Table 3. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for esophageal squamous cell carcinoma according to family history of esophageal cancer in first-degree relatives^*.

Family history of esophageal cancer in relatives	Cases (n = 619)	Controls (n = 772)	OR (95% CI)†	OR (95% CI)‡
First degree relatives
No	367	545	Reference	Reference
Yes	195	153	1.91 (1.49–2.46)	1.85 (1.42–2.41)
1 affected	150	132	1.70 (1.29–2.22)	1.68 (1.27–2.23)
≥2 affected	45	21	3.28 (1.92–5.62)	2.93 (1.67–5.12)
P for trend			<0.001	<0.001
Parents
No	439	614	Reference	Reference
Yes	129	102	1.68 (1.26–2.24)	1.63 (1.20–2.20)
1 affected of parents	116	100	1.53 (1.14–2.06)	1.49 (1.09–2.03)
2 affected of parents	13	2	9.11 (2.04–40.72)	7.96 (1.74–36.32)
P for trend			<0.001	<0.001
Father	60	50	1.58 (1.06–2.36)	1.46 (0.97–2.21)
Mother	82	54	2.04 (1.41–2.94)	2.02 (1.39–2.95)
Siblings
No	483	635	Reference	Reference
Yes	92	64	2.09 (1.48–2.95)	2.04 (1.41–2.94)
1 affected of siblings	82	57	2.07 (1.44–2.97)	2.04 (1.39–2.99)
≥2 affected of siblings	10	7	2.30 (0.86–6.17)	2.04 (0.73–5.69)
P for trend			0.03	0.02

^*Occurrence of esophageal cancer was very rare in offspring, so the result was not shown.

^†Adjusted for age (continuous) and sex.

^‡Adjusted for age (continuous), family size (continuous), sex, education (Illiteracy/primary school/primary high school/secondary high school and above), tobacco smoking (never/ever smoker of any tobacco), alcohol drinking (never/ever), missing & filled teeth (MFT, none/1 ~ 4/ ≥ 4), times of tooth brushing per day (<2 times/ ≥ 2 times), daily consumption of pickled vegetables (<10 g/≥ 10 g) and daily consumption of fresh fruits (<27.5 g/ ≥ 27.5 g).