title: Reproductive factors and risk of esophageal squamous cell carcinoma in northern Iran: a case-control study in a high-risk area and literature review.
abstract: Several epidemiologic studies have suggested an inverse association between female reproductive factors and the risk of esophageal squamous cell carcinoma (ESCC), but the evidence is not conclusive. We examined the association of the number of pregnancies, live births, and miscarriages/stillbirths in women and the association of the number of children in both sexes with the risk of ESCC in Golestan Province, a high-risk area in Iran. Data from 297 histopathologically confirmed ESCC cases (149 women) and 568 controls (290 women) individually matched to cases for age, sex, and neighborhood of residence were included in this analysis. Conditional logistic regression was used to calculate odds ratios (ORs) and the corresponding 95% confidence intervals (CIs). The average numbers of live births and miscarriages/stillbirths among the controls were 8.2 and 0.8, respectively. Women with six or more live births were at ~1/3 the risk of ESCC as those with 0-3 live births; the OR (95% CI) for having 6-7 live births was 0.33 (0.12-0.92). In contrast, the number of miscarriages/stillbirths was associated with an increase in the risk of ESCC. The OR (95% CI) for at least three versus no miscarriages/stillbirths was 4.43 (2.11-9.33). The number of children in women was suggestive of an inverse association with ESCC, but this association was not statistically significant; in men, no association was observed. The findings of this study support a protective influence of female hormonal factors on the risk of ESCC. However, further epidemiological and mechanistic studies are required to prove a protective association.
authors.affiliation: Digestive Disease Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. farhad.islami@mssm.edu
authors.forename: Farhad
authors.initials: F
authors.lastname: Islami
authors.forename: Yin
authors.initials: Y
authors.lastname: Cao
authors.forename: Farin
authors.initials: F
authors.lastname: Kamangar
authors.forename: Dariush
authors.initials: D
authors.lastname: Nasrollahzadeh
authors.forename: Haji-Amin
authors.initials: HA
authors.lastname: Marjani
authors.forename: Ramin
authors.initials: R
authors.lastname: Shakeri
authors.forename: Saman
authors.initials: S
authors.lastname: Fahimi
authors.forename: Masoud
authors.initials: M
authors.lastname: Sotoudeh
authors.forename: Sanford M
authors.initials: SM
authors.lastname: Dawsey
authors.forename: Christian C
authors.initials: CC
authors.lastname: Abnet
authors.forename: Paolo
authors.initials: P
authors.lastname: Boffetta
authors.forename: Reza
authors.initials: R
authors.lastname: Malekzadeh
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D004938:Esophageal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005843:Geography; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D010298:Parity / Q000502:physiology; D011247:Pregnancy; D017584:Reproductive History; D012307:Risk Factors; D050497:Stillbirth / Q000453:epidemiology