Prevalence Of Thyroid Nodules Research Articles

Thyroid disease in northern Italian children born around the time of the Chernobyl nuclear accident

The Chernobyl nuclear accident of 1986 caused a dramatic increase in the incidence of thyroid cancers in exposed children in Belarus. Airborne radioactivity from the reactor spread over northern Italy, where rainout gave rise to low levels of radioactivity at ground level. As the latency between exposure to ionising radiation and development of thyroid cancer is thought to be about 10 years, in 1996/1997 all children born in 1985 and 1986 and attending school in an area of Milan, Italy were examined for thyroid nodules. A total of 3949 children were examined by two physicians blinded to the examination and diagnosis of the other. The children were to be reassessed in 2001/2002. In total, 1% had palpable nodules. The nodule diagnoses were: Hurtle cell adenoma (one), thyroglossal duct cyst (one), thyroid cyst (four) and thyroiditis (four). The prevalence of thyroid disease in the cohort was indistinguishable from that of populations not exposed to radioactive pollution. Only 10 children re-presented for examination 5 years later; all were negative. The direct costs of the study were estimated at 21,200 Euros. The high cost of the study in relation to reassuring lack of increase in thyroid nodule prevalence suggests that further studies are not justified.

Influence of regular iodine intake by iodine tablets and age on the urinary iodine excretion, thyroid volume and nodules

Most studies estimate the iodine status of a population by determination of urinary iodine excretion based on creatinine excretion. The mean urinary iodine/ creatinine ratio of a study population can be biased by intake of iodine tablets by a part of the population. Moreover higher creatinine excretion rates in younger ages could influence the mean urinary iodine/ creatinine excretion ratio of a study population. Lack of recognition of these variables could lead to erroneous judgement of a populations iodine supply.However most studies of iodine supplementation did not evaluate the influence of iodine tablets or age correlated creatinine excretion. We investigated a cohort of 805 employees and students of the University of Leipzig. First, we assessed iodine and creatinine excretion in spot urine samples. Second we used a special food questionnaire to assess for other sources of nutritional iodine intake e.g. iodine tablets, fish consumption etc. Third, we determined the actual prevalence of goiter and thyroid nodules in our probands by high resolution ultrasonography.The mean urinary iodine excretion in our cohort was 109±81µg iodine/g creatinine level indicating a borderline adequate iodine intake (100–200µg/g creatinine). The frequency of thyroid nodules was 30% and the frequency of goiter 11%. As expected, probands with regular intake of iodine tablets, prescribed because of „thyroid disorders“, had significantly higher values of urinary iodine excretion (169±130µg iodine/g creatinine) compared to participants without (103±87µg iodine/g creatinine). Besides iodine tablets, no other „nutritional“ factor had a significant impact on urinary iodine excretion. Creatinine excretion was negatively correlated with the age of the probands.The nutritional iodine intake in our cohort was found to be still suboptimal because of insufficient iodine supplementation through iodized salt. The intake of iodine tablets can bias the estimated mean urinary iodine excretion of a study population thus leading to false judgement of its iodine status.

High occurrence of thyroid multinodularity and low occurrence of subclinical hypothyroidism among tobacco smokers in a large population study.

Tobacco smoking increases the risk of goitre and Graves' disease, but the association with thyroid nodularity and hypothyroidism has not been settled. We investigated 4649 subjects from the general population with questionnaires, thyroid ultrasonography and blood tests. The results were analysed in multivariate regression models. Tobacco smoking was associated with an increased prevalence of thyroid multinodularity (odds ratio (OR) 1.9; 95% confidence interval (CI) 1.4-2.5), but not with increased prevalence of solitary thyroid nodules. The tendency was for a stronger association in the area with the most pronounced iodine deficiency (P for interaction=0.08). Lower levels of serum TSH were found among tobacco smokers (P<0.001), but this association disappeared when adjustment was made for thyroid nodularity and thyroid Volume. The prevalence of elevated TSH levels was markedly reduced among smokers (OR 0.47; 95% CI 0.33-0.67). No association was found between smoking and hyperthyroidism. The observed associations seem to be explainable by the blocking of iodine uptake and organification in the thyroid by thiocyanate, a degradation product of cyanide in tobacco smoke.

Relations between various measures of iodine intake and thyroid volume, thyroid nodularity, and serum thyroglobulin , ,

Iodine intake can be measured in various ways, and each method may have advantages and disadvantages. We sought to investigate the potential associations of various measures of iodine intake with thyroid volume, prevalence of thyroid nodules, and serum thyroglobulin. We also sought to identify, if possible, groups at risk of thyroid disease because of their food choices. This cohort study included 4649 randomly selected subjects with mild-to-moderate iodine deficiency; the subjects lived in 2 cities in Denmark. Iodine intake was estimated by using a food-frequency questionnaire and by measuring iodine excretion in spot urine samples. Thyroid volume and nodularity were measured with ultrasonography. In multiple linear regression models, significant inverse relations were found between thyroid volume and estimated 24-h iodine excretion, iodine intake from diet plus supplements, iodine intake from diet/kg body wt, and milk intake (P = 0.001 for all), but not urinary iodine excretion measured as a concentration (P = 0.40). All measures of iodine intake were significantly related to serum thyroglobulin concentration (P <or= 0.002), but only some measures of iodine intake were significantly related to the prevalence of thyroid nodules. Even in a geographic area where mild iodine deficiency is common, a significant relation between iodine intake and thyroid volume was found. All measures of iodine intake, except iodine excretion measured as a urinary concentration, predicted thyroid volume. Serum thyroglobulin concentration appears to be a good marker of iodine status. Subgroups with low intakes of milk and milk products had an increased risk of thyroid disease.

Fallout exposure in the Semipalatinsk Nuclear Test Site area and the induction of thyroid nodules diseases

From 1949 through 1989, nuclear weapons testing carried out by the former Soviet Union at the Semipalatinsk Nuclear Test Site (SNTS), resulted in substantial levels of radiation exposure of settlements and their residents near the test site area. The results of dose reconstruction indicate a dose range from 2.0 mSv to 2.5 Sv. To investigate the possible relationship between radiation exposure and the thyroid gland abnormalities prevalence, we conducted a thyroid screening study of 3000 exposed and non-exposed current residents of the eight villages near the test site, all the residents were of similar ages (<20) at the time of the fallout and follow-up study of 311 inhabitants as well. Prevalent nodules were identified by ultrasound, malignancy was determined by fine needle aspiration biopsy and cytopathology, and circulating levels of thyroid hormones were assayed from blood samples. The nodular thyroid gland was identified in 920 of the study participants, of whom 506 were recommended for fine-needle aspiration biopsy. Furthermore, 65 cases had evidence of prior thyroid surgery. The thyroid nodule prevalence was 36% among exposed and 26% among the non-exposed residents, and increased significantly with increasing estimated age-modified gamma-ray doses (ERR=5.2 per 1 Gy, CI 95%=2.7–8.5). The cytopathology review identified 30 papillary carcinomas in 27 cases and 10 follicular neoplasms in 10 cases. The high frequency of the thyroid dysfunction and thyroiditis among the exposed has been documented. This study revealed an apparently strong association between the fallout exposure and thyroid disease prevalence, and suggests more detailed molecular research of the thyroid cancer induction should be carried out.

The effect of pregnancy on thyroid nodule formation.

Epidemiology data have revealed a higher prevalence of nodular goiters in women than men in both iodine-sufficient and iodine-deficient areas. Increased prevalence of thyroid nodules has also been reported in women with higher gravidity. However, the association between pregnancy and thyroid nodule formation has never been studied. The aim of our study was to evaluate the incidence of thyroid nodules during pregnancy and determine whether pregnancy will induce thyroid nodule formation. Two hundred twenty-one healthy southern Chinese women in the first trimester of their pregnancy were studied prospectively. Thyroid ultrasonography, thyroid function tests, and urinary iodine excretion were measured at first, second, and third trimesters of pregnancy as well as 6 wk and 3 months postpartum. Thyroid nodules (>2 mm in any dimension on ultrasonography) were detected in 34 (15.3%) subjects at first trimester, with 12 (5.4%) subjects having more than one nodule. Eight subjects had clinically palpable nodules. Women with thyroid nodules were older (P < 0.01) and had higher gravidity (P < 0.02) than those women without thyroid nodules. The volume of the single/dominant nodules increased from 60 (14--344) mm(3), median (interquartile range) at first trimester to 65 (26-472) mm(3) at third trimester (P < 0.02). These nodules remained enlarged at 103 (25-461) mm(3) 6 wk postpartum (P < 0.005) and 73 (22-344) mm(3) at 3 months postpartum (P < 0.05). Patients with thyroid nodules had lower serum TSH values (P < 0.03) and higher Tg levels (P < 0.05) throughout pregnancy. Appearance of new nodules was detected in 25 (11.3%) women as pregnancy advanced so that by 3 months postpartum, the incidence of thyroid nodular disease was 24.4% (P < 0.02 vs. first trimester). Compared with those with no detectable nodules throughout pregnancy, subjects with new nodule formation had higher urinary iodine excretion from second trimester onward (P all < 0.05). However, no difference could be detected in their TSH and Tg levels throughout pregnancy. Fine-needle aspiration on nodules greater than 5 mm in any dimension after delivery (n = 21) confirmed the majority having histological features consistent with nodular hyperplasia. No thyroid malignancy was detected. In conclusion, pregnancy is associated with an increase in the size of preexisting thyroid nodules as well as new thyroid nodule formation. This may predispose to multinodular goiter in later life.

Parity is associated with increased thyroid volume solely among smokers in an area with moderate to mild iodine deficiency.

Pregnancy has been suggested as part of the explanation of the gender difference in the prevalence of goitre, but opposing results have been reported on the association between pregnancy and goitre. We investigated the association between parity and thyroid volume and a possible impact of iodine deficiency and tobacco smoking on this association. A comparative, cross-sectional study of 3712 women randomly sampled from the general population in two geographical areas with moderate and mild iodine deficiency. The participants answered questionnaires with an obstetric anamnesis, and ultrasonography of the thyroid was performed. Data were analysed in linear models and logistic regression analysis to adjust for age, iodine status, use of oral contraceptives and smoking habits. Women with present or recent pregnancies were excluded from the analyses. A higher thyroid volume was found among parous than among nulliparous women (P=0.007). The association between parity and thyroid volume was strongest in the youngest age groups, in the region with the most severe iodine deficiency, and among smokers. No association was found between parity and the prevalence of solitary or multiple thyroid nodules. Number of births, age at menarche or menopause, the number of fertile years, and age at first childbirth were not associated with thyroid volume. Pregnancy increases thyroid volume, particularly when combined with tobacco smoking and iodine deficiency. The effect is probably reversible seen over a spectrum of several years.

Incidentally Found Thyroid Nodules in Women with no Previous Thyroid Disease: Its Significance

Purpose: To determine the prevalence of thyroid nodules discovered incidentally at ultrasonography and to reassess their significance. Materials and Methods: During a six-month period and using a high-frequency transducer, 1033 subjects with suspected breast disease underwent a prospective study of the thyroid. We determined the prevalence of thyroid nodules according to age, and the malignancy rate. Results: Focal thyroid nodules were detected in 291 women (28.2%), their prevalence increasing with age (p

Non-palpable thyroid nodules in a borderline iodine-sufficient area: Detection by ultrasonography and follow-up

Thyroid ultrasonography was performed in 482 subjects, free of known thyroid disease and living in a borderline iodine-sufficient urban area, to assess the prevalence of non-palpable thyroid nodules and evaluation their evolute during a 3-yr follow-up. The mean (+/-SD) thyroid volume in the whole study group was 10.9+/-3.7 ml and was higher in males (12.9+/-3.6 ml) than in females (9.2+/-2.9 ml) (p<0.0001). Thyroid volume was correlated with body surface, height and weight, while no correlation was present with lean and fat body mass. Goiter was found in 5/256 females and in 13/226 males. Thyroid nodules were found in 27/482 subjects (18 females, 9 males). Single nodules were found in 17/464 subjects (3.66%) with a thyroid gland of normal volume and in 4/18 subjects (22.2%) with goiter (chi2=10.21; p=0.001). Multiple nodules were found in 3/464 subjects (0.6%) with a thyroid of normal volume and in 3/18 (16.6%) subjects with goiter (chi2=24.31; p<0.0001). The prevalence of thyroid nodules was significantly higher in females >35 yr than in those <34 yr (chi2=7.47; p=0.0062). A significant increase (>30%) of nodular volume was found in 5 subjects, while an increased number of nodules was found in 8. In conclusion, thyroid ultrasonography reveals the presence of thyroid nodules in a significant proportion of apparently thyroid disease-free subjects living in a borderline iodine-sufficient urban area. Incidentally discovered thyroid nodules are associated with goiter and are likely to progress in volume and number.

Thyroid Nodules with Microfollicular Findings Reported on Fine-Needle Aspiration: Invariably Surgical Treatment?

To assess whether fine-needle aspiration (FNA) can be a diagnostic procedure for identification of malignant thyroid nodules when the smear reveals the cytologic (microfollicular) finding of "follicular neoplasm" (FN). We reviewed a group of 79 patients with FN who underwent surgical treatment and evaluated the possible significance of the cytologic features of anisokaryosis, amount of colloid, and nuclear overlapping (NO). We excluded from the study those patients with FN who had other highly suspicious cytologic features, such as sporadic grooves and sporadic pseudonucleoli. In our series of 79 patients with FN at FNA, we found anisokaryosis in 49.4%, scant or no colloid in 31.6%, and NO in 5.1%. Thyroid cancer (TC)--follicular cancer or follicular variant of papillary cancer--was found in six patients (7.6%): four patients (10.2%) with anisokaryosis and two patients (5.0%) without anisokaryosis (P<0.5; chi2 test). All the patients with malignant lesions had scant or no colloid in the smears, and four of them were those with NO. Therefore, TC was found in 24.0% of nodules with scant or no colloid versus 0.0% of nodules with abundant colloid (P<0.001; chi2 test), and TC was found in 100% of nodules with NO versus 2.6% of nodules without NO (P<0.001; chi2 test). Because of the high prevalence of thyroid nodules and the frequency of FN at FNA, the number of unnecessary interventions may be very high. FNA cannot be diagnostic in FN because invasion of the tumor capsule and blood vessels can be evidenced only at histologic examination. Although it is common opinion that microfollicular nodules should be surgically treated, simple cytologic features can help select patients at low risk who can be monitored and reassessed clinically and by FNA. Patients with high-risk cytologic features such as NO should be advised that a total thyroidectomy may be necessary.

Alcohol consumption is associated with reduced prevalence of goitre and solitary thyroid nodules.

Goitre prevalence is dependent on iodine intake and smoking habits, but further risk factors have only been examined briefly. We examined the association between alcohol consumption and the prevalence of thyroid enlargement and nodularity. Cross-sectional population study with ultrasonography of the thyroid gland and assessment of alcohol intake and smoking habits from questionnaires. Four thousand six-hundred and forty-nine men and women aged 18-65 years, randomly selected from the Danish Civil Registration System. Thyroid volume and prevalence of thyroid enlargement, multiple nodules or a solitary nodule in the thyroid. Abstainers and participants with a low alcohol consumption (< 7 drinks/week) had the same prevalence of thyroid enlargement and nodularity, but participants with moderate (8-28 drinks/week for women, 8-42 for men) or high (> 28/42 drinks/week) alcohol consumption had much lower prevalence of thyroid abnormalities. Possible confounding by sex, age, iodine status and smoking was considered in all models. Odds ratios compared to abstainers for thyroid enlargement were 0.74 [95% confidence interval (CI) 0.57-0.96] for moderate- and 0.44 (95% CI 0.22-0.88) for high alcohol consumption. Odds ratios compared to abstainers for a solitary nodule were 0.64 (95% CI 0.42-0.96) for moderate- and 0.41 (95% CI 0.12-1.37) for high alcohol consumption. Mean thyroid volume was 13.5 ml among abstainers compared to 10.9 ml among participants with high alcohol consumption (P < 0.001). Both wine- and beer consumption were associated to lower prevalence of thyroid abnormalities. Increasing levels of alcohol consumption were associated to lower prevalence of thyroid enlargement and to lower prevalence of a solitary nodule in the thyroid, and indications of a causal relationship were found.

Prevalence of goiter and iodine deficiency in Saxony is less than previously assumed. A study 6 years after discontinuation of general iodization of table salt

Germany is a known area of goitre endemicity. In East Germany (former German Democratic Republic), iodization of pre-packed table salt was introduced in 1985 and was only abolished after German reunification in 1990. Public awareness campaigns have concentrated on the use of iodized salt in the products of bakers and butchers as well as canned and frozen food since. Reports in the literature give figures of goitre prevalence (13 to 69%) inconsistent with each other and with our own clinical experience (about 30%). We undertook a prospective cross-sectional study with a non randomly selected population (craftsmen and -women) covering Saxony in 1996, 1,129 and 1,594 adults were examined in 1996 and 1997, respectively, using a questionnaire, ultrasound, and measurement of urinary iodine excretion (1996 only). We found the following (mean) results in men/women in 1996: thyroid volume 23.0 +/- 1.3/17.1 +/- 1.5 ml, prevalence of goitre 32.1/31.3%, prevalence of thyroid nodules 21.1/23.0%, urinary iodine excretion (per creatinine) 86.4 +/- 1.3/104 +/- 24.1 nmol/mmol (97.1 +/- 1.4/117 +/- 27.1 micrograms/g). In 1997 the results were as follows: thyroid volume 20.9 +/- 1.2/15.7 +/- 2.1 ml, prevalence of goitre 25.6/23.6%, prevalence of thyroid nodules 16.4/19.8%. Whilst goitre and iodine deficiency are still endemic in Saxony, both have been improving despite the abolition of general table salt iodization.

Prevalência de bócio e nódulos tiroideanos detectados através de ultra-som em população com mais de 50 anos

O objetivo deste trabalho foi estudar a prevalência de bócio e nódulos em uma população com mais de 50 anos, comparando-a com grupo controle composto pelos filhos. Para isso, foram avaliados 101 indivíduos (19M / 82 F) com idades entre 51 e 85 anos e 65 filhos (18 M / 47 F) com idades entre 14 e 50 anos. Utilizamos o ultra-som para diagnóstico de bócio e nódulos, mas foi feita, também, avaliação clínica com palpação da tiróide. A prevalência de bócio e nódulos foi maior nos indivíduos com mais de 50 anos (15,8% e 18,8%, respectivamente), do que nos filhos (3,1% e 7,7%, respectivamente), Não observamos correlação entre volume tiroideano e idade. A palpação da tiróide se mostrou pouco sensível para detecção de bócio e nódulos, mas com alta especificidade. Concluímos que a prevalência de bócio e nódulos é maior na população com mais de 50 anos, embora sem correlação entre volume tiroideano e idade. O ultra-som se mostrou melhor que a palpação isoladamente, na detecção de alterações do volume e presença de nódulos tiroideanos.

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

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. 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. 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.

Validation of ultrasonography of the thyroid gland for epidemiological purposes.

Ultrasonography of the thyroid is often used in epidemiological surveys, thus thorough characterization of the interobserver variation of the different parameters obtained is important. Various methods have been used for measuring thyroid volume, and different formulas have been used for calculation of thyroid volume from the measured dimensions. In this article, two principles of thyroid volume measurement are described in detail: the wellknown method based on the three axes of each lobe and a new principle based on planimetry in two planes. The interobserver variation of the examination and the measuring procedure in itself were tested on 25 participants in a population study. A comparison of postmortem ultrasonography of the thyroid and results of an autopsy was performed. Good correlation and agreement between observers was found for thyroid volume (r = 0.98) and prevalence of thyroid nodules (kappa = 0.72), whereas echogenecity and echopattern showed little agreement. The correlation of thyroid volume by ultrasonography to autopsy results was satisfactory (r = 0.93), but the volume tended to be slightly underestimated even when using the formula pi/6(= 0.52)*length*width*depth. No major differences were found between the performance of the two principles of volume calculation. We conclude that when the measuring procedure is well defined, results of ultrasonography are comparable between observers for thyroid volume and prevalence of thyroid nodules, but not for echogenecity or echopattern. The formula of length*depth*width*pi/6 is suitable for thyroid volume measurement.

Lack of association between thyroid and adrenal nodules: a histological study.

The prevalence of thyroid nodules is increased in patients with Cushing's disease, but the possibility of an association between thyroid and adrenal nodules in other patient groups has not been formally tested. We have evaluated the co-existence of thyroid and adrenal nodules in retrospective and prospective autopsy studies. Retrospective (83 autopsies) and prospective (29 autopsies) blinded studies of thyroid and adrenal gland histopathology were performed by two experienced histopathologists in unselected autopsies. The presence of nodules, defined as areas of tissue having discrete edges within the gland parenchyma seen as a step difference between the cells or architecture adjacent to the nodule, was determined for each gland. No association was found between the presence of adrenal and thyroid nodules in either the retrospective or prospective studies (p>0.2 for both). In the retrospective study, 23% of specimens had thyroid nodules and 28% adrenal nodules. In the prospective study, 24% of specimens had thyroid nodules and 7% adrenal nodules. The proportion of patients with adrenal nodules in the prospective study was significantly less than that in the retrospective study. In conclusion, thyroid and adrenal nodules are frequent autopsy findings in the general population but we have found no evidence of a relationship between the occurrence of nodules in these glands.

A progress report of the Marshall Islands nationwide thyroid study: an international cooperative scientific study.

The objective of this report is to present a summary of progress of the Marshall Islands Nationwide Thyroid Study. As well known, the US atomic weapons testing program in the Pacific was conducted primarily between 1946 and 1958 in the Marshall Islands. The nuclear tests resulted in radioactive contamination of a number of atolls and resulted in exposure of Marshallese to undefined levels before our study. Little information has been paid to health consequences among residents of the nearly twenty inhibited atolls except for some information about nodular thyroid disease which was reported on by an US group. In a cooperative agreement with the Government of the Marshall Islands, between 1993 and 1997 we studied the prevalence of both thyroid nodules and thyroid cancer among 4766 Marshallese potentially exposed to radioiodines from bomb test fallout. That group represents more than 65% of the population at risk. We diagnosed 45 thyroid cancers and 1398 benign thyroid nodules. In addition, 23 study participants had been operated on prior to our study for thyroid cancer. Presently, we are developing a database of information to estimate radiation doses and planning a statistical analysis to determine if a dose-response relationship exists. These data will be important for the health promotion of exposed people all over the world including Hiroshima, Nagasaki, Semipalatinsk, Chernobyl and other locations. A timely completion is important for purpose of assisting Marshallese as well as to add the global understanding of radiation induced thyroid cancer.

An Investigation Into the Prevalence of Thyroid Disease on Kwajalein Atoll, Marshall Islands

The prevalence of thyroid nodules and thyroid cancer was studied in the indigenous population residing on Ebeye Island, Kwajalein Atoll, in the Republic of the Marshall Islands. This island, centrally located in the nation, is home to about 25% of the nation's population, many who have migrated there from other atolls. The objective of the study was to obtain thyroid disease rate statistics on as much of the population as possible that was alive during the years of nuclear testing and to test the hypothesis that described a linearly decreasing prevalence of palpable nodules with increasing distance from the Bikini test site. 1,322 Marshallese born before 1965 were given a thyroid examination using neck palpation, fine needle aspiration biopsy, and high resolution ultrasound imaging. Approximately 40% of the total population living on this island who are at risk from exposure to radioactive fallout during the years 1946-1958 were screened. Of that group, 815 were alive at the time of the BRAVO test on 1 March 1954. Two hundred sixty-six people with thyroid nodules were found (32.6%): 132 were palpable nodules (16.2%), and 134 were nodules that could be diagnosed with ultrasound only (15.7%). Prevalence of palpable nodules was particularly high in men and women older than 60 y, in men who were 6 to 15 y of age at the time of the BRAVO test, and in women 1 to 10 y of age at the time of the BRAVO test. In 22 people, the clinical diagnosis was most likely cancer though histopathological evidence was only available from 11 operated cases. Of the 11 operated cases, 10 were cancer. Cancer prevalence was particularly high in those women born between 1944 and 1953 (7/220 = 3.2%), i.e., who were children during the early years of nuclear testing. The Ebeye data showed a marginally significant correlation between palpable nodule prevalence among women and distance to Bikini (r = -0.44, p = 0.06). This report summarizes the clinical findings of the thyroid examinations, the age distributions for nodular disease and cancer, and examines the relationship between prevalence of nodules and present day levels of 137Cs in the environment of each atoll.

An analysis of fine-needle aspiration biopsy of the thyroid in children and adolescents

Fine-needle aspiration biopsy (FNAB) has proven safe and efficacious in the evaluation nodular thyroid disease in adults. Only one study has evaluated FNAB exclusively in children, for whom the prevalence of thyroid nodules and the probability of malignancy are different. In addition, no study has compared the accuracy of FNAB with that of other diagnostic procedures in the evaluation of thyroid nodules in children. The authors report the results of FNAB in 18 children evaluated for thyroid nodules between 1985 and 1994. The overall accuracy of FNAB was similar to that of other diagnostic procedures, including thyroid scintiscan and ultrasonography, but none of these was sufficiently accurate to be used as the sole predictor of malignancy. There were three false-negative biopsy results; this limited the overall accuracy and suggests that children with negative FNAB results should be monitored cautiously.

Is occupationally induced exposure to radiation a risk factor of thyroid nodule formation?

The prevalence of thyroid nodules was studied with ultrasonography in a group of male hospital workers (n = 44) who had been exposed occupationally to x-rays. This group was compared with a group of nonexposed workers (n = 88) who were age- and sex-matched with the exposed workers. Thyroid nodules were detected in 18 (41%) of the exposed workers, compared with 11 (13%) of the nonexposed controls. Both groups were subdivided with respect to age (i.e., 30-39 y, 40-49 y, 50-59 y), and there was a higher and significant relative risk for thyroid nodule formation in the exposed group. We also divided the groups into subgroups according to levels of exposure (i.e., nonexposed, exposed for < 20 y, and exposed for > 20 y), and a significant result was obtained with the linear-trend chi-square test. The preliminary results of our study suggest that occupationally induced exposure to radiation may be a risk factor for thyroid nodule formation.