Utility of the Visceral Adiposity Index and Hypertriglyceridemic Waist Phenotype for Predicting Incident Hypertension

BACKGROUND: The aim of this study was to assess the utility of the visceral adiposity index (VAI) and the hypertriglyceridemic waist (HTGW) phenotype as possible hypertension (HTN) predictors in a high-risk population without diabetes and HTN. METHODS: Incident HTN over a 7-year follow-up was assessed among 1,375 first-degree non-diabetic and non-hypertensive relatives of consecutive patients with type 2 diabetes who were 30 to 70 years of age. HTN was defined as a blood pressure reading ≥140/90 mm Hg or the use of antihypertensive medications. We examined the incidence of HTN across VAI quintiles and four groups defined according to baseline fasting serum triglyceride (TG) levels and waist circumference (WC). RESULTS: The VAI and the HTGW phenotype at baseline were related to an increased risk for HTN. In comparison with the lowest VAI quintile, the highest VAI quintile showed a significant associated with HTN in an age- and gender-adjusted model (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.07 to 2.55). Those with HTGW were 2.3 times (OR, 2.27; 95% CI, 1.54 to 3.35) more likely to develop HTN than those with a normal WC and normal TG levels. CONCLUSION: Greater VAI values weakly predicted HTN, whereas the HTGW phenotype was a stronger predictor of incident HTN in an Iranian high-risk population.

Prevalence of Goitre in Isfahan, Iran, Fifteen Years After Initiation of Universal Salt Iodization.

This cross-sectional study investigated the prevalence of goitre in Isfahan, a centrally-located city in Iran, 15 years after the initiation of universal salt iodization. In total, 2,523 Isfahani adults (1,275 males, 1,248 females) aged >20 years were selected by multi-stage cluster-sampling method. Goitre rate, serum thyroidstimulating hormone (TSH), thyroxine (T4), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), and urinary iodine concentration (UIC) were measured and compared between the goitrous (n=478) and the non-goitrous (n=2,045) participants. The total goitre rate was 19% (n=478) of the 2,523 adults. The rate of Grade I and II goitre was 12.4% (n=312) and 6.6% (n=166) respectively. The total goitre rate, Grade I and II goitre were more prevalent among women than among men. Hypothyroidism was observed in 6.4% (130/2,045) and 18.6% (89/478) of the non-goitrous and goitrous participants respectively [odds ratio (OR)=3.6, 95% confidence interval (CI) 2.7-4.9, p=0.001]. Hyperthyroidism was present in 0.8% (17/2,045) and 5.2% (29/478) of the non-goitrous and goitrous adults respectively (OR=9.0, 95% CI 4.9-16.6, p=0.001). Hypothyroidism was more prevalent in Grade II than in Grade I goitre and among those without goitre (31.3%, 14.1%, and 6.4% respectively) (p=0.001). Positive TPOAb was observed in 24% (n=50) of the non-goitrous and 33.5% (n=84) of the goitrous subjects (p=0.03). Positive TPOAb was observed in 24.6% (35 of 142) of the Grade I and 45% (49 of 109) of the Grade II goitrous adults (p=0.001). Positive TgAb was observed in 21.6% (n=45) of the non-goitrous and 35.9% (n=90) of the goitrous adults (p=0.001). Positive TgAb was observed in 30.3% (43 of 142) of the Grade I and 43.1% (47 of 109) of the Grade II goitrous adults (p=0.04). The median UIC was 18 μg/dL (range 1-80 μg/dL). It was 17.9 μg/dL and 19 μg/dL in the non-goitrous and goitrous adults respectively. After 15 years of successful universal salt iodization in Isfahan, goitre is still endemic, which may be due to thyroid autoimmunity. However, other environmental or genetic factors may have a role.

Normal values of thyroid gland in Isfahan, an iodine replete area

Because of different values of thyroid volume in different populations, and the effects of different trace element and geographic substances on thyroid volume, we decided to evaluate thyroid volume and its determinants using ultrasound in healthy adults of Isfahan, a centrally located city in Iran, an iodine replete area. In a cross-sectional study, 1500 healthy adults were enrolled by cluster sampling. Serum TSH level and morning urine iodine level were measured. Thyroid exam was performed according to WHO criteria and history of previous or present thyroid disease was taken. If all the mentioned results were normal they were considered clinically normal. One third of these normal subjects referred for thyroid ultrasonography. If ultrasonography of thyroid parenchyma texture was normal, and there was no nodule by sonography [thyroid incidentaloma], thyroid volume was measured using ellipsoid formula [XxYxZx[PI]/6]. Correlation between thyroid volume and age, sex, BMI, TSH level and urinary iodine concentration [UIC] was determined by Pearson correlation coefficient, t-Test and Kolmogorov-Smirnov. Thyroid volume more than 97% of this population was considered as goiter sonographically. Data expressed asonean +/- SD, unless otherwise stated. We finally studied 200 subjects [123 Males, 77 females, average age: 37.27 +/- 11.80 Years]. The overall thyroid volume was 9.53 +/- 3.68 ml. Males thyroid volume [10.73 +/- 3.44 ml] was significantly higher than the females one [7.71 +/- 2.63 ml] [P<0.001]. The thyroid volume ranges were 3-23.9 ml, 3.6-23.9 ml and 3-14.3 ml in all, males and females, respectively. Thyroid volume values more than 97 percentile of this reference range were 10.14 ml, 11.48 ml and 8.37 ml in all, males and females respectively, and were considered goiter sonographically. Thyroid volume had a positive correlation with age [r = 0.163, P = 0.022], but did not have correlation with serum TSH, UIC, and BMI, in both sexes. There was a strong correlation between thyroid volume, and height and body surface area [r = 0.48, P<0.001]. It was documented that thyroid volume is higher in male sex and increases with age, and have a positive correlation with body surface area and height

Iodine repletion thyrotoxicosis and atrial fibrillation in Isfahan, Iran

Iodized salt was reintroduced in Iran in 1989. Just before distribution of iodized salt, thyrotoxicosis was observed in 3.7% of the patients with atrial fibrillation [AF] in university teaching hospitals in Isfahan, a centrally located city in Iran. As repletion of iodine may increase the rate of autoimmune thyroid diseases and toxic multinodular goiter, this study was designed to evaluate the rate of thyrotoxicosis in patients with AF in the same hospitals after about a decade of iodized salt consumption. In a case-control study with convenience sampling, 100 patients with AF and an equal number of age- and sex-matched subjects taking the same medications were selected as case and control groups, respectively, in university hospitals in 1997. Eight% of patients with atrial fibrillation had overt thyrotoxicosis versus one% in the control group [odds ratio=8.6, 95% CI= 6.5 to 10.7, P<0.02]. Thyrotoxicosis in patients with AF was 8 times higher than in the control group without AF. In comparison with the period before use of iodized salt, AF more than doubled [8% vs. 3.7%]. Conclusion:Thyroid function should be evaluated in all patients older than 40 years of age with AF. The benefits of iodine supplementation are great, but more attention should be paid to the complications of iodine repletion, including thyrotoxicosis and its frequent accompaniment, AF