http://orcid.org/0000-0002-1390-9753
Figures
Abstract
Purpose
To characterize smoking and alcohol use, and to describe predictors of oral cancer knowledge among a predominantly African-American population.
Methods
A cross-sectional study was conducted between September, 2013 among drag racers and fans in East St. Louis. Oral cancer knowledge was derived from combining questionnaire items to form knowledge score. Covariates examined included age, sex, race, marital status, education status, income level, insurance status, tobacco and alcohol use. Adjusted linear regression analysis measured predictors of oral cancer knowledge.
Results
Three hundred and four participants completed questionnaire; 72.7% were African Americans. Smoking rate was 26.7%, alcohol use was 58.3%, and mean knowledge score was 4.60 ± 2.52 out of 17. In final adjusted regression model, oral cancer knowledge was associated with race and education status. Compared with Caucasians, African Americans were 29% less likely to have high oral cancer knowledge (β = -0.71; 95% CI: -1.35, -0.07); and participants with a high school diploma or less were 124% less likely to have high oral cancer knowledge compared with college graduates (β = -1.24; 95% CI: -2.44, -0.41).
Conclusions
There was lower oral cancer knowledge among African Americans and those with low education. The prevalence of smoking was also very high. Understanding predictors of oral cancer knowledge is important in future design of educational interventions specifically targeted towards high-risk group for oral cancer.
Citation: Osazuwa-Peters N, Adjei Boakye E, Hussaini AS, Sujijantarat N, Ganesh RN, Snider M, et al. (2017) Characteristics and predictors of oral cancer knowledge in a predominantly African American community. PLoS ONE 12(5): e0177787. https://doi.org/10.1371/journal.pone.0177787
Editor: Hajo Zeeb, Leibniz Institute for Prvention Research and Epidemiology BIPS, GERMANY
Received: December 11, 2016; Accepted: May 3, 2017; Published: May 17, 2017
Copyright: © 2017 Osazuwa-Peters et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: Data is attached to the manuscript as a supplementary file.
Funding: The authors received no specific funding for this work.
Competing interests: The authors have declared that no competing interests exist.
Introduction
There will be an estimated 48,330 new cases of oral cavity & pharynx cancer (or oral cancer) in the United States in 2016, resulting in 9,570 deaths [1]. The causal factors associated with oral cancer are tobacco and excessive alcohol use, as well as human papillomavirus (HPV) infection; HPV being mostly associated with oropharyngeal subset [1–3]. There has been a steady decrease in the incidence of tobacco and alcohol associated oral cancer in the United States, while the HPV-associated oropharynx cancer has increased about 225% in the same time period [4–6]. However, tobacco and alcohol are still associated with at least 75% of all cases of head and neck cancers [7,8], and individuals who smoke and drink heavily have 30 to 48 increased odds of developing oral cancer compared to non-smokers or non-drinkers [1,9].
Although adult smoking rates in the United States is on a decline, coinciding with a decrease in oral cancer incidence, this decrease is not uniform across all social and demographic groups [10,11]. In cities and urban areas across the United States, there remains an increasing incidence of tobacco and alcohol use among African Americans [12]. Smoking rates, significantly higher than the national average have also been reported among fans at National Association for Stock Car Auto Racing (NASCAR) events [13,14].
It is a generally held belief that at least three-quarters of all oral cancers could be prevented as they are mostly associated with modifiable health behaviors, including smoking and alcohol use [8]. Along with primary prevention through avoiding risky behaviors, early detection often leads to better prognosis, and is a key objective in the Healthy People 2020 initiative [15]. However, early detection is not often realistic for most individuals, only one-third of patients present with early stage oral cancer disease [16]. The United States Preventive Services Task Force (USPSTF) guidelines on cancer screenings state that there is currently no evidence of any mortality benefits associated with mass screening of asymptomatic individuals for oral cancer [17], and recommends that asymptomatic oral cancer screening should be done as part of routine dental or medical check-up. However, there are more than 100 million Americans without dental insurance[18], and access to healthcare is a major driver of disparities in the community [19,20]. This indicates that there remains the need to provide some form of oral cancer screening services to specific populations deemed high-risk who may not have access to healthcare. In Kerala, India, a clinical trial involving almost 100,000 participants demonstrated that there could be some mortality benefits in mass oral cancer screening, especially among high-risk individuals [21]. There has also been other successful mass oral cancer screening programs in New York, and Maryland [22,23], as well as interventions in Italy and England employing the use of educational leaflets in increasing knowledge of oral cancer [24,25]. Compared to the cost of managing oral cancer, community oral cancer screenings and educational measures may be far more cost-effective [24,26]. During community oral cancer screening events, there is also an additional value of providing education and general awareness about oral cancer risk factors [27], since population knowledge levels are suboptimal [28–32], and knowledge level has been shown to be associated with oral cancer screening practices [33–37]. Other than community mass oral cancer screenings, there have also been other studies from Florida, Maryland, North Carolina, and New York that employed telephone-based surveys to elicit awareness of oral cancer, as well as knowledge of oral cancer risk factors (tobacco and alcohol) among whites, blacks, and other racial/ethnic groups [28,33,38,39].
Since urban African American communities, and race car fans both have high smoking rates, we sought to measure smoking rates in the two groups discussed above, as there is presently no study exclusively focused on drag race attendees who are predominantly African Americans. Previous studies on oral cancer and smoking rates among NASCAR fans have been predominated by Caucasians, since the sport has a much larger Caucasian following than African Americans [13,14,40]. We hypothesized that smoking rates will be higher in this community than the national average; and will be associated with educational levels, whereby those highly education will less likely be smokers. We also hypothesized that oral cancer knowledge will be low in this population, especially among African Americans.
The objectives of this study were to characterize smoking and alcohol use, and describe predictors of oral cancer knowledge among a predominantly African-American population of drag racing drivers and their fans.
Methods
Study design and participants
This was a cross-sectional study conducted between September 13–14, 2013 among drag racers and fans in East St. Louis. The study used a convenience sample that included drag racers and spectators at the Black Sunday race event hosted by the United Black Drag Racers Association (UBDRA) at Gateway Motorsports Park in East St. Louis. About 3,800 individuals attended the event and oral cancer screening and survey administration was done on September 13 and 14. The UBDRA provided a designated area with tents for different health screenings, including oral head and neck cancer screening. Participants of all races aged 18 years or older were eligible to take part in the study, and eligible individuals were asked to complete a survey as well as receive a complimentary oral head and neck cancer screening. Out of the approximately 3000 possible participants, 303 participants agreed to fill out the questionnaire resulting in a participation rate of about 10% which is similar to previous studies focusing on NASCAR fans [31]. In appreciation for their time, each participant was rewarded with a raffle ticket upon survey completion. Prizes available for raffle were of minimal monetary value, donated to the cancer outreach team by community partners. The Saint Louis University Institutional Review Board approval was obtained prior to beginning data collection and the study was performed in accordance with the Declaration of Helsinki (Protocol ID: 23696, approved on August 30, 2013).
Data collection
The study employed a previously validated 50-item, paper-based questionnaire adapted from previous studies [22,41–43] which had focused on similar or same population. Sociodemographic factors in the study include age, sex, race (Caucasian, African American, Others—which combines low-frequency responses), marital status (married/cohabitating, not married), education (≤ high school diploma, some college/associate degree, and college graduate or higher), household income (< $20,000; $25,000 –$39,999; $40,000 –$74,999; ≥ $75,000), and insurance status (yes, no). Cigarette smoking and alcohol use were assessed with the questions “Do you smoke?” and “Do you drink alcohol?” respectively. Results were coded as yes and no for both variables.
Knowledge of oral cancer
Participants were asked 17 questions to gauge their knowledge of oral cancer. General questions included such questions as: “In your opinion, oral cancers are more common in which age group?” “In your opinion, in which gender are oral cancers more common?” and “Does early diagnosis improve recovery from oral cancers?” Furthermore, basic questions concerning pathophysiology were asked such as “In your opinion, where are the most likely locations of oral cancers?” “In your opinion, which of these could cause oral cancer?” “How do you imagine oral cancers look like in the mouth?” “Can oral cancers manifest without initial complaint, pain, or symptom?” and “Is oral cancer a contagious disease?” Participants’ answers to the 17 questions were scored as 1 for correct and 0 for incorrect responses. Each participant’s answers were summed to create a scale, “knowledge score” with 17 being the highest and 0 being the lowest. All the questions with correct answers and respondent responses are presented in a table in the results section.
Data analysis
Bivariate association between participant characteristics and oral cancer knowledge were assessed using an independent samples t-test, one-way ANOVA and simple linear regression where appropriate. Multivariate linear regression model was used to assess the association between predictor variables and oral cancer knowledge score. All variables were included in the multivariable model regardless of their association with the outcome variable. Analyses were performed using SAS Version 9.4 (SAS Institute Inc, Cary, NC). Statistical tests were two-tailed and the significance level set at p < 0.05.
Results
A total of 304 participants (data in S1 Study Dataset) between 19 and 88 years (mean [SD], 48 [13]) completed the survey. More than 50% of participants were middle aged (45–64 years). Sixty five percent of participants identified themselves as males, 72.7% self-identified as African Americans, and 75.7% indicated they had health insurance. Smoking rate was 26.7% and 58.3% reported currently using alcohol. Mean oral cancer knowledge score was 4.6 (SD = 2.5) (Table 1). Bivariate analyses using an independent samples t-test, one-way ANOVA or simple linear regression revealed an association between age, sex, race, education and household income, and oral cancer knowledge score (Table 1). In addition, a chi-square test showed that tobacco use was significantly associated with educational status (Fig 1).
Chi-square test = 9.9174, p = 0070
Oral cancer knowledge
Table 2 contains the oral cancer knowledge questions used in the study as well as the correct answers for each question and participants’ responses. In the adjusted linear regression model, race and education remained significant predictors of oral cancer knowledge (Table 3). Compared with African Americans, Caucasians had higher oral cancer knowledge (β = 0.99; 95% CI: 0.32, 1.66). Participants with high school diploma or less had lower oral cancer knowledge compared with those with college degree or higher (β = -1.24; 95% CI: -2.44, -0.41). All other variables were not statistically significant predictors of oral cancer knowledge.
Discussion
African Americans are considered high-risk for developing tobacco-associated oral cancer [20,44]. This study aimed to quantify tobacco and alcohol rates, as well as predictors of oral cancer knowledge in a population of drag race attendees predominated by African Americans. Our results showed that smoking rate was 26.7% compared to 15.1% nationally [45]. This is consistent with previous findings that race car attendees at NASCAR smoke more compared to the general public [13,14,27]; however rate was lower than what was reported in a previous Caucasian dominated NASCAR race (31%) [40]. The high smoking rates found in our study lend support to the idea that screenings events associated with motor sports may provide an avenue for increasing awareness about main risk factors for developing oral cancer [27]. Also, significantly fewer smokers graduated from college compared with nonsmokers, supporting a previous study by White et al [40]. Our results support the notion that higher educational level is associated with diminished tobacco usage [46], and highlights the need for targeted interventions to reduce tobacco use in individuals with high school or less education.
Oral cancer knowledge
Most of participants had lower knowledge of oral cancer, irrespective of their smoking or drinking habits, however smokers perceived their risk of developing oral cancer to be higher than nonsmokers. The association between tobacco use and health risks has been targeted in previous interventions [47], and mass media oral cancer campaigns in states such as Florida, Maryland, and North Carolina have led efforts in increasing awareness of the association between smoking and oral cancer [23,29,30]. However, more targeted awareness campaigns may be needed, tailored specifically to various populations with characteristics that make them high-risk for developing oral cancer.
Predictors of oral cancer knowledge
Our study aimed at understanding the sociodemographic predictors of oral cancer knowledge, an important information in designing interventions to decrease cancer risk taking behaviors. After adjusting for all known covariates in our final model, there was a significant association between race, educational level, and oral cancer knowledge. African Americans traditionally have poorer oral cancer outcomes [48], and in our study, we found that they also had lower oral cancer knowledge compared with Caucasians. Since African Americans are also more likely to present with advanced stage disease than Caucasians [48], our finding of lower oral cancer knowledge in this population raises the question whether poor knowledge may be a contributing factor to late stage presentation among African Americans. If so, reducing racial disparities associated with knowledge of oral cancer could help improve early detection and increase survival rates, key elements of the Healthy People 2020 program.
Educational status was significantly associated with oral cancer knowledge. It is concerning that participants with a high school diploma or below had lower oral cancer knowledge than those with a college degree. A previous study from New York [22] that included African Americans found that educational level predicted awareness of an oral cancer exam, but not of oral cancer knowledge. Another study that assessed whether educational level predicts oral cancer knowledge was done in an American Indian population [11]. Coupled with our other finding that higher education was associated with significantly lower smoking rate, there may be some merit in designing educational interventions specific for African Americans with a history of chronic tobacco use, and those with little education. Among African Americans, this (those with little education) may be the subgroup that would benefit the most from an oral cancer screening and education effort, given the other associated risk factors [49].
Strengths and limitations
One of the main strengths of this study is that it is a product of a community based screening, rather than hospital based. A recent study indicates that compared to hospital-based screenings, community-based events are more effective in attracting participants with high-risk behaviors for oral cancer [27]. These high-risk behaviors have been described in the literature to include smoking and alcohol consumption, along with male predominance [49]. Based on these parameters, our study captured a high-risk group. Also, our study established that race—being African American, and educational status—having only a high school or less, are independent predictors of oral cancer knowledge among a predominantly African American population. We believe these predictors should be added to what is already known about characteristics of oral cancer high-risk groups. Attempts to identify and describe high-risk groups can help to gear screening efforts toward the populations that see greatest benefits from early cancer detection.
Some of the limitations of this study include survey limitations. Since our survey was paper based and voluntary, some of the completed surveys had some unanswered items. Participants with incomplete data were not excluded from the analysis which could lead to selection bias. However, all missing items were accounted for during data analysis; thus, we are confident that our results are not differentially skewed by the unanswered items. An additional limitation was that the sample for this study was limited to an event in one locality. Therefore, the results may not be representative of the general population of African Americans. However, we believe that since these results are from a primarily family entertainment event, it is more likely representative of the general population than if it was a hospital-based event, or even a health fair. A third limitation is the relatively small sample size. There were 3800 attendees at the drag racing event where the data was collected, but only 304 participated in the study. The fact that study and screening booth was in the vendor area, detached from the center of the racing event may explain this low number of study participants. However, this sample size is quite comparable to those from previous motor car associated oral cancer studies [13,40,50].
Future studies and educational interventions are needed in this population, and more interventions should be tailored to meet the needs of those with low educational levels, especially those with high school education or less. In addition, there is need to quantify actual oral cancer knowledge gains as a result of health education in this population; as well as to determine whether screening and educational efforts impact on tobacco and other high-risk behaviors. Future studies could also explore how educational leaflets [24,51] and other education strategies [52] tailored specifically to this population could lead to increase oral cancer knowledge. Finally, since African Americans are also more likely to present with advanced stage disease than Caucasians [48], future studies should investigate how poor oral cancer knowledge correlate with stage of presentation among oral cancer patients, stratified by race and other key factors, including gender.
Conclusions
Oral cancer knowledge is generally poor in the community and worse among the African Americans in our study population. With the changing landscape in oral cancer epidemiology, it is important that factors that predict oral cancer knowledge and risk perception be incorporated when designing interventions to prevent and detect oral cancer among African Americans and other high risk groups.
Supporting information
S1 Study Dataset. Analytical dataset used in the study.
https://doi.org/10.1371/journal.pone.0177787.s001
(SAS7BDAT)
Author Contributions
- Conceptualization: NOP MAV.
- Data curation: NOP EAB ASH NS RNG MS DT.
- Formal analysis: NOP EAB.
- Investigation: NOP EAB ASH NS RNG MS DT MAV.
- Methodology: EAB NOP.
- Project administration: NOP EAB MAV.
- Supervision: NOP MAV.
- Validation: EAB NOP.
- Visualization: EAB NOP MAV.
- Writing – original draft: NOP EAB ASH NS RNG MS DT MAV.
- Writing – review & editing: NOP EAB ASH NS RNG MS DT MAV.
References
- 1.
American Cancer Society (2015) Cancer Facts & Figures 2015. Atlanta: American Cancer Society.
- 2. Llewellyn CD, Johnson NW, Warnakulasuriya S (2004) Factors associated with delay in presentation among younger patients with oral cancer. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 97: 707–713. pmid:15184852
- 3. Osazuwa-Peters N (2013) Human papillomavirus (HPV), HPV-associated oropharyngeal cancer, and HPV vaccine in the United States—do we need a broader vaccine policy? Vaccine 31: 5500–5505. pmid:24095883
- 4. D'Souza G, Dempsey A (2011) The role of HPV in head and neck cancer and review of the HPV vaccine. Preventive medicine 53: S5–S11. pmid:21962471
- 5. Marur S, D'Souza G, Westra WH, Forastiere AA (2010) HPV-associated head and neck cancer: a virus-related cancer epidemic. Lancet Oncol 11: 781–789. pmid:20451455
- 6. Malloy KM, Ellender SM, Goldenberg D, Dolan RW (2013) A survey of current practices, attitudes, and knowledge regarding human papillomavirus-related cancers and vaccines among head and neck surgeons. JAMA Otolaryngol Head Neck Surg 139: 1037–1042. pmid:23989246
- 7. Hashibe M, Brennan P, Benhamou S, Castellsague X, Chen C, Curado MP, et al. (2007) Alcohol drinking in never users of tobacco, cigarette smoking in never drinkers, and the risk of head and neck cancer: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium. J Natl Cancer Inst 99: 777–789. pmid:17505073
- 8. Warnakulasuriya S (2009) Global epidemiology of oral and oropharyngeal cancer. Oral Oncol 45: 309–316. pmid:18804401
- 9. Rodriguez T, Altieri A, Chatenoud L, Gallus S, Bosetti C, Negri E, et al. (2004) Risk factors for oral and pharyngeal cancer in young adults. Oral Oncol 40: 207–213. pmid:14693246
- 10. Luryi AL, Yarbrough WG, Niccolai LM, Roser S, Reed SG, Nathan C-AO, et al. Public Awareness of Head and Neck Cancers: A Cross-Sectional Survey. JAMA Otolaryngology–Head & Neck Surgery.
- 11. Dwojak S, Deschler D, Sargent M, Emerick K, Guadagnolo BA, Petereit D (2015) Knowledge and screening of head and neck cancer among american indians in South dakota. Am J Public Health 105: 1155–1160. pmid:25320895
- 12. Carter JM, Winters RD, Lipin R, Lookabaugh S, Cai D, Friedlander PL (2013) A faith- and community-based approach to identifying the individual at risk for head and neck cancer in an inner city. Laryngoscope 123: 1439–1443. pmid:23401194
- 13. Hapner ER, Wise JC (2011) Results of a Large-Scale Head and Neck Cancer Screening of an At-Risk Population. Journal of Voice 25: 480–483. pmid:20346618
- 14. Hapner ER, Bauer KL, Wise JC (2011) The Impact of a Community-Based Oral, Head, and Neck Cancer Screening for Reducing Tobacco Consumption. Otolaryngology—Head and Neck Surgery.
- 15.
U.S. Department of Health and Human Services Healthy People 2020. Washington, DC.
- 16. Subramanian S, Chen A (2013) Treatment patterns and survival among low-income medicaid patients with head and neck cancer. JAMA Otolaryngol Head Neck Surg 139: 489–495. pmid:23598992
- 17. Moyer VA (2014) Screening for oral cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 160: 55–60. pmid:24276469
- 18.
Services UDoHaH Oral Health in America: A Report of the Surgeon General—Executive Summary Rockville, MD: US Department of Health and Human Services, National Institute of Dental and Craniofacial Research, National Institutes of Health.
- 19. Morse DE, Kerr AR (2006) Disparities in oral and pharyngeal cancer incidence, mortality and survival among black and white Americans. J Am Dent Assoc 137: 203–212. pmid:16521387
- 20. Silverman S (2001) Demographics and occurrence of oral and pharyngeal cancers The outcomes, the trends, the challenge. The Journal of the American Dental Association 132: 7S–11S. pmid:11803655
- 21. Sankaranarayanan R, Ramadas K, Thomas G, Muwonge R, Thara S, Mathew B, et al. (2005) Effect of screening on oral cancer mortality in Kerala, India: a cluster-randomised controlled trial. The Lancet 365: 1927–1933.
- 22. Cruz GD, Le Geros RZ, Ostroff JS, Hay JL, Kenigsberg H, Franklin DM (2002) Oral cancer knowledge, risk factors and characteristics of subjects in a large oral cancer screening program. J Am Dent Assoc 133: 1064–1071; quiz 1094. pmid:12198985
- 23. Maybury C, Horowitz AM, Goodman HS (2012) Outcomes of oral cancer early detection and prevention statewide model in Maryland. J Public Health Dent 72 Suppl 1: S34–38.
- 24. Petti S, Scully C (2007) Oral cancer knowledge and awareness: primary and secondary effects of an information leaflet. Oral Oncol 43: 408–415. pmid:16996779
- 25. Humphris GM, Ireland RS, Field EA (2001) Immediate knowledge increase from an oral cancer information leaflet in patients attending a primary health care facility: a randomised controlled trial. Oral Oncol 37: 99–102. pmid:11120490
- 26. Subramanian S, Sankaranarayanan R, Bapat B, Somanathan T, Thomas G, Mathew B, et al. (2009) Cost-effectiveness of oral cancer screening: results from a cluster randomized controlled trial in India. Bull World Health Organ 87: 200–206. pmid:19377716
- 27. Harris MS, Phillips DR, Sayer JL, Moore MG (2013) A comparison of community-based and hospital-based head and neck cancer screening campaigns: identifying high-risk individuals and early disease. JAMA Otolaryngol Head Neck Surg 139: 568–573. pmid:23787414
- 28. Riley JL, Pomery EA, Dodd VJ, Muller KE, Guo Y, Logan HL (2013) Disparities in knowledge of mouth or throat cancer among rural Floridians. J Rural Health 29: 294–303. pmid:23802931
- 29. Tomar SL, Logan HL (2005) Florida adults' oral cancer knowledge and examination experiences. J Public Health Dent 65: 221–230. pmid:16468464
- 30. Patton LL, Agans R, Elter JR, Southerland JH, Strauss RP, Kalsbeek WD (2004) Oral cancer knowledge and examination experiences among North Carolina adults. J Public Health Dent 64: 173–180. pmid:15341141
- 31. Osazuwa-Peters N, Wang DD, Namin A, Vivek J, O'Neill M, Patel PV, et al. (2015) Sexual behavior, HPV knowledge, and association with head and neck cancer among a high-risk group. Oral Oncol 51: 452–456. pmid:25683135
- 32. Warnakulasuriya KA, Harris CK, Scarrott DM, Watt R, Gelbier S, Peters TJ, et al. (1999) An alarming lack of public awareness towards oral cancer. Br Dent J 187: 319–322. pmid:10589135
- 33. Horowitz AM, Moon H-s, Goodman HS, Yellowitz JA (1998) Maryland Adults' Knowledge of Oral Cancer and Having Oral Cancer Examinations. Journal of Public Health Dentistry 58: 281–287. pmid:10390710
- 34. Howell JL, Shepperd JA, Logan H (2013) Barriers to oral cancer screening: a focus group study of rural Black American adults. Psychooncology 22: 1306–1311. pmid:22926896
- 35. Shepperd JA, Howell JL, Logan H (2014) A survey of barriers to screening for oral cancer among rural Black Americans. Psychooncology 23: 276–282. pmid:24115516
- 36. Choi Y, Dodd V, Watson J, Tomar SL, Logan HL, Edwards H (2008) Perspectives of African Americans and dentists concerning dentist-patient communication on oral cancer screening. Patient Educ Couns 71: 41–51. pmid:18242933
- 37. Ostroff JS, Hay JL, Schantz SP, Maher MM (2000) A survey of smoking status and cancer risk perceptions among participants attending a hospital-based head and neck screening program. Psychology & Health 14: 979–990.
- 38. Patton LL, Agans R, Elter JR, Southerland JH, Strauss RP, Kalsbeek WD (2004) Oral Cancer Knowledge and Examination Experiences Among North Carolina Adults. Journal of Public Health Dentistry 64: 173–180. pmid:15341141
- 39. Oh J, Kumar J, Cruz G (2008) Racial and ethnic disparity in oral cancer awareness and examination: 2003 New york state BRFSS. J Public Health Dent 68: 30–38. pmid:18248342
- 40. White LJ, Chin-Quee AL, Berg CJ, Wise JC, Hapner ER (2012) Differences in Head and Neck Cancer Risk Perception between Smoking and Nonsmoking NASCAR Attendees. Otolaryngology—Head and Neck Surgery 147: 63–68. pmid:22368040
- 41. Cannick GF, Horowitz AM, Drury TF, Reed SG, Day TA (2005) Assessing oral cancer knowledge among dental students in South Carolina. J Am Dent Assoc 136: 373–378. pmid:15819353
- 42. Reed SG, Duffy NG, Walters KC, Day TA (2005) Oral cancer knowledge and experience: a survey of South Carolina medical students in 2002. J Cancer Educ 20: 136–142. pmid:16122360
- 43. Carter LM, Ogden GR (2007) Oral cancer awareness of undergraduate medical and dental students. BMC Med Educ 7: 44. pmid:18005417
- 44. Ragin CC, Langevin SM, Marzouk M, Grandis J, Taioli E (2011) Determinants of head and neck cancer survival by race. Head Neck 33: 1092–1098. pmid:20967872
- 45.
Prevention CfDCa (2015) Current Cigarette Smoking Among Adults in the United States.
- 46. Gilman SE, Martin LT, Abrams DB, Kawachi I, Kubzansky L, Loucks EB, et al. (2008) Educational attainment and cigarette smoking: a causal association? International Journal of Epidemiology 37: 615–624. pmid:18180240
- 47. Siahpush M, McNeill A, Hammond D, Fong GT (2006) Socioeconomic and country variations in knowledge of health risks of tobacco smoking and toxic constituents of smoke: results from the 2002 International Tobacco Control (ITC) Four Country Survey. Tob Control 15 Suppl 3: iii65–70.
- 48. Osazuwa-Peters N, Christopher KM, Hussaini AS, Behera A, Walker RJ, Varvares MA (2016) Predictors of stage at presentation and outcomes of head and neck cancers in a university hospital setting. Head Neck 38 Suppl 1: E1826–1832.
- 49. Gourin CG, Kaboli KC, Blume EJ, Nance MA, Koch WM (2009) Characteristics of participants in a free oral, head and neck cancer screening program. Laryngoscope 119: 679–682. pmid:19213043
- 50. White LJ, Creighton FX Jr, Wise JC, Hapner ER (2014) Association between HPV and Head and Neck Cancer: Differences in Understanding among Three Distinct Populations. American Journal of Cancer Prevention 2: 14–19.
- 51. Humphris GM, Duncalf M, Holt D, Field EA (1999) The experimental evaluation of an oral cancer information leaflet. Oral Oncol 35: 575–582. pmid:10705093
- 52. Lopez-Jornet P, Camacho-Alonso F, Minano FM, Sanchez-Siles M (2013) Evaluation of the different strategies to oral cancer knowledge: a randomized controlled study. Psychooncology 22: 1618–1623. pmid:22962026