A large, population-based study of age-related associations between vaginal pH and human papillomavirus infection

BMC Infectious Diseases

Table 1 Risk of testing PCR positive for HPV at each visit given vaginal pH measurement, stratified by age at visit

Vaginal pH Level	N	Percent with PCR Positive HPV	Odds of Testing HPV Positive^a (95% CI)	p-value (trend)
All Women^b
4.0	2,139	19.1	0.7 (0.7-0.8)
4.5	17,201	23.8	ref^c
5.0	7,246	25.6	1.2 (1.1-1.3)
5.5	1,976	25.2	1.2 (1.1-1.4)	< 0.001
Age at Visit
< 25 years
4.0	114	22.8	0.5 (0.3-0.8)
4.5	1,417	38.3	ref
5.0	404	40.8	1.1 (0.9-1.4)	0.009
5.5	82	41.5	1.1 (0.7-1.8)
25-34 years
4.0	798	22.7	0.8 (0.7-1.0)
4.5	5,436	26.5	ref
5.0	1,517	29.8	1.2 (1.0-1.3)
5.5	240	29.2	1.1 (0.9-1.5)	0.007
35-44 years
4.0	842	17.5	0.9 (0.7-1.1)
4.5	5,244	19.6	ref
5.0	1,407	21.4	1.1 (1.0-1.3)
5.5	194	16.0	0.8 (0.5-1.1)	0.088
45-54 years
4.0	310	13.6	0.8 (0.5-1.1)
4.5	2,912	17.2	ref
5.0	1,432	19.8	1.2 (1.0-1.4)
5.5	372	18.0	1.1 (0.8-1.4)	0.051
55-64 years
4.0	48	12.5	0.4 (0.2-1.0)
4.5	1,253	25.1	ref
5.0	1,194	23.3	0.9 (0.7-1.1)
5.5	481	23.9	0.9 (0.7-1.2)	0.209
65+ years
4.0	27	22.2	0.7 (0.3-1.9)
4.5	939	27.7	ref
5.0	1,292	29.1	1.1 (0.9-1.3)
5.5	607	29.7	1.1 (0.8-1.4)	0.773

^a Generalized estimating equation models with an independent correlation structure were used to estimate the odds of testing positive for HPV given pH measurements at each visit
^b Adjusted for age at visit
^c A pH of 4.5 was used as the referent category because it provided the most stable comparison

ISSN: 1471-2334