title: Dietary nitrate and nitrite and the risk of thyroid cancer in the NIH-AARP Diet and Health Study.
abstract: During the past several decades, an increasing incidence of thyroid cancer has been observed worldwide. Nitrate inhibits iodide uptake by the thyroid, potentially disrupting thyroid function. An increased risk of thyroid cancer associated with nitrate intake was recently reported in a cohort study of older women in Iowa. We evaluated dietary nitrate and nitrite intake and thyroid cancer risk overall and for subtypes in the National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study, a large prospective cohort of 490,194 men and women, ages 50-71 years in 1995-1996. Dietary intakes were assessed using a 124-item food frequency questionnaire. During an average of 7 years of follow-up we identified 370 incident thyroid cancer cases (170 men, 200 women) with complete dietary information. Among men, increasing nitrate intake was positively associated with thyroid cancer risk (relative risk [RR] for the highest quintile versus lowest quintile RR = 2.28, 95% confidence interval [CI]: 1.29-4.041; p-trend <0.001); however, we observed no trend with intake among women (p-trend = 0.61). Nitrite intake was not associated with risk of thyroid cancer for either men or women. We evaluated risk for the two main types of thyroid cancer. We found positive associations for nitrate intake and both papillary (RR = 2.10; 95% CI: 1.09-4.05; p-trend = 0.05) and follicular thyroid cancer (RR = 3.42; 95% CI: 1.03-11.4; p-trend = 0.01) among men. Nitrite intake was associated with increased risk of follicular thyroid cancer (RR = 2.74; 95%CI: 0.86-8.77; p-trend = 0.04) among men. Our results support a role of nitrate in thyroid cancer risk and suggest that further studies to investigate these exposures are warranted.
authors.affiliation: Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, MD 20852-7244, USA. kilfoyb@mail.nih.gov
authors.forename: Briseis A
authors.initials: BA
authors.lastname: Kilfoy
authors.forename: Yawei
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yikyung
authors.initials: Y
authors.lastname: Park
authors.forename: Theodore R
authors.initials: TR
authors.lastname: Holford
authors.forename: Arthur
authors.initials: A
authors.lastname: Schatzkin
authors.forename: Albert
authors.initials: A
authors.lastname: Hollenbeck
authors.forename: Mary H
authors.initials: MH
authors.lastname: Ward
mesh_terms: D004032:Diet; D015930:Diet Records; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000008:administration & dosage*; D009573:Nitrites / Q000008:administration & dosage*; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013964:Thyroid Neoplasms / Q000139:chemically induced*
chemical_list: D009566:Nitrates; D009573:Nitrites
references.citation: Eur J Cancer. 2002 Sep;38(13):1762-8
references.pmid: 12175693
references.citation: Carcinogenesis. 1991 May;12(5):873-7
references.pmid: 2029752
references.citation: Eur J Pharmacol. 1994 Nov 1;292(1):1-38
references.pmid: 7867685
references.citation: Cancer Surv. 1987;6(4):719-38
references.pmid: 3330686
references.citation: Am J Epidemiol. 2003 Jul 1;158(1):1-13
references.pmid: 12835280
references.citation: Epidemiology. 2006 Jul;17(4):375-82
references.pmid: 16699473
references.citation: J Cancer Res Clin Oncol. 1991;117(2):133-43
references.pmid: 2036128
references.citation: Stat Med. 1989 May;8(5):551-61
references.pmid: 2657958
references.citation: Zentralbl Bakteriol Mikrobiol Hyg B. 1985 Feb;180(2-3):311-8
references.pmid: 3993260
references.citation: Int J Epidemiol. 1984 Sep;13(3):324-31
references.pmid: 6490303
references.citation: Am J Clin Nutr. 2009 Jan;89(1):347-53
references.pmid: 19056579
references.citation: Nutrition. 2002 Mar;18(3):247-54
references.pmid: 11882398
references.citation: Cancer Causes Control. 2009 Jul;20(5):525-31
references.pmid: 19016336
references.citation: Cancer Surv. 1989;8(2):443-58
references.pmid: 2696589
references.citation: Am J Epidemiol. 2000 Aug 1;152(3):279-86
references.pmid: 10933275
references.citation: Cancer Causes Control. 1997 May;8(3):292-308
references.pmid: 9498894
references.citation: Thyroid. 2007 Sep;17(9):811-7
references.pmid: 17956155
references.citation: Epidemiology. 2010 May;21(3):389-95
references.pmid: 20335813
references.citation: Am J Epidemiol. 2001 Dec 15;154(12):1119-25
references.pmid: 11744517
references.citation: Cancer Lett. 1997 Mar 19;114(1-2):259-61
references.pmid: 9103306
references.citation: Cancer Res. 1983 Nov;43(11):5570-4
references.pmid: 6616484
references.citation: Thyroid. 1998 Sep;8(9):827-56
references.pmid: 9777756
references.citation: Environ Sci Technol. 2006 Dec 15;40(24):7834-40
references.pmid: 17256535
references.citation: Cancer Epidemiol Biomarkers Prev. 2009 Mar;18(3):784-91
references.pmid: 19240234
references.citation: Int J Cancer. 1994 Jun 1;57(5):638-44
references.pmid: 8194870
references.citation: Cancer Lett. 1991 Nov;60(2):121-7
references.pmid: 1933836
references.citation: Epidemiology. 2003 Mar;14(2):183-90
references.pmid: 12606884
references.citation: J Manag Care Pharm. 2008 Apr;14(3 Suppl):2-6
references.pmid: 18439060
references.citation: Br J Nutr. 1999 May;81(5):349-58
references.pmid: 10615207
references.citation: Public Health Nutr. 2008 Feb;11(2):183-95
references.pmid: 17610761
references.citation: Br J Cancer. 1993 Feb;67(2):330-40
references.pmid: 8431362
references.citation: Nature. 1974 Apr 12;248(449):601-2
references.pmid: 4824029
references.citation: Eur J Endocrinol. 2006 May;154(5):599-611
references.pmid: 16645005
references.citation: Cancer. 1974 Dec;34(6):2072-6
references.pmid: 4474057
references.citation: Eur J Cancer Prev. 2006 Apr;15(2):178-86
references.pmid: 16523016
references.citation: Cancer Epidemiol Biomarkers Prev. 2009 Apr;18(4):1092-100
references.pmid: 19293311
references.citation: J Am Diet Assoc. 1998 Dec;98(12):1412-7
references.pmid: 9850109