Table 2. Positive correlation between CT, HPV, and cervical cancer.

CT: Chlamydia trachomatis; HPV: human papillomavirus; HrHPV: high-risk human papillomavirus; LSIL: low-grade squamous intraepithelial lesion; CC: cervical cancer

Author	Year of publication	Study design	Population characteristics	Sample size	Outcome
Chen et al. [8]	2020	Cross-sectional study	Gynecology clinic in southern Hunan, China	5,006	CT infection was associated with HrHPV infection with an odds ratio of 1.74 (95% CI: 1.10–2.74, p=0.017)
Ssedyabane et al. [4]	2019	Cross-sectional study	Age: 25-80 years; hospital in southwestern Uganda	93	There is a likelihood of association between HPV-CT coinfection and the cytological diagnosis of LSIL (Spearman's rho=0.2784, prob >|t|=0.0069)
Madaan et al. [7]	2019	Cross-sectional study	Age: 18-45 years; STI clinic in New Delhi, India	90	A highly significant association was found between HPV-CT coinfection and cervical abnormal cytology (p=0.001)
Lv et al. [24]	2019	Cross-sectional study	Age: 20-70 years; outpatient clinic in Shanghai, China	826	Data evaluated showed that CT (OR: 3.538) is a risk factor for hrHPV infection (p<0.05)
Mancini et al. [25]	2018	Cohort study	Multicenter, Italy	164	A high percentage (15/16; 94%) of CT-HPV coinfections have high-grade cervical lesions more frequently than those infected with HPV only
Zhu et al. [6]	2016	Meta-analysis	22 studies	4,291	CT was significantly linked to increased CC risk in prospective studies (OR: 2.21, 95% CI: 1.88-2.61)
Arnheim Dahlström et al. [26]	2011	Prospective cohort study	4 major biobanks in Nordic countries	1,000,000	Previous exposure to CT; had a strongly increased risk for CC (OR: 1.9; 95% CI: 1.5-2.3)