Do vitamin D levels affect antibody titers produced in response to HPV vaccine?

Figures & data

Figure 1. Reverse cumulative distribution curves for antibody concentrations after quadrivalent HPV vaccine administration, by HPV type and by total serum vitamin D level (<30 versus ≥30 ng/mL). Legend: The percentage of participants achieving a specified log-transformed concentration was plotted, comparing ≥30 vs. <30 ng/mL of total serum vitamin D levels. Using the Mantel-Cox log rank test, these values differ significantly (P < 0.05).

Figure 2. Distribution of log transformed HPV antibody levels (mMerck unit/mL) associated with total serum vitamin D levels (ng/mL).

Table 1. Demographics by vitamin D level (top) and by log transformed HPV antibody titers (bottom)

		Serum vitamin D level
Demographics	Overall, N = 173	Low (<30 ng/mL), N = 113	Normal (≥30 ng/mL), N=60	P value^#
Age, %				.320
≤21 years	52.6	50.4	58.3
>21 years	47.4	49.6	41.7
Group assignment, %				.415
6 month	49.7	64.4	35.6
12 month	50.3	67.0	33.0
Sexual orientation, %
Homo/bisexual	13.3	52.2	47.8	.102
Heterosexual	86.6	68.2	31.8
Race, %
Non-white	18.5	22.6	10.0	.029
White	81.5	77.4	90.0
Uses supplement containing vitamin D, %	32.9	38.0	28.0	.160
	Log transformed HPV antibody titers
Demographics	HPV6	HPV11	HPV16	HPV18
Age, %
≤21 years	7.0 (1.0)**	7.5 (0.9)†	8.8 (0.9)**	7.0 (1.0)*
>21 years	6.6 (1.0)	7.0 (1.0)	8.3 (1.2)	6.5 (1.3)
Group assignment, %
6 month	6.7 (1.0)	7.0 (1.0)†	8.5 (1.1)	6.6 (1.3)
12 month	7.0 (1.1)	7.6 (0.8)	8.7 (1.1)	6.9 (1.0)
Sexual orientation, %
Homo/bisexual	6.6 (1.2)	7.1 (1.2)	8.3 (1.4)	6.5 (1.6)
Heterosexual	6.9 (1.0)	7.3 (0.9)	8.6 (1.0)	6.8 (1.1)
Race, %
Non-white	6.7 (1.3)	7.3 (1.0)	8.4 (1.3)	7.0 (1.5)
White	6.9 (1.0)	7.3 (1.0)	8.6 (1.0)	6.7 (1.1)

^# For difference between low and normal vitamin D levels.

* P<0.05 for difference between groups.

** P<0.01 for difference between groups.

^† P<.001 for difference between groups.

Table 2. Association of HPV geometric mean titer (GMT) by HPV type with age, race, sexual orientation and vitamin D level (≥ 30 vs. < 30 ng/mL; top) and by overall vitamin D level (bottom) using linear regression; N = 173

	HPV6		HPV11		HPV16		HPV18
Variable	Beta (SE)	P value	Beta (SE)	P value	Beta (SE)	P value	Beta (SE)	P value
Dose 3 at 12 months, ref. = 6 months	.27 (.15)	.084	.55 (.14)	<.001	.23 (.16)	.148	.24 (.18)	.180
Age at enrollment	−.08 (.036)	.030	−.12 (.03)	<.001	−.09 (.04)	.012	−.10 (.04)	.019
Vitamin D level	−.02 (.01)	.002	−.03 (.01)	<.001	−.02 (.01)	.004	−.02 (.01)	.016
White race, ref. = non-white	.30 (.21)	.148	.04 (.18)	<.001	.26 (.21)	.219	−.24 (.24)	.305
Heterosexual, ref. = homo/bisexual	.33 (.23)	.146	.14 (.20)	.819	.35 (.23)	.131	.25 (.26)	.332
Dose 3 at 12 months, ref. = 6 months	.23 (.16)	.133	.52 (.14)	<.001	.19 (.16)	.216	.21 (.18)	.243
Age at enrollment	−.08 (.04)	.033	−.12 (.03)	<.001	−.09 (.04)	.014	−.10 (.04)	.021
Vitamin D level <30 ng/mL, ref. = ≥30 ng/mL	−.43 (.17)	.011	−.53 (.15)	<.001	−.39 (.17)	.022	−.37 (.19)	.052
White race, ref. = non-white	.24 (.21)	.242	−.01 (.18)	.969	.20 (.21)	.341	−.30 (.24)	.206
Heterosexual, ref. = homo/bisexual	.26 (.23)	.257	.06 (.20)	.776	.29 (.24)	.224	.19 (.26)	.467