@article {1231, title = {Subclinical hypothyroidism and the risk of coronary heart disease and mortality.}, journal = {JAMA}, volume = {304}, year = {2010}, month = {2010 Sep 22}, pages = {1365-74}, abstract = {

CONTEXT: Data regarding the association between subclinical hypothyroidism and cardiovascular disease outcomes are conflicting among large prospective cohort studies. This might reflect differences in participants{\textquoteright} age, sex, thyroid-stimulating hormone (TSH) levels, or preexisting cardiovascular disease.

OBJECTIVE: To assess the risks of coronary heart disease (CHD) and total mortality for adults with subclinical hypothyroidism.

DATA SOURCES AND STUDY SELECTION: The databases of MEDLINE and EMBASE (1950 to May 31, 2010) were searched without language restrictions for prospective cohort studies with baseline thyroid function and subsequent CHD events, CHD mortality, and total mortality. The reference lists of retrieved articles also were searched.

DATA EXTRACTION: Individual data on 55,287 participants with 542,494 person-years of follow-up between 1972 and 2007 were supplied from 11 prospective cohorts in the United States, Europe, Australia, Brazil, and Japan. The risk of CHD events was examined in 25,977 participants from 7 cohorts with available data. Euthyroidism was defined as a TSH level of 0.50 to 4.49 mIU/L. Subclinical hypothyroidism was defined as a TSH level of 4.5 to 19.9 mIU/L with normal thyroxine concentrations.

RESULTS: Among 55,287 adults, 3450 had subclinical hypothyroidism (6.2\%) and 51,837 had euthyroidism. During follow-up, 9664 participants died (2168 of CHD), and 4470 participants had CHD events (among 7 studies). The risk of CHD events and CHD mortality increased with higher TSH concentrations. In age- and sex-adjusted analyses, the hazard ratio (HR) for CHD events was 1.00 (95\% confidence interval [CI], 0.86-1.18) for a TSH level of 4.5 to 6.9 mIU/L (20.3 vs 20.3/1000 person-years for participants with euthyroidism), 1.17 (95\% CI, 0.96-1.43) for a TSH level of 7.0 to 9.9 mIU/L (23.8/1000 person-years), and 1.89 (95\% CI, 1.28-2.80) for a TSH level of 10 to 19.9 mIU/L (n = 70 events/235; 38.4/1000 person-years; P <.001 for trend). The corresponding HRs for CHD mortality were 1.09 (95\% CI, 0.91-1.30; 5.3 vs 4.9/1000 person-years for participants with euthyroidism), 1.42 (95\% CI, 1.03-1.95; 6.9/1000 person-years), and 1.58 (95\% CI, 1.10-2.27, n = 28 deaths/333; 7.7/1000 person-years; P = .005 for trend). Total mortality was not increased among participants with subclinical hypothyroidism. Results were similar after further adjustment for traditional cardiovascular risk factors. Risks did not significantly differ by age, sex, or preexisting cardiovascular disease.

CONCLUSIONS: Subclinical hypothyroidism is associated with an increased risk of CHD events and CHD mortality in those with higher TSH levels, particularly in those with a TSH concentration of 10 mIU/L or greater.

}, keywords = {Adolescent, Adult, Aged, Aged, 80 and over, Coronary Disease, Female, Humans, Hypothyroidism, Male, Middle Aged, Mortality, Prospective Studies, Risk, Thyrotropin, Young Adult}, issn = {1538-3598}, doi = {10.1001/jama.2010.1361}, author = {Rodondi, Nicolas and den Elzen, Wendy P J and Bauer, Douglas C and Cappola, Anne R and Razvi, Salman and Walsh, John P and Asvold, Bj{\o}rn O and Iervasi, Giorgio and Imaizumi, Misa and Collet, Tinh-Hai and Bremner, Alexandra and Maisonneuve, Patrick and Sgarbi, Jos{\'e} A and Khaw, Kay-Tee and Vanderpump, Mark P J and Newman, Anne B and Cornuz, Jacques and Franklyn, Jayne A and Westendorp, Rudi G J and Vittinghoff, Eric and Gussekloo, Jacobijn} } @article {1545, title = {Subclinical hyperthyroidism and the risk of coronary heart disease and mortality.}, journal = {Arch Intern Med}, volume = {172}, year = {2012}, month = {2012 May 28}, pages = {799-809}, abstract = {

BACKGROUND: Data from prospective cohort studies regarding the association between subclinical hyperthyroidism and cardiovascular outcomes are conflicting.We aimed to assess the risks of total and coronary heart disease (CHD) mortality, CHD events, and atrial fibrillation (AF) associated with endogenous subclinical hyperthyroidism among all available large prospective cohorts.

METHODS: Individual data on 52 674 participants were pooled from 10 cohorts. Coronary heart disease events were analyzed in 22 437 participants from 6 cohorts with available data, and incident AF was analyzed in 8711 participants from 5 cohorts. Euthyroidism was defined as thyrotropin level between 0.45 and 4.49 mIU/L and endogenous subclinical hyperthyroidism as thyrotropin level lower than 0.45 mIU/L with normal free thyroxine levels, after excluding those receiving thyroid-altering medications.

RESULTS: Of 52 674 participants, 2188 (4.2\%) had subclinical hyperthyroidism. During follow-up, 8527 participants died (including 1896 from CHD), 3653 of 22 437 had CHD events, and 785 of 8711 developed AF. In age- and sex-adjusted analyses, subclinical hyperthyroidism was associated with increased total mortality (hazard ratio[HR], 1.24, 95\% CI, 1.06-1.46), CHD mortality (HR,1.29; 95\% CI, 1.02-1.62), CHD events (HR, 1.21; 95\%CI, 0.99-1.46), and AF (HR, 1.68; 95\% CI, 1.16-2.43).Risks did not differ significantly by age, sex, or preexisting cardiovascular disease and were similar after further adjustment for cardiovascular risk factors, with attributable risk of 14.5\% for total mortality to 41.5\% forAF in those with subclinical hyperthyroidism. Risks for CHD mortality and AF (but not other outcomes) were higher for thyrotropin level lower than 0.10 mIU/L compared with thyrotropin level between 0.10 and 0.44 mIU/L(for both, P value for trend, .03).

CONCLUSION: Endogenous subclinical hyperthyroidism is associated with increased risks of total, CHD mortality, and incident AF, with highest risks of CHD mortality and AF when thyrotropin level is lower than 0.10 mIU/L.

}, keywords = {Adolescent, Adult, Age Distribution, Aged, Aged, 80 and over, Atrial Fibrillation, Cause of Death, Cohort Studies, Coronary Artery Disease, Female, Humans, Hyperthyroidism, Male, Middle Aged, Prognosis, Prospective Studies, Risk Assessment, Severity of Illness Index, Sex Distribution, Survival Analysis, Switzerland, Thyroid Function Tests, Thyrotropin, Young Adult}, issn = {1538-3679}, doi = {10.1001/archinternmed.2012.402}, author = {Collet, Tinh-Hai and Gussekloo, Jacobijn and Bauer, Douglas C and den Elzen, Wendy P J and Cappola, Anne R and Balmer, Philippe and Iervasi, Giorgio and Asvold, Bj{\o}rn O and Sgarbi, Jos{\'e} A and V{\"o}lzke, Henry and Gencer, Bari{\c s} and Maciel, Rui M B and Molinaro, Sabrina and Bremner, Alexandra and Luben, Robert N and Maisonneuve, Patrick and Cornuz, Jacques and Newman, Anne B and Khaw, Kay-Tee and Westendorp, Rudi G J and Franklyn, Jayne A and Vittinghoff, Eric and Walsh, John P and Rodondi, Nicolas} } @article {6553, title = {Thyroid antibody status, subclinical hypothyroidism, and the risk of coronary heart disease: an individual participant data analysis.}, journal = {J Clin Endocrinol Metab}, volume = {99}, year = {2014}, month = {2014 Sep}, pages = {3353-62}, abstract = {

CONTEXT: Subclinical hypothyroidism has been associated with increased risk of coronary heart disease (CHD), particularly with thyrotropin levels of 10.0 mIU/L or greater. The measurement of thyroid antibodies helps predict the progression to overt hypothyroidism, but it is unclear whether thyroid autoimmunity independently affects CHD risk.

OBJECTIVE: The objective of the study was to compare the CHD risk of subclinical hypothyroidism with and without thyroid peroxidase antibodies (TPOAbs).

DATA SOURCES AND STUDY SELECTION: A MEDLINE and EMBASE search from 1950 to 2011 was conducted for prospective cohorts, reporting baseline thyroid function, antibodies, and CHD outcomes.

DATA EXTRACTION: Individual data of 38 274 participants from six cohorts for CHD mortality followed up for 460 333 person-years and 33 394 participants from four cohorts for CHD events.

DATA SYNTHESIS: Among 38 274 adults (median age 55 y, 63\% women), 1691 (4.4\%) had subclinical hypothyroidism, of whom 775 (45.8\%) had positive TPOAbs. During follow-up, 1436 participants died of CHD and 3285 had CHD events. Compared with euthyroid individuals, age- and gender-adjusted risks of CHD mortality in subclinical hypothyroidism were similar among individuals with and without TPOAbs [hazard ratio (HR) 1.15, 95\% confidence interval (CI) 0.87-1.53 vs HR 1.26, CI 1.01-1.58, P for interaction = .62], as were risks of CHD events (HR 1.16, CI 0.87-1.56 vs HR 1.26, CI 1.02-1.56, P for interaction = .65). Risks of CHD mortality and events increased with higher thyrotropin, but within each stratum, risks did not differ by TPOAb status.

CONCLUSIONS: CHD risk associated with subclinical hypothyroidism did not differ by TPOAb status, suggesting that biomarkers of thyroid autoimmunity do not add independent prognostic information for CHD outcomes.

}, keywords = {Adult, Aged, Aged, 80 and over, Autoantibodies, Coronary Disease, Female, Humans, Hypothyroidism, Incidence, Male, Middle Aged, Prevalence, Prognosis, Risk Factors, Seroepidemiologic Studies, Severity of Illness Index, Young Adult}, issn = {1945-7197}, doi = {10.1210/jc.2014-1250}, author = {Collet, Tinh-Hai and Bauer, Douglas C and Cappola, Anne R and Asvold, Bj{\o}rn O and Weiler, Stefan and Vittinghoff, Eric and Gussekloo, Jacobijn and Bremner, Alexandra and den Elzen, Wendy P J and Maciel, Rui M B and Vanderpump, Mark P J and Cornuz, Jacques and D{\"o}rr, Marcus and Wallaschofski, Henri and Newman, Anne B and Sgarbi, Jos{\'e} A and Razvi, Salman and V{\"o}lzke, Henry and Walsh, John P and Aujesky, Drahomir and Rodondi, Nicolas} } @article {6800, title = {Subclinical Hypothyroidism and the Risk of Stroke Events and Fatal Stroke: An Individual Participant Data Analysis.}, journal = {J Clin Endocrinol Metab}, volume = {100}, year = {2015}, month = {2015 Jun}, pages = {2181-91}, abstract = {

OBJECTIVE: The objective was to determine the risk of stroke associated with subclinical hypothyroidism.

DATA SOURCES AND STUDY SELECTION: Published prospective cohort studies were identified through a systematic search through November 2013 without restrictions in several databases. Unpublished studies were identified through the Thyroid Studies Collaboration. We collected individual participant data on thyroid function and stroke outcome. Euthyroidism was defined as TSH levels of 0.45-4.49 mIU/L, and subclinical hypothyroidism was defined as TSH levels of 4.5-19.9 mIU/L with normal T4 levels.

DATA EXTRACTION AND SYNTHESIS: We collected individual participant data on 47 573 adults (3451 subclinical hypothyroidism) from 17 cohorts and followed up from 1972-2014 (489 192 person-years). Age- and sex-adjusted pooled hazard ratios (HRs) for participants with subclinical hypothyroidism compared to euthyroidism were 1.05 (95\% confidence interval [CI], 0.91-1.21) for stroke events (combined fatal and nonfatal stroke) and 1.07 (95\% CI, 0.80-1.42) for fatal stroke. Stratified by age, the HR for stroke events was 3.32 (95\% CI, 1.25-8.80) for individuals aged 18-49 years. There was an increased risk of fatal stroke in the age groups 18-49 and 50-64 years, with a HR of 4.22 (95\% CI, 1.08-16.55) and 2.86 (95\% CI, 1.31-6.26), respectively (p trend 0.04). We found no increased risk for those 65-79 years old (HR, 1.00; 95\% CI, 0.86-1.18) or >= 80 years old (HR, 1.31; 95\% CI, 0.79-2.18). There was a pattern of increased risk of fatal stroke with higher TSH concentrations.

CONCLUSIONS: Although no overall effect of subclinical hypothyroidism on stroke could be demonstrated, an increased risk in subjects younger than 65 years and those with higher TSH concentrations was observed.

}, keywords = {Adult, Asymptomatic Diseases, Female, Humans, Hypothyroidism, Incidence, Male, Risk Factors, Stroke, Thyrotropin}, issn = {1945-7197}, doi = {10.1210/jc.2015-1438}, author = {Chaker, Layal and Baumgartner, Christine and den Elzen, Wendy P J and Ikram, M Arfan and Blum, Manuel R and Collet, Tinh-Hai and Bakker, Stephan J L and Dehghan, Abbas and Drechsler, Christiane and Luben, Robert N and Hofman, Albert and Portegies, Marileen L P and Medici, Marco and Iervasi, Giorgio and Stott, David J and Ford, Ian and Bremner, Alexandra and Wanner, Christoph and Ferrucci, Luigi and Newman, Anne B and Dullaart, Robin P and Sgarbi, Jos{\'e} A and Ceresini, Graziano and Maciel, Rui M B and Westendorp, Rudi G and Jukema, J Wouter and Imaizumi, Misa and Franklyn, Jayne A and Bauer, Douglas C and Walsh, John P and Razvi, Salman and Khaw, Kay-Tee and Cappola, Anne R and V{\"o}lzke, Henry and Franco, Oscar H and Gussekloo, Jacobijn and Rodondi, Nicolas and Peeters, Robin P} } @article {6798, title = {Thyroid function within the normal range and risk of coronary heart disease: an individual participant data analysis of 14 cohorts.}, journal = {JAMA Intern Med}, volume = {175}, year = {2015}, month = {2015 Jun}, pages = {1037-47}, abstract = {

IMPORTANCE: Some experts suggest that serum thyrotropin levels in the upper part of the current reference range should be considered abnormal, an approach that would reclassify many individuals as having mild hypothyroidism. Health hazards associated with such thyrotropin levels are poorly documented, but conflicting evidence suggests that thyrotropin levels in the upper part of the reference range may be associated with an increased risk of coronary heart disease (CHD).

OBJECTIVE: To assess the association between differences in thyroid function within the reference range and CHD risk.

DESIGN, SETTING, AND PARTICIPANTS: Individual participant data analysis of 14 cohorts with baseline examinations between July 1972 and April 2002 and with median follow-up ranging from 3.3 to 20.0 years. Participants included 55,412 individuals with serum thyrotropin levels of 0.45 to 4.49 mIU/L and no previously known thyroid or cardiovascular disease at baseline.

EXPOSURES: Thyroid function as expressed by serum thyrotropin levels at baseline.

MAIN OUTCOMES AND MEASURES: Hazard ratios (HRs) of CHD mortality and CHD events according to thyrotropin levels after adjustment for age, sex, and smoking status.

RESULTS: Among 55,412 individuals, 1813 people (3.3\%) died of CHD during 643,183 person-years of follow-up. In 10 cohorts with information on both nonfatal and fatal CHD events, 4666 of 48,875 individuals (9.5\%) experienced a first-time CHD event during 533,408 person-years of follow-up. For each 1-mIU/L higher thyrotropin level, the HR was 0.97 (95\% CI, 0.90-1.04) for CHD mortality and 1.00 (95\% CI, 0.97-1.03) for a first-time CHD event. Similarly, in analyses by categories of thyrotropin, the HRs of CHD mortality (0.94 [95\% CI, 0.74-1.20]) and CHD events (0.97 [95\% CI, 0.83-1.13]) were similar among participants with the highest (3.50-4.49 mIU/L) compared with the lowest (0.45-1.49 mIU/L) thyrotropin levels. Subgroup analyses by sex and age group yielded similar results.

CONCLUSIONS AND RELEVANCE: Thyrotropin levels within the reference range are not associated with risk of CHD events or CHD mortality. This finding suggests that differences in thyroid function within the population reference range do not influence the risk of CHD. Increased CHD risk does not appear to be a reason for lowering the upper thyrotropin reference limit.

}, keywords = {Cohort Studies, Coronary Disease, Humans, Hypothyroidism, Thyrotropin}, issn = {2168-6114}, doi = {10.1001/jamainternmed.2015.0930}, author = {Asvold, Bj{\o}rn O and Vatten, Lars J and Bj{\o}ro, Trine and Bauer, Douglas C and Bremner, Alexandra and Cappola, Anne R and Ceresini, Graziano and den Elzen, Wendy P J and Ferrucci, Luigi and Franco, Oscar H and Franklyn, Jayne A and Gussekloo, Jacobijn and Iervasi, Giorgio and Imaizumi, Misa and Kearney, Patricia M and Khaw, Kay-Tee and Maciel, Rui M B and Newman, Anne B and Peeters, Robin P and Psaty, Bruce M and Razvi, Salman and Sgarbi, Jos{\'e} A and Stott, David J and Trompet, Stella and Vanderpump, Mark P J and V{\"o}lzke, Henry and Walsh, John P and Westendorp, Rudi G J and Rodondi, Nicolas} }