Complex sentence: A 2014 systematic review and meta-analysis, examining 37 studies involving 251,808 participants, found that indoor tanners had a 16 percent increased risk of developing melanoma, which increased to 23 percent for North Americans.
Split into simpler sentences: A 2014 systematic review and meta-analysis examined 37 studies involving 251,808 participants. The authors found that indoor tanners have a 16 percent increased risk of developing melanoma, which increased to 23 percent for North Americans.