Mitochondrial energetics and contents evaluated by flow cytometry in human maternal and umbilical cord blood.

Background: Mitochondrial dysfunction may relate to metabolic disorders. The relation between maternal and fetal mitochondrial function needs attention due to heritage.Objectives: To evaluate the use of the staining methods TetraMethylRhodamine Methyl Ester (TMRM) and Mitotracker Green (MTG) for flow cytometric measurements of umbilical cord blood mitochondrial function. Methods: 53 euthyroid at-term pregnant women and their offspring were included by blood collections. The offspring had blood drawn from the clamped umbilical cord. Flow cytometry with MTG, TMRM and Propidium Iodide were performed the following day. A cell count (antibody coating and flow cytometry) was performed for 9 maternal and cord samples. As a quality control, blood of 32 healthy donors was evaluated by flow cytometric analyzes same day as sampling and the following day to test stability of the measurements.Results: Cord mitochondrial measurements were lower than maternal. Maternal and cord mitochondrial function were positively correlated, especially reflected by MTG fluorescence-intensity (FI). Samples stored presented with very changed fluorescence patterns. However, the fluorescence intensity ratios MTG/TMRM of stained white blood cells were related within same day measurements, depicting an extensive and common bioenergetic cellular change.Conclusion: Cord blood flow cytometry by MTG- and TMRM- staining is possible with fluorescence intensity positively correlated to maternal fluorescence intensity. Storage of blood triggers mitochondrial dynamics. The methods are applicable with certain reservations, and they benefit from their non-invasive character compared to mitochondrial evaluation by muscle-biopsies.

Corrigendum to "Impaired Fertility Associated with Subclinical Hypothyroidism and Thyroid Autoimmunity: The Danish General Suburban Population Study".

[This corrects the article DOI: 10.1155/2015/132718.].

Danish Rural Eye Study: Epidemiology of Adult Visual Impairment.

PURPOSE: To examine the frequency and causes of visual impairment (VI) in a select population of Danish adults. METHODS: A total of 3843 adults aged 20-94 years from the Danish General Suburban Population Study (GESUS) were included in the population-based, cross-sectional ophthalmological study, Danish Rural Eye Study (DRES). All DRES participants received a comprehensive general health examination preceding their eye examination, including measurement of best-corrected visual acuity (BCVA) for each eye, bilateral 45° retinal fundus photographs and further ophthalmological examination where indicated. RESULTS: Overall, 3826 of 3843 participants (99.6%) had bilateral visual acuity measurements. The overall frequency of VI (BCVA <20/40 in the better-seeing eye) was 0.4% (95% confidence interval, CI, 0.2-0.7%; n = 15) among all DRES participants, 0.6% (95% CI 0.3-1.0%; n = 15) among participants >50 years and 3.7% (95% CI 2.1-6.5%; n = 11) in participants >80 years. The primary causes of VI in the better-seeing eye were age-related macular degeneration (AMD) in 46.7% (7/15) and cataract in 26.7% (4/15). A total of 43.3% (n = 115) of participants >80 years were pseudophakic in one or both eyes. The frequency of diabetes (HbA1c ≥ 48 mmol/mol or self-reported diagnosis) was 5.9% (n = 227), including 1.3% (n = 51) newly diagnosed in the GESUS. Of participants determined to have VI due to exudative AMD, 50% had received anti-vascular endothelial growth factor (VEGF) treatment. CONCLUSION: We report a relatively low frequency of VI among Danish adults over 59 years of age compared with that observed 10-15 years ago, which is both consistent with other recent Scandinavian studies and reflective of our relatively healthy and mobile population sample.

Impaired Fertility Associated with Subclinical Hypothyroidism and Thyroid Autoimmunity: The Danish General Suburban Population Study.

INTRODUCTION: The aim of this study was to estimate the significance of TSH, thyroid peroxidase antibody (TPOAb), and mild (subclinical) hypothyroidism in women from The Danish General Suburban Population Study (GESUS) on the number of children born, the number of pregnancies, and the number of spontaneous abortions. METHODS: Retrospective cross sectional study of 11254 women participating in GESUS. Data included biochemical measurements and a self-administrated questionnaire. RESULTS: 6.7% had mild (subclinical) hypothyroidism and 9.4% prevalent hypothyroidism. In women with mild hypothyroidism TPOAb was significantly elevated and age at first child was older compared to controls. TSH and TPOAb were negatively linearly associated with the number of children born and the number of pregnancies in the full cohort in age-adjusted and multiadjusted models. TSH or TPOAb was not associated with spontaneous abortions. Mild (subclinical) hypothyroidism was associated with a risk of not having children and a risk of not getting pregnant in age-adjusted and multiadjusted models. Prevalent hypothyroidism was not associated with the number of children born, the number of pregnancies, or spontaneous abortions. CONCLUSION: Impaired fertility is associated with TSH, TPOAb, and mild (subclinical) hypothyroidism in a Danish population of women.

Is suppressed thyroid-stimulating hormone (TSH) associated with subclinical depression in the Danish General Suburban Population Study?

BACKGROUND: The first phase of the Danish General Suburban Population Study (GESUS) including 8214 individuals was an attempt to evaluate the association between subclinical hypothyroidism without or with elevated peroxidase antibodies and depression. No such association was found. In the second phase, including 14,787 individuals, we have focused on suppressed TSH (thyroid-stimulating hormone) and depression. AIMS: To evaluate to what extent suppressed TSH is associated with subclinical depression. METHODS: The total scores of the Major Depression Inventory (MDI) were used to evaluate subclinical depression, both by its total score and by an algorithm of the subthreshold depressed by presence of at least three of the 10 ICD-10 depression symptoms. Serum levels of TSH were used to classify the individuals into suppressed (TSH < 0.4 mIU/l), elevated (TSH ≥ 3.8 mIU/l) and normal reference (TSH between 0.4 and 3.7 mIU/l). RESULTS: We identified 285 individuals with suppressed TSH and 1266 individuals with elevated TSH. The MDI total score was 7.55 in suppressed TSH individuals, 6.22 in elevated TSH individuals and 6.52 in normal reference individuals (P = 0.01). When the MDI was used diagnostically to identify subclinical depression, the prevalence was 8.07% in suppressed TSH individuals, 5.8% in normal reference individuals and 5.29% in elevated TSH individuals. CONCLUSION: This population-based study supports that persons with suppressed TSH (subclinical hyperthyroidism) seem to have a risk, although small, of subclinical depression.

Well-being and depression in individuals with subclinical hypothyroidism and thyroid autoimmunity - a general population study.

BACKGROUND: The association between subclinical hypothyroidism (SCH), with and without raised thyroid peroxidase antibodies (anti-TPO), and well-being or depression is still controversial, in spite of many studies on the topic. AIMS: In this large general population study of 8214 individuals, we aim to clarify the significance of elevated levels of anti-TPO as a marker of poor well-being and depression in euthyroid individuals and individuals with SCH. METHODS: In participants from the Danish General Suburban Population Study (GESUS), serum thyroid stimulating hormone (TSH), total triiodothyronine (tT3), free thyroxine (fT4) and anti-TPO was measured. Prevalence of poor well-being and depression was measured using the WHO-5 Well-being questionnaire and WHO MDI [Major (ICD-10) Depression Inventory] questionnaire. RESULTS: Raw score for well-being or depression overall and stratified for sex was not more significantly different in euthyroid individuals than in individuals with SCH, with or without high anti-TPO, except that euthyroid women with elevated anti-TPO had better well-being (P = 0.03) compared with euthyroid women with anti-TPO within the reference range. CONCLUSION: Elevated anti-TPO levels cannot be used as a general marker of poor well-being or depression in the general population.

Weight Gain and Serum TSH Increase within the Reference Range after Hemithyroidectomy Indicate Lowered Thyroid Function.

Background. Weight gain is frequently reported after hemithyroidectomy but the significance is recently discussed. Therefore, the aim of the study was to examine changes in body weight of hemithyroidectomized patients and to evaluate if TSH increase within the reference range could be related to weight gain. Methods. In a controlled follow-up study, two years after hemithyroidectomy for benign euthyroid goiter, postoperative TSH and body weight of 28 patients were compared to preoperative values and further compared to the results in 47 matched control persons, after a comparable follow-up period. Results. Two years after hemithyroidectomy, median serum TSH was increased over preoperative levels (1.23 versus 2.08 mIU/L, P < 0.01) and patients had gained weight (75.0 versus 77.3 kg, P = 0.02). Matched healthy controls had unchanged median serum TSH (1.70 versus 1.60 mIU/L, P = 0.13) and weight (69.3 versus 69.3 kg, P = 0.71). Patients on thyroxin treatment did not gain weight. TSH increase was significantly correlated with weight gain (r = 0.43, P < 0.01). Conclusion. Two years after hemithyroidectomy for benign euthyroid goiter, thyroid function is lowered within the laboratory reference range. Weight gain of patients who are biochemically euthyroid after hemithyroidectomy may be a clinical manifestation of a permanently decreased metabolic rate.

Persistent cellular metabolic changes after hemithyroidectomy for benign euthyroid goiter.

BACKGROUND: The significance of perturbations of thyroid-stimulating hormone (TSH) and thyroid hormones within the laboratory reference ranges after hemithyroidectomy is unknown. Our aim was to examine changes in TSH and thyroid hormones after hemithyroidectomy for benign euthyroid goiter, focusing on tissue response by examining the mitochondrial membrane potential (MMP) of peripheral blood mononuclear cells (PBMCs) and basal oxygen consumption (V˙O2). MATERIALS AND METHODS: In a prospective study on 28 patients and controls, we examined serum TSH and thyroid hormones before hemithyroidectomy and 1, 3, 6 and 12 months after hemithyroidectomy for benign euthyroid goiter. In the hemithyroidectomy group, flow cytometry was used to measure the MMP of tetramethylrhodamine methyl ester (TMRM)- and MitoTracker Green (MTG)-stained PBMCs, and V˙O2 was measured by an Oxycon Pro apparatus. RESULTS: One year after hemithyroidectomy, TSH had increased from a median of 0.97 mIU/l (interquartile range, IQR: 0.69-1.50 mIU/l) to 2.10 mIU/l (IQR: 1.90-3.00 mIU/l; p < 0.001); free thyroxine (fT4) had decreased from a median of 16.0 pmol/l (IQR: 14.9-17.0 pmol/l) to 14.8 pmol/l (IQR: 14.1-16.4 pmol/l; p = 0.009), whereas total triiodothyronine variations did not differ from those in controls. Concomitantly, the MMP of TMRM- and MTG-stained PBMCs was increased by 58% (p < 0.001) and 22% (p = 0.008), respectively. V˙O2 was increased by 14% (p = 0.01). CONCLUSION: Hemithyroidectomy for benign euthyroid goiter induced persistently increased TSH and decreased fT4, sustained mitochondrial hyperpolarization and increased V˙O2. Our results demonstrate a decrease after hemithyroidectomy of the metabolic state to which the individual is adapted, with persistent cellular metabolic changes in a hemithyroidectomized patient group which is normally considered clinically and biochemically euthyroid.

Prevalence of depression, quality of life and antidepressant treatment in the Danish General Suburban Population Study.

BACKGROUND: The Danish General Suburban Population Study (GESUS), the objective of which is to facilitate epidemiological and genetic research, has included the Major Depression Inventory (MDI) and the WHO-Five Well-Being Index (WHO-5) among the medical health questionnaires. We were thus in a position to compare the 2-week prevalence of ICD-10 depression in the period from 2010 to 2012 with our previous Danish general population study from 2003, in which the MDI was also included. AIMS: The aim of our analysis was not only to evaluate the point prevalence of ICD-10 depression but also to describe the prevalence of antidepressants received by the respondents in the GESUS study and the correspondence to their subjective well-being on the WHO-5 questionnaire. METHODS: To evaluate the validity (scalability) of the MDI and the WHO-5 in the GESUS study we performed the non-parametric Mokken analysis. The scalability of the MDI and the WHO-5 was quite acceptable. RESULTS: In total, 14,787 respondents were available from a response rate of 50%. The 2-week prevalence of ICD-10 depression was 2.3%, which is rather similar to the 2.8% in our 2003 study. The rate of people receiving antidepressants increased consistently with increasing severity of ICD-10 depression. CONCLUSION: This study has confirmed that the use of the MDI to obtain an ICD-10 depression diagnosis gives rather conservative estimates of the 2-week prevalence of depression in the Danish general population. The prescription of antidepressants depends on the severity of the ICD-10 depression diagnosis.

Pregnancy-induced alterations in mitochondrial function in euthyroid pregnant women and pregnant women with subclinical hypothyroidism; relation to adverse outcome.

BACKGROUND: It is well documented that overt hypothyroidism is associated with adverse pregnancy outcomes, but studies of subclinical hypothyroidism have demonstrated conflicting results. OBJECTIVE: Thyroid hormones are known to regulate mitochondrial function, and the aim of this study was to examine the possible relationship of subclinical hypothyroidism and mitochondrial dysfunction to adverse pregnancy outcomes in pregnant women. METHODS: Women in their third trimester of pregnancy (n = 113) who did not receive thyroid medication were included in this cross-sectional study. All participants were interviewed, and their thyroid status was determined. All participants had concentrations of thyroid hormones (fT4 and tT3) within the reference range. In addition to thyroid status, mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) were measured by flow cytometry. To establish a reference range of MMP and ROS, a group of euthyroid, nonpregnant women were used as euthyroid controls. Adverse pregnancy outcome was defined as preterm delivery, preeclampsia, placental abruption, Apgar score <7 points 1 minute after birth, or postpartum hemorrhage. RESULTS: The prevalence of subclinical hypothyroidism among pregnant women was 17% (n = 19), and the number of overall adverse pregnancy outcomes was increased (p = 0.02) compared with that in euthyroid pregnant women. Preeclampsia, poor Apgar score, and postpartum hemorrhage were more frequent in the subclinical hypothyroidism group than in the euthyroid group (p = 0.04, p = 0.001 and p = 0.03, respectively), and more women showed prolonged gestation and gave birth later than 41 weeks of gestation than in the euthyroid group (p = 0.04). Compared with euthyroid, nonpregnant controls, a physiological upregulation of mitochondrial function was observed in euthyroid pregnant women. This was impaired in pregnant women with subclinical hypothyroidism. Compared with euthyroid, nonpregnant controls, pregnant women had increased ROS regardless of their thyroid status. CONCLUSION: We speculate that the unfavorable effects on mitochondrial function in women with subclinical hypothyroidism may be associated with higher prevalence of adverse pregnancy outcomes.

Study design, participation and characteristics of the Danish General Suburban Population Study.

INTRODUCTION: The aim of this article was to describe the study design, participants and baseline characteristics of The Danish General Suburban Population Study (GESUS) and to compare suburban participants with age- and gender-matched urban participants from the Copenhagen General Population Study (CGPS). MATERIAL AND METHODS: Data from questionnaire, health examination, biochemical measurements and public registers were collected. RESULTS: In GESUS the overall participation rate was 49.3% (response n = 10,621 of total n = 21,557). Among people aged 40-79 years, the participation rate was 53.9% (8,797/16,310). Participants were more frequently women, had a higher median age, a higher frequency of marriage/registered partnerships, but had a lower frequency of co-morbidities and death in the follow-up period (January 2010-May 2011 (diseases)/June 2011 (death) than the non-participants. GESUS has sufficient power to study effects of rare and common exposures or genetic variants on the occurrence of common multifactorial diseases. Compared with an age- and gender-matched urban population (n = 10,618, CGPS), participants in GESUS (n = 10,618) were less physically active, smoked less and ingested less alcohol, had higher anthropometric measures, less undiagnosed hypertension but more undiagnosed diabetes, had a lower frequency of elevated total cholesterol and low-density lipoprotein chol-esterol but higher frequency of decreased high-density lipoprotein cholesterol and elevated triglycerides. CONCLUSION: In GESUS, participants had a better health profile than non-participants, and participants in GESUS had a different cardiovascular risk profile than participants in the CGPS. FUNDING: The study received funding from the following: Johan and Lise Boserup Foundation; TrygFonden; Det Kommunale Momsfond; Johannes Fog's Foundation; Region Zealand; Region Zealand Foundation; Naestved Hospital; Naestved Hospital Foundation; The National Board of Health; Danish Agency for Science, Technology and Innovation. TRIAL REGISTRATION: not relevant.

Peripheral markers of thyroid function: the effect of T4 monotherapy vs T4/T3 combination therapy in hypothyroid subjects in a randomized crossover study.

BACKGROUND: A recent randomized controlled trial suggests that hypothyroid subjects may find levothyroxine (l-T4) and levotriiodothyronine combination therapy to be superior to l-T4 monotherapy in terms of quality of life, suggesting that the brain registered increased T3 availability during the combination therapy. HYPOTHESIS: Peripheral tissue might also be stimulated during T4/T3 combination therapy compared with T4 monotherapy. METHODS: Serum levels of sex hormone-binding globulin (SHBG), pro-collagen-1-N-terminal peptide (PINP), and N-terminal pro-brain natriuretic peptide (NT-proBNP) (representing hepatocyte, osteoblast, and cardiomyocyte stimulation respectively) were measured in 26 hypothyroid subjects in a double-blind, randomized, crossover trial, which compared the replacement therapy with T4/T3 in combination (50 µg T4 was substituted with 20 µg T3) to T4 alone (once daily regimens). This was performed to obtain unaltered serum TSH levels during the trial and between the two treatment groups. Blood sampling was performed 24 h after the last intake of thyroid hormone medication. RESULTS: TSH remained unaltered between the groups ((median) 0.83 vs 1.18 mU/l in T4/T3 combination and T4 monotherapy respectively; P=0.534). SHBG increased from (median) 75 nmol/l at baseline to 83 nmol/l in the T4/T3 group (P=0.015) but remained unaltered in the T4 group (67 nmol/l); thus, it was higher in the T4/T3 vs T4 group (P=0.041). PINP levels were higher in the T4/T3 therapy (48 vs 40 µg/l (P<0.001)). NT-proBNP did not differ between the groups. CONCLUSIONS: T4/T3 combination therapy in hypothyroidism seems to have more metabolic effects than the T4 monotherapy.

Thyroid hormone effect on human mitochondria measured by flow cytometry.

BACKGROUND: Mitochondrial function may be impaired in a number of diseases including metabolic syndrome, cardiovascular disease and endocrine disorders. Therefore it is important to be able to measure mitochondrial function in human cells. PURPOSE: The aim of the present study was to evaluate a method to measure mitochondrial function in human derived cells, which also would reflect regulation by thyroid hormones. METHODS: The MDA-MB-231 cell line (a human breast cancer cell line) was incubated with bioactive iodothyronines (T(4), 3'-3, 5-T(3), 3, 5-T(2)) 50 nmol/l for 3 h. Mitochondrial membrane potentials (MMP) were measured by a flow cytometer after staining with Tetramethylrhodamine methyl ester (TMRM). Also, the effect of TRIAC (a stimulator of thyroid hormone nuclear receptors) and L-Carnitine (an inhibitor of thyroid hormone passage into the nucleus) was examined. FINDINGS: It was possible to measure mitochondrial membrane potential (MMP) in human derived cells and to examine thyroid hormone effects using flow cytometry. Bioactive iodothyronines increased mitochondrial membrane potential. TRIAC had no effect and L-Carnitine only inhibited T(4) stimulation of membrane potential. CONCLUSION: Flow cytometry may be a valuable method for examining and testing mitochondrial function in human cells. Our findings demonstrate increase of mitochondrial membrane potential and an extra nuclear short time effect of 3, 5-T(2) on mitochondrial activity.

Effect of combination therapy with thyroxine (T4) and 3,5,3'-triiodothyronine versus T4 monotherapy in patients with hypothyroidism, a double-blind, randomised cross-over study.

BACKGROUND: Treatment of hypothyroidism with 3,5,3'-triiodothyronine (T(3)) is controversial. A recent meta-analysis concludes that no evidence is present in favour of using T(3). However, the analysis included a mixture of different patient groups and dose-regimens. OBJECTIVE: To compare the effect of combination therapy with thyroxine (T(4)) and T(3) versus T(4) monotherapy in patients with hypothyroidism on stable T(4) substitution. Study design Double-blind, randomised cross-over. Fifty micrograms of the usual T(4) dose was replaced with either 20 microg T(3) or 50 microg T(4) for 12 weeks, followed by cross-over for another 12 weeks. The T(4) dose was regulated if needed, intending unaltered serum TSH levels. Evaluation Tests for quality of life (QOL) and depression (SF-36, Beck Depression Inventory, and SCL-90-R) at baseline and after both treatment periods. Inclusion criteria Serum TSH between 0.1 and 5.0 mU/l on unaltered T(4) substitution for 6 months. RESULTS: A total of 59 patients (55 women); median age 46 years. When comparing scores of QOL and depression on T(4) monotherapy versus T(4)/T(3) combination therapy, significant differences were seen in 7 out of 11 scores, indicating a positive effect related to the combination therapy. Forty-nine percent preferred the combination and 15% monotherapy (P=0.002). Serum TSH remained unaltered between the groups as intended. CONCLUSION: In a study design, where morning TSH levels were unaltered between groups combination therapy, (treated with T(3) 20 microg once daily) was superior to monotherapy by evaluating several QOL, depression and anxiety rating scales as well as patients own preference.

Transient hyperthyroxinemia in newborns from women with autoimmune thyroid disease and raised levels of thyroid peroxidase antibodies.

OBJECTIVE: Although it is well established that maternal thyroid disease and increased levels of thyrotropin receptor antibodies (TRab) during pregnancy are associated with a number of complications, is the significance of increased levels of thyroid peroxidase antibodies (TPOab) alone a matter for discussion? The aim of the present study was to examine whether transplacental passage of TPOab from women with autoimmune thyroid disease (AITD) interferes with thyroid function in the neonate. METHODS: Pregnant women with AITD (raised levels of TPOab) and their neonates were monitored with regard to variations of thyroid hormones, thyrotropin (TSH), and TPOab. Pregnant women with non-AITD served as controls. RESULTS: The neonates from mothers with AITD, independently of the presence also of TRab in the mothers, had a transient hyperthyroxinemia one week following birth. Neonatal TPOab correlated with that of the mothers at gestation and was cleared concomitantly with normalization of thyroxine. A high frequency (21%) of severe hyperbilirubinemia was observed in neonates from mothers with AITD. CONCLUSION: Children of mothers with raised levels of TPOab, have a transient hyperthyroxinemia one week after birth accompanied by a high frequency of hyperbilirubinemia suggesting that clinical examination and blood testing should be performed consecutively during the first postnatal week.

Magnetic resonance imaging determination of extraocular eye muscle volume in patients with thyroid-associated ophthalmopathy and proptosis.

PURPOSE: Recent studies concerning the association between extraocular muscle (EOM) enlargement in thyroid-associated ophthalmopathy (TAO) and immunological and clinical activity have not been conclusive, probably due to a lack of uniform imaging methods (ultrasonography, computer tomography [CT] or magnetic resonance imaging [MRI]) and difficulties in the determination of EOM volume. The aim of the present study was to examine the significance of EOM enlargement as established by MRI-based volume determination, with reference to proptosis and the presence of autoantibodies, clinical activity and the duration of active disease. METHODS: We determined EOM volume using MRI in 15 patients concomitantly with the determination of TSH, thyroid hormones, thyrotropin receptor antibodies (TRab) thyroid peroxidase antibodies (TPOab) and clinical activity score (CAS) at entry. We also established the duration until cessation of clinically active TAO. RESULTS: All 15 patients had bilateral EOM enlargement, but swelling of orbital fatty tissue was absent. Significant correlations between thickness of musculi rectales and proptosis, values of TRab, CAS, and duration of activity were observed. CONCLUSION: Our results support the hypothesis of a role of thyrotropin receptor antibodies in the pathogenesis of TAO and suggest that only EOM enlargement is responsible for proptosis in TAO.

The significance of clinical euthyroidism on reference range for thyroid hormones.

BACKGROUND: The reference range for thyroid hormones and thyroid stimulating hormone (TSH) is usually established either by using the manufacturer's recommendations or by analyzing blood tests from a serum bank or from the local laboratory staff, assuming that they are healthy and euthyroid. The aim of this study was to examine the significance of clinical euthyroidism and a normal basal oxygen consumption on the reference range for thyroid hormones and TSH. METHODS: A clinical examination, including information on medication, was performed on 31 apparently healthy persons. The following determinations were made for all of the subjects: basal oxygen consumption, serum TSH, serum total T(3), and serum total T(4). T(4) uptake for calculation of FT(4)I was also measured. RESULTS: The clinical examination and determination of VO(2) reduced what initially appeared to be a euthyroid and healthy population by 32%. This also resulted in a narrower reference interval than that suggested by the manufacturer (range) (TSH: 0.35-5.50 mU/l, T(4): 58-140 nmol/l, T(3): 0.9-2.8 nmol/l) or than that established in the initially selected population (TSH=0.76-3.90 mU/l, T(4)=54-168 nmol/l, T(3)=1.27-2.74 nmol/l, FT(4)I=64-123 a.u.). In the finally selected population, this was TSH=0.76-3.90 mU/l, T(4)=59-127 nmol/l, T(3)=1.45-2.74 nmol/l, and FT(4)I=64-120 a.u. CONCLUSION: The method of selecting the population for establishing the reference interval for thyroid hormones and TSH influences the reference ranges. Neglecting to deal with this problem may invalidate screening procedures, especially for subclinical diseases.

Incidence of gestational hypertension in gestational diabetes mellitus.

The purpose of this study has been to establish the incidence of gestational hypertension (GH) in women with gestational diabetes mellitus (GDM) and to examine the frequency of complications in women with co-existent GDM and GH. Furthermore, we wished to evaluate the significance of urine albumin excretion determined by the urine albumin creatinine ratio (ACR). A total of 215 successive pregnancies with risk factors for gestational diabetes, as defined by the Danish National Board of Health screened for gestational diabetes by the WHO criteria, were reviewed. Women who had a normal OGTT during the screening served as controls. Gestational hypertension was defined as a mean arterial pressure (MAP) >105 mmHg (systolic BP > or = 140 mmHg and/or diastolic BP > or = 90 mmHg). The two groups were comparable with regard to initial body mass index (BMI) and MAP. GH appeared with a higher frequency in women with GDM (28%) than in women with normal OGTT (10%) P=0.003 chi(2) test. Serious complications (perinatal mortality, malformations, acute caesarean section) also appeared with a higher frequency in women with GH and GDM (10%) than in women with GH but with normal OGTT (2%) P=0.0083 chi(2) test. We observed a significant increase in ACR in the group with complications (GDM and GH) during gestation regardless of intensive antihypertensive treatment. We also observed that ACR was significantly higher in women with GDM and GH when compared to women with GDM and a normal blood pressure. The BMI was consistently higher in women with GH, regardless of whether they had GDM or not as compared to the normotensive group. GH appears with a higher frequency in women with GDM and the co-existence seems correlated with a higher frequency of complications. The correlation between urine albumin excretion and complications might suggest that regulating GH should strive to normalise ACR in women with GDM.