. 2016 May 26;11(5):e0156215. doi: 10.1371/journal.pone.0156215

Table 2. Risk of cervical adenocarcinoma given by C. trachomatis infection in the first and last smear, calculated as odds ratio via conditional logistic regression where possible.

	Smear	Matched cases/controls	Exposed cases/controls^a	Odds ratio	95% Conf.int.
AIS	First	128	5/4	1.25	0.34–4.65
	Last	128	0/2	NA^b	NA^b
AC	First	158	3/1	3.00	0.31–28.84
	Last	158	2/0	NA^b	NA^b

^a Matched case/control pairs that differ in exposure and contribute to the OR estimation, reported as exposed cases/exposed controls

^b Could not be calculated due to perfect separation (no exposed cases or controls)

Footnote: AIS–adenocarcinoma in situ, AC–adenocarcinoma