Vitamin D in esophageal cancer: Is there a role for chemoprevention?

Table 1 Studies investigating correlations between vitamin D and esophageal squamous cell dysplasia and carcinoma

Ref.	Study design/location	Vitamin D exposure/status/genetics studies	Statistical correlation
Abnet et al[27]	Cross-sectional study	25-hydroxyvitamin D serum level	RR = 1.86, 95%CI: 1.35-2.62
	China
Chen et al[28]	Prospective study	25-hydroxyvitamin D serum level	ESCC in men:
	China		HR = 1.77, 95%CI: 1.16-2.70
Lipworth et al[29]	Case-control study	Vitamin D dietary intake	ESCC:
	Italy		OR = 0.58, 95%CI: 0.39-0.86
Tran et al[30]	Case-control study	Ultraviolet B radiation	ESCC: No association
	Australia
Wang et al[24]	Case-control study	Genetic polymorphisms	ESCC: No association
	China

ESCC: Esophageal squamous cell carcinoma; OR: Odds ratio; RR: Relative risk; HR: Hazard ratio; CI: Confidence interval.