Human papillomavirus vaccination uptake: a longitudinal study showing ethnic differences in the influence of the intention-to-vaccinate among parent-daughter dyads

Figures & data

Table 1. Baseline socio-demographic characteristics of the parents/guardians of 12–13 year-old girls, HPV-vaccination intention, actual childhood vaccination and HPV vaccination uptake, stratified by country of birth of parents; HPV vaccination acceptability study in Amsterdam, the Netherlands, 2014

	Total		Dutch versus non-Dutch
			Dutch		non-Dutch
	(n = 438)		(n = 273)		(n = 165)
	n	%	n	%	n	%	p-value1
Socio-demographic characteristics
Gender, parents^1
Female	395	90%	250	92%	145	88%	0.278
Male	42	10%	23	8%	19	12%
Age, parents
Median age (IQR) in years	45	(42–48)	46	(43–49)	44	(39–48)	<0.001
≤ 45 years	182	42%	95	35%	87	53%	<0.001
45–54 years	236	54%	168	62%	68	42%
≥ 55 years	18	4%	10	4%	8	5%
Education, parents^2
Low	168	39%	84	31%	84	52%	<0.001
Intermediate	140	32%	98	36%	42	26%
High	127	29%	91	33%	36	22%
Religion, parents
No religion	240	55%	199	73%	41	25%	<0.001
Protestantism^3	79	18%	45	17%	34	21%
Catholicism^4	54	12%	26	10%	28	17%
Islam	49	11%	0	0%	49	30%
Other	12	3%	2	1%	10	6%
HPV Vaccination Intention (5 point-scale, range −2 to 2)
Median (IQR), parents	2	(1–2)	2	(1–2)	2	(1–2)
Mean (SD), parents	1.47	0.92	1.53	0.90	1.36	0.96	0.013
Median (IQR), daughters	1.5	(1–2)	1.5	(1–2)	1.5	(1–2)
Mean (SD), daughters	1.32	0.91	1.36	0.90	1.25	0.92	0.146
HPV vaccination status daughters^5
No vaccination	53	12%	27	10%	26	16%	0.068
≥ 1 vaccination	385	88%	246	90%	139	84%
Infant, toddler and preschool children vaccination^6
Not all	14	3%	6	2%	8	5%	0.126
All	424	97%	267	98%	157	95%
School-age vaccination^7
Not all	19	4%	9	3%	10	6%	0.169
All	419	96%	264	97%	155	94%
Overall childhood vaccination status^8
Not all	21	5%	9	3%	12	7%	0.059
All	417	95%	264	97%	153	93%

Abbreviations: IQR, interquartile range; SD, standard deviation.

Data were missing for gender (n = 1), age (n = 2), education (n = 3) and religion (n = 4).

1. Continuous variables were compared using a Wilcoxon rank-sum test. Categorical variables were compared using a Pearson’s chi-squared test.

2. Education was based on the highest level of education and categorized into low (no education, primary level), intermediate (lower general secondary school, higher secondary school, or secondary vocational school) and high (university-preparatory school, polytechnic, or university).

3. Includes all Christian religions not belonging to the Catholic category.

4. Includes Coptic Christian and Greek-orthodox.

5. As rounded percentages are shown here, totals may exceed 100%.

6. In the Netherlands, a girl is offered the following vaccinations between 0 and 4 years of age (without exceptions): DTaP (diphtheria-tetanus-acellular pertussis vaccine), HiB (Haemophilus influenza type b vaccine), MMR (measles-mumps-rubella vaccine). The PCV (pneumococcal conjugate vaccine) was introduced in 2006 and was therefore not applicable in this cohort.

7. In the Netherlands, a girl is offered the following vaccinations at 9 years of age (without exceptions): DTP and MMR.

8. Overall vaccination status between 0 and 9 years. As the HPV vaccination is given at the age of 12 to 13 years, this vaccine was not included in the overall childhood vaccination status.

Table 2. Association between HPV vaccination intention and vaccination uptake of 12–13 year-old daughters and their parents stratified by ethnicity. HPV vaccination acceptability in Amsterdam, the Netherlands, 2014

	Dutch (n = 273)		non-Dutch (n = 165)		non-Dutch vs. Dutch (n = 438)
	OR	95%CI	OR	95%CI	xOR	95%CI
Model 1 (12–13 year-old girls)
Intention 12–13 year-old girls (−2;2)	4.87	(2.97–8.01)	3.79	(2.28–6.30)	0.78	(0.38–1.58)
Model 2 (parents)
Intention parent (−2;2)	7.55	(3.98–14.32)	2.54	(1.68–3.85)	0.34	(0.16–0.72)

Abbreviations: CI, confidence interval; OR, odds ratio.

Interpretation of the OR of intention: if intention increases with one unit, we expect the odds to be HPV vaccinated to increase with the specified OR for intention (e.g. if intention among Dutch girls increases with one unit, we expect to see the odds to be HPV vaccinated to increase 4.87 times).

Interpretation of xOR: this is the odds ratio of the interaction factor. It indicates the factor with which the OR of the Dutch group should be multiplied to obtain the odds ratio for intention in the non-Dutch group (e.g. the xOR for intention for non-Dutch parents is 0.34. In order to obtain the odds ratio for the non-Dutch group for the effect of one step increase in intention on the HPV vaccination uptake, we multiply the OR of the Dutch parents (7.55) with the xOR (0.34), resulting in an OR of 2.54. So the effect of intention on vaccination uptake is significantly less strong in the non-Dutch parents compared to the Dutch parents.

Figure 1. Heat map of the marginal prediction of HPV vaccination uptake corresponding to each combination of HPV vaccination intention among parents and their daughters. (a). Dutch parent-daughter dyads. (b). Non-Dutch parent-daughter dyads. Circle size is proportional to the number of parent-daughter dyads for a given combination of intentions; non-observed combinations were omitted from the graph. The color of the circle indicates that ≥80% (green), 60–79% (yellow), 40–59% (orange), 20–39% (pink) or <20% (red) of daughters for a given combination were vaccinated against HPV

Figure 2. Generalized structural equation model including determinants of the intention of parents and daughters associated with HPV vaccination uptake. 2a. Dutch parent-daughter dyads. 2b. Non-Dutch parent-daughter dyads. The numbers next to each pathway indicate the regression coefficient (β) and the 95% confidence interval. ε indicates the random error component within the individual regression models. In the Dutch GSEM: the pathway between attitude and past experiences with cervical cancer was removed from the model as it was not significant

de Martel C, Plummer M, Vignat J, Franceschi S. Worldwide burden of cancer attributable to HPV by site, country and HPV type. Int J Cancer. 2017;141:664–70. doi:10.1002/ijc.30716.

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