The study was approved by the Medical College of Wisconsin Institutional Review Board. Our sample was one of convenience. We recruited 150 mothers who where the parent or legal guardian of a daughter who had not received the HPV vaccine. Mothers were 50 Hispanic, 50 non-Hispanic white, and 50 African American. In an attempt to control for important demographic variables, such as income, education, and insurance status, that may account for cross-cultural differences, we recruited only mothers who were receiving Women Infant and Children (WIC) federal program services at one of four city Health Department clinics in Milwaukee, Wisconsin. The eligibility requirements to receive WIC are determined by the U.S. Department of Health. To be eligible to receive WIC, women must be a) pregnant or the new mother of an infant up to age 5, b) resident of the state where she is applying to receive WIC services, and c) between 100 and 185% of the federal poverty guidelines.
Mothers were approached while waiting to be seen by a WIC program coordinator and asked if they would like to answer a brief questionnaire that would determine their eligibility to participate in the study. Mothers who volunteered answered a brief screening questionnaire to check that they met eligibility criteria. Mothers who self-reported being the parents or legal guardians of a daughter between the ages of 6 and 19 who had not been vaccinated against HPV were asked to participate in the study. All study materials were available in English and Spanish.
Participants answered a demographic questionnaire assessing age, number of children and their ages, education level, employment, and insurance status. Participants were also asked if they had previously thought about vaccinating their daughters against HPV and, if so, to name the place where they heard about the HPV vaccine. Prior experience with cervical neoplasia or cancer, HPV, or another sexually transmitted infection (STI) was assessed by asking mothers to indicate if they personally had been diagnosed with cervical cancer or neoplasia, HPV, or another STI and if they knew someone (friend or relative) who had been diagnosed. Response options were yes and no.
Intention to vaccinate daughters was the main outcome measure and was assessed with a measure that consisted of 5 items assessing intention to vaccinate, intention to convince daughter to get the vaccine if she objected, intention to convince a significant other if he or she objected, and intention to talk to a pediatrician or healthcare provider about it. Response options ranged from 1, definitely no, to 7, definitely yes. The Cronbach alpha for the Hispanic group was 0.91, for the non-Hispanic white group was 0.90, and for the African American group was 0.88.
The personal predictors of intention to vaccinate daughters were also assessed. Perceptions of risk were assessed with the following three items: How likely is your daughter to acquire HPV in her lifetime? What are the chances that your daughter will acquire HPV in her lifetime? and What is the probability that your daughter will acquire HPV in her lifetime? Response options for the first 2 items ranged from 1, very unlikely/almost zero, to 7, very likely/almost certain. Response options for the third item ranged from 0 to 100% in increments of 10. The first two items assessing risk perceptions were combined to form one scale. We included a slight variation in wording (e.g., likely vs. chances) in an attempt to capture slight variations in participants' nonquantitative estimates of risk. Interitem correlations were 0.87 for the Hispanic group, 0.93 for the non-Hispanic white group, and 0.84 for the African American group.
Perceived benefits of vaccinating daughters were assessed with the following item: “How effective is the vaccine in protecting against HPV? Response options ranged from 1, not at all, to 7, very much. Severity of acquiring HPV were assessed with the following three items: If your daughter acquired HPV, how severe would the consequences be? How traumatic would it be for your daughter? How embarrassed would your daughter be? Response options ranged from 1, not at all, to 7, very much. Interitem correlations were 0.91 for the Hispanic group, 0.90 for the non-Hispanic white group, and 0.88 for the African American group.
Barriers against vaccinating daughters were assessed with a variety of items asking about the potential side effects of the vaccine, worry that vaccination will lead to early initiation of sexual relations, more sexual activity, discouragement from engaging in other cancer-prevention activities such as cervical cancer screening, number of required vaccine shots, vaccine cost, and daughters' fear of vaccination. Response options ranged from 1, not at all, to 7, very much. Because of low interitem correlations, only the 2 items that assessed sexual-related barriers were combined to form one scale. Interitem correlations were 0.77 for the Hispanic group 0.86 for the non-Hispanic white group, and 0.87 for the African American group. The rest of the items assessing barriers were included in the analyses as individual predictors.
Normative predictors were assessed with the following item: How many of your friends' daughters have been vaccinated against HPV? Response options were none of them, some of them, almost all, and all of them. The extent to which the decision to vaccinate was shared was assessed with the following item: How much of the decision to vaccinate your daughter is up to you? Response options ranged from 1, not up to me, to 7, entirely up to me. This question was followed with an open-ended question that asked participants to state their relationship with the person with whom they shared the decision.
We first conducted a series of regression equations to understand if norms predicted additional variation, beyond that predicted by prior experience with HPV, neoplasia, and other STIs and barriers and health beliefs, in intention to vaccinate daughters across ethnic groups. Thus, we conducted separate multivariate blocked linear regressions for each ethnic group. In step one, we entered the variables that assessed prior experience with HPV, cervical neoplasia or cancer, and an STI using the forced entry procedure. Our rationale for entering prior experience with HPV, cervical neoplasia, or other STIs in the first step was to determine if barriers to vaccination and health beliefs predicted additional variation above and beyond prior experience. In the second step, we entered all the barriers to vaccination and health beliefs. In the third step of the equation, we entered norms. We entered norms in the last step of the equation to understand the percentage of variance that norms would account for after all the hypothesized variables had been included in the model. Our intent was to understand whether normative aspects may contribute differently to the behavioral intentions of members of certain cultural groups.
We conducted a final analysis to formally test whether culture (Hispanic, non-Hispanic white, and African American) moderates the expected relationship between intention to vaccinate daughters and norms, and we followed the procedure recommended by Cohen et al.15
and created two dummy codes for the variable ethnic group. The first code compared African Americans with Hispanics and non-Hispanic whites. Consequently, African Americans were coded 1, and the other two groups were coded 0. The second code compared Hispanics with African Americans and non-Hispanic whites Consequently, Hispanics were coded 1, and the other two groups were coded 0. We conducted a blocked hierarchical regression analysis to predict vaccination intentions by entering in the first step of the equation education and insurance status, as there were significant differences in these variables as a function of ethnicity; We then entered codes, norms, and the products of each of the codes and norms in the second step of the equation. The significance of higher-order terms independent of first-order terms would suggest the presence of interactions and would lend support to findings obtained when analyses are conducted separately for each ethnic group.