Reproductive factors and risk of papillary thyroid cancer in women.
The authors conducted a population-based case-control study of 410 women residing in three counties in western Washington State who were aged 18-64 years when diagnosed with papillary thyroid cancer in 1988-1994 and 574 controls to assess the effects of pregnancy history and other aspects of reproductive life on risk of this disease. Among women aged 45-64, the authors observed no associations with number of live births, age at first live birth, or age at last live birth. Risk was somewhat increased in women <45 years who had given birth within the previous 5 years; this association was most evident among women who reported that cancer symptoms had led to diagnosis. Among women who had given birth within the last 5 years, risk was greatest among those with two or more births during that time period (relative risk (RR) = 4.2, 95% confidence interval (CI): 2.0, 8.9, relative to parous women whose last birth was >5 years before the reference date). Risk of thyroid cancer was also associated with lactation during the previous 5 years (e.g., RR = 2.9, 95% CI: 1.5, 5.5, among parous women who had breastfed > or =12 months, vs. 0-1 months, during that interval). Our results suggest that thyroid stimulation during both pregnancy and lactation may result in a transient increase in risk of papillary thyroid cancer.
Rossing
M A
MA
Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
Voigt
L F
LF
Wicklund
K G
KG
Daling
J R
JR
D000231:Adenocarcinoma, Papillary / Q000453:epidemiology / Q000209:etiology*; D000293:Adolescent; D000328:Adult; D002291:Carcinoma, Papillary / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007774:Lactation; D008423:Maternal Age; D008875:Middle Aged; D010298:Parity; D011247:Pregnancy; D018570:Risk Assessment; D013964:Thyroid Neoplasms / Q000453:epidemiology / Q000209:etiology*