[Behavior of some anthropometric, clinical and biochemical variables in boys and girls 8 to 12 years of age from the longitudinal study of the metropolitan area]. / Comportamiento de algunas variables antropométricas, clinicas y bioquimicas en varones y hembras de 8 a 12 años de edad del Estudio Longitudinal del Area Metropolitana.

A longitudinal principal components analysis was used to summarize trends or intraindividual changes in weight, height, blood pressure, serum cholesterol and triglycerides in 32 boys and 28 girls from the Caracas Longitudinal Study (1976-1982), who started follow-up at age 8. A first component was identified for each variable, it represents a measure of position across the whole age period, a "canalization pattern". This component accounted for most of the total variance. The second component represents an unidirectional change in relative position of the values of the variable, a "decanalization pattern", and a third pattern summarized deviations around a position level: "recanalization pattern". The results from the correlation analyses between the components indicate a positive and significant association between the identified trends. These patterns allow predictability of "high and low risk" factors of non-communicable chronic diseases.

[Tracking of body height, body weight, body mass index, blood lipids and glucose in upper strata girls in Caracas, Venezuela]. / Canalización de talla, peso, índice de masa corporal, lípidos y glucosa séricos en niñas de los estratos sociales altos de Caracas, Venezuela.

In the Caracas Longitudinal Study, the canalization of 24 girls that started follow-up at age 4, 43 at age 8, and 32 at age 12 in: height (H), weight (W), Body Mass Index (BMI), cholesterol (CHOL), triglycerides (TG) and glucose (GL), was studied using Schneiderman n Tracking Index (TI) and age to age correlations. TI presented a gradient H > W > BMI > CHOL and lower in TG and GL. TI of all variables diminished increased with age and in BMI and CHOL. Age to age correlations were significant at all ages in H, W. and BMI and higher in CHOL (p < 0.01) compared to TG and GL. The significant tracking of H, W, BMI and lipids, specially CHOL, is relevant in prevention of non-communicable chronic diseases.

Relations between fasting serum insulin, glucose, and dihydroepiandrosterone-sulfate concentrations in obese patients with hypertension: short-term effects of antihypertensive drugs.

A randomized, single-blind, placebo-controlled study was conducted in 82 obese patients with mild to moderate essential hypertension, to determine the incidence of hyperinsulinemia, the relations between fasting insulin and dihydroepiandrosterone-sulfate (DHEA-S) levels, and the short-term effects of antihypertensives on DHEA-S and insulin serum concentrations. Increased insulin/glucose ratios (IGR) suggestive of insulin resistance were found in half of our patients. Hyperinsulinemic and normoinsulinemic obese patients with hypertension had comparable fasting glucose and DHEA-S concentrations and comparable blood pressure (BP) levels. Thus no relations were found between fasting insulin and DHEA-S levels. Fasting hyperinsulinemia was found in only half of the obese subjects with hypertension, suggesting that not all obese patients with hypertension are at the same high cardiovascular risk. Short-term treatment with captopril, prazosin, verapamil, atenolol, or hydrochlorothiazide (HCTZ) reduced BP; greater BP reduction was observed with drugs with vasodilatory effects. Captopril, prazosin, and verapamil reduced fasting insulin levels, whereas atenolol and hydrochlorothiazide did not. The former drugs reduced fasting insulin levels that were either within normal limits or in the hyperinsulinemic range. None of the drug treatments produced significant increases in serum DHEA-S concentrations, although some of them considerably reduced fasting insulin levels. No relations between insulin and DHEA-S levels were observed either at baseline or at the end of the antihypertensive treatment. The BP reduction resulting from the peripheral vasodilation may explain the insulin-reducing action of captopril, verapamil, and prazosin. These results further emphasize the large heterogeneity present in the pathophysiologic mechanisms operating in obesity and hypertension.

The thyroid status of the Yanomamö Indians of southern Venezuela: 1992 update.

Previous reports described an apparent paradox in the clinical expression of endemic iodine deficiency in Amazonian Indians, who were severely iodine deficient but had no goiter and were clinically euthyroid. To confirm and explain this unique observation, we estimated the iodine intake and evaluated the functional and structural thyroid status of an isolated population of Yanomamö Indians (n = 104) in southern Venezuela. Twenty-six children, 32 adolescents, and 46 adults were studied with serum thyroid function tests, spot urinary iodide concentration determinations, and sonographic measurement of thyroid gland volume. A subset of adolescents and adults (n = 35) had 24-h fractional thyroidal 131I uptake determinations. No individual with goiter, clinical hypothyroidism, or cretinism was observed. Children had higher mean serum T4 (114.5 vs. 102.9 nmol/L; P < 0.02) and serum T3 (2.96 vs. 2.46 nmol/L; P < 0.02) concentrations than adults, with 2% and 50%, respectively, of children having levels more than 2 SD above the mean for a North American reference population. Serum TSH concentrations were also higher in children than adults (3.3 vs. 2.3 mU/L; P < 0.02), with 25% of the subjects above the reference range. Mean urinary iodide was 61 +/- 29 micrograms/L (range, 10-178 micrograms/L), reflecting borderline iodine sufficiency. Thyroidal 131I uptake values were 28 +/- 7%, with 33% above the upper limit of normal (30%). Compared to an iodine-replete Swedish population, the thyroid gland volume was above normal (> mean + 2 SD) in 71% of the study children. We conclude that the Yanomamö have borderline iodine deficiency, associated in children with predictably higher serum T3 and TSH concentrations and a high prevalence of small goiters. The basis for the apparent change in their dietary iodide intake over the past 30 yr is unclear, as is the explanation for their previously postulated resistance to goitrogenesis with more profound iodine deficiency.

Suppression of pituitary TSH secretion in the patient with a hyperfunctioning thyroid nodule.

10 patients with a single hyperfunctioning thyroid nodule each were studied for pituitary thyrotropin (TSH) suppression. They were judged to be euthyroid on clinical grounds. The total thyroxine (T(4)D), free thyroxine (FT(4)), total triiodothyronine (T(3)D), and free triiodothyronine (FT(3)) were normal in most of the patients. Incorporation of (131)I into the hyperfunctioning thyroid nodules was not suppressed by the administration of physiological doses of T(3). Basal serum TSH concentrations were undetectable (<0.5 - 1.0 muU/ml) in all patients. The metabolic clearance of TSH in one patient before and after excision of the thyroid nodule was unchanged (40 vs. 42 ml/min) whereas the calculated production rate was undetectable before the operation (<29 mU/day) and normal after (103 mU/day). These data, in one patient, suggest that the undetectable concentration of TSH in these patients is a result of suppressed TSH secretion rather than accelerated TSH clearance. In eight patients, basal serum TSH concentrations failed to increase after the intravenous administration of 200 mug of thyrotropin-releasing hormone (TRH); minimal increases in serum TSH concentrations were observed in two patients. The suppression of TSH was evident despite "normal" concentrations of circulating thyroid hormones. The observation that normal serum concentrations of T(4)D, FT(4), T(3)D, and FT(3) may be associated with undetectable basal serum TSH concentrations and suppressed TSH response to TRH was also found in four hypothyroid patients given increasing doses of L-thyroxine and sequential TRH stimulation tests.