Dataset Information

Thyrotropin levels in a population with no clinical, autoantibody, or ultrasonographic evidence of thyroid disease: implications for the diagnosis of subclinical hypothyroidism.

ABSTRACT:

Context

The current debate regarding whether to decrease the upper limit for the TSH reference range to 2.5 microIU/ml has considerable potential impact on the diagnosis and treatment of subclinical hypothyroidism worldwide.

Objective

We report an analysis of TSH distribution in a population with no evidence of thyroid disease, including a normal thyroid ultrasound.

Design

A subset of the Hanford Thyroid Disease Study cohort was used to examine the TSH distribution in a population having no evidence of thyroid disease, seronegative thyroid autoantibodies, no history of thyroid medications, and a normal thyroid ultrasound. The shape of the TSH distribution was compared with the Gaussian and lognormal distributions.

Setting

This study was performed in the general community.

Participants

Of 1861 Hanford Thyroid Disease Study participants with TSH measured by ELISA who also had thyroid peroxidase antibody measurements, 766 comprised the normal reference group 3 (NRG-3) with no evidence of thyroid disease, including no positive antibodies and normal thyroid ultrasound.

Main outcome measure

TSH was measured.

Results

The TSH distribution in the NRG (NRG-3) was right skewed and followed an approximate lognormal distribution. The best estimates of the 97.5th percentile, the percentage above 2.5 microIU/ml, and the percentage above 3.0 microIU/ml for TSH by 3rd generation immunochemiluminometric assay are 4.1 microIU/ml, 20% and 10.2%, respectively.

Conclusion

These results indicate that the TSH reference range should be narrowed and support a value of approximately 4.0 as the upper-reference limit.

SUBMITTER: Hamilton TE

PROVIDER: S-EPMC2729186 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature

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Publications

Thyrotropin levels in a population with no clinical, autoantibody, or ultrasonographic evidence of thyroid disease: implications for the diagnosis of subclinical hypothyroidism.

Hamilton Thomas E TE Davis Scott S Onstad Lynn L Kopecky Kenneth J KJ

The Journal of clinical endocrinology and metabolism 20080129 4

<h4>Context</h4>The current debate regarding whether to decrease the upper limit for the TSH reference range to 2.5 microIU/ml has considerable potential impact on the diagnosis and treatment of subclinical hypothyroidism worldwide.<h4>Objective</h4>We report an analysis of TSH distribution in a population with no evidence of thyroid disease, including a normal thyroid ultrasound.<h4>Design</h4>A subset of the Hanford Thyroid Disease Study cohort was used to examine the TSH distribution in a pop ...[more]

PMID: 18230665

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Project description:BackgroundFew studies have focused on the association between lifestyle and subclinical hypothyroidism (SCH). The purpose of this study was to investigate the association between lifestyle and thyroid function in SCH.MethodsThis study was a part of a community-based and cross-sectional study, the Epidemiological Survey of Thyroid Diseases in Fujian Province, China. A total of 159 participants with SCH (81 males and 78 females) and 159 euthyroid (87 males and 72 females) participants without any missing data were included in the analysis. General information and lifestyle information including sleep, exercise, diet and smoking habits of the participants was collected by questionnaire and Pittsburgh sleep quality index scale (PSQI) was collected. Thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroid peroxidase antibody (TPOAb), thyroid globulin antibody (TgAb) and urine iodine concentration (UIC) were tested. Thyroid homeostasis parameter thyroid' s secretory capacity (SPINA-GT), Jostel's TSH index (TSHI), thyrotroph T4 sensitivity index (TTSI) were calculated. Logistic regression and multiple linear regression were performed to assess associations.ResultsCompared with euthyroid subjects, patients with SCH were more likely to have poor overall sleep quality (15.1 vs.25.8 %, P = 0.018) and l less likely to stay up late on weekdays (54.7 vs. 23.9 % P < 0.001). In SCH group, exercise was the influencing factor of TSH (β= -0.224, P = 0.004), thyroid secretory capacity (β = 0.244, P = 0.006) and thyrotropin resistance (β = 0.206, P = 0.009). Iodine excess was the influencing factor of thyroid secretory capacity (β = 0.209, P = 0.001) and pituitary thyroid stimulating function (β = 0.167, P = 0.034). Smoking was the influencing factor of pituitary thyroid stimulating function (β = 0.161, P = 0.040). Staying up late on weekends was the influencing factor of thyroid secretory capacity (β = 0.151, P = 0.047). After adjusting for possible confounders, logistic regression showed that those with poor overall sleep quality assessed by PSQI and iodine excess had an increased risk of SCH (OR 2.159, 95 %CI 1.186-3.928, P = 0.012 and OR 2.119, 95 %CI 1.008-4.456, P = 0.048, respectively).ConclusionsLifestyle including sleep, smoking, diet and exercise was closely related to thyroid function especially thyroid homeostasis in SCH.

Project description:BACKGROUND:Atrial fibrillation (AF) is a highly prevalent disorder leading to heart failure, stroke, and death. Enhanced understanding of modifiable risk factors may yield opportunities for prevention. The risk of AF is increased in subclinical hyperthyroidism, but it is uncertain whether variations in thyroid function within the normal range or subclinical hypothyroidism are also associated with AF. METHODS:We conducted a systematic review and obtained individual participant data from prospective cohort studies that measured thyroid function at baseline and assessed incident AF. Studies were identified from MEDLINE and EMBASE databases from inception to July 27, 2016. The euthyroid state was defined as thyroid-stimulating hormone (TSH) 0.45 to 4.49 mIU/L, and subclinical hypothyroidism as TSH 4.5 to 19.9 mIU/L with free thyroxine (fT4) levels within reference range. The association of TSH levels in the euthyroid and subclinical hypothyroid range with incident AF was examined by using Cox proportional hazards models. In euthyroid participants, we additionally examined the association between fT4 levels and incident AF. RESULTS:Of 30?085 participants from 11 cohorts (278?955 person-years of follow-up), 1958 (6.5%) had subclinical hypothyroidism and 2574 individuals (8.6%) developed AF during follow-up. TSH at baseline was not significantly associated with incident AF in euthyroid participants or those with subclinical hypothyroidism. Higher fT4 levels at baseline in euthyroid individuals were associated with increased AF risk in age- and sex-adjusted analyses (hazard ratio, 1.45; 95% confidence interval, 1.26-1.66, for the highest quartile versus the lowest quartile of fT4; P for trend ?0.001 across quartiles). Estimates did not substantially differ after further adjustment for preexisting cardiovascular disease. CONCLUSIONS:In euthyroid individuals, higher circulating fT4 levels, but not TSH levels, are associated with increased risk of incident AF.

Dataset Information

Thyrotropin levels in a population with no clinical, autoantibody, or ultrasonographic evidence of thyroid disease: implications for the diagnosis of subclinical hypothyroidism.

Context

Objective

Design

Setting

Participants

Main outcome measure

Results

Conclusion

Publications

Thyrotropin levels in a population with no clinical, autoantibody, or ultrasonographic evidence of thyroid disease: implications for the diagnosis of subclinical hypothyroidism.

Similar Datasets

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