According to the data, a large proportion (10%) of the Spanish population has some evidence of thyroid dysfunction. High TPOAb concentrations were associated with both hypo- and hyperthyroidism, whereas high UI concentrations were associated with hypothyroidism.

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Persons with morbid obesity might be inappropriately classified if the standard ranges of normality of TSH for the normal-weight population are applied to them.

Objective: The aim of this study was to examine possible associations between ambient temperature and obesity in the Spanish population using an ecological focus. Methods: The Di@bet.es study is a national, cross-sectional, population-based survey of cardiometabolic risk factors and their association with lifestyle. Sample: 5,061 subjects in 100 clusters. Variables: Clinical, demographic and lifestyle survey, physical examination, and blood sampling. The mean annual temperature ( C) for each study site was collected from the Spanish National Meteorology Agency . Results: The prevalence rates of obesity in the different geographical areas divided according to mean annual temperature quartiles were 26.9% in quartile 1 (10.4-14.5 C), 30.5% in quartile 2 (14.5-15.5 C), 32% in quartile 3 (15.5-17.8 C), and 33.6% in quartile 4 (17.8-21.3 C) (P 5 0.003). Logistic regression analyses including multiple socio-demographic (age, gender, educational level, marital status) and lifestyle (physical activity, Mediterranean diet score, smoking) variables showed that, as compared with quartile 1, the odd ratios for obesity were 1.20 (1.01-1.42), 1.35 (1.12-1.61), and 1.38 (1.14-1.67) in quartiles 2, 3, and 4, respectively (P 5 0.001 for difference, P < 0.001 for trend). Conclusions: Our study reports an association between ambient temperature and obesity in the Spanish population controlled for known confounders.

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Previous studies have suggested that iron deficiency (ID) may impair thyroid hormone metabolism, however replication in wide samples of the general adult population has not been performed. We studied 3846 individuals free of thyroid disease, participants in a national, cross sectional, population based study representative of the Spanish adult population. Thyroid stimulating hormone (TSH), free thyroxin (FT4) and free triiodothyronine (FT3) were analyzed by electrochemiluminescence (E170, Roche Diagnostics). Serum ferritin was analyzed by immunochemiluminescence (Architect I2000, Abbott Laboratories). As ferritin levels decreased (>100, 30–100, 15–30, <15 µg/L) the adjusted mean concentrations of FT4 (p < 0.001) and FT3 (p < 0.001) descended, whereas TSH levels remained unchanged (p = 0.451). In multivariate logistic regression models adjusted for age, sex, UI, BMI and smoking status, subjects with ferritin levels <30 µg/L were more likely to present hypothyroxinemia (FT4 < 12.0 pmol/L p5): OR 1.5 [1.1–2.2] p = 0.024, and hypotriiodothyroninemia (FT3 < 3.9 pmol/L p5): OR 1.8 [1.3–2.6] p = 0.001 than the reference category with ferritin ≥30 µg/L. There was no significant heterogeneity of the results between men, pre-menopausal and post-menopausal women or according to the iodine nutrition status. Our results confirm an association between ID and hypothyroxinemia and hypotriiodothyroninemia in the general adult population without changes in TSH.

Objective It has been proposed that a mild form of acquired resistance to thyroid hormone may occur in the general population. Its clinical significance remains largely unknown. The objective of the study was to explore whether a newly described thyroid hormone resistance index is associated with the risk of mortality in a sample of community-dwelling euthyroid subjects representative of the adult population of Spain. Design Longitudinal observational study including 3750 individuals, free of thyroid disease, TPO antibodies-negative (<50 IU/mL) and with TSH levels within the euthyroid range (≥0.5 and ≤5.0 mUI/mL) participating in the nationwide study Di@bet.es (2008–2010). Methods We used the Thyroid Feedback Quantile-based Index (TFQI) as a marker of resistance to thyroid hormone. The study population was grouped into categories according to their TFQI values at baseline. Fatal events were ascertained from the national death registry (end of follow-up December 2016). Results A total of 231 deaths were recorded during an average follow-up of 7.3 years. Compared with the category with the highest sensitivity to free thyroxine (TFQI ≤ p5) (reference), the relative risk of mortality in the categories with TFQI > p5 and ≤p25; >p25 and ≤p50; >p50 and ≤p75; >p75 and ≤p95 and >p95 were 1.01, (0.47–2.19), 1.42 (0.68–2.97), 1.54 (0.74–3.22), 1.47 (0.70–3.11) and 2.61 (1.16–5.89), respectively (P for trend 0.003). The association remained significant after multivariate adjustment of the data (P for trend 0.017). Conclusions A thyroid hormone resistance index focused on deviations of the average pituitary response to thyroid hormones may be associated with all-cause mortality independently of other conventional risk factors and comorbidities.

Background: Muscle ultrasonography of the quadriceps rectus femoris (QRF) is a technique on the rise in the assessment of muscle mass in application of nutritional assessment. The aim of the present study is to assess the usefulness of muscle ultrasonography in patients with cystic fibrosis, comparing the results with other body composition techniques such as anthropometry, bioelectrical impedance analysis (BIA), dual-energy X-ray absorptiometry (DXA), and handgrip strength (HGS). At the same time, we intend to assess the possible association with the nutritional and respiratory status. Methods: This was a prospective observational study in adult patients with cystic fibrosis in a clinically stable situation. Muscle ultrasonography of the QRF was performed, and the results were compared with other measures of body composition: anthropometry, BIA, and DXA. HGS was used to assess muscle function. Respiratory parameters were collected, and nutritional status was assessed using Global Leadership Initiative on Malnutrition (GLIM) criteria. Results: A total of 48 patients were included, with a mean age of 34.1 ± 8.8 years. In total, 24 patients were men, and 24 patients were women. Mean BMI was 22.5 ± 3.8 kg/m2. Mean muscular area rectus anterior (MARA) was 4.09 ± 1.5 cm2, and mean muscular circumference rectus was 8.86 ± 1.61 cm. A positive correlation was observed between the MARA and fat-free mass index (FFMI) determined by anthropometry (r = 0.747; p < 0.001), BIA (r = 0.780; p < 0.001), and DXA (r = 0.678; p < 0.001), as well as muscle function (HGS: r = 0.790; p < 0.001) and respiratory parameters (FEV1; r = 0.445, p = 0.005; FVC: r = 0.376, p = 0.02; FEV1/FVC: r = 0.344, p = 0.037). A total of 25 patients (52.1%) were diagnosed with malnutrition according to GLIM criteria. Differences were observed when comparing the MARA based on the diagnosis of malnutrition (4.75 ± 1.65 cm2 in normo-nourished vs. 3.37 ± 1.04 in malnourished; p = 0.014). Conclusions: In adults with cystic fibrosis, the measurements collected by muscle ultrasound of the QRF correlate adequately with body composition techniques such as anthropometry, BIA, DXA, and handgrip strength. Muscle ultrasound measurements, particularly the MARA, are related to the nutritional status and respiratory function of these patients.