Alcohol consumption as a risk factor for autoimmune thyroid disease: a prospective study.

BACKGROUND

Alcohol consumption has been identified as a protective factor for some autoimmune diseases like rheumatoid arthritis and systemic lupus erythematosus.

OBJECTIVE

We hypothesized that alcohol consumption would reduce the risk of developing autoimmune thyroid disease (AITD).

STUDY DESIGN

Two nested case-control studies in the prospective Amsterdam AITD cohort. Follow-up was 5 years, with annual assessments. In study A, we compared alcohol consumption between cases (subjects who during follow-up remained euthyroid but developed thyroid peroxidase antibodies (TPO-Ab), called event) and controls (subjects who remained euthyroid and TPO-Ab-negative). In study B, we compared alcohol consumption between cases (subjects who during follow-up developed overt hypothyroidism, called event) and controls (subjects who did not develop overt hypothyroidism). For each case, 2 controls were selected, matched for age, duration of follow-up and smoking behavior at baseline and at the time of event.

RESULTS

In study A, alcohol consumption did not differ between cases and controls at any time point. In study B, the number of subjects consuming >10 units of alcohol per week was not different between cases and controls at study entrance (8.3 vs. 14.5%, NS), but lower at 1 year before (5.3 vs. 19.7%, p = 0.041) and at the time of event (6.7 vs. 23.7%, p = 0.044); respective odds ratios are 0.54 (0.14-2.06), 0.23 (0.05-1.04) and 0.23 (0.05-1.06).

CONCLUSION

Alcohol consumption is not associated with de novo development of TPO-Ab, but is lower in subjects who developed overt hypothyroidism. The data suggest alcohol consumption may protect against overt autoimmune hypothyroidism.