High factor sunscreen can decrease risk of melanoma by 33%

A study published in the Journal of Clinical Oncology by the University of Oslo found that using a high factor sunscreen (more than factor 15) can decrease the risk of melanoma by 33%.  The study followed 140,000 Norwegian women for an average of 10 years and found that using sunscreen however does not always guarantee protection.  

Research showed that often those using a lower protection factor had a higher chance of cancer than those who didn't use any at all.   The explanation for this paradox is that some of those were using sunscreen to prolong sun exposure to acquire a tan using a low protection factor (less than 15) often forgetting to reapply or missing exposed areas when applying the lotion.  This complacency often meant those not using any sunscreen at all were more careful about sun exposure and had a lower risk of developing melanoma than those using the lowest protection factors.