Subclinical Hypothyroidism and the Risk of Stroke Events and Fatal Stroke: An Individual Participant Data Analysis.
The Journal of clinical endocrinology and metabolism 2015 ; 100: 2181-91.
Chaker L, Baumgartner C, den Elzen WP, Ikram MA, Blum MR, Collet TH, Bakker SJ, Dehghan A, Drechsler C, Luben RN, Hofman A, Portegies ML, Medici M, Iervasi G, Stott DJ, Ford I, Bremner A, Wanner C, Ferrucci L, Newman AB, Dullaart RP, Sgarbi JA, Ceresini G, Maciel RM, Westendorp RG, Jukema JW, Imaizumi M, Franklyn JA, Bauer DC, Walsh JP, Razvi S, Khaw KT, Cappola AR, Völzke H, Franco OH, Gussekloo J, Rodondi N, Peeters RP, and Thyroid Studies Collaboration Thyroid Studies Collaboration
DOI : 10.1210/jc.2015-1438
PubMed ID : 25856213
PMCID : PMC4454799
The objective was to determine the risk of stroke associated with subclinical hypothyroidism.
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 Unpublished studies were identified through the Thyroid Studies Collaboration.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.
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.
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.