Effect of smoking intensity on thyroid volume, thyroid nodularity and thyroid function: the Melen study.
OBJECTIVE
The purpose of our study was to determine the association between smoking habit, goiter, thyroid functions and ultrasonographic nodularity in moderately iodine deficient area.


METHODS
The MELEN study is a prospectively designed survey on the prevalence of thyroid diseases in Turkish adults. A total of 2298 subjects with a mean age of 50 (age range 18 to 92) were interviewed. Smoking habits were registered from questionnaires and subsequent interviews with a physician. Thyroid ultrasonography was performed and interpreted by the same experienced physician, using the same equipment. After an overnight fast, blood samples were collected from all the study subjects for the determination of serum free thyroxine, thyroid stimulating hormone (TSH) were measured.


RESULTS
Mean thyroid volumes of current smokers were significantly lower than either former or never smokers (P=0.014). There were no difference according to smoking habits on goiter and established multinodularity in current smokers (P<0.05). Heavy smokers (>20 pack/year) had higher thyroid volumes, higher goiter and multinodular goiter (MNG) prevalence than moderate smokers (P<0.001). Thyrotoxicosis (TSH<0.35) cases were more frequent among heavy smokers than moderate smokers (14.1% versus 8.2%, P<0.001; respectively). Heavy smoking independently predicted goiter (odds ratio: 1.459 [95% confidence interval: 1.029 and 2.068]; P=0.034).


CONCLUSIONS
Heavy smoking was associated with increased prevalence of thyroid multinodularity and goiter in respect to moderate smoking. No association was found between smoking habit and thyroid dysfunction.
Chest Disease Department, Duzce University School of Medicine, Konuralp-Duzce, Turkey.
L Y
LY
Aydin
Y
Y
Aydin
F H
FH
Besir
H
H
Fahri Besir
H
H
Demirin
H
H
Yildirim
E
E
Önder
T
T
Dumlu
G
G
Celbek
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001772:Blood Cell Count; D015992:Body Mass Index; D015897:Comorbidity; D005260:Female; D006042:Goiter / Q000453:epidemiology / Q000209:etiology; D006044:Goiter, Nodular / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D007455:Iodine / Q000172:deficiency; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D015995:Prevalence; D011446:Prospective Studies; D012424:Rural Population / Q000706:statistics & numerical data; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D016606:Thyroid Nodule / Q000453:epidemiology / Q000209:etiology*; D013971:Thyrotoxicosis / Q000453:epidemiology / Q000209:etiology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014421:Turkey / Q000453:epidemiology; D014463:Ultrasonography; D014505:Urban Population / Q000706:statistics & numerical data; D055815:Young Adult
D013972:Thyrotropin; D007455:Iodine; D013974:Thyroxine