Abstract
Among caregivers of adolescent girls, awareness of human papillomavirus (HPV) is strongly associated with vaccine uptake. Little is known, however, about the predictors of HPV awareness among low-income ethnic minority groups in the U.S. The purpose of this study is to understand demographic factors associated with HPV awareness among low-income, ethnic minority mothers in Los Angeles County. We conducted a cross-sectional study of caregivers of adolescent girls through the Los Angeles County Department of Public Health Office of Women’s Health’s hotline. The majority of the participants were foreign-born (88%), one quarter lacked a usual source of care, and one quarter lacked public or private health insurance for their daughter. We found that one in three participants had never heard of HPV or the vaccine. Mothers that were unaware of HPV were significantly more likely to conduct the interview in a language other than English and to lack health insurance for their daughters. HPV vaccine awareness was much lower in our caregiver sample (61%) than in a simultaneous national survey of caregivers (85%). The associations between lack of awareness and use of a language other than English, as well as lack of health insurance for their daughter indicate the need for HPV vaccine outreach efforts tailored to ethnic minority communities in the U.S.
Keywords: Human papillomavirus, Vaccination, Health disparities, Cervical cancer prevention, Low-income
1. Introduction
The benefits of the prophylactic human papillomavirus (HPV) vaccines will not be fully realized without high levels of coverage across all eligible populations. Despite the availability of the HPV vaccine since 2006, rates for initiation of the three dose series among adolescent girls in the U.S. hover at around 57% [1]. Ethnic minority women bear a disproportionate burden of cervical cancer in the U.S. [2]. Although data from the National Immunization Survey suggest ethnic minority adolescents may initiate the HPV vaccine at a higher rate than non-Latino whites [3], a number of other studies suggest HPV vaccine initiation rates among ethnic minorities may be lower than national estimates, at least in some settings [4–8].
A growing number of studies have assessed correlates of HPV vaccine uptake among adolescent girls [4,9–11]. In prior studies, HPV and HPV vaccine awareness among caregivers have been found to be two of the strongest predictors of vaccine uptake among adolescent girls [5,11–15]. These findings are consistent with numerous health behavior theories, which posit that knowledge, of which awareness is the most basic form, is a necessary condition for health behavior change [16–18]. Many of these prior studies, however, focus on national samples and provide little information about underserved populations or racial/ethnic minorities.
This study reports on data from a survey of mothers of vaccine-eligible girls in Los Angeles to assess rates and correlates of HPV vaccine initiation [5]. The purpose of this study was to identify correlates of HPV awareness, including demographics, health care access, general vaccine attitudes, and childhood vaccine history among mothers of adolescent girls eligible for the vaccine, for future intervention development.
2. Materials and methods
2.1. Setting
The study was a collaboration between the University of California, Los Angeles (UCLA) and the Los Angeles County Department of Public Health, Office of Women’s Health (OWH). The OWH operates a multi-language health education hotline targeting low-income, uninsured, and ethnic minority women in the county. OWH operates the telephone hotline in six languages (English, Spanish, Korean, Cantonese, Mandarin, Armenian), receiving approximately 10,000 calls per year from low-income women (<200% of the federal poverty level). Services provided include telephone education about preventive health issues and referrals to preventive health care appointments. UCLA project staff provided hotline operators with training in research interviewing techniques, the study protocol, and human subjects research protections. OWH hotline operators were responsible for conducting recruitment and data collection activities with continued guidance from UCLA.
2.2. Identification of participants and study procedures
All women who called into the hotline between January 2009 and January 2010 were screened for eligibility. Eligible women were between the ages of 18 and 65, spoke one of the hotline’s six most common languages at the time of the study (English, Spanish, Mandarin, Cantonese, Korean, Armenian), and were the primary medical decision-maker for a girl 9 to 18 years of age. Callers with more than one age-eligible girl were asked to provide information about the one with the earliest birth month. After addressing the caller’s primary need, the operators introduced the study, screened interested women for eligibility, obtained verbal informed consent, and proceeded to complete the telephone interview with willing, eligible callers. All participants (n = 490) received HPV vaccine print materials in their preferred language and a $10 grocery store gift certificate. The study was approved by the Institutional Review Boards of the Los Angeles County Department of Public Health and UCLA.
2.3. Survey instrument and conceptual framework
Development of the survey instrument was guided by the Health Behavior Framework, utilizing items drawn from population-based surveys and our own prior work, as has been previously described [5]. As necessary, items were modified to ensure appropriateness for administration by telephone to a low-literacy, low-education, and multilingual population. The survey instrument was translated from English into all hotline languages using established methods that utilized at least two bilingual translators for each language and an iterative review process [5,19–21]. The 75-item survey for the parent study assessed a broad range of topics related to HPV vaccination. However, given the purpose of this study was to assess factors associated with HPV awareness, analyses for the present study utilized data on a limited number of relevant topics: demographic characteristics, access to care, general vaccine attitudes, and HPV knowledge and awareness.
2.4. Measures
The main study outcome was HPV awareness among mothers/caregivers, which was measured through the dichotomous (yes/no) question “Have you ever heard of human papillomavirus, or HPV?” Women were also asked whether they were aware of the HPV vaccine (yes/no), and if applicable, the source of HPV vaccine awareness. Among mothers who were aware of HPV, follow-up questions assessed whether they knew that HPV causes cervical cancer, is sexually transmitted, and resolves without treatment.
For mothers, demographics including age, race/ethnicity, household income, education, nativity, years in U.S. (among foreign-born), insurance status, and having a usual source of care, were measured. General attitudes toward vaccines were captured through two perception questions related to the vaccine benefits and side effects. For adolescent girls, measures of age, insurance status, usual source of care, and receipt of childhood vaccines were based on mother report. Caregiver covariates included age, income (<$12,000, ≥ $12,000), insurance status (any, none), usual source of care (yes, no), ethnicity (Latina, Chinese, Korean, African American, other), and language of interview (English, non-English). Adolescent girl covariates included age, insurance status (any, none), usual source of care (yes, no), and receipt of all childhood vaccines (yes, no).
2.5. Statistical analysis
Descriptive statistics were conducted to characterize the sample with regard to demographics, access to health care, and the main study outcome: awareness of HPV. t-Tests and chi-square analyses were used to assess bivariate relationships between HPV awareness and demographic factors of the mothers and daughters, access to care of the mothers and daughters, general vaccine attitudes of mothers. Multivariate logistic regression analyses were then conducted to identify independent correlates of HPV awareness controlling for other factors. Statistical significance of variables in the bivariate analyses (p < 0.05), tests of multicollinearity, and conceptual importance of predictors informed the selection of variables included in our final multivariate model. Adjusted odds ratios (OR) with 95% confidence intervals (95% CI) are reported, and statistical significance was assessed at the 0.05 level. Data were analyzed using SAS version 9.2 (SAS Institute, 2008).
3. Results
Demographic information is displayed in Table 1. The study participants (n = 490) were almost exclusively foreign-born (88%) and about half were Latina (52%), 20% Chinese and 13% Korean. Women in the “other” race/ethnicity category (7%) reported being non-Hispanic white, multiracial, or from other Asian subgroups. Among foreign-born women, the mean number of years in the U.S. was 18. Nearly half of women had less than a high school diploma (47%), and the majority made less than $24,000 per year (74%). Respondents were 44 years of age on average, consistent with the typical age of parent of adolescent children.
Table 1.
Demographic and health care characteristics of mothers/caregivers and adolescent girls (n = 490).
| Characteristic | % | N |
|---|---|---|
| Mothers/caregivers | ||
| Age (mean, SD) | 44 (7.22) | 481 |
| Race/ethnicity | ||
| Latina | 52% | 255 |
| Chinese | 20% | 98 |
| Korean | 13% | 66 |
| African American | 8% | 38 |
| Other race | 7% | 33 |
| Interview language | ||
| English | 19% | 92 |
| Non-English | 81% | 398 |
| Household income | ||
| <$12,000 or unemployed | 36% | 162 |
| $12,000 to <$24,000 | 38% | 175 |
| ≥$24,000 | 26% | 118 |
| Education | ||
| <High school diploma | 47% | 223 |
| High school diploma | 28% | 132 |
| Any college or more | 25% | 120 |
| Nativity | ||
| Foreign-born | 88% | 432 |
| Born in U.S. | 12% | 58 |
| Years in U.S., among foreign-born (mean, SD) | 18 (8.74) | 422 |
| Insurance status | ||
| Uninsured | 75% | 366 |
| Public or private insurance | 25% | 121 |
| Have usual source of care | ||
| Yes | 51% | 247 |
| No | 49% | 241 |
| General vaccine attitudes | ||
| Agrees immunization against disease is a good thing | 92% | 447 |
| Agrees immunizations have more side effects than benefits | 12% | 59 |
| Adolescent girls | ||
| Age (mean, SD) | 14 (2.84) | 487 |
| Insurance status | ||
| Uninsured | 26% | 127 |
| Private or public insurance | 74% | 362 |
| Have usual source of care | ||
| Yes | 71% | 349 |
| No | 29% | 141 |
| Received childhood vaccines | ||
| Yes | 96% | 468 |
| No | 4% | 20 |
Close to two-thirds of mothers reported that they had heard of HPV (63%) with a similar proportion reporting they had heard specifically of the HPV vaccine (61%) (Table 2). The proportion of caregivers who had heard of HPV was lowest among Koreans (45%), followed by Latinas (64%) and Chinese (66%), and highest among African Americans (68%) or those reporting “other” race/ethnicity (69%) (data not shown). Among mothers who were aware of HPV (n = 306), two-thirds of respondents were knowledgeable that HPV causes cervical cancer, 71% knew that HPV is a sexually transmitted disease, and only 4% knew that HPV usually resolves without treatment. Mothers reported having heard of the HPV vaccine from a variety of sources, the most common being from a doctor or nurse (66%) and the least common from the web (3%).
Table 2.
Mother/caregiver HPV awareness and knowledge.
| % | N | |
|---|---|---|
| HPV awareness | ||
| Heard of HPV | 63% | 306 |
| Heard of HPV vaccine | 61% | 294 |
| Source of HPV vaccine awareness (among HPV vaccine aware mothers/caregivers)* | ||
| Doctor or nurse | 66% | 193 |
| Family or friends | 21% | 61 |
| Newspaper/magazine | 16% | 46 |
| TV advertisement | 31% | 90 |
| TV news | 30% | 87 |
| Web | 3% | 8 |
| Radio | 6% | 18 |
| Other | 6% | 19 |
| HPV knowledge (among HPV aware mothers) | % correct | N |
| HPV causes cervical cancer. | 66% | 200 |
| HPV is a sexually transmitted disease. | 71% | 215 |
| HPV usually goes away without treatment. | 4% | 12 |
Not mutually exclusive categories.
Table 3 presents results of the bivariate analyses. Because the proportion of mothers who were aware of HPV was approximately 20 percentage points lower among Koreans compared to all other racial/ethnic groups in descriptive analyses, we subsequently collapsed this variable into Korean vs. non-Korean for further analyses. Factors significantly associated with a higher likelihood of HPV awareness among mothers included non-Korean ethnicity, completing the interview in English (vs. another language), greater years in the U.S. (among foreign born), and having a usual source of care. Mothers who reported that their daughters were insured and had gotten their childhood vaccines were significantly more likely to have heard of HPV than mothers whose daughters lacked insurance or had not received childhood vaccines in unadjusted analyses. In multivariate logistic regression analyses (Table 4), only two factors independently predicted a higher likelihood of HPV awareness: completing the interview in English (aOR 2.27, 95% CI 1.24, 4.16) and the daughter being insured (aOR 2.40, 95% CI 1.34, 4.29).
Table 3.
Sample characteristics by HPV awareness.
| Characteristic | % Aware | N |
|---|---|---|
| Mothers/caregivers | ||
| Age (mean, SD) | ||
| Aware | 43.58 (7.25) | 300 |
| Not aware | 44.22 (7.19) | 180 |
| Race/ethnicity** | ||
| Korean | 45% | 30/66 |
| Non-Korean | 65% | 276/423 |
| Interview language*** | ||
| English | 78% | 71/91 |
| Non-English | 59% | 235/398 |
| Household income | ||
| <$12,000 or unemployed | 65% | 106/162 |
| ≥$12,000 | 62% | 182/293 |
| Education | ||
| ≤High school diploma | 61% | 215/355 |
| Any college or more | 68% | 82/120 |
| Nativity | ||
| Foreign-born | 61% | 264/431 |
| Born in U.S. | 72% | 42/58 |
| Years in U.S. (among foreign-born)** | ||
| <15 Years | 51% | 67/131 |
| ≥15 Years | 67% | 233/349 |
| Insurance status | ||
| Uninsured | 61% | 222/365 |
| Public or private insurance | 69% | 83/121 |
| Have usual source of care* | ||
| Yes | 67% | 166/246 |
| No | 58% | 139/241 |
| General vaccine attitudes | ||
| Immunization against disease is a good thing | ||
| Agrees | 63% | 280/447 |
| Disagrees/neither | 64% | 25/39 |
| Immunizations have more side effects than benefits | ||
| Agrees | 54% | 32/59 |
| Disagrees/neither | 64% | 273/425 |
| Adolescent girls | ||
| Age | ||
| <14 years | 59% | 125/211 |
| ≥14 years | 65% | 180/275 |
| Insurance status** | ||
| Uninsured | 52% | 66/127 |
| Private or public insurance | 66% | 240/362 |
| Have usual source of care | ||
| Yes | 65% | 227/348 |
| No | 56% | 79/141 |
| Received childhood vaccines* | ||
| Yes | 63% | 297/468 |
| No | 40% | 8/20 |
p < 0.05.
p < 0.01.
p < 0.001.
Table 4.
Multivariate correlates of HPV awareness.
| Covariates | Adjusted OR (95% CI) |
|---|---|
| Mothers/caregivers | |
| Age (continuous) | 0.97 (0.94, 1.00) |
| Household income < $12,000 (Ref: ≥$12,000) | 1.05 (0.68, 1.62) |
| Any insurance (Ref: no insurance) | 0.92 (0.54, 1.57) |
| Have a usual source of care (Ref: no) | 1.40 (0.88, 2.22) |
| Non-Korean ethnicity (Ref: Korean) | 1.68 (0.86, 3.28) |
| English interview (Ref: Non-English) | *2.27 (1.24, 4.16) |
| Adolescent girl | |
| Age (continuous) | 1.08 (0.99, 1.16) |
| Any insurance (Ref: no insurance) | *2.40 (1.34, 4.29) |
| Have usual source of care (Ref: no) | 0.67 (0.37, 1.22) |
| Received childhood vaccines (Ref: did not) | 1.54 (0.54, 4.42) |
p ≤0.05.
Given the substantially lower level of awareness among Korean mothers, we conducted additional analyses to assess other potential differences in demographics between Korean mothers and mothers from other racial/ethnic groups (data not shown). Compared to mothers from other racial/ethnic groups, Korean mothers reported higher levels of income and education and were more likely to be foreign born and complete the interview in a language other than English. Korean mothers were also less likely to report having a usual source of care, health insurance for their daughter, or to report that their daughter had received her childhood vaccinations. Further, they were more likely to agree that “vaccines have more side effects than benefits” compared to mothers from other racial/ethnic groups (ps ≤0.05).
4. Discussion
Results revealed that about one third of mothers in our sample were not aware of HPV, with a similar proportion not aware of the HPV vaccine. These levels of awareness are somewhat lower than other studies conducted around the same time. Dorell and colleagues [3] showed that among a national sample of caregivers for teens, 92% had heard of HPV and 85% had heard of the HPV vaccine. This finding suggests the need for efforts to enhance awareness as an important step in increasing use of the vaccine in low-income ethnic minority communities.
Another purpose of this study was to identify correlates of awareness that might provide guidance for future intervention efforts. In unadjusted analyses, we found a number of factors associated with HPV awareness. Lack of awareness was most common among Korean women in our sample; however, race/ethnicity did not emerge as a significant predictor in multivariate analyses, which suggests that race/ethnicity may be associated with other correlates we examined. For example, Korean mothers in our sample were less likely to have a usual source of care or to report their daughter had health insurance or had completed her childhood vaccinations compared to women from other racial/ethnic groups. Understanding that Korean mothers may be at greater risk for poor awareness could prove valuable for program planning and outreach efforts targeted toward this particular community, even if that lack of awareness is associated with other factors. Exploration of multidimensional constructs underlying cultural values and preferences contributing to differences in HPV awareness would be a valuable contribution by future studies.
Daughters’ receipt of childhood vaccines was also a strong correlate of HPV awareness in unadjusted analyses, although general attitude toward vaccines was not associated with awareness. Conceivably, mothers who reported that their daughters received all their childhood vaccines have a history of engagement with the health care system, which may have resulted in greater awareness of HPV. It is possible that a favorable attitude toward vaccines was not a significant predictor because attitude does not reflect greater access to the health care system, an important source of HPV information. In our study, two-thirds of women heard about the vaccine from a doctor or nurse, suggesting that leveraging providers may be a promising strategy to increase HPV recommendations and the need of further investigation of potential gaps in information dissemination in the clinical setting.
While daughter’s insurance status was associated with HPV awareness, having a usual source of care was not associated with HPV awareness in the adjusted analyses. Enrolling a daughter in a health insurance plan (typically public insurance in our sample) may reflect greater engagement with the health care system and higher health literacy than simply having a usual source of care. Similarly, completing the survey in English, a marker for English language proficiency, was related to higher likelihood of HPV awareness. All girls in our sample, regardless of insurance status, were eligible to receive the vaccine for free or at low cost through the Vaccines for Children program if visiting a county-affiliated immunization clinic. Our results point to the need for linguistically targeted outreach to ensure that all women regardless of insurance status or language preferences receive accurate and culturally-appropriate information about the HPV vaccine and how the vaccine can be accessed for free or at low cost.
Awareness is a necessary but not sufficient condition for performing a health behavior. As women become aware of the HPV, they may have additional questions or concerns that may function as barriers to getting their daughters vaccinated. Future research will be necessary to identify these concerns as they arise, which will help shape ongoing vaccine promotion efforts.
A few study limitations should be noted. Given the cross-sectional nature of the study, our findings demonstrate associations between predictors and HPV awareness but do not establish causality. In addition, our ability to compare across ethnic groups is limited given the unequal sample sizes across groups. Furthermore, mother report of childhood vaccine receipt was not verified through medical record review. Thus, over- or underreporting may have occurred, and this measure may have been subject to recall bias or differences in interpretation. Finally, findings from our low-income, ethnically diverse sample may not be generalizable to other populations.
In summary, these study results point to a need for interventions to ensure that all mothers of adolescent girls, regardless of insurance status or language, have the information they need to make an educated decision about getting the HPV vaccine for their daughters. Though there is a paucity of published educational interventions among low-literate or minority populations [22], interventions involving culturally- and community-informed messaging have shown efficacy in increasing HPV and HPV vaccine knowledge and intent to vaccinate girls [23–25]. Targeting outreach efforts to ethnically diverse populations to ensure widespread dissemination of information about HPV and the vaccine thus holds the promise of ultimately enhancing uptake across the population and reducing the burden of cervical cancer on society’s most vulnerable groups.
Acknowledgments
We gratefully acknowledge the mothers who participated in the study and the Office of Women’s Health hotline operators who conducted the telephone interviews. This work was supported by CDC/NCI UCLA Cancer Prevention and Control Research Network (U48 DP000056/SIP 16-04).
Footnotes
Conflict of interest statement
The authors have no potential conflicts of interest to disclose.
Contributor Information
Beth A. Glenn, Email: bglenn@ucla.edu, bethaglenn@hotmail.com.
Jennifer Tsui, Email: jk1341@cinj.rutgers.edu.
Rita Singhal, Email: risinghal@ph.lacounty.gov.
Leah Sanchez, Email: leahsanchez@ucla.edu.
Narissa J. Nonzee, Email: nnonzee@ucla.edu.
L. Cindy Chang, Email: clichang@ucla.edu.
Victoria M. Taylor, Email: vtaylor@fhcrc.org.
Roshan Bastani, Email: bastani@ucla.edu.
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