Risk factors for medullary thyroid carcinoma: a pooled analysis.
OBJECTIVE
To investigate risk factors for medullary thyroid cancer (MTC).


METHODS
We conducted a pooled analysis of 14 case-control studies from Europe, North America, and Asia, including 67 medullary cancers (43 women and 24 men) diagnosed in ten studies. Of the original 4776, we selected five controls per case matched on study, gender, and age. The pooled odds ratios (OR) were estimated using conditional logistic regression.


RESULTS
Education, weight, and body mass were not associated with MTC, but a significant positive relationship was seen with height (OR = 2.6 for highest vs lowest tertile). Significant excess risks were associated with a history of thyroid nodules (OR = 12), hypertension (OR = 2.3), gallbladder disease (OR = 4.3), and allergies (OR = 2.2). Among current smokers, a decreased risk of MTC was observed with increasing number of cigarettes. The risk was significantly elevated among women having a first birth after age 25 years, but no clear pattern emerged for other reproductive factors.


CONCLUSIONS
Although the number of MTC was small, we detected several significant associations, including prior thyroid and other diseases.
Negri
Eva
E
Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. evanegri@marionegri.it
Ron
Elaine
E
Franceschi
Silvia
S
La Vecchia
Carlo
C
Preston-Martin
Susan
S
Kolonel
Laurence
L
Kleinerman
Ruth A
RA
Mabuchi
Kiyohiko
K
Jin
Fan
F
Wingren
Gun
G
Hallquist
Arne
A
Levi
Fabio
F
Linos
Athena
A
Fraumeni
Joseph F
JF
D000328:Adult; D000367:Age Factors; D000368:Aged; D001208:Asia / Q000453:epidemiology; D018276:Carcinoma, Medullary / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D005060:Europe / Q000453:epidemiology; D005260:Female; D005705:Gallbladder Diseases / Q000150:complications; D006801:Humans; D006967:Hypersensitivity / Q000150:complications; D006973:Hypertension / Q000150:complications; D008297:Male; D008875:Middle Aged; D009656:North America / Q000453:epidemiology; D016017:Odds Ratio; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking; D013964:Thyroid Neoplasms / Q000453:epidemiology / Q000209:etiology*; D016606:Thyroid Nodule / Q000150:complications