Exposure to environment chemicals and its possible role in endocrine disruption of children from a rural area

Endocrine disrupting chemicals (EDCs), including pesticides and metals, are present in rural areas, endangering the health of exposed populations. This work aimed to investigate the possible association between the exposure to these xenobiotics and thyroid dysfunction in children living in a rural community of Southern Brazil. Fifty-four children aged 5-16 years participated in this study. Peripheral biomarker evaluations were performed in periods of low and high exposure to pesticides. Thyroid ultrasonography was evaluated in the high exposure period. Blood levels of chromium (Cr), manganese (Mn), mercury (Hg), and lead (Pb), as well as hair Pb levels were positively correlated with thyroid stimulating hormone (TSH) concentrations and negatively associated with free thyroxine (fT4) levels in the low exposure period. Prolactin was positively associated with hair Mn in both periods. In the ultrasound tests, the majority of children presented a normal echogenicity of thyroid. Glucose was inversely associated with the biomarker of exposure to cholinesterase inhibitor insecticides, butyrylcholinesterase (BuChE). Lipid profile was above the recommended levels in both periods. In summary, our results show that children environmentally exposed to a mixture of xenobiotics in an agricultural community may have health impairments, especially on thyroid function, dyslipidemia, and glucose homeostasis disruption.

Reliable Quantification of the Potential for Equations Based on Spot Urine Samples to Estimate Population Salt Intake: Protocol for a Systematic Review and Meta-Analysis

Background

Methods based on spot urine samples (a single sample at one time-point) have been identified as a possible alternative approach to 24-hour urine samples for determining mean population salt intake.

Objective

The aim of this study is to identify a reliable method for estimating mean population salt intake from spot urine samples. This will be done by comparing the performance of existing equations against one other and against estimates derived from 24-hour urine samples. The effects of factors such as ethnicity, sex, age, body mass index, antihypertensive drug use, health status, and timing of spot urine collection will be explored. The capacity of spot urine samples to measure change in salt intake over time will also be determined. Finally, we aim to develop a novel equation (or equations) that performs better than existing equations to estimate mean population salt intake.

Methods

A systematic review and meta-analysis of individual participant data will be conducted. A search has been conducted to identify human studies that report salt (or sodium) excretion based upon 24-hour urine samples and spot urine samples. There were no restrictions on language, study sample size, or characteristics of the study population. MEDLINE via OvidSP (1946-present), Premedline via OvidSP, EMBASE, Global Health via OvidSP (1910-present), and the Cochrane Library were searched, and two reviewers identified eligible studies. The authors of these studies will be invited to contribute data according to a standard format. Individual participant records will be compiled and a series of analyses will be completed to: (1) compare existing equations for estimating 24-hour salt intake from spot urine samples with 24-hour urine samples, and assess the degree of bias according to key demographic and clinical characteristics; (2) assess the reliability of using spot urine samples to measure population changes in salt intake overtime; and (3) develop a novel equation that performs better than existing equations to estimate mean population salt intake.

Results

The search strategy identified 538 records; 100 records were obtained for review in full text and 73 have been confirmed as eligible. In addition, 68 abstracts were identified, some of which may contain data eligible for inclusion. Individual participant data will be requested from the authors of eligible studies.

Conclusions

Many equations for estimating salt intake from spot urine samples have been developed and validated, although most have been studied in very specific settings. This meta-analysis of individual participant data will enable a much broader understanding of the capacity for spot urine samples to estimate population salt intake.

Association of busulfan and cyclophosphamide conditioning with sleep disorders after hematopoietic stem cell transplantation

New indications and conditioning regimens for hematopoietic stem cell transplantation (HSCT) have emerged in the last 10 years. Previous studies have shown the association of HSCT with late effects such as sleep disorders. The aim of this study was to determine the prevalence and factors associated with sleep disorders following HSCT in a population considering these new trends. Sixty-one individuals 1-10 years after allogeneic HSCT were surveyed using the DSM-IV-TR criteria for sleep disorders. Factors related to conditioning and graft-versus-host disease were collected from medical records. A prevalence of sleep disorders of 26.2% was found. Busulfan-cyclophosphamide conditioning was an independent risk factor in a multivariate analysis (relative risk, RR: 3.74, 95% CI: 1.1-12.6; p = 0.03), which also included sex (RR: 2.37, 95% CI: 1.0-5.7; p = 0.05) and age (RR: 1.03, 95% CI: 0.99-1.07; p = 0.11). Sleep disorders were frequent following HSCT. Patients who were treated with busulfan-cyclophosphamide had a higher risk of developing this complication. Female sex was also possibly a risk factor.

Low bone mineral density is associated with insulin resistance in bone marrow transplant subjects

Post-BMT subjects have an increased bone fracture risk. Additionally, several factors were associated with osteopenia and osteoporosis in these individuals. We aimed to identify other factors associated with osteopenia and osteoporosis in allogeneic post-BMT subjects. We conducted a cross-sectional study with 47 allogeneic post- BMT subjects. Serum 25-hydroxyvitamin D (25(OH)D), parathyroid hormone, ferritin, vitamin B(12), insulin, glucose, cholesterol and triglyceride levels were measured. Insulin resistance and secretion were estimated through the homeostatic model assessment for insulin resistance (HOMA-IR) and homeostatic model assessment for beta-cell function (HOMA-B), respectively. A bone densitometry (BMD) was also obtained. The median time after BMT was 47.7 (12-115) months. Osteoporosis was identified in 17.0% of the subjects and osteopenia in 19.7%. The mean serum ferritin (P=0.002), insulin (P<0.0001), glucose (P=0.003) and triglyceride (P=0.018) levels were higher in individuals with osteopenia/osteoporosis. HOMA-IR (P<0.0001) and HOMA-B (P<0.0001) were increased in post-BMT subjects with osteopenia/osteoporosis. There was no other factor associated with the outcome. After adjustments ferritin, serum 25(OH)D and HOMA-IR remained independently associated with osteopenia/osteoporosis; however triglycerides no longer were. In conclusion, in the present study, low serum 25(OH)D levels, high serum ferritin levels and insulin resistance were associated with osteopenia/osteoporosis in post-BMT subjects.

Hypovitaminosis D and secondary hyperparathyroidism in resident physicians of a general hospital in southern Brazil

OBJECTIVES

To evaluate the prevalence of hypovitaminosis D and secondary hyperparathyroidism in resident physicians of a general hospital in southern Brazil and identify associated factors.

DESIGN

Cross-sectional study.

POPULATION

Resident physicians of Hospital de Clinicas de Porto Alegre, Porto Alegre, southern Brazil.

PARTICIPANTS

Seventythree subjects age 26.4+/-1.9.

MEASUREMENTS

Serum PTH, 25- hydroxyvitamin D [25(OH)D], total calcium, phosphorus, magnesium, creatinine, and alkaline phosphatase were measured. In addition calcium, creatinine, and magnesium were measured in urine. Fractional excretion of calcium and magnesium were calculated. Calcium intake was estimated by a food intake questionnaire.

RESULTS

Mean serum levels of 25(OH)D were 17.9+/-8.0 ng/ml and 57.4% presented 25(OH)D below 20 ng/ml. Secondary hyperparathyroidism, defined as serum PTH > or =48 pg/ml and normal or low serum calcium, was identified in 39.7% of the individuals. Mean serum levels of magnesium were higher (p=0.02) and the fractional excretion of calcium was lower (p<0.001) in individuals with secondary hyperparathyroidism. Serum PTH levels were positively correlated with body mass index (r=0.33 and p=0.006) and serum magnesium levels (r=0.33 and p=0.02) and negatively correlated with serum 25(OH)D levels (r=-0.33 and p=0.008), estimated calcium intake (r=-0.25 and p=0.04), and fractional excretion of calcium (r=-0.34 and p=0.009).

CONCLUSION

Vitamin D deficiency and secondary hyperparathyroidism was very common in resident physicians. Therefore, measures to prevent this situation should be recommended.

Thyroid volume is associated with family history of thyroid disease in pregnant women with adequate iodine intake: a cross-sectional study in southern Brazil

Maternal euthyroidism is important for fetal neural development. For this reason, adequate iodine nutrition during pregnancy is an important public health objective and should be periodically revised. The objective of this study was to measure urinary iodine (UI) excretion and the factors associated with thyroid volume (TV), in a group of healthy pregnant women in southern Brazil, to evaluate iodine nutrition. The median UI of the 147 women was 224 microg/l (P25=164 microg/l and P75=286 microg/l). Serum levels of free T4 and thyroglobulin did not correlate with UI, but there was a weak inverse correlation between serum TSH levels and UI (r=-0.200; p=0.02). TV, calculated through ultrasound in 57 women, was significantly associated with family history of thyroid diseases (p=0.002) and BMI (p=0.03), but there was no association with UI, corrected or not for creatinine, serum free T4, TSH or thyroglobulin, current or past smoking, gestational age, parity or oral contraceptive.

CONCLUSIONS

The healthy pregnant women studied had adequate iodine intake. In this situation, the main thyroid size determinants are probably genetic factors.

High prevalence of hypovitaminosis D and secondary hyperparathyroidism in elders living in nonprofit homes in South Brazil

OBJECTIVES

Hypovitaminosis D (HD) and secondary hyperparathyroidism (SHP) are common in elders, and many factors could contribute to them. The objectives of this study were to estimate the prevalence of HD, SHP, and its associated factors, in individuals living in nonprofit homes for elders in south Brazil. Design Cross-sectional study.

METHODS

Serum 25-hydroxyvitamin D 25(OH)D, intact parathyroid hormone (PTH), total calcium, phosphorus, alkaline phosphatase, magnesium, creatinine, and albumin levels were measured in late spring, November, 2005. The presence of factors potentially related with HD and SHP-age, sex, weight, height, skin phototype, sun exposure, exercise, smoking, use of < or = 5 medications or diuretics or alcohol, and daily calcium ingestion.

RESULTS

102 subjects age 77.8 +/- 9.0 were included in the study. HD was found in 85.7% and SHP in 53% of the subjects. The estimated daily calcium ingestion was 720 mg. There was no association between serum 25(OH)D levels and any of the risk factors evaluated. Serum 25(OH)D levels were correlated with serum PTH (r = -0.358, P = 0.000), calcium (r = 0.306, P = 0.002), and albumin (r = 0.253, P = 0.011) levels. In univariate analysis, SHP was positively associated with age (P = 0.006), and female sex (0.007); and negatively associated with sunlight exposure (P = 0.020), GFR (P = 0.000), Ln25(OH)D (P = 0.002), and total serum calcium (P = 0.024). After multivariate model adjustment, age [OR 1.09 (CI 1.01-1.18); P = 0.024], Ln25(OH)D [OR 0.92 (CI 0.08-0.74); P = 0.013], GFR [OR 0.96 (CI 0.92-0.99); P = 0.013], and hydrochlorothiazide treatment [OR 7.63 (CI 1.67-34.9); P = 0.008] were independently associated with SHP.

CONCLUSIONS

HD and SHP are highly prevalent in elders living in old-age homes. No associations were established between common risk factors and low serum levels of 25(OH)D levels; however, SHP was independently related with age, 25(OH)D, GFR, and hydrochlorothiazide use.

The effect of a single dose versus a daily dose of cholecalciferol on the serum 25-hydroxycholecalciferol and parathyroid hormone levels in the elderly with secondary hyperparathyroidism living in a low-income housing unit

We designed a randomized, double-blind, controlled clinical trial to compare the effect of two regimens for administering cholecalciferol on the serum 25-hydroxycholecalciferol [25(OH)D] levels and in the reversion of secondary hyperparathyroidism in the elderly living in a low-income housing unit in the city of Porto Alegre, southern Brazil. We studied 28 individuals ranging in age from 65 to 102 years with serum parathyroid hormone (PTH) levels greater than 48 pg/ml and normal or reduced serum calcium levels. Subjects were randomized to receive oral cholecalciferol, as a single dose of 300 000 IU (group 1) or 800 IU (group 2) daily for 9 months. Both groups received 1250 mg calcium carbonate per day. Serum 25(OH)D and PTH levels were measured at baseline and after 1, 2, 3, 6, and 9 months. Serum 25(OH)D levels in group 1 were significantly higher than in group 2 during the study (P < 0.001). After 1 (P < 0.001) and 2 (P < 0.04) months of treatment, mean serum 25(OH)D levels were higher in group 1. The number of subjects who reached serum 25(OH)D levels >/=20 ng/dl was higher in group 1, after the first (P < 0.001) and third (P = 0.008) months. In the short term, a single 300 000 IU oral dose of vitamin D(3) was more effective than 800 IU per day to increase serum 25(OH)D levels in elderly persons, living in a low-income housing unit, who were taking 500 mg elementary calcium supplement per day.

Ultrasonography: is it useful in the diagnosis of cancer in thyroid nodules?

The role of ultrasonography (US) in the diagnosis of cancer in thyroid nodules is not well-established. The aim of the present study was to evaluate US performance in predicting cancer in thyroid nodules using a novel approach. Two hundred and eighty-nine patients with thyroid nodular disease were evaluated with clinical, biochemical and cytopathological examinations. Eighty patients with palpable solitary thyroid nodules or multinodular goiters who were to undergo surgery were included, and had a US exam performed by one of us. Some US characteristics of thyroid nodules were associated to cancer: absent halo, hypoechogenicity and microcalcifications, with sensitivity, respectively, of 56, 44 and 56%, and specificity of, respectively, 80, 83 and 94%. These findings were considered positive and were studied in two different combinations: simultaneous, when two or more were positive, and parallel, when any positive finding was present. When positive findings were studied simultaneously, sensitivity ranged 25 to 38% and specificity ranged 89 to 97%. Microcalcifications, associated or not to other findings, were highly specific for thyroid cancer, but they were only present in half of the malignancies. When positive findings were studied in parallel, sensitivity ranged 69 to 81% and specificity ranged 70 to 81%. The parallel combination of hypoechogenicity or microcalcifications or absent halo improved US sensitivity to 81% with an acceptable specificity (70%). This method is potentially useful to help us select patients for surgery when fine-needle aspiration biopsy is repetitively non-diagnostic or select for biopsy incidentally discovered non-palpable nodules.

Low-dose adrenocorticotropin test in patients with the acquired immunodeficiency syndrome

Adrenocortical insufficiency is a serious complication of AIDS. Usually, integrity of the hypothalamo-pituitary-adrenal (HPA) axis in AIDS patients is assessed by measuring basal cortisol levels and cortisol response to 250 microg of ACTH. Recent studies suggest that a lower ACTH dose increases the sensitivity of the procedure. In the present study, we investigated the prevalence of adrenal hypofunction in AIDS patients using a low-dose ACTH test (1 microg), evaluated the clinical characteristics that might suggest this diagnosis, and the diseases and/or drugs that could be associated with it. We prospectively evaluated 63 very ill AIDS patients and 16 normal controls. A standard examination assessed the presence of signs and symptoms of adrenal insufficiency. Blood samples were collected before and 30 and 40 minutes after an injection of 1 microg 1-24 ACTH. No opportunistic disease, signs, symptoms or drugs were associated with an abnormal cortisol response to ACTH. The lowest stimulated cortisol level in the control group was 18.5 microg/dL; cortisol levels > or = 18 microg/dL were taken to indicate a normal HPA axis. Test results revealed that 12/63 AIDS patients (19%) had an abnormal HPA axis. With these data in mind, we suggest a prospective adrenal function evaluation of all severely ill AIDS patients.

Estradiol decreases iodide uptake by rat thyroid follicular FRTL-5 cells

Estradiol has well-known indirect effects on the thyroid. A direct effect of estradiol on thyroid follicular cells, increasing cell growth and reducing the expression of the sodium-iodide symporter gene, has been recently reported. The aim of the present investigation was to study the effect of estradiol on iodide uptake by thyroid follicular cells, using FRTL-5 cells as a model. Estradiol decreased basal iodide uptake by FRTL-5 cells from control levels of 2.490 +/- 0.370 to 2.085 +/- 0.364 pmol I-/microg DNA at 1 ng/ml (P<0.02), to 1.970 +/- 0.302 pmol I-/microg DNA at 10 ng/ml (P<0.003), and to 2.038 +/- 0.389 pmol I-/microg DNA at 100 ng/ml (P<0.02). In addition, 4 ng/ml estradiol decreased iodide uptake induced by 0.02 mIU/ml thyrotropin from 8.678 +/- 0.408 to 7.312 +/- 0.506 pmol I-/microg DNA (P<0.02). A decrease in iodide uptake by thyroid cells caused by estradiol has not been described previously and may have a role in goiter pathogenesis.

A novel mutation (M310L) in the thyroid hormone receptor beta causing resistance to thyroid hormone in a Brazilian kindred and a neonate

Resistance to thyroid hormone (RTH) is an inherited syndrome of reduced tissue responsiveness to thyroid hormone (T3) caused by mutations in the thyroid hormone receptor beta (TRbeta). The index patient of the family reported here, a 17-year-old woman, came to medical attention because of a diffuse goiter, short stature, and learning disabilities. Biochemical tests revealed an elevated free T4 of 5.2 ng/dl (0.8-2.1), a T3 of 270 ng/dl (80-220), and a nonsuppressed TSH of 1.79 mU/l (0.4-4). Administration of exogenous T4 or T3 did not result in the usual TSH suppression, prompting the clinical diagnosis of RTH. Her father and one of her brothers also had clinical and biochemical findings consistent with RTH. Direct sequence analysis of the TRbeta gene revealed a heterozygous transition 928A>G in exon 9 resulting in substitution of methionine 310 by leucine (M310L). This novel receptor mutant has a reduced affinity for T3 ( approximately 10% of normal) and dominant negative properties that are similar in comparison to other RTH mutations. The index patient had a normal pregnancy and delivery. At birth, the female neonate had no goiter, a significantly elevated T4, and increased TSH. The diagnosis of RTH was confirmed by sequencing the TRbeta gene. She was underweight at birth and her length was between the 5th and 10th percentile. At 26 months, her height remained at the 10th percentile but her bone age was 18 months, suggesting mild hypothyroidism at the level of the bone. In contrast, increased heart rate and restlessness are consistent with hyperthyroidism in other tissues, such as the heart and possibly the brain.

[Prevalence of thyroid nodules in 40 years-old or old women]

OBJECTIVES

Thyroid nodules constitute a very common clinical problem and the differential diagnosis includes thyroid cancer. As thyroid cancer is rare, it is important to know the prevalence of thyroid nodules in cohorts strongly predisposed to this problem to be able to measure its impact on the health care system, and to devise appropriate diagnostic strategies. The aim of this study was to determine the prevalence of thyroid nodules in women 40 year-old or older by echography.

METHODS

Between August 1996 and December 1997, 207 women, 40 year-old or older, were consecutively evaluated by thyroid echography in the Radiology Division of the Hospital de Clínicas de Porto Alegre. Patients who came to the Division to be submitted to thyroid echography were excluded. The mean age of patients studied was 54.7 years (median: 53, range: 40-86 years). One hundred and twenty three patients (54.9%) had a normal thyroid and eighty-two had an abnormal gland (39.6%). Thyroid nodules were detected in seventy-three women (35.3%) and these were larger than 1 cm in 35 women (16.9%). Women without thyroid nodules were younger (53.1 +/-10.7 years) than women with thyroid nodules (58.2 +/-10.6 years) p=0.001; and the prevalence of any thyroid nodule (p=0.001) or nodules larger than 1 cm (p=0.007) increased with age.

CONCLUSIONS

Thyroid nodules are very common in women 40 year-old or older, their prevalence increases with age in this cohort and these nodules are potentially palpable (larger than one cm) in one of six women in this age group It is important to have these data in mind when ordering thyroid echographic studies in women 40 year-old or older.

Post-partum thyroiditis in South Brazil presenting as thyrotoxicosis: prevalence and risk factors

The prevalence of post-partum thyroiditis (PPT) has been reported in several countries (1.9 to 16.7%) but is not known in Brazil. Several factors have been associated to its development, such as a female sex of the newborn, PPT in a previous pregnancy, a family history of thyroid disease and cigarette smoking. To investigate the prevalence of PPT and its risk factors in a southern Brazilian city, a three-cross-sectional observation study was performed. PPT was diagnosed in 14/284 subjects (5.3%) and all cases had thyrotoxicosis (13 sub-clinical and one clinical). Serum total T4 and free T4 were higher and serum TSH was lower in PPT subjects. Anti-thyroid antibodies were positive in 16.7% of PPT subjects and in 4.5% of those with no thyroid dysfunction. Goiter was identified in 14.3% of PPT subjects and in 15% of no PPT subjects. Thyroid was hardened more frequently in PPT subjects (21.4%) than in others (5.2%). Male sex of the newborn was associated to PPT, increasing 11 times the risk of PPT. Cigarette smoking was associated to PPT in group II subjects. There was no clinical sign or symptom able to contribute to this diagnosis, except the presence of hardened thyroid. Based on these findings, PPT, manifesting itself as mild thyrotoxicosis, is a common problem in southern Brazil and is associated to male sex of the newborn.

Estradiol increases proliferation and down-regulates the sodium/iodide symporter gene in FRTL-5 cells

Goiter (increased thyroid gland size) is more prevalent in women than men, even in areas where iodine levels in the diet are sufficient. We investigated a possible role of estrogen on thyroid follicular cell growth using rat FRTL-5 thyroid follicular cells as a model. Estrogen receptor-alpha (ERalpha) messenger RNA was present in FRTL-5 cells using a RT-PCR assay and was confirmed by Western blot analysis. An estrogen-responsive reporter gene was transfected into FRTL-5 cells to test the functionality of the endogenous ERs. Estradiol increased the activity of the reporter gene, and the antagonist, ICI182780, inhibited ER-dependent transcription. To extend this analysis, we examined the effect of estradiol on FRTL-5 cell growth. Estradiol increased FRTL-5 cell growth in a time- and concentration-dependent manner in either the absence or presence of TSH. Because iodine is known to inhibit thyroid cell growth, the effect of estradiol on the expression of the sodium/iodide symporter (NIS) was assessed as a potential target of estrogen action. Estradiol blocked TSH-induced NIS expression, and treatment of cells with estradiol and ICI182780 restored TSH-induced NIS expression to normal levels. These data demonstrate that FRTL-5 cells contain functional ERs that enhance cell growth and inhibit expression of the NIS. The demonstration of a direct effect of estradiol on thyroid follicular cells raises the possibility that it may play a role in the sexually dimorphic prevalence of goiter.

Suprasellar germinoma: an unusual clinical presentation

A case is described of suprasellar tumor with diabetes insipidus, diminishing visual acuity, inferior bitemporal quadrantanopia, and hypopituitarism in a 19-year-old man. Computerized tomographic scan of the brain after contrast injection demonstrated periventricular enhancement. Diagnosis of germinoma was made on the basis of clinical and radiographic information and a biopsy that revealed malignant cells. The tumor responded well to radiation therapy. Diagnostic difficulties were created by systemic manifestations unrelated to endocrinopathy. Pertinent literature is reviewed.