Artikel
Association of thyroid stimulating hormone with changes in anthropometric markers
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Veröffentlicht: | 20. September 2011 |
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Background: Obesity is considered one of the most important risk factors for a multitude of chronic diseases. Due to the influence on the metabolic system, the role of thyroid function on anthropometric markers of body weight is of increasing interest. While the association of thyroid function and body weight among subjects with overt thyroid dysfunction is considered certain, investigations on association among subjects with subclinical hyper- or hypothyroidism showed inconsistent results. Furthermore, there are few longitudinal data regarding the association between thyroid function and other anthropometric markers than body weight such as body mass index (BMI), waist-circumference or waist-to-hip-ratio.
Aim/objective: We aimed to investigate the association of thyroid stimulating hormone (TSH) at baseline with changes in different anthropometric markers between baseline and follow-up among euthyroid subjects.
Methods: We used longitudinal data from the population-based SHIP- and CARLA studies. Subjects with thyroid medication at baseline or outside the serum TSH range of 0.3-3.0 mlU/l were excluded from the analyses. Multivariable regression models were calculated adjusting for different covariates as follows: age, sex, baseline value of the anthropometric marker (e.g. baseline BMI), smoking, follow-up-time and study.
Results: For our analyses, 3,705 (1,985 males and 1,720 females) subjects were eligible with a mean age at baseline of 52.1 years (SD: 15.5). The average follow-up-time was 4.9 years. Mean TSH at baseline was 0.8 mlU/l (0.5). Mean weight at baseline and follow-up was 78.7 kg (15.4) and 80.0 kg (16.0), respectively, resulting in a mean relative change of 1.8 %. Baseline BMI was 27.4 (4.6) and BMI at follow-up was 28.0 (4.8). The mean relative change in BMI from baseline to follow-up was 2.3 %. TSH at baseline was associated with a higher baseline BMI (0.7 kg/m2; 95%CI 0.33-1.00 per 1 mIU/l increase), but only slightly with BMI decrease at follow-up (-0.05kg/m2; 95%CI -0.18-0.10). Serum TSH was also slightly associated with a weight loss of 0.24 kg per increase of 1 mlU/l TSH (95%CI -0.65-0.15) between baseline and follow-up. In the cross-sectional analyses, an increase of 1 mlU/l TSH was associated with a higher baseline weight of 1.3 kg (95%CI 0.27-2.3).
Conclusion: Our analyses showed associations between TSH at baseline and different anthropometric markers in the cross-sectional analyses among subjects with a serum TSH range of 0.3-3.0mlU/l. However, we could not observe clear associations between thyroid function (as assessed by serum TSH concentration) and changes in these anthropometric markers in the longitudinal analyses.