Association of pelvic inflammatory disease (PID) with ovarian cancer: a nationwide population-based retrospective cohort study from Taiwan

Table 1 Baseline variables for patients with PID and women without PID (controls)

	Patients with PID		Controls		P value*
	(n = 64,925)		(n = 129,850)
	n	%	n	%
Age, years					> 0.99
< 20	4529	6.98	9058	6.98
20–30	20,215	31.1	40,430	31.1
30–40	18,739	28.8	37,478	28.8
40–50	14,073	21.6	28,146	21.6
50–60	4866	7.49	9732	7.49
≥ 60	2503	3.86	5006	3.86
Mean (SD)^†	35.43 (12.1)		35.38 (12.3)		0.37
Comorbidity
Lynch syndrome and colon cancer	69	0.11	108	0.08	0.11
Breast cancer	257	0.40	538	0.41	0.54
Uterine cancer	66	0.10	67	0.05	< 0.0001
Rectum cancer	52	0.08	80	0.06	0.13
Endometriosis	4,241	6.53	2,552	1.97	< 0.0001
Infertility	3,455	5.32	3,263	2.51	< 0.0001
Obesity	524	0.81	860	0.66	0.0003
Monthly income (NTD)					< 0.0001
< 15,000	31,211	48.0	64,575	49.7
15,000–29,999	27,453	42.3	50,240	38.7
≥ 30,000	6,261	9.64	15,035	11.6

PID pelvic inflammatory disease, SD standard deviation, NTD New Taiwan dollar
^*P values were determined using the Chi-square test for comparisons between women with PID and controls
^†Mean follow-up times were 9.44 years (SD, 3.62) for the PID cohort and 9.24 years (SD, 3.71) for controls

ISSN: 1472-6874