Abstract
Background
Sun protection messages in the United States emphasize sunscreen use, although its efficacy in skin cancer prevention remains controversial.
Methods
We used data from NHANES 2003–2006, restricted to adult whites (n = 3,052) to evaluate how Americans protect themselves from the sun. Participants completed questionnaires on the frequency with which they used sunscreen, wore a hat, long sleeves, or stayed in the shade, in addition to the number of sunburns in the past year.
Results
Although using sunscreen is the most common sun protective behavior (30%), frequent sunscreen use was not associated with fewer sunburns. However, the odds of multiple sunburns were significantly lower in individuals who frequently avoided the sun by seeking shade (OR = 0.70, p < 0.001) or wearing long sleeves (OR = 0.73, p = 0.01).
Conclusions
Our findings suggest that shade and protective clothing may be more effective than sunscreen, as typically used by Americans.
Keywords: Sunprotection, Sunscreen, Skin cancer, Sunburn
Introduction
Sun protection messages in the United States have emphasized sunscreen use [1–3], more than sun avoidance or wearing protective clothing. However, the efficacy of sunscreen for skin cancer prevention remains controversial. International sun protection programs including the successful Australian SunSmart program have emphasized sun avoidance and protective clothing with sunscreen use complementing but not replacing these methods [4, 5]. Although it is clear that sunscreen is effective in blocking UVB and preventing sunburn in controlled conditions and can prevent actinic damage and squamous cell carcinoma (SCC) [6, 7], it is unclear how effective sunscreen is as typically used by the general population. Assessing the efficacy of sunscreen or skin cancer prevention is further complicated by the fact that sunscreen is often applied prior to prolonged outdoor sun exposure[8–10] and by individuals with risk factors such as fair skin or a personal or family history of skin cancer.
To our knowledge, no study to date has examined how Americans protect themselves from the sun or the relative effectiveness of different sun protective behaviors on sunburns. Our objectives were (a) to describe the prevalence of sun protective behaviors in the US and (b) to evaluate the association between sunburn and different sun protective behaviors including wearing sun protective clothing, shade use, and sunscreen, as typically used by Americans.
Materials and methods
The National Health and Nutrition Examination Survey (NHANES) is a biennial, nationally representative, cross-sectional survey including data collected via household interviews and standardized physical examinations conducted in specially equipped mobile examination centers [11]. We restricted our analysis to adult participants (aged 20–60) during two NHANES cycles 2003–2004 and 2005–2006 where self-reported sun protection information was collected. A total of 20,470 individuals were surveyed by NHANES, and the dermatology questionnaire was administered to a random subset (n = 6,549). We restricted our analysis to non-Hispanic whites (n = 3,052). Complete data were available for 2,338 individuals.
Participants were asked the following questions; “When you go outside on a very sunny day, for more than 1 h, how often do you: (a) stay in the shade? (b) wear a hat that shades your face ears and neck? (c) wear a long sleeved shirt? (d) use sunscreen?.” Possible answers included are as follows: never, rarely, sometimes, most of the time, or always. In order to have intuitive categories and stable estimates, we collapsed these responses into three prespecified frequency categories: rare (never or rarely), moderate (sometimes), and frequent (most of the time or always). Participants were also asked “How many times in the past year have you had a sunburn?” These were divided into 0, 1, and ≥2 (multiple).
Logistic regression comparing multiple to no sunburns was performed using each of the sun protection variables as exposure variables. Multivariate analyses were adjusted for age, gender, BMI, sun sensitivity, physical activity compared to peers, income, education, season, and binge alcohol drinking. p values are two sided. All analyses were adjusted for weighted sampling technique (STATA 10.0 SVY) making results applicable to the entire US population. Missing data were excluded.
Results
The most common sun protective behavior used by white adult Americans is sunscreen, with over 30% of individuals reporting frequently using sunscreen when in the sun for more than 1 h. While 25% of Americans frequently stay in the shade, only 16% regularly wear a hat, and 6% report frequently wearing long sleeves. Over half of white Americans report at least one sunburn, and 26% reported two or more sunburns in the past year. Table 1 shows the demographic and sun protection characteristics of white Americans according to number of sunburns.
Table 1.
Demographic characteristics according to number of sunburns, NHANES 2003–2006
| Overall N (%) | Number of sunburns |
|||
|---|---|---|---|---|
| 0% (range) | 1% (range) | 2 + % (range) | ||
| Overall | 44.3% | 29.4% | 26.4% | |
| Age | ||||
| 20–29 | 835 (22.3) | 31 (26–35) | 34 (30–37) | 36 (32–40) |
| 30–39 | 775 (23.8) | 38 (33–44) | 30 (26–33) | 32 (28–35) |
| 40–49 | 743 (29.2) | 43 (39–48) | 31 (27–34) | 26 (23–29) |
| 50–59 | 699 (24.7) | 63 (59–67) | 24 (20–27) | 13 (11–16) |
| Gender | ||||
| Male | 1,429 (49.4) | 39 (35–43) | 32 (29–35) | 30 (26–33) |
| Female | 1,623 (50.6) | 49 (46–53) | 27 (25–30) | 23 (21–26) |
| Sun Sensitivity | ||||
| Severe burn | 515 (16.2) | 37 (32–42) | 25 (21–30) | 38 (34–41) |
| Mild burn | 1,209 (40.4) | 35 (32–39) | 32 (29–36) | 32 (29–35) |
| Tan | 454 (14.9) | 58 (52–63) | 27 (22–31) | 16 (12–20) |
| Nothing | 849 (28.5) | 53 (48–57) | 30 (25–34) | 17 (14–21) |
| Shade | ||||
| Rare | 1, 019 (33.5) | 41 (36–45) | 31 (28–34) | 28 (24–32) |
| Moderate | 1,263 (41.9) | 39 (35–42) | 33 (30–36) | 28 (26–30) |
| Frequent | 769 (24.6) | 58 (54–63) | 21 (17–25) | 21 (17–24) |
| Long sleeves | ||||
| Rare | 2,471 (80.6) | 42 (39–46) | 30 (27–32) | 28 (26–29) |
| Moderate | 8,392 (13.8) | 47 (40–55) | 30 (25–35) | 23 (17–28) |
| Frequent | 161 (5.5) | 57 (47–66) | 25 (17–32) | 19 (12–26) |
| Sunscreen use | ||||
| Rare | 1,384 (44.4) | 50 (47–53) | 29 (26–32) | 21 (18–23) |
| Moderate | 733 (25.4) | 34 (30–38) | 32 (28–36) | 34 (31–38) |
| Frequent | 907 (30.2) | 43 (40–47) | 29 (26–32) | 28 (25–31) |
| Hat | ||||
| Rare | 2,105 (68.2) | 44 (40–47) | 29 (27–32) | 27 (24–29) |
| Moderate | 460 (15.8) | 41 (36–47) | 33 (28–39) | 25 (22–29) |
| Frequent | 459 (16.0) | 47 (43–51) | 26 (23–30) | 26 (23–30) |
| Income | ||||
| $0–19.9 k | 407 (9.9) | 55 (49–61) | 23 (17–29) | 22 (18–26) |
| $20–39 k | 697 (22.7) | 46 (41–51) | 29 (26–32) | 25 (21–28) |
| $40–59 k | 530 (19.6) | 46 (43–50) | 28 (24–31) | 26 (22–30) |
| $60–69 k | 225 (8.6) | 38 (29–47) | 33 (26–40) | 29 (22–36) |
| $70+ | 1,042 (39.2) | 41 (37–44) | 32 (29–35) | 28 (25–31) |
| Education | ||||
| Did not graduate High school | 308 (8.4) | 53 (46–59) | 28 (23–33) | 19 (14–25) |
| High school | 796 (26.4) | 45 (41–50) | 30 (26–33) | 25 (20–30) |
| Some college | 1,044 (35.1) | 43 (39–46) | 32 (28–35) | 26 (23–29) |
| College graduate or higher | 900 (30.1) | 43 (39–47) | 27 (24–30) | 30 (27–33) |
| Physical activity | ||||
| Less activity than others | 777 (24.0) | 51 (48–54) | 25 (21–28) | 24 (22–27) |
| Same | 1,276 (42.8) | 44 (39–48) | 31 (28–34) | 26 (22–29) |
| More activity than others | 977 (33.2) | 40 (37–44) | 31 (27–34) | 29 (26–32) |
| Binge drinking | ||||
| No | 2,163 (82.8) | 43 (40–46) | 29 (27–32) | 28 (26–30) |
| Yes | 449 (17.2) | 44 (40–49) | 31 (26–37) | 24 (20–28) |
Table 2 presents the multivariate-adjusted odds ratio of multiple sunburns, among individuals who frequently engaged in sun protective behaviors compared to those who rarely did so. The odds of multiple sunburns were significantly lower in individuals who frequently avoided the sun by seeking shade (OR = 0.70, 95% CI 0.58, 0.83, p < 0.001) and in those who frequently wore long sleeves (OR = 0.73, 95% CI 0.57, 0.93, p = 0.01). Frequent sunscreen use was associated with higher odds of multiple sunburns (OR = 1.23, 95% CI 1.06, 1.42, p = 0.01). Hat use was not associated with multiple sunburns (OR = 0.91, 95% CI 0.78, 1.07, p = 0.15).
Table 2.
Odds ratio (OR) of multiple sunburns according to sun protective behaviors (Frequent use vs rare use) among US whites, 2003–2006 (n = 2,338).
| OR (95% CI) | p trend | |
|---|---|---|
| Shade | 0.70 (0.58, 0.83) | <0.001 |
| Long sleeves | 0.73 (0.57, 0.93) | 0.01 |
| Sunscreen | 1.23 (1.06, 1.42) | 0.01 |
| Hat | 0.91 (0.78, 1.07) | 0.15 |
Multivariate model adjusted for age, gender, BMI, income, education, season, sun sensitivity, alcohol intake, physical activity
Discussion
Our results indicate that despite being the most common sun protective behavior used by white Americans, sunscreen use is not associated with fewer sunburns. On the other hand, frequent shade and long sleeve use are associated with fewer self-reported burns in this population. These results raise important questions about the relative efficacy of these sun protective behaviors.
The major limitations of this study are the cross-sectional design and the lack of information on individual sun exposure habits. For example, pale individuals who are more susceptible to sunburn could very plausibly also use more sunscreen. Although we did not have information on individual sun exposure habits, we attempted to reduce the impact of these potential sources of bias by restricting our analysis to whites, adjusting for sun sensitivity, physical activity, and other socioeconomic factors. Furthermore, because all sun protective behaviors examined were self-reported by the same participants, we would expect any bias due to sun exposure habits to apply to all four behaviors. Our findings persisted despite these adjustments, which could suggest that the differences noted are more likely to be real.
These findings add to the literature by providing comparative data on sun protective behaviors and are consistent with prior studies of the determinants of sunburn and prevalence of sun protection behaviors in the US [12–14]. Previous analyses in NHANES demonstrated an inverse association of frequent shade and long sleeve use with lower serum 25-hydroxyvitamin D levels, which is a proxy for UV exposure. Interestingly, frequent sunscreen use was directly associated with higher vitamin D levels (Linos et al. submitted), which further supports the present findings. Prior studies have shown that sunscreen is rarely applied as thickly as recommended (2 mg/cm2) and that sunscreen use associated with higher sun exposure [8–10]. Taken together, these findings could suggest that shade and long sleeve use may be more effective at reducing UV exposure than sunscreen, as typically used by the American population.
The goal of any health policy should be to reduce overall burden of disease, and hence both the risks of skin cancer (especially melanoma) and benefits of vitamin D [15] must be considered when making sun protection recommendations. This trade-off has been explored in a thoughtful way by several scientists [16–18]. Although both UVA and UVB are involved in skin carcinogenesis, only UVB is required for vitamin D synthesis, so it may be possible to take advantage of this difference to create tailored sun protection recommendations for different latitudes, times of day, or seasons [19–21]. Interestingly, a recent study showed that shade use may differentially filter UVA over UVB light, making this another optimal way to sun protect while ensuring adequate vitamin D synthesis [22].
While sunscreen use may be effective in preventing SCC [7], its efficacy for melanoma prevention remains controversial [23–25], so sunscreen should not be the sole recommended agent used for sun protection. Since barrier methods including clothing and shade are generally more effective than sunscreen in reducing exposure to solar UV, greater emphasis should be placed on these approaches. Adopting comprehensive prevention strategies such as SunSmart are a high priority to reduce excessive sun exposure given the continuing increase in melanoma [26, 27] and non-melanoma skin cancer [28]. Future strategies must go beyond education alone and address practical, environmental, and behavioral barriers to sustainable sun protection [29].
Footnotes
Impact These findings highlight the need for comprehensive prevention strategies given the persistent rising rates of skin cancer in the United States.
Contributor Information
Eleni Linos, Department Dermatology, Stanford University School of Medicine, 450 Broadway St, Pavillion C, Redwood City, CA 94063, USA.
Elizabeth Keiser, Department Dermatology, Stanford University School of Medicine, 450 Broadway St, Pavillion C, Redwood City, CA 94063, USA.
Teresa Fu, Department Dermatology, Stanford University School of Medicine, 450 Broadway St, Pavillion C, Redwood City, CA 94063, USA.
Graham Colditz, Siteman Cancer Center, Washington University School of Medicine, St Louis, MO, USA.
Suephy Chen, Department of Dermatology, Emory University, Atlanta, GA, USA; Division of Dermatology, Department of Medicine, Atlanta VA Medical Center, Decatur, GA, USA.
Jean Y. Tang, Department Dermatology, Stanford University School of Medicine, 450 Broadway St, Pavillion C, Redwood City, CA 94063, USA
References
- 1.AAD Be Sun Smart Campaign. http://www.aad.org/public/sun/smart.html.
- 2.AMA http://www.ama-assn.org/ama1/pub/upload/mm/39/sunteen.pdf.
- 3.AMA American Medical Association 2010 http://www.ama-assn.org/ama/pub/news/news/2010-new-policies.shtml.
- 4.Green AC, Williams GM. Point: sunscreen use is a safe and effective approach to skin cancer prevention. Cancer Epidemiol Biomarkers Prev. 2007;16(10):1921–1922. doi: 10.1158/1055-9965.EPI-07-0477. [DOI] [PubMed] [Google Scholar]
- 5.Berwick M. Counterpoint: sunscreen use is a safe and effective approach to skin cancer prevention. Cancer Epidemiol Biomarkers Prev. 2007;16(10):1923–1924. doi: 10.1158/1055-9965.EPI-07-0391. [DOI] [PubMed] [Google Scholar]
- 6.Matsuoka LY, Ide L, Wortsman J, MacLaughlin JA, Holick MF. Sunscreens suppress cutaneous vitamin D3 synthesis. J Clin Endocrinol Metab. 1987;64(6):1165–1168. doi: 10.1210/jcem-64-6-1165. [DOI] [PubMed] [Google Scholar]
- 7.Green A, Williams G, Neale R, Hart V, Leslie D, Parsons P, et al. Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial. Lancet. 1999;354(9180):723–729. doi: 10.1016/S0140-6736(98)12168-2. [DOI] [PubMed] [Google Scholar]
- 8.Thieden E, Philipsen PA, Sandby-Moller J, Wulf HC. Sunscreen use related to UV exposure, age, sex, and occupation based on personal dosimeter readings and sun-exposure behavior diaries. Arch Dermatol. 2005;141(8):967–973. doi: 10.1001/archderm.141.8.967. [DOI] [PubMed] [Google Scholar]
- 9.Autier P, Boniol M, Dore JF. Sunscreen use and increased duration of intentional sun exposure: still a burning issue. Int J Cancer. 2007;121(1):1–5. doi: 10.1002/ijc.22745. [DOI] [PubMed] [Google Scholar]
- 10.Davis KJ, Cokkinides VE, Weinstock MA, O'Connell MC, Wingo PA. Summer sunburn and sun exposure among US youths ages 11 to 18: national prevalence and associated factors. Pediatrics. 2002;110(1 Pt 1):27–35. doi: 10.1542/peds.110.1.27. [DOI] [PubMed] [Google Scholar]
- 11.CDC Centers for disease control and prevention, national center for health statistics. National health and nutrition examination survey data sets and related documentation. 2009 Internet: http://www.cdc.gov/nchs/nhanes/nhanes_questionnaires.htm.
- 12.Brown TT, Quain RD, Troxel AB, Gelfand JM. The epidemiology of sunburn in the US population in 2003. J Am Acad Dermatol. 2006;55(4):577–583. doi: 10.1016/j.jaad.2006.05.029. [DOI] [PubMed] [Google Scholar]
- 13.Santmyire BR, Feldman SR, Fleischer AB., Jr Lifestyle high-risk behaviors and demographics may predict the level of participation in sun-protection behaviors and skin cancer primary prevention in the United States: results of the 1998 National Health Interview Survey. Cancer. 2001;92(5):1315–1324. doi: 10.1002/1097-0142(20010901)92:5<1315::aid-cncr1453>3.0.co;2-i. [DOI] [PubMed] [Google Scholar]
- 14.Hall HI, Saraiya M, Thompson T, Hartman A, Glanz K, Rimer B. Correlates of sunburn experiences among US adults: results of the 2000 National Health Interview Survey. Public Health Rep. 2003;118(6):540–549. doi: 10.1016/S0033-3549(04)50290-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Holick MF. Vitamin D status: measurement, interpretation, and clinical application. Ann Epidemiol. 2009;19(2):73–78. doi: 10.1016/j.annepidem.2007.12.001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Cicarma E, Porojnicu AC, Lagunova Z, Dahlback A, Juzeniene A, Moan J. Sun and sun beds: inducers of vitamin D and skin cancer. Anticancer Res. 2009;29(9):3495–3500. [PubMed] [Google Scholar]
- 17.Moan J, Porojnicu AC, Dahlback A, Setlow RB. Addressing the health benefits and risks, involving vitamin D or skin cancer, of increased sun exposure. Proc Natl Acad Sci USA. 2008;105(2):668–673. doi: 10.1073/pnas.0710615105. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Webb AR, Kift R, Durkin MT, O'Brien SJ, Vail A, Berry JL, et al. The role of sunlight exposure in determining the vitamin D status of the UK white adult population. Br J Dermatol. 2010;163(5):1050–1055. doi: 10.1111/j.1365-2133.2010.09975.x. [DOI] [PubMed] [Google Scholar]
- 19.Samanek AJ, Croager EJ, Gies P, Milne E, Prince R, McMichael AJ, et al. Estimates of beneficial and harmful sun exposure times during the year for major Australian population centres. Med J Aust. 2006;184(7):338–341. doi: 10.5694/j.1326-5377.2006.tb00267.x. [DOI] [PubMed] [Google Scholar]
- 20.Sliney DH, Wengraitis S. Is a differentiated advice by season and region necessary? Prog Biophys Mol Biol. 2006;92(1):150–160. doi: 10.1016/j.pbiomolbio.2006.02.007. [DOI] [PubMed] [Google Scholar]
- 21.Turnbull DJ, Parisi AV. Optimizing solar UV-radiation exposures for vitamin D3: comparing global and diffuse spectral UV radiation. Radiat Res. 2008;169(3):344–349. doi: 10.1667/RR1136.1. [DOI] [PubMed] [Google Scholar]
- 22.Turnbull DJ, Parisi AV. Latitudinal variations over Australia of the solar UV-radiation exposures for vitamin D3 in shade compared to full sun. Radiat Res. 2010;173(3):373–379. doi: 10.1667/RR1951.1. [DOI] [PubMed] [Google Scholar]
- 23.Green AC, Williams GM, Logan V, Strutton GM. Reduced melanoma after regular sunscreen use: randomized trial follow-up. J Clin Oncol. 2011;29(3):257–263. doi: 10.1200/JCO.2010.28.7078. [DOI] [PubMed] [Google Scholar]
- 24.Chang YM, Barrett JH, Bishop DT, Armstrong BK, Bataille V, Bergman W, et al. Sun exposure and melanoma risk at different latitudes: a pooled analysis of 5700 cases and 7216 controls. Int J Epidemiol. 2009;38(3):814–830. doi: 10.1093/ije/dyp166. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Gorham ED, Mohr SB, Garland CF, Chaplin G, Garland FC. Do sunscreens increase risk of melanoma in populations residing at higher latitudes? Ann Epidemiol. 2007;17(12):956–963. doi: 10.1016/j.annepidem.2007.06.008. [DOI] [PubMed] [Google Scholar]
- 26.Linos E, Swetter SM, Cockburn MG, Colditz GA, Clarke CA. Increasing burden of melanoma in the United States. J Invest Dermatol. 2009;129(7):1666–1674. doi: 10.1038/jid.2008.423. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Ries . Cancer Statistics Review 1975–2004. National Cancer Institute; 2008. [Google Scholar]
- 28.Rogers HW, Weinstock MA, Harris AR, Hinckley MR, Feldman SR, Fleischer AB, et al. Incidence estimate of nonmelanoma skin cancer in the United States, 2006. Arch Dermatol. 2010;146(3):283–287. doi: 10.1001/archdermatol.2010.19. [DOI] [PubMed] [Google Scholar]
- 29.Branstrom R, Kasparian NA, Chang YM, Affleck P, Tibben A, Aspinwall LG, et al. Predictors of sun protection behaviors and severe sunburn in an international online study. Cancer Epidemiol Biomarkers Prev. 2010;19(9):2199–2210. doi: 10.1158/1055-9965.EPI-10-0196. [DOI] [PMC free article] [PubMed] [Google Scholar]