Although sun protection is highly recommended by dermatologists for skin cancer risk-reduction and the prevention of premature aging or pigmentary disorders, adherence to the recommendations is not commonly observed among US Hispanics.13 Moreover, a large number of US Hispanics reside in areas with high UV index with a high degree of sun seeking behavior. Among Hispanic adults who report engaging in sun protection, they do so mostly by staying in the shade (53.7%) rather than use of sunscreen (32.3%) or wearing sun protective clothes (18.1%); while 36.7% of the subjects surveyed indicated that they never use sunscreen.14,15 There are sociodemographic factors that contribute to the adherence to safe sun behaviour such as education, age, and gender, etc, therefore there is a need to raise awareness of skin cancer risks, advocate for preventive measures and educate on benefits of sunscreen and sun protection among US Hispanics.16
The benefits of topical agents for reversal of sun damage has been well established. Use of retinoic acid and its derivatives or other drugs to reverse and improve sun damaged skin has been demonstrated in many studies.17,18 Long-term sunscreenuse along with other topical agents have also been shown to prevent photodamage and hyperpigmentation in fair-skinned subjects.19 For effective photoprotection, sunscreen products containing both SPF and PPD are essential to battle the harmful UVB (skin cancer risks) and UVA (photo-aging risks).20 Daily use of a broad-spectrum sunscreen (SPF 30) over a one-year period has also been demonstrated to improve clinical parameters of photodamage in phototype I-III subjects.10 However, a comprehensive long-term sunscreen use study in skin of color is lacking. Therefore, this study was designed to assess the benefits of sunscreen of SPF30/PPD 20 in Hispanic women of Fitzpatrick skin types IV and V over 12 months in comparison to a real-life observational group with subjects who did not use sunscreen regularly.
MATERIALS AND METHODS
The investigation was approved by an independent institutional review board, and it was conducted in accordance with the principles of the 1975 Declaration of Helsinki; written informed consent was obtained from all study subjects before enrollment. The study was performed in 2 study centers, one in Los Angeles, CA, the other in Washington DC, to observe geographic and climate variation.
Healthy female Hispanic subjects between the ages of 45-65 with Fitzpatrick phototype IV and V, with mild to moderate signs of photoaging and pigmentary concerns (fine lines, wrinkles, rough texture, uneven skin tone, hyperpigmented spots, and sun-induced dyschromia) were recruited. Subjects were recruited on a rolling admission basis and received a SPF 30/PPD 20 formula to add to their daily skin care routine. The Washington, DC study was conducted from May 2016 to August 2017, while the Los Angeles (LA) study was conducted from March 2016 to May 2018. 30 subjects were enrolled in Washington, DC while 22 were enrolled in Los Angeles. The subjects were evaluated at 3, 6, 9, and 12 months at each center for signs of aging and dyschromia with clinical grading and instrumental measurements. In addition, a real-life observation was conducted at the same centers during the same time, with age- and photo-type matched subjects of similar skin conditions (n=30 in Washington DC and n=22 in LA enrolled) who were not regular sunscreen users and maintained their normal routine.
At the end of 12 months, 24 subjects in the sunscreen study and 16 subjects in the real-life observation study completed all evaluations.
A broad spectrum, photo-stable sunscreen with SPF 30/PPD 20 was applied daily in the morning to the entire face, both hands, and forearms for 12 months. Re-application every 2-3 hours was recommended during sun exposure. The composition of active ingredients in the sunscreen formulation was Avobenzone (3%), Homosalate (12%), Octisalate (5%), Octocrylene (1.7%), and Oxybenzone (3%). The use of the study formulation was monitored, by weighing the product to insure adherence to the daily use of the formulation across the one-year study. All subjects were allowed to use a simple moisturizer, without known antiaging actives, as and when required. Subjects were advised to avoid excessive sun exposure during the study and were recommended to apply the sunscreen every 2-3 hours and take shelter/wear protective clothing when sun exposure was unavoidable.
Clinical evaluations by the dermatologist were carried out at baseline, 3, 6, 9, and 12-month time points. The assessment was performed in situ for efficacy parameters using modified Griffith’s scale. Dermatologist grading was conducted by a single physician using a scale of 0 (none) to 9 (most severe) and evaluated the following signs of skin quality and photodamage: texture, skin tone evenness, overall hyperpigmentation, dark spots (intensity and number), overall skin quality (smoothness, radiance, overall imperfections), loss of elasticity, fine lines, coarse wrinkles, and skin blotchiness. These parameters were evaluated on the face on the following locations: forehead, temple, crow’s feet area, under eye, nose, cheeks, and chin; as well as on the neck and both hands.
Instrumental measurements were performed with the Minolta CR-400/410, a reflectance spectrophotometer (chromameter) for