Background

The value of additional photoprotection provided by use of high–sun protection factor (SPF) sunscreens is controversial, and limited clinical evidence exists.

Objective

To compare the sunburn protection provided by SPF 100+ and SPF 50+ sunscreen in conditions of actual use.

Methods

A total of 199 healthy men and women (≥18 years) participated in a natural sunlight, single-exposure, split-face, randomized, double-blind study in Vail, Colorado. Each participant wore both sunscreens simultaneously during activities, with no use restrictions other than designation of the treatment area. Erythema was clinically assessed on the day following exposure. Comparative efficacy was evaluated through bilateral comparison of sunburn between treatment areas and erythema score, as evaluated separately for each treatment area.

Results

Following an average 6.1 ± 1.3 hours of sun exposure, investigator-blinded evaluation identified 55.3% of the participants (110 of 199) as more sunburned on the SPF 50+ protected side and 5% (10 of 199) on the SPF 100+ protected side. After exposure, 40.7% of the participants (81 of 199) exhibited increased erythema scores (by ≥1) on the SPF 50+ protected side as compared with 13.6% (27 of 199) on the SPF 100+ protected side.

Limitations

Single-day exposure may not extrapolate to benefits of longer-term protection.

Conclusion

SPF 100+ sunscreen was significantly more effective in protecting against sunburn than SPF 50+ sunscreen in actual use conditions.

中文翻译：

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与实际使用中的SPF 50+相比，SPF 100+防晒霜对晒伤的防护作用更强：一项随机，双盲，双面自然日光照射临床试验的结果

背景

通过使用高防晒系数（SPF）防晒霜提供的附加光防护价值尚有争议，并且临床证据有限。

客观的

在实际使用条件下比较SPF 100+和SPF 50+防晒霜提供的防晒保护。

方法

共有199名健康的男性和女性（≥18岁）参加了在科罗拉多州韦尔进行的自然阳光，单次暴露，双脸，随机，双盲研究。每个参与者在活动期间同时戴着两个防晒霜，除了指定治疗区域外，没有其他使用限制。在暴露后的第二天对红斑进行了临床评估。通过对治疗区域之间的晒伤和红斑评分进行双边比较来评估比较疗效，分别针对每个治疗区域进行评估。

结果

在平均6.1±1.3小时的日照后，研究者盲目评估确定55.3％的参与者（199名中的110名）在受SPF 50+保护的一侧被更多晒伤，而在SPF 100+受保护的一侧则有5％（199名中的10名）被晒伤。边。暴露后，有40.7％的参与者（199名中的81名）在SPF 50+受保护的一侧表现出红斑得分增加（≥1），而在SPF 100+受保护的一侧则表现出了13.6％（199名中的27名）。

局限性

单日暴露可能无法推断出长期保护的好处。

结论

在实际使用条件下，SPF 100+防晒霜比SPF 50+防晒霜更有效地防止晒伤。