Smoking cessation is followed by a sharp but transient rise in the incidence of overt autoimmune hypothyroidism - A population-based case-control study

TY - JOUR

T1 - Smoking cessation is followed by a sharp but transient rise in the incidence of overt autoimmune hypothyroidism - A population-based case-control study

AU - Carlé, Allan

AU - Pedersen, Inge Bülow

AU - Knudsen, Nils

AU - Perrild, Hans

AU - Ovesen, Lars

AU - Rasmussen, Lone Banke

AU - Jørgensen, Torben

AU - Laurberg, Peter

N1 - © 2012 Blackwell Publishing Ltd.

PY - 2012/11

Y1 - 2012/11

N2 - Background Current smoking is associated with a low prevalence of thyroid autoantibodies. On the other hand, smoking withdrawal enhances thyroid autoantibody level and may be a risk factor for the development of hypothyroidism. The aim of this study was to assess the association between smoking habits (smoking cessation in particular) and development of autoimmune hypothyroidism. Design Population-based, case-control study. Participants Cases (n = 140) newly diagnosed with primary autoimmune overt hypothyroidism were identified prospectively by population monitoring (2 027 208 person-years of observation) of all thyroid function tests performed in the two well-defined geographical areas. Individually, age-, sex- and region-matched euthyroid controls (n = 560) were simultaneously included from the same population. Measurements Participants gave details on smoking habits including smoking withdrawal and other lifestyle factors. Smoking habits were verified by measuring urinary cotinine (a nicotine metabolite). Results Incident hypothyroidism was very common in people who had recently stopped smoking: OR vs never smokers (95%-CI); quit smoking <1 years, 7·36 (2·27-23·9); 1-2 years, 6·34 (2·59-15·3); 3-10 years, 0·75 (0·30-1·87); >10 years, 0·76 (0·38-1·51). Results were consistent in both sexes and irrespective of age. Within two years after smoking cessation, the percentage of hypothyroid cases attributable to cessation of smoking was 85%. The current smoking was not associated with altered risk of developing overt hypothyroidism [OR, 0·92 (0·57-1·48)]. Conclusions The risk of having overt autoimmune hypothyroidism diagnosed is more than 6-fold increased the first 2 years after cessation of smoking. Clearly, smoking cessation is vital to prevent death and severe disease. However, awareness of hypothyroidism should be high in people who have recently quit smoking, and virtually any complaint should lead to thyroid function testing.

AB - Background Current smoking is associated with a low prevalence of thyroid autoantibodies. On the other hand, smoking withdrawal enhances thyroid autoantibody level and may be a risk factor for the development of hypothyroidism. The aim of this study was to assess the association between smoking habits (smoking cessation in particular) and development of autoimmune hypothyroidism. Design Population-based, case-control study. Participants Cases (n = 140) newly diagnosed with primary autoimmune overt hypothyroidism were identified prospectively by population monitoring (2 027 208 person-years of observation) of all thyroid function tests performed in the two well-defined geographical areas. Individually, age-, sex- and region-matched euthyroid controls (n = 560) were simultaneously included from the same population. Measurements Participants gave details on smoking habits including smoking withdrawal and other lifestyle factors. Smoking habits were verified by measuring urinary cotinine (a nicotine metabolite). Results Incident hypothyroidism was very common in people who had recently stopped smoking: OR vs never smokers (95%-CI); quit smoking <1 years, 7·36 (2·27-23·9); 1-2 years, 6·34 (2·59-15·3); 3-10 years, 0·75 (0·30-1·87); >10 years, 0·76 (0·38-1·51). Results were consistent in both sexes and irrespective of age. Within two years after smoking cessation, the percentage of hypothyroid cases attributable to cessation of smoking was 85%. The current smoking was not associated with altered risk of developing overt hypothyroidism [OR, 0·92 (0·57-1·48)]. Conclusions The risk of having overt autoimmune hypothyroidism diagnosed is more than 6-fold increased the first 2 years after cessation of smoking. Clearly, smoking cessation is vital to prevent death and severe disease. However, awareness of hypothyroidism should be high in people who have recently quit smoking, and virtually any complaint should lead to thyroid function testing.

U2 - 10.1111/j.1365-2265.2012.04455.x

DO - 10.1111/j.1365-2265.2012.04455.x

M3 - Journal article

C2 - 22651374

SN - 0300-0664

VL - 77

SP - 764

EP - 772

JO - Clinical Endocrinology

JF - Clinical Endocrinology

IS - 5

ER -