Objective: To examine a possible relationship between alcohol consumption and thyroid volume and function.
Subjects: A total of 1493 subjects (599 males aged 45-60 years and 894 females aged 35-60 years) with no known thyroid disorders who were participating in the SUpplémentation en VItamines et Minéraux AntioXydants (SU.VI.MAX) study.
Measures: Daily dietary intakes and alcohol consumption in grams per day were based on five 24-h dietary records. Thyroid volume and structure were measured by ultrasonography. At baseline, TSH and free T4 (FT4) were measured.
Results: Male and female drinkers consumed (mean +/- SD), respectively, 30.6 +/- 23.3 and 14.2 +/- 13.4 g of ethanol per day. There was a decrease in carbohydrate intake with higher alcohol consumption among both male (P = 0.0001) and female drinkers (P = 0.06). Alcohol intake was associated with higher thyroid volume in males and females independently of iodine status. Multivariate odds ratios (ORs, with 95% confidence intervals) of thyroid enlargement (sex-specific 85th percentile values of > or = 20 ml for males, > or = 14 ml for females) in males and females who drank > or = 45 and > or = 20 g/day, respectively, were 2.22 (1.10-4.47) and 2.11 (1.15-3.90) compared with low drinkers, and 11.75 (2.15-64.12) and 2.03 (1.04-3.96) compared with abstainers. ORs were slightly increased when smokers were excluded. Alcohol intake was associated with low FT4 levels in male drinkers independently of TSH.
Conclusions: An increasing dose-response relationship was found between alcohol intake levels and ORs for thyroid enlargement in both males and females. Alcohol consumption was strongly associated with a higher risk in females.