Thyrotropin levels and their relationship with cardiovascular risk factors in the island of Gran Canaria, Spain. Implications of lowering the upper reference limit of thyrotropin stimulating hormone.

OBJECTIVE: To characterize the cardiovascular risk profile of subjects with high and normal-high concentrations of serum TSH in a sample of adult Spanish subjects from the island of Gran Canaria. DESIGN: Cross-sectional population-based study. SUBJECTS: After excluding 28 individuals on current treatment with levothyroxine and 9 others with TSH levels below the range of normality (0.3-4.9 mU/l), 704 randomly selected subjects (412 women; age range: 30-82 yr) belonging to the Telde Study were assessed. MEASUREMENTS: Participants underwent physical examination and fasting blood analyses to determinate TSH, serum lipids, homocysteine, fibrinogen, von Willebrand factor, plasminogen activator inhibitor- 1, C-reactive protein, and insulin. RESULTS: Twenty-nine participants had serum TSH concentrations above the normal range of normality. Among all the studied variables, only female sex and diastolic blood pressure were significantly associated with TSH levels > or =5 mU/l in a multivariate logistic regression analysis. If the upper normal limit of TSH was reduced up to 2.4 mU/l, an additional group of 106 subjects would be considered to have elevated TSH levels. A serum TSH > or =2.5 mU/l was positive and independently associated with female sex, body mass index, total cholesterol, and homocysteine, and negatively associated with smoking. CONCLUSIONS: Although the impact of serum TSH levels on cardiovascular risk cannot be established from these findings, TSH values within the upper part of the usually accepted normal range were demonstrated to be associated with well-recognized risk factors for cardiovascular disease.

Differences in traditional and emerging cardiovascular risk factors of subjects discordantly classified by metabolic syndrome definitions of the International Diabetes Federation and the National Cholesterol Education Program.

BACKGROUND AND AIM: Several working definitions of metabolic syndrome have been proposed for clinical use. However, individuals can be discordantly classified as having or not having metabolic syndrome depending on the choice of one or another definition. This study compared the cardiovascular risk profile of subjects concordantly and discordantly diagnosed by the criteria of the National Cholesterol Education Program (NCEP) and the criteria of the International Diabetes Federation (IDF). METHODS AND RESULTS: Nine hundred and twenty-nine non-diabetic adult subjects belonging to a cross-sectional population-based study in Gran Canaria island (Spain) were assessed. Participants completed a questionnaire and underwent physical examination, fasting blood analyses, and a standardized oral glucose tolerance test. Two hundred and four subjects (22%) had metabolic syndrome according to both definitions, 31 (3.3%) only by the IDF criteria, and 5 (0.5%) only by the NCEP criteria. Participants fulfilling both proposals showed more adverse age and sex-adjusted measures of BMI, waist, HDL cholesterol, triglycerides, post-load glucose, HOMA-IR and plasminogen inhibitor activator-1 (PAI-1) than individuals exclusively satisfying the IDF criteria. Moreover, in contrast to subjects meeting both criteria, those that fulfilled only the IDF criteria had levels of BMI, waist, total and HDL cholesterol, post-load glucose, glycated HbA1c, C-reactive protein, PAI-1 and fibrinogen not significantly different from those observed in subjects without metabolic syndrome. CONCLUSION: The IDF definition identifies a surplus of individuals whose cardiovascular risk profile, particularly regarding to some non-traditional cardiovascular risk factors, is less adverse than that observed in subjects also diagnosed by the NCEP definition.

Use of confirmatory factor analysis for the identification of new components of the metabolic syndrome: the role of plasminogen activator inhibitor-1 and Haemoglobin A1c.

BACKGROUND AND AIM: This study was aimed to identify additional components of metabolic syndrome from a set of cardiovascular risk markers. METHODS AND RESULTS: The homeostasis model assessment of insulin resistance (HOMA-IR), C-reactive protein, fibrinogen, plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor, homocysteine, Haemoglobin A1c (HbA1c), and lipoprotein(a) were assessed in a population-based sample of 902 nondiabetic adult subjects. Those biomarkers that were associated with metabolic syndrome were evaluated by multiple regression analysis, along with other traditional cardiovascular risk factors. Confirmatory factor analysis (CFA) was used to test the hypothesis that both the established components of metabolic syndrome and the novel variables identified by the regression analysis were associated with a single underlying factor. HOMA-IR, PAI-1 and HbA1c were the only biomarkers independently related to metabolic syndrome. CFA validated a one-factor model that included these variables. Moreover, the indices of goodness of fit were better for this expanded model than those obtained for a previously validated one-factor model that was restricted to the conventional elements of the syndrome. CONCLUSIONS: These findings show that PAI-1 and HbA1c are singularly linked to metabolic syndrome. Their elevation is presumably another manifestation of the same pathophysiological mechanism that underlies the recognized traits of the syndrome.

Diabetes mellitus and impaired glucose regulation in the Canary Islands (Spain): prevalence and associated factors in the adult population of Telde, Gran Canaria.

AIMS: To estimate the prevalence and the determinants of diabetes mellitus and impaired glucose regulation (IGR) in an adult Canarian population. METHODS: Cross-sectional study. One thousand and thirty subjects aged 30-82 years were randomly selected. Participants completed a survey questionnaire and underwent blood pressure measurements, anthropometry, blood samples, and a 75-g standardized oral glucose tolerance test. RESULTS: The age-standardized prevalence of diabetes was 15.8% (95% confidence interval: 11.8-19.8) in men and 10.6% (7.1-14.1) in women. Total prevalence was 13.2% (11.1-15.2). Among individuals with diabetes, 55.4% of men and 38.2% of women were not previously diagnosed. The age-standardized prevalences of impaired glucose tolerance and impaired fasting glycaemia were 11.4% (9.5-13.4) and 2.8% (1.8-3.8), respectively. In multivariate analyses, age, waist circumference, serum triglycerides, and familial history of diabetes were independently associated with diabetes in both sexes, while a value of C-reactive protein (CRP) >/= 1 mg/l showed an association with diabetes, but only in men. Age and triglycerides were related to impaired glucose regulation (IGR) in both sexes, waist circumference was related to IGR exclusively in men, and familial diabetes exclusively in women. Statistically significant interactions between gender and both CRP and triglycerides were found with respect to diabetes, and between gender and both waist circumference and triglycerides for IGR. CONCLUSIONS: Compared with the rest of Spain, the prevalence of diabetes is moderately increased in this area of the Canary Islands. Along with other well-established risk factors, CRP was independently associated with diabetes, but only in the male population.

Prevalence of the metabolic syndrome in the island of Gran Canaria: comparison of three major diagnostic proposals.

AIMS: The present study was conducted to estimate the prevalence of the metabolic syndrome in a Canarian population, and to compare its frequency as defined by the most commonly used working definitions. METHODS: Cross-sectional population-based study. One thousand and thirty adult subjects were randomly selected from the local census of Telde, a city located on the island of Gran Canaria. Participants completed a survey questionnaire and underwent physical examination, fasting blood analyses, and a 75-g standardized oral glucose tolerance test. The prevalence of the metabolic syndrome was estimated according to the definitions proposed by the World Health Organization (WHO), the European Group for the Study of Insulin Resistance (EGIR) and the National Cholesterol Education Program (NCEP), the latter with the original (6.1 mmol/l) and the revised criterion (5.6 mmol/l) for abnormal fasting glucose. RESULTS: The adjusted prevalence of the metabolic syndrome was 28.0, 15.9, 23.0 and 28.2%, using the WHO, EGIR, NCEP and revised NCEP criteria, respectively. The measure of agreement (kappa statistic) was 0.57 between the WHO and the original NCEP definitions, and 0.61 between the WHO and the revised NCEP definitions. After excluding diabetic subjects, the agreement between the EGIR and WHO proposals was fairly good (kappa=0.70), whereas concordance of the EGIR with the original and the revised NCEP definitions was moderate (kappa=0.47 and 0.46, respectively). CONCLUSIONS: Whichever the considered diagnostic criteria, the prevalence of the metabolic syndrome in this area of the Canary Islands is greater than that observed in most other European populations.