Involvement of stress in the pathogenesis of autoimmune thyroid disease: a prospective study.

BACKGROUND

An association between stress and autoimmune thyroid disease (AITD) (especially Graves' hyperthyroidism) has been reported, but all studies so far on this topic have been retrospective.

OBJECTIVE

To evaluate prospectively the relationship between stress and (i) de novo occurrence of thyroid antibodies and (ii) development of overt autoimmune hyper-/hypothyroidism.

STUDY DESIGN

Two nested case-control studies in a prospective cohort of 790 euthyroid women who were 1st or 2nd degree relatives of AITD patients. Follow-up was five year, with annual assessments including questionnaires on stressful life events, daily hassles, and mood. In study A, cases were subjects who developed TPO-Ab but remained euthyroid during follow-up (called event). In study B, cases were subjects who developed overt hypothyroidism (TSH>5.7 mU/l and FT4<9.3 pmol/l) or overt hyperthyroidism (TSH<0.4 mU/l and FT4>20.1 pmol/l) during follow-up (called event). For each case, two controls were selected, matched for age and duration of follow-up; controls in study A remained TPO-Ab negative, and in study B remained without overt hyper-/hypothyroidism.

OUTCOMES

Contrast in questionnaire responses between cases and controls at baseline, at one year prior to the event and at time of event.

RESULTS

Exposure to stress was not different between subjects who developed or did not develop TPO-Ab (study A). No differences were observed in stress questionnaires between hyper-/hypothyroid cases and controls at any time point, but hypothyroid cases had less negative feelings than controls at the time of diagnosis (study B).

CONCLUSION

The data suggest that stress is not involved in the pathogenesis of AITD.