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Biomedical subjects

Lone Banke Rasmussen

Publications and source records attributed to Lone Banke Rasmussen.

8 recordsLinked to original sources
PubMed2006

[Selenium and health].

Selenium is an essential micronutrient. The average selenium intake in Danish adults is close to the recommended level of 40-50 mg/day. There is no scientific documentation showing that an increased selenium intake will result in disease prevention. However, a preventive effect on some cancers and hearth disease cannot be ruled out. Fortification of foods via increased selenium content in fertilizers is a possible way of increasing selenium intake. The tolerable upper intake level of 60 mg/day in children 1-3 years old must not be exceeded, which makes fortification difficult.

Adult↗
PubMed2006

Increase in incidence of hyperthyroidism predominantly occurs in young people after iodine fortification of salt in Denmark.

CONTEXT: To prevent goiter and nodular hyperthyroidism, iodine fortification (IF) of salt was introduced in Denmark in 1998. We prospectively registered all new cases of overt hyperthyroidism in two areas of Denmark before and for the first 6 yr after iodine fortification. METHODS: We used a computer-based register of all new cases of hyperthyroidism in two population subcohorts with moderate iodine deficiency (Aalborg, n = 310,124) and mild iodine deficiency (Copenhagen, n = 225,707), respectively. Data were obtained 1) before IF (1997-1998); 2) during voluntary IF (1999-2000); 3) during the early (2001-2002) period of mandatory IF; and 4) during the late (2003-2004) period with mandatory IF. RESULTS: The overall incidence rate of hyperthyroidism increased [baseline, 102.8/100,000/year; voluntary IF, 122.8; early mandatory IF, 140.7; late mandatory IF, 138.7 (P for trend <0.001)]. Hyperthyroidism increased in both sexes (P < 0.001) and in all age groups: 0-19, 20-39, 40-59, and 60+ yr (P for trend <0.001). The increase was relatively highest in young adults aged 20-39 yr: late mandatory IF (percent increase from baseline), age 20-39, 160%, P < 0.001; age 40-59, 29%, P < 0.01; age 60+ yr, 13%, P = not significant. CONCLUSION: Even a cautious iodization of salt results in an increase in the incidence rate of hyperthyroidism. Contrary to current concepts, many of the new cases were observed in young subjects, and are presumably of autoimmune origin. Furthermore, monitoring is expected to show a decrease in the number of elderly subjects suffering from nodular hyperthyroidism.

Adolescent↗
PubMed2006

Thyroid peroxidase and thyroglobulin auto-antibodies in patients with newly diagnosed overt hypothyroidism.

OBJECTIVES: Thyroid autoimmunity is a major cause for hypothyroidism. We describe thyroid auto-antibodies in patients with various nosological subtypes of hypothyroidism identified in a population study. DESIGN: Population-based follow-up study identifying all new cases of hypothyroidism in an open cohort. METHODS: We established a monitoring system, and identified all new cases with primary overt hypothyroidism (n = 685) in a 4 year period in a well-defined population cohort (2,027,208 person-years of observation). Patients were sub-classified into: spontaneous hypothyroidism, presumably of autoimmune origin (n = 578); non-spontaneous hypothyroidism (associated with medication, delivery, neck-irradiation or subacute thyroiditis, n = 97); and congenital hypothyroidism (n = 10). A total of 186 adult patients (61% of those invited) underwent thyroid ultrasonography and measurements of antibodies against thyroid peroxidase (TPOAb) and thyroglobulin (TgAb). RESULTS: In spontaneously hypothyroid patients: >99% were antibody-positive (TPOAb or TgAb), TPOAb were more often measurable than TgAb (95.9 vs. 80.7%, p < 0.001). A statistically significant but modest correlation was observed between the two antibodies (Pearson's r2 = 0.11, p < 0.001). In a multivariate regression model both TPOAb and TgAb were positively associated with thyroid enlargement (p < 0.001), whereas no association was found with sex, age, iodine deficiency level or serum TSH level. We found no differences in patient characteristics between those who mainly developed TPOAb vs. those who preferentially harboured TgAb. CONCLUSIONS: Autoimmunity played a dominant role in practically all patients classified as spontaneously hypothyroid. Thyroid enlargement was associated with high levels of TPOAb and TgAb. We found no clue to why some spontaneously hypothyroid patients predominantly developed TPOAb whereas others mainly generated TgAb.

Autoantibodies↗
PubMed2006

Epidemiology of subtypes of hypothyroidism in Denmark.

OBJECTIVE: Studies of hypothyroidism are often based on referred patients, and limited information is available on the incidence rates of subtypes of hypothyroidism in the general population. We therefore studied incidences of subtypes of primary, overt hypothyroidism in a Danish population cohort and compared incidences in two subcohorts with different levels of iodine intake. DESIGN: A prospective population-based study, monitoring a well-defined cohort representative of the Danish population. METHODS: The Danish Investigation of Iodine Intake and Thyroid Diseases registry of hyper- and hypothyroidism was established as part of the monitoring of the iodine fortification of salt in Denmark. A computer-based system linked to laboratory databases identified all patients diagnosed with new, biochemically overt hypothyroidism in populations living in Aalborg (moderate iodine deficiency, n = 311,102) and Copenhagen (mild iodine deficiency, n = 227,632). We subsequently evaluated all identified patients to verify incident thyroid disease, and subclassified hypothyroidism into nosological types. RESULTS: During a 4-year period (2,027,208 person-years) 685 new cases of overt hypothyroidism were diagnosed in the cohort; the incidence rate was 32.8 per 100,000 person-years (standardised to the Danish population). Nosological types of hypothyroidism were: spontaneous (presumably autoimmune) 84.4%, post-partum 4.7%, amiodarone-associated 4.0%, subacute thyroiditis 1.8%, previous radiation or surgery 1.8%, congenital 1.6% and lithium-associated 1.6%. Crude incidence rates were 29.0 around Aalborg and 40.6 in an area of Copenhagen. The higher incidence rate of hypothyroidism in the area with higher iodine intake was caused solely by more cases of spontaneous (presumably autoimmune) hypothyroidism, whereas the incidence of non-spontaneous hypothyroidism (all types combined) was significantly lower in the area with higher iodine intake. CONCLUSION: In a population-based study we observed a higher incidence of hypothyroidism with higher iodine intake. This was due solely to the entity of spontaneous hypothyroidism. The occurrence of overt hypothyroidism was relatively low in Denmark.

Adolescent↗
PubMed2006

Lack of association between thyroid autoantibodies and parity in a population study argues against microchimerism as a trigger of thyroid autoimmunity.

BACKGROUND: Thyroid autoimmunity is more common in females than in males. One possible explanation for this female preponderance may be the effect of oestrogens on the immune system. It has also been suggested that foetal microchimerism involving transfer of foetal cells into maternal tissue during pregnancy may play an important role. OBJECTIVE: We investigated the association between the presence of circulating thyroid autoantibodies and previous pregnancy, parity and the use of oral contraceptives (OCs) and hormone replacement therapy (HRT) in a population cohort. METHODS: We examined 3712 women randomly selected from the general population. Serum was analysed for thyroid peroxidase antibody (TPO-Ab) and thyroglobulin antibody (Tg-Ab) using assays based on an RIA technique (DYNO test). Data were analysed in logistic regression models to adjust for possible confounders. Women previously treated for thyroid disease or with pregnancy within 1 year prior to the study were excluded from the analyses. RESULTS: In both univariate and multivariate models and whether the presence of TPO-Ab and Tg-Ab was investigated alone or in combination, findings were negative with respect to an association between circulating thyroid antibodies and previous pregnancy, number of pregnancies, parity and previous abortion. There was no association between thyroid autoantibodies and use of OCs. Women aged 60-65 years receiving HRT now or previously had a lower prevalence of Tg-Ab (univariate, P = 0.01; multivariate, P = 0.02). No such association was observed between HRT and TPO-Ab. CONCLUSION: In this population study there was no association between previous pregnancy, parity and thyroid antibodies, which argues against the role of microchimerism as a trigger of thyroid autoimmunity. Exogenous oestrogens may reduce aspects of autoimmunity.

Adolescent↗
PubMed2005

A population study of the association between thyroid autoantibodies in serum and abnormalities in thyroid function and structure.

OBJECTIVE: Patients with autoimmune overt hypothyroidism may present with goitrous Hashimoto's disease or autoimmune atrophic thyroiditis. Little is known about the prevalence of subclinical autoimmune hypothyroidism. The aims of this study were to evaluate the association between thyroid autoantibodies in serum and abnormalities in thyroid function and structure, and to study the thyroid volume in subjects with subclinical autoimmune hypothyroidism. DESIGN: A population study including 4649 randomly selected subjects. MEASUREMENTS: Blood tests were used to analyse for thyroid peroxidase autoantibodies (TPO-Ab), thyroglobulin autoantibodies (Tg-Ab), TSH, fT3 and fT4. RESULTS: Thyroid volume was categorized as small (< 6.6 ml) in 4.7%, normal (6.6-14.9 ml) in 60.4% and large (> 14.9 ml) in 34.9% of participants. Thyroid nodules were found in 29.7%. Serum TSH was low (< 0.4 mIU/l) in 4.7%, normal (0.4-3.6) in 91.0% and high (> 3.6) in 4.3%. The prevalence rate of subclinical goitrous Hashimoto's disease was 0.62% and of subclinical autoimmune atrophic thyroiditis 0.24%. There was a strong association between large volume and autoantibodies, but only in subjects with elevated TSH (P < 0.001). An association between thyroid nodules and TPO-Ab in univariate analyses (P < 0.001) was due to confounding by sex and age (multivariate model, P = 0.23). CONCLUSION: We identified a subgroup of the population with subclinical goitrous Hashimoto's disease and a smaller subgroup with subclinical autoimmune atrophic thyroiditis. This relationship between small and large thyroid volume in subclinical disease is opposite to that in overt disease, which may suggest that the period between development of a small volume with circulating autoantibodies and overt hypothyroidism is relatively short.

Adolescent↗