencing (V4) | Gingival sulcus- swab sample | 3mo. |
| Xiaohua Zhao | 2025 | China | 63.36 ± 11.65/54.50 ± 7.62 | 14/8 | 16S rRNA sequencing (V3-V4) | Saliva | 7d |
| Lihe Yao | 2025 | China | 59.69 ± 11.53/63.08 ± 12.95 | 32/25 | 16S rRNA sequencing (V1-V9) | Subgingival plaque | 48 h |
| Huidi Wang | 2022 | China | 53.90 ± 8.80/57.00 ± 8.80 | 47/34 | 16S rRNA sequencing (V4) | Gingival sulcus- swab sample | 3mo. |
| Wenbo Sun | 2023 | China | 57.00 ± 7.90/57.00 ± 8.60 | 52/46 | 16S rRNA sequencing (V3-V4) | Saliva | 24 h |
| Muhammed Manzoor | 2025 | Multicenter | 39.40 ± 7.70/40.10 ± 7.60 | 134/138 | 16S rRNA sequencing (V1-V2) | Subgingival plaque sample | case:112d control:68d |
| Qiuxing He | 2025 | China | 59.52 ± 5.02/58.71 ± 3.74 | 30/30 | 16S rRNA sequencing | Throat swab | 24 h |
| Muhammed Manzoor | 2024 | Multicenter | 41.98 ± 2.32/41.67 ± 2.15 | 155/153 | Shotgun metagenomic sequencing | Saliva | NR |
| Xiaohong Zheng | 2026 | China | 63.13 ± 8.29/62.06 ± 6.83 | 100/31 | 16S rRNA sequencing | Saliva | 24 h |