Small differences in thyroid function may be important for body mass index and the occurrence of obesity in the population
ABSTRACT Increasing prevalence of overweight in the population is a major concern globally; and in the United States, nearly one third of adults were classified as obese at the end of the 20th century. Few data have been presented regarding an association between variations in thyroid function seen in the general population and body weight.
The aim of this study was to investigate the association between thyroid function and body mass index (BMI) or obesity in a normal population.
A cross-sectional population study (The DanThyr Study) was conducted.
In all, 4649 participants were investigated, and 4082 were eligible for these analyses after exclusion of subjects with previous or present overt thyroid dysfunction.
The study examined the association between category of serum TSH or serum thyroid hormones and BMI or obesity in multivariate models, adjusting for possible confounding.
We found a positive association between BMI and category of serum TSH (P < 0.001) and a negative association between BMI and category of serum free T(4) (P < 0.001). No association was found between BMI and serum free T(3) levels. The difference in BMI between the groups with the highest and lowest serum TSH levels was 1.9 kg/m(2), corresponding to a difference in body weight of 5.5 kg among women. Similarly, the category of serum TSH correlated positively with weight gain during 5 yr (P = 0.04), but no statistically significant association was found with weight gain during 6 months (P = 0.17). There was an association between obesity (BMI > 30 kg/m(2)) and serum TSH levels (P = 0.001).
Our results suggest that thyroid function (also within the normal range) could be one of several factors acting in concert to determine body weight in a population. Even slightly elevated serum TSH levels are associated with an increase in the occurrence of obesity.
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ABSTRACT: Thyroid disease is a common problem among women of reproductive age but often goes undiagnosed. Maternal thyroid disease has been associated with increased risk of craniosynostosis. We hypothesized that known risk factors for thyroid disease would be associated with risk of craniosynostosis among women not diagnosed with thyroid disease. Analyses included mothers of 1,067 cases and 8,494 population-based controls who were interviewed for the National Birth Defects Prevention Study. We used multivariable logistic regression to estimate adjusted odds ratios (AOR) and 95% confidence intervals (CI). After excluding women with diagnosed thyroid disease, younger maternal age (AOR 0.7, 95% CI 0.6-0.9, for <25 years versus 25-29), black or other race-ethnicity (AOR 0.3, 95% CI 0.2-0.4 and AOR 0.6, 95% CI 0.4-0.8, respectively, relative to non-Hispanic whites), fertility medications or procedures (AOR 1.5, 95% CI 1.2-2.0), and alcohol consumption (AOR 0.8, 95% CI 0.7-0.9) were associated with risk of craniosynostosis, based on confidence intervals that excluded 1.0. These associations with craniosynostosis are consistent with the direction of their association with thyroid dysfunction (i.e., younger age, black race-ethnicity and alcohol consumption are associated with reduced risk and fertility problems are associated with increased risk of thyroid disease). This study thus provides support for the hypothesis that risk factors associated with thyroid dysfunction are also associated with risk of craniosynostosis. Improved understanding of the potential association between maternal thyroid function and craniosynostosis among offspring is important given that craniosynostosis carries significant morbidity and that thyroid disease is under-diagnosed and potentially modifiable. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.American Journal of Medical Genetics Part A 02/2015; 167(4). DOI:10.1002/ajmg.a.36953 · 2.05 Impact Factor
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ABSTRACT: Hypothyroxinaemia early in pregnancy may impair fetal brain development. Increased body weight has been associated with low thyroxine concentrations in non-pregnant women. In pregnant women, morbid maternal obesity is a risk factor for thyroid dysfunction. But whether lesser degrees of overweight that are much more common could be a risk factor for hypothyroxinaemia in pregnancy is unclear. The objective of this study was to investigate if overweight increases risk for thyroid dysfunction, and specifically hypothyroxinaemia, in iodine-deficient pregnant women. We performed a cross-sectional study at first hospital visit among healthy Thai pregnant women. We measured weight and height, urinary iodine concentration (UIC), serum thyroid hormones and thyroglobulin. Pre-pregnancy weight and relevant dietary factors were determined by questionnaire, and body mass index (BMI) was used to classify weight status. Among 514 women (mean gestational age, 11 weeks) with a median UIC of 111 μg dL(-1) , indicating mild iodine deficiency, 12% had low free thyroxine (fT4) concentrations: 3% had overt hypothyroidism; 7% had subclinical hypothyroidism; and 8% had isolated hypothyroxinaemia. Based on pre-pregnancy BMI, 26% of women were overweight or obese. In a multiple regression model, BMI was a negative predictor of fT4 (β = -0.20, P < 0.001). Compared to normal weight women, the prevalence ratio (95% CI) of a low fT4 in overweight women was 3.64 (2.08-6.37) (P < 0.01). Iodine-deficient pregnant Thai women who are overweight have a 3.6-fold higher risk of hypothyroxinaemia in the first trimester compared to normal weight women. Targeted screening should consider overweight a potential risk factor for thyroid dysfunction in pregnant women in iodine-deficient areas.Maternal and Child Nutrition 08/2013; 10(1). DOI:10.1111/mcn.12040 · 2.97 Impact Factor
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ABSTRACT: Background: Thyroid function has been suggested to interfere with tumour biology and prognosis in different cancers. The present study was performed to investigate the impact of pre-therapeutic serum thyroid-stimulating hormone (TSH) levels on the prognosis of patients with endometrial cancer. Methods: Pre-therapeutic serum TSH was investigated in 199 patients with endometrial cancer. After stratification in TSH risk groups, univariate and multivariable survival analyses were performed. Results: Elevated TSH was independently associated with poor disease-specific survival in univariate/multivariable survival analyses (P=0.01 and P=0.03, respectively). Conclusion: Thyroid-stimulating hormone may serve as a novel and independent prognostic parameter for disease-specific survival in patients with endometrial cancer.British Journal of Cancer 06/2013; 109(1). DOI:10.1038/bjc.2013.282 · 4.82 Impact Factor