Copyright © eContent Management Pty Ltd. Contemporary Nurse (2014) 47(1–2): 97–107.
Mothers’ knowledge, health beliefs and intentions to vaccinate their daughters against human papillomavirus in Korea Jin-Sun Kim and Hee-Young Kang Department of Nursing, Chosun University, Gwangju, South Korea
Abstract: This study aimed to identify the factors influencing Korean mothers’ intentions to vaccinate their daughters against human papillomavirus (HPV). In Korea, a mother’s will is a key determinant for daughters receiving the cervical cancer vaccine. The factors influencing mothers’ intentions to vaccinate their daughters against HPV were the perceived benefits of the vaccine, having acquaintances with cervical cancer experiences, awareness of the cervical cancer vaccine, believing that one’s daughter needs regular Pap smears, and occupation; these variables explained 32% of the variance. The perceived benefits of the vaccine were the strongest predictor of mothers’ intentions. The findings of the current study suggested that mothers’ perceived benefits about the HPV vaccine play an important role in their choice to vaccinate their daughters.
Keywords: mothers, beliefs, intention, human papillomavirus vaccine, cervical cancer
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uman papillomavirus (HPV) is a major risk factor for cervical cancer (Moscicki, 2008). HPV has been detected in more than 90% of patients with cervical cancer. In particular, it has been reported that HPV-16 and HPV-18 account for more than 70% of the cases of cervical cancer (Bosch & Munoz, 2002). According to the data from the International Agency for Research on Cancer (2013), the incidence of cervical cancer in Korea (10.8 per 100,000 persons per year) was higher than the average rate among more developed regions the United States (9 per 100,000 persons per year). Recently, an HPV vaccine with proven efficacy has been developed, and it has been approved by 80 countries, including the USA’s and Korea’s Food & Drug Administrations. The USA and Korea recommend that 9–26-year-old girls and women receive the vaccine (Rhee et al., 2010). HPV vaccination has generated hope of substantially lowering the incidence of cervical cancer (Kim, Park, & Park, 2010; Kwan et al., 2009). Therefore, to prevent cervical cancer, it is important for the target population to accept HPV vaccination and receive the vaccine. Mothers’ acceptance and behavioral intentions to have their daughters vaccinated have a major impact on HPV vaccination (Dempsey, Abraham, Dalton, & Ruffin, 2009; Waller, Marlow, & Wardle, 2006).
Knowledge about HPV and HPV vaccination are very important factors that increase behavioral intentions to receive the vaccine (Choi et al., 2008; Rosenstock, Strecher, & Becker, 1988; Walsh et al., 2008), but it has been reported that the understanding of knowledge about HPV and HPV vaccination are low among the general public (Choi et al., 2008; Walsh et al., 2008). In addition, health beliefs about vaccination promote behavioral intentions to vaccinate and have an important impact on vaccination (Kahn, Rosenthal, Hamann, & Bernstein, 2003). Accordingly, it is important to provide mothers of daughters with knowledge about HPV and to improve their health beliefs about vaccination. This study, based on the Health Belief Model (HBM), considered behavioral intentions, which are a preceding factor of compliance with a preventive health behavior, as a key variable. Rosenstock et al. (1988) reported that knowledge has direct and indirect influences on behavioral intentions. The HBM consists of five constructs proposed to influence the likelihood that an individual will engage in a given health behavior to avoid an undesirable health consequence. These constructs include perceived susceptibility (the perceived likelihood that one will experience a consequence), perceived severity (the perceived seriousness of the consequences associated with the condition), perceived benefits (the potential
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advantages of engaging in the health behavior to prevent the undesired consequence), and perceived barriers (the perceived obstacles to engaging in the health behavior). Cues to action, which represent the fifth construct, trigger appropriate health behaviors (Becker & Maiman, 1975; Rosenstock et al., 1988). The HBM has been used in previous studies to identify beliefs about HPV, cervical cancer, and the acceptability of the HPV vaccine among women (Hsu et al., 2009; Kahn et al., 2003; Lopez & McMahan, 2007; Marlow, Forster, Wardle, & Waller, 2009). However, the authors of previous studies are unaware of any Korean studies based on the HBM that have been conducted to identify the factors associated with mother’s intentions to vaccinate their daughters and themselves. Those types of studies have been conducted in different cultures. The aims of this study were to examine mothers’ intentions to vaccinate their daughters against HPV and the factors associated with mothers’ intentions to vaccinate their daughters. The specific aims of this study are as follows: (a) to identify the differences in mothers’ intentions to vaccinate their daughters against HPV by the participants’ demographic and HPV-related characteristics, (b) to measure the participants’ knowledge and health beliefs about HPV and HPV vaccination and their intentions to received the HPV vaccine, (c) to assess the correlation between the participants’ knowledge and health beliefs about HPV and HPV vaccination and their intentions to vaccinate their daughters against HPV, and (d) to identify the factors associated with the participants’ intentions to vaccinate their daughters against HPV. Methods Design This is a cross-sectional study that aimed to identify the factors associated with mothers’ intentions to vaccinate their daughters against HPV. This study was based on the HBM, which explains personal health behaviors. Behavioral intentions, which precede compliance with preventive health behaviors, were used as a key variable (i.e., mothers’ intentions to recommend that their daughters receive the HPV vaccine to 98
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consequently prevent cervical cancer). In this study, perceived susceptibility refers to the perceived likelihood of HPV infection and cervical cancer. Perceived severity refers to the perceived seriousness of HPV infection and cervical cancer. The perceived benefits are the potential advantages of HPV vaccination, cost, and availability. The perceived barriers are the adverse effects of the vaccine. Cues to action refer to persuasive appeals from the media, family, friends, or a health care provider. Sample The participants in this study were a convenience sample of mothers (with daughters) aged 30 years and older who had a good understanding of the content of the survey, who could communicate with spoken words, and who agreed to participate in this study after hearing and understanding the explanation of the purpose and procedures of this study. Using the G*Power 3.1.2. program, the calculated necessary sample size was 116 for regression analysis with five independent variables to detect an effect size of 0.80, two-sided alpha of 0.05, and power of 80%. Therefore, sample size of this study was enough to attain adequate statistical power to detect a meaningful effect. Assuming that some participants would drop out, we aimed to survey at least 130 people. There were 129 questionnaires returned; of these, 113 questionnaires were analyzed after eliminating two incomplete questionnaires and 14 people whose daughters had been vaccinated against HPV more than once. Research tools A self-administered questionnaire was developed that consisted of four domains: Demographic and HPV-related characteristics, knowledge, and health beliefs about HPV and HPV vaccination, and mothers’ intentions to vaccinate their daughters against HPV. All of the questions were adapted and modified from previous relevant published studies and survey instruments. The content validity was verified by two obstetric/ gynecologic doctors. To establish cross-cultural adaptability, translation, back translation and pilot testing were conducted. The translation was
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Mothers’ knowledge to vaccinate their daughters against HPV completed by two authors of this study, and the back translation was conducted by two bilingual individuals. No discrepancies were found. A pilot study was conducted with five mothers. One item was modified to reflect the feedback from the pilot study. Moreover, this questionnaire included a fact sheet that was developed by the researchers and validated by the two doctors. The fact sheet explained that HPV was a STI responsible for genital warts and cervical cancer. Moreover, the fact sheet explained that a HPV vaccine had been developed and was available to prevent the infection. The adverse effects and the price of the HPV vaccine were also mentioned. Knowledge about HPV and HPV vaccination The participants’ knowledge about HPV and HPV vaccination was measured using a modified version of the Knowledge and Perceptions Survey (KAPS) developed by Yacobi et al. (1999). The KAPS was developed to measure the perceived severity, susceptibility, knowledge of HPV, and intentions to change behavior. Only the knowledge scale was used in this study. Knowledge was investigated using yes-or-no questions. The knowledge scale included 13 true-orfalse items. The responses were coded such that each correct answer received a score of one, and ‘incorrect’ or ‘unsure’ answers were coded as zero. The knowledge score was calculated by summing the scores for the correct answers. The total possible scores ranged from 0–13, with higher scores reflecting higher levels of knowledge. Good face validity, construct validity, and internal consistency have been reported for this scale (Yacobi et al., 1999). The internal consistency indicated by the Kuder–Richardson Formula 20 (KR-20) for this study sample was 0.87. Health beliefs about HPV and HPV vaccination The participants’ health beliefs toward HPV and HPV vaccination were measured using seven subscales of the Health Belief Model (Rosenstock et al., 1988) developed by Hsu et al. (2009). The instrument used a five-point Likert response scale from one (strongly disagree) to five (strongly
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agree) and included 17 items on various topics: susceptibility to HPV infection and cervical cancer (two items), disease severity (three items), perceived benefits (three items), cost and availability (two items), adverse effects of the vaccine (three items), attributes of HPV (one item) and cues to action (three items). Hsu et al. (2009) reported that the internal reliability of the scale ranged from 0.57–0.82. The Cronbach’s alpha for this study sample was 0.84. Mothers’ intentions to vaccinate their daughters against HPV The participants’ intentions to have their daughters vaccinated against HPV were measured using a visual analog scale (VAS). The participants were asked, ‘What is the likelihood of your having your daughter get the HPV vaccine?’ and instructed to place a mark on a 10-cm (100-mm) horizontal VAS. An answer of 0 cm indicated no intention, whereas 10 cm indicated the strongest intention. Data collection This study collected data in communities located in a metropolitan district with schools and churches, in most cases. The study period was from July 27–October 6, 2011. Before collecting the data, the researcher explained the purpose of this study to the participants. The participants’ written informed consent was obtained voluntarily after attending to the ethical aspects of participation and explaining that their anonymity would be respected. The data were collected using a self-report structured questionnaire. We surveyed the participants in person, and it took approximately 15 minutes to complete each questionnaire. Data analysis The data were analyzed using PASW/PC version 18.0. The following analyses were conducted: (a) the demographic and HPV-related characteristics, the participants’ knowledge and health beliefs about HPV and HPV vaccination, and the level of intention to receive the HPV vaccine were analyzed with descriptive statistics; (b) the differences in mothers’ intentions to vaccinate their daughters against HPV according to the participants’ demographic
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and HPV-related characteristics were analyzed using a t-test or a one-way ANOVA; (c) to assess the correlation between the study variables and HPV vaccination intentions, Pearson’s correlation coefficients were calculated; and (d) stepwise multiple regression analysis was used to identify the factors associated with the participants’ intentions to vaccinate their daughters against HPV. Ethical considerations To ensure that ethical principles were followed, this study was conducted after being approved by the Institutional Review Board (IRB) at our university. To further address the ethical aspects of participation, we explained the purpose of this study and offered tips for filling out the questionnaires to mothers individually. Written informed consent was obtained from all of the study participants, and they were informed that they could withdraw from the study at any time, though they had agreed to participate in the study. In addition, the participants were informed about the risks and benefits associated with participating in the study and that their anonymity would be preserved. We encrypted the files with passwords selected by the participants to prevent their information from being exposed and deleted all unnecessary identifying information. The participants were given small gifts in return for completing the questionnaires. Results Characteristics of the participants and differences in mothers’ intentions to vaccinate their daughters against HPV according to their demographics and HPV-related characteristics Of the participants who received this survey, the average age was 44.76 years; 66.4% attended college or received higher education; and 46.9% were Christians. The participants responded that 62.8% of them were working, and 61.1% perceived that they belonged to the middle class. With regard to HPV-related characteristics, 70.8% of the participants had never heard of HPV before, and 84.1% had heard of the cervical cancer vaccine. Of the participants, 90.3% said they wanted to know more about HPV. None of the respondents had a history of 100
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HPV infection. Most of them (97.3%) had no history of genital warts or STDs. The proportion of respondents who had never received a Papanicolaou test (34.5%) was higher than the proportion who received one regularly (19.5%). Furthermore, 67.3% responded that the purpose of the Papanicolaou test was to test for cervical cancer. Of the participants, 86.7% responded that none of their acquaintances had a history of cervical cancer, whereas 13.3% had acquaintances who had experienced it. The respondents who said their daughters needed to get a Pap smear regularly comprised 55.8% of the sample, and 77.9% had never talked about the HPV vaccine with their daughters. Of the respondents, 59.3% would be willing to pay for HPV vaccination if it were more than $110 per one shot, and 95.6% said they would be willing to do it if it were free. Looking into the differences in mothers’ intentions to vaccinate their daughters against HPV according to the participants’ demographics and HPV-related factors (Table 1), there were differences associated with occupation (p = 0.002), awareness of the cervical cancer vaccine (p = 0.003), having acquaintances with cervical cancer experiences (p = 0.004), and believing that one’s daughter needs regular Pap smears (p