A study published in JAMA examined more than 2,500 scientific papers released from January 2010 through September 2025, including randomized clinical trials, meta-analyses and clinical guidelines.
Pew Research Center is a nonpartisan, nonadvocacy fact tank that informs the public about the issues, attitudes and trends shaping the world.
Some results have been hidden because they may be inaccessible to you
Show inaccessible results