Table 2.
Assessment of study quality.
| Author | Selection | Comparability | Outcome | Total score |
|---|---|---|---|---|
| Buettner | ★★★★ | ★★ | ★★★ | 9 |
| Chen | ★★★★ | ★★ | ★★ | 8 |
| Cho | ★★★★ | ★★ | ★★ | 8 |
| Hu | ★★★ | ★ | ★★ | 6 |
| Kitano | ★★★★ | ★ | ★ | 6 |
| Ramen | ★★★ | ★★ | ★★★ | 8 |
| Saito | ★★★★ | ★ | ★ | 6 |
| Yoh | ★★★★ | ★ | ★★ | 7 |
| Zhang | ★★★★ | ★ | ★ | 6 |
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.