Comparison of sun exposure and protection behaviors between urban and rural residents without a history of melanoma in the Midwestern United States

Abstract

To the Editor: Skin cancer is rising in the United States despite being considered mostly preventable. Skin cancer mortality is higher in rural versus urban populations,1Henley S.J. Anderson R.N. Thomas C.C. Massetti G.M. Peaker B. Richardson L.C. Invasive cancer incidence, 2004–2013, and deaths, 2006–2015, in nonmetropolitan and metropolitan counties—United States.MMWR Surveill Summ. 2017; 66: 1-13Crossref Scopus (167) Google Scholar but the role of ultraviolet radiation (UVR) risk behaviors in this discrepancy remains unclear. Given the increased outdoor lifestyle in rural areas, understanding UVR risk behaviors will inform future interventions. We compared summer sun exposure and protection behaviors by urban/rural status among adults living in the Midwest. We hypothesized that rural residents would report poorer sun behaviors than urban residents.2Matthews K.A. Croft J.B. Lui Y. et al.Health-related behaviors by urban-rural county classification—United States, 2013.MMWR Surveill Summ. 2017; 66: 1-8Crossref PubMed Scopus (139) Google Scholar We analyzed health behaviors from a cross-sectional follow-up survey, conducted from July to October 2015, of the Skin Health Study. Methods are described elsewhere.3Vogel R.I. Strayer L.G. Engelman L. et al.Sun exposure and protection behaviors among long-term melanoma survivors and population controls.Cancer Epidemiol Biomarkers Prev. 2017; 26: 607-613Crossref PubMed Scopus (27) Google Scholar Briefly, the Skin Health Study was a 2004 to 2009 population-based case-control study of individuals with versus without melanoma that assessed associations between risk of melanoma and indoor tanning use. This secondary analysis was restricted to control subjects (n = 660, 59.9% among eligible) who completed the follow-up survey. Control subjects subsequently diagnosed with melanoma (n = 21) or residing outside of the Midwest (n = 18) were excluded. Data, including residential status, are reported from the follow-up survey only. Primary outcomes were self-reported measures of sun exposure and protection behaviors during the summer.4Glanz K. Yaroch A.L. Dancel M. et al.Measures of sun exposure and sun protection practices for behavioral and epidemiologic research.Arch Dermatol. 2008; 144: 217-222Crossref PubMed Scopus (248) Google Scholar Each measure was dichotomized as optimal/suboptimal as previously defined3Vogel R.I. Strayer L.G. Engelman L. et al.Sun exposure and protection behaviors among long-term melanoma survivors and population controls.Cancer Epidemiol Biomarkers Prev. 2017; 26: 607-613Crossref PubMed Scopus (27) Google Scholar: suboptimal defined as average daily sun exposure of ≥2 hours; ≥1 sunburn in the past year; never/rarely/sometimes using sunscreen, wearing a shirt with sleeves or a hat with a wide brim, and staying in the shade. Urban/rural status was defined by Rural Urban Commuting Area codes based on participants' residential ZIP codes at follow-up. We included potential confounders identified a priori: age, sex, education, annual household income, body mass index, current smoking, phenotypic risk, and family history of melanoma. We compared outcomes between rural/urban participants using chi-square tests and multivariable logistic regression models in SAS software (v 9.4; SAS Institute Inc, Cary, NC). Of 621 included in the analysis, 77.1% were classified as urban residents, reflective of the Minnesota population distribution. Urban participants were younger, more educated, and reported higher incomes than rural participants (Table I).Table IDemographic characteristics among urban and rural participantsUrban (N = 479)Rural (N = 142)P valueAge at survey, y, N (mean ± SD)479 (55.5 ± 8.9)142 (56.5 ± 9.2).22Body mass index, kg/m2, N (mean ± SD)479 (27.7 ± 5.8)142 (28.0 ± 5.2).60Sex, n (%).96 Female289 (60.3)86 (60.6) Male190 (39.7)56 (39.4)Race, n (%).02 Other23 (4.8)1 (0.7) White, non-Hispanic456 (95.2)141 (99.3)College graduate, n (%)<.0001 No204 (43.2)98 (69.5) Yes268 (56.8)43 (30.5)Marital status, n (%).47 Never married/widowed/divorced90 (19.0)23 (16.3) Married/partnered384 (81.0)118 (83.7)Income, n (%)<.0001 <$75,000145 (30.7)73 (51.8) $75,000-$149,999192 (40.7)37 (26.2) ≥$150,00086 (18.2)11 (7.8) Prefer not to say49 (10.4)20 (14.2)Current smoker, n (%).43 No438 (92.2)128 (90.1) Yes37 (7.8)14 (9.9)Phenotypic risk index, n (%).22 Low181 (38.0)50 (35.2) Intermediate213 (44.7)58 (40.9) High83 (17.4)34 (23.9)Family history of melanoma, n (%).74 No331 (69.1)96 (67.6) Yes148 (30.9)46 (32.4)SD, Standard deviation. Open table in a new tab SD, Standard deviation. Rural participants more often spent ≥2 hours outside on weekdays than urban participants (59.6 vs 40.3%; crude odds ratio = 2.28 [95% confidence interval 1.55-3.36], P < .0001) with similar results for weekend day exposure (Table II). Experience of sunburns was similar across groups. Rural participants were more likely to report suboptimal sunscreen behavior (69.0 vs 59.8%, crude odds ratio = 1.54 [95% confidence interval 1.03-2.31], P = .03; not significant in the multivariate model). While not statistically significant, rural participants were more likely to report suboptimal behaviors for all other sun protection behaviors.Table IISun exposure and protection behaviors compared between rural and urban participantsUrbanRuralUnadjustedAdjusted model∗Adjusted for sex, age, education, annual household income, smoking status, and body mass index.n (%)n (%)OR rural vs urban (95% CI)P valueOR rural vs urban (95% CI)P valueHours outside in summer on weekdays ≤1 hour281 (59.7)57 (40.4)1 (reference)1 (reference) ≥2 hours190 (40.3)84 (59.6)2.28 (1.55-3.36)<.00011.82 (1.21-2.76).005Hours outside in summer on weekend days ≤1 hour103 (21.9)21 (14.9)1 (reference)1 (reference) ≥2 hours368 (78.1)120 (85.1)1.60 (0.96-2.67).071.79 (1.01-3.18).05No. of sunburns in past 12 months 0299 (63.4)90 (63.8)1 (reference)1 (reference) ≥1173 (36.7)51 (36.2)0.95 (0.64-1.40).780.97 (0.62-1.49).88When outside in the summer on a warm sunny day, how often do you… Wear sunscreen, n (%)Optimal†Reported always or often doing the behavior when outside in the summer on a warm sunny day.191 (40.2)44 (31.0)1 (reference)1 (reference)Suboptimal‡Reported never, rarely, or sometimes doing the behavior when outside in the summer on a warm sunny day.284 (59.8)98 (69.0)1.54 (1.03-2.31).031.26 (0.80-2.00).31 Wear shirt with sleeves, n (%)Optimal†Reported always or often doing the behavior when outside in the summer on a warm sunny day.319 (67.3)85 (59.9)1 (reference)1 (reference)Suboptimal‡Reported never, rarely, or sometimes doing the behavior when outside in the summer on a warm sunny day.155 (32.7)57 (40.1)1.39 (0.94-2.05).101.39 (0.89-2.17).15 Wear a hat with brim, n (%)Optimal†Reported always or often doing the behavior when outside in the summer on a warm sunny day.109 (23.1)28 (19.7)1 (reference)1 (reference)Suboptimal‡Reported never, rarely, or sometimes doing the behavior when outside in the summer on a warm sunny day.363 (76.9)114 (80.3)1.22 (0.77-1.95).400.99 (0.59-1.65).95 Stay in the shade, n (%)Optimal†Reported always or often doing the behavior when outside in the summer on a warm sunny day.142 (29.9)32 (22.5)1 (reference)1 (reference)Suboptimal‡Reported never, rarely, or sometimes doing the behavior when outside in the summer on a warm sunny day.333 (70.1)110 (77.5)1.47 (0.95-2.28).091.37 (0.85-2.21).2CI, Confidence interval; OR, odds ratio.∗ Adjusted for sex, age, education, annual household income, smoking status, and body mass index.† Reported always or often doing the behavior when outside in the summer on a warm sunny day.‡ Reported never, rarely, or sometimes doing the behavior when outside in the summer on a warm sunny day. Open table in a new tab CI, Confidence interval; OR, odds ratio. These findings are consistent with the few studies on this topic. Rural (vs urban) residents were less likely to use sunscreen or seek shade in one unadjusted analysis,5Zahnd W.E. Goldfarb J. Scaife S.L. Francis M.L. Rural-urban differences in behaviors to prevent skin cancer: an analysis of the Health Information National Trends Survey.J Am Acad Dermatol. 2010; 62: 950-956Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar though differences disappeared when controlling for confounders. Unadjusted comparisons may be more relevant if demographic characteristics are highly correlated with rural status itself. Midwestern rural residents may have greater summer sun exposure and poorer sun protection behaviors. Interventions are needed to address safe sun behaviors in this population to reduce their burden of skin cancer. None disclosed.