@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 Unpublished studies were identified through the Thyroid Studies Collaboration.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 {7238, title = {Thyroid Function Within the Reference Range and the Risk of Stroke: An Individual Participant Data Analysis.}, journal = {J Clin Endocrinol Metab}, volume = {101}, year = {2016}, month = {2016 Nov}, pages = {4270-4282}, abstract = {

CONTEXT: The currently applied reference ranges for thyroid function are under debate. Despite evidence that thyroid function within the reference range is related with several cardiovascular disorders, its association with the risk of stroke has not been evaluated previously.

DESIGN AND SETTING: We identified studies through a systematic literature search and the Thyroid Studies Collaboration, a collaboration of prospective cohort studies. Studies measuring baseline TSH, free T4, and stroke outcomes were included, and we collected individual participant data from each study, including thyroid function measurements and incident all stroke (combined fatal and nonfatal) and fatal stroke. The applied reference range for TSH levels was between 0.45 and 4.49 mIU/L.

RESULTS: We collected individual participant data on 43 598 adults with TSH within the reference range from 17 cohorts, with a median follow-up of 11.6 years (interquartile range 5.1-13.9), including 449 908 person-years. Age- and sex-adjusted pooled hazard ratio for TSH was 0.78 (95\% confidence interval [CI] 0.65-0.95 across the reference range of TSH) for all stroke and 0.83 (95\% CI 0.62-1.09) for fatal stroke. For the free T4 analyses, the hazard ratio was 1.08 (95\% CI 0.99-1.15 per SD increase) for all stroke and 1.10 (95\% CI 1.04-1.19) for fatal stroke. This was independent of cardiovascular risk factors including systolic blood pressure, total cholesterol, smoking, and prevalent diabetes.

CONCLUSION: Higher levels of TSH within the reference range may decrease the risk of stroke, highlighting the need for further research focusing on the clinical consequences associated with differences within the reference range of thyroid function.

}, issn = {1945-7197}, doi = {10.1210/jc.2016-2255}, author = {Chaker, Layal and Baumgartner, Christine and den Elzen, Wendy P J and Collet, Tinh-Hai and Ikram, M Arfan and Blum, Manuel R and Dehghan, Abbas and Drechsler, Christiane and Luben, Robert N and Portegies, Marileen L P and Iervasi, Giorgio and Medici, Marco and Stott, David J and Dullaart, Robin P and Ford, Ian and Bremner, Alexandra and Newman, Anne B and Wanner, Christoph and Sgarbi, Jos{\'e} A and D{\"o}rr, Marcus and Longstreth, W T and Psaty, Bruce M and Ferrucci, Luigi and Maciel, Rui M B and Westendorp, Rudi G and Jukema, J Wouter and Ceresini, Graziano and Imaizumi, Misa and Hofman, Albert and Bakker, Stephan J L and Franklyn, Jayne A and Khaw, Kay-Tee and Bauer, Douglas C and Walsh, John P and Razvi, Salman and Gussekloo, Jacobijn and V{\"o}lzke, Henry and Franco, Oscar H and Cappola, Anne R and Rodondi, Nicolas and Peeters, Robin P} }