Thyroid volume in Swedish school children: a national, stratified, population-based survey.

BACKGROUND/OBJECTIVES: Sweden has had a salt iodination program since 1936. This first national surveillance study on iodine nutrition infers an adequate level of urinary iodine concentration (UIC 125 µg/l) and the aim is now to evaluate thyroid volume (Tvol) in the same national sample. SUBJECTS/METHODS: A stratified probability proportionate to size cluster sampling was used to obtain a representative national sample of Swedish children aged 6-12 years. Median Tvol obtained ultrasonographically and the prevalence of enlarged thyroid glands were compared with an international reference standard. Regional differences were evaluated through comparisons of Tvol between coastal and inland areas, urban and rural regions, and former goitre and non-goitre regions. RESULTS: Tvol was correlated with age, body surface area (BSA), weight, height and body mass index for both sexes (P<0.0001) but not with UIC. The most important predictors for Tvol were age (girls: P<0.0001, boys: P=0.001) and BSA (girls: P<0.0001, boys: P<0.01). Median Tvol was higher in Sweden than in the reference study (P<0.0001). The prevalence of goitre was higher in Sweden (correlated to age 22.3%, BSA 15.7%, weight 17.6%, height 12.9%) than in the international reference (correlated to age 2.5%, BSA 2.5%, weight 2.5%, height 2.5%) (P<0.0001). Thyroids were larger in boys from urban and former non-goitre areas. CONCLUSIONS: Tvols were higher in Swedish school children than in the international reference study although iodine intake is considered optimal in Sweden. These findings underline the importance of regular monitoring of iodine intake, especially with regard to the decreased intake of table salt that is likely to follow initiation of health campaigns.

Paediatric CT examinations in 19 developing countries: frequency and radiation dose.

The aims of this study were to investigate the frequency of computed tomography (CT) examinations for paediatric patients below 15 y of age in 128 CT facilities in 28 developing countries of Africa, Asia and Eastern Europe and to assess the magnitude of CT doses. Radiation dose data were available from 101 CT facilities in 19 countries. The dose assessment was performed in terms of weighted CT dose index (CTDI(w)), volume CT index and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. The results show that on average the frequency of paediatric CT examinations was 20, 16 and 5 % of all CT examinations in participating centres in Africa, Asia and Eastern Europe, respectively. Eleven CT facilities in six countries were found to use adult CT exposure parameters for paediatric patients, thus indicating limited awareness and the need for optimisation. CT images were of adequate quality for diagnosis. The CTDI(w) variations ranged up to a factor of 55 (Africa), 16.3 (Asia) and 6.6 (Eastern Europe). The corresponding DLP variations ranged by a factor of 10, 20 and 8, respectively. Generally, the CTDI(w) and DLP values in Japan are lower than the corresponding values in the three regions in this study. The study has indicated a stronger need in many developing countries to justify CT examinations in children and their optimisation. Awareness, training and monitoring of radiation doses is needed as a way forwards.

Patient doses in CT examinations in 18 countries: initial results from International Atomic Energy Agency projects.

The purpose of this prospective study at 73 facilities in 18 countries in Africa, Asia and Eastern Europe was to investigate if the CT doses to adult patients in developing countries are higher than international standards. The dose assessment was performed in terms of weighted computed tomography dose index (CTDIw) and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. Except in one case, the mean CTDIw values were below diagnostic reference level (DRL) while for DLP, 17 % of situations were above DRLs. The resulting CT images were of adequate quality for diagnosis. The CTDIw and DLP data presented herein are largely similar to those from two recent national surveys. The study has shown a stronger need to create awareness and training of radiology personnel as well as monitoring of radiation doses in many developing countries so as to conform to the ALARA principle.

Adequate iodine nutrition in Sweden: a cross-sectional national study of urinary iodine concentration in school-age children.

BACKGROUND/OBJECTIVES: Sweden has a long-standing salt iodization program; however, its effects on iodine intake have never been monitored on a national level. The objective of this study was to evaluate iodine nutrition in the Swedish population by measuring the urinary iodine concentration (UIC) in a national sample of Swedish school-age (6-12 years of age) children. SUBJECTS/METHODS: A stratified probability proportionate to size cluster sampling method was used to obtain a representative national sample of school-age children from 30 clusters. Spot urine samples were collected for UIC analysis using a modified Sandell-Kolthoff method. RESULTS: The median UIC of the children (n=857) was 125 microg/l (range 11-757 microg/l). The proportion of children with a UIC <100 microg/l was 30.0% and the proportion of children with a UIC <50 and >300 microg/l was 5.5 and 3.0%, respectively. CONCLUSIONS: The iodine nutritional status of the Swedish population is adequate. Iodized table salt remains the main dietary source of iodine in Swedish diet. Recommendations to reduce total salt intake in the population urge increased use of iodized salt in the production of processed foods. Pregnant and lactating women with high iodine requirements may still be at risk for low iodine intake. This study will serve as the basis for future monitoring of iodine nutritional status in Sweden.

Determination of intrathyroidal iodine by X-ray fluorescence analysis in 60- to 65-year olds living in an iodine-sufficient area.

OBJECTIVES: X-ray fluorescence (XRF) is a non-invasive method for determining the iodine content of the thyroid gland in vivo. In spite of the obvious clinical value of such a method in situations of iodine deficiency or iodine overload, the method has not so far been widely used. The objective was to investigate the applicability of the XRF method in a larger number of subjects. DESIGN AND SUBJECTS: The study comprised 37 individuals, aged 60-65 years, who had spent their entire life with iodine supplementation through iodinated table salt. Individuals with (previous) thyroid disease were excluded. The individual thyroid function had previously been evaluated by measurements of thyroid-related hormones, thyroid volume and 131-Iodine (131I) uptake which indicated a sufficient iodine intake of the population in the area. Iodine in the right thyroid lobe in each subject was examined using XRF. RESULTS: The mean thyroid iodine concentration was 0.4 mg mL(-1), corresponding to a mean total iodine content of 5.2 mg (range 0.9-20.2). There was a pronounced difference between individuals. No correlation was found between iodine concentration and 131I uptake or thyroid volume. Neither was iodine content and 131I uptake correlated. CONCLUSIONS: In a population living under iodine-sufficient conditions, a large variation of iodine stored in the thyroid is compatible with euthyroidism. Determination of the iodine pool by XRF investigation is feasible in a clinical setting and the method offers a unique possibility to study the intrathyroidal iodine pool in subjects with thyroid disease. The low radiation dose enables the use of the method in pregnant women and also in young individuals.

Effect of lifelong iodine supplementation on thyroid 131-I uptake: a decrease in uptake in euthyroid but not hyperthyroid individuals compared to observations 50 years ago.

BACKGROUND: In Sweden, iodine has been added to table salt (10 mg/kg) since 1936; this amount was increased in 1966 to 50 mg/kg. OBJECTIVE: To investigate a euthyroid Swedish population (n = 44, 60-65 years) with its entire lifespan with iodine supplementation as for 24-h 131-I uptake (24 h IU) and thyroid nodularity (thyroid scintigraphy). To compare the euthyroid 24 h IU with uptake of thyrotoxic individuals, and with observations from 1955. METHODS: The 24 h IU was used in euthyroid individuals after oral administration of 0.1 MBq/2.7 microCi radioiodine and imaging of the thyroid gland was carried out using 99mTc-pertechnetate. RESULTS: In 1999-2000, the mean 24 h IU in the euthyroid individuals was 21% (range 11-33%) and the normal (central 95%) reference interval was 14-30%. Scintigraphy suggested multinodular goitre in three euthyroid individuals. In Graves' patients (n = 53, 50-65 years), the mean 24 h IU was 61% (range 29-89%). In 1955, the 24 h IU in euthyroid individuals was higher (38%, range 10-70%), while hyperthyroid patients had uptake values similar to those recorded in the present investigation (mean 62%, range 40-90%). CONCLUSIONS: The population sample studied had to be small for ethical reasons. We conclude that the reference interval for 24 h IU is 14-30% in this population that had spent its entire lifespan with iodine supplementation. This is lower than that recorded in a Swedish euthyroid population half a century ago having had low-grade table-salt iodine supplementation for 20 years. Values for hyperthyroid patients, however, do not appear to have been affected likewise.

Urinary iodine and thyroid volume in a Swedish population.

OBJECTIVE: To evaluate the present efficacy of an iodine supplementation programme working in Sweden since 1936 by studying the iodine excretion in urine and determining the thyroid volume in a population in a semi-rural community. DESIGN: A cross-sectional population screening comprising three age groups with randomly selected individuals: group 1 (children): 7-9 years, n = 61 (invited 70); group 2 (teenagers): 15-17 years, n = 61 (invited 63), and group 3 (adults): 60-65 years; n = 57 (invited 73). MAIN MEASUREMENTS: Urinary iodine was measured spectrophotometrically; thyroid volume by ultrasonography. RESULTS: The median values for urinary iodine concentration in the three age groups were 194 microg L(-1), 246 microg L(-1) and 190 microg L(-1), respectively, indicating an adequate iodine intake. In the 7-9 year olds, the median value of the thyroid volume was 4.7 mL, which coincides with the recently established upper limit of normal children of that age, 4.0-4.8 mL (ICCIDD, International Council for control iodine deficiency disorders). One eight-year-old boy had a pronounced goiter. Four teenagers and one adult were found to have an enlarged thyroid gland according to earlier established reference volumes (15 years >16 mL; adults > 25 mL). CONCLUSION: We conclude that the iodine intake in our region is sufficient in age groups ranging from young children to pre-retirement adults.

Screening for thyroid disease of 15-17-year-old schoolchildren in an area with normal iodine intake.

OBJECTIVE: The prevalence of thyroid disease in Swedish schoolchildren is today insufficiently known. The aim of the study was therefore to determine the prevalence of abnormal thyroid function and thyroid autoimmunity in teen-age schoolchildren and to compare the findings with a healthy control group of 60-65-year-old inhabitants from the same community. SETTING: A semirural community of approximately 15,000 inhabitants. DESIGN: Cross-sectional study. MAIN OUTCOME MEASURES: Thyroid volume and serum concentrations of serum thyrotropin (TSH), total and free thyroxine (T4), total and free 3,5,3'-triiodothyronine (T3), and antithyroperoxidase antibodies (TPOAb). RESULTS: Four schoolchildren (7%, 59 screened) had elevated TPOAb concentration, three of the subjects being girls (8%). One girl with a goitre was overtly hypothyroid and one girl showed borderline-high serum TSH concentration suggesting subclinical autoimmune thyroid disease. One euthyroid boy had a goitre and high concentration of TPOAb. The serum free T3 concentration was significantly higher in 15-17-year-old than 60-65-year-old (7.4 vs. 6.4 pmol L(-1), P < 0.001). The concentrations of other thyroid hormones and of TSH in 15-17-year-old did not differ from those of the 60-65-year-old. CONCLUSIONS: We found three cases of thyroid disease in need of immediate attention or later follow-up. The prevalence of autoimmune thyroid disease was high as indicated from TPOAb measurements. Thyroid tests including TPOAb measurement should be performed on wide indications when teenagers seek medical advice. The reference intervals for teen-age children for commonly used first line tests (TSH and free T4) do not differ from those for adults.

[Ultrasonic measurement of residual urine is considerate and reliable]. / Skonsamt och säkert att mäta residualurin med ultraljud.

The measurement of residual urine is often an invaluable aid in the examination of patients with prostate enlargement. As a result of the increasing scope of pharmacological treatment options in cases of such urinary problems, more such investigations are now being performed in primary care. Traditionally, residual urine has been measured by catheterisation of the urethra, which is associated with a risk of infection and other complications. As experience of ultrasound measurement of residual urine in 30 patients at a primary health centre suggests it to be a rapid, easily tolerated method unaccompanied by complications, it would seem to be an appropriate procedure even for use in the elderly with any of a variety of chronic diseases. It was also found easy for various categories of staff to learn.