T Lorenzen

Steno Diabetes Center, Gjentofte, Capital Region, Denmark

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Publications (15)45.48 Total impact

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    ABSTRACT: Fifty-five Danish families with two offspring concordant for type 1 diabetes-identified through a nationwide population-based survey, and 57 “true sporadic” cases-matched with familial cases for age at onset, but with no IDDM-affected first-degree relatives and long disease duration, and 110 control subjects were typed for putative genetic susceptibility markers for type 1 diabetes identified from a pathogenetic model. The markers included MHC class I, II and III loci, the manganese superoxide dismutase (MnSOD) locus (chr. 6q), interleukin-1β (IL1B), the IL-1 receptor antagonist (IL1RN), and the IL-1 type 1 receptor (IL1RI) loci (each chr. 2q). No significant differences between familial and sporadic cases were found within the MHC region (including the following loci: HLA-DQ,-DR, heat shock protein (HSP) 70, tumour necrosis factor (TNF), HLA-B and-A). In both groups of patients 11% were negative for both DQA1*0301-DQB 1*0302 and DQA1*0501-DQB1*0201 genotypes, and 7% of the type 1 diabetics had genotypes unable to encode a susceptibility DQαβ heterodimer. Disease association was found for the IL1RN (p = 0.04) and for the IL1RI (p = 0.03). When comparing controls and only familial cases with type 1 diabetes for the IL1RN polymorphism a difference was observed (p = 0.003). For the IL1B RFLP a trend for difference was observed between familial cases and control subjects (p = 0.046), whereas no differences between sporadic cases and control subjects could be demonstrated neither at the IL1B nor at the IL1RN loci. A difference in the MnSOD pattern was observed between sporadic cases and controls (p = 0.04).
    07/2009; 19(3):169-178.
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    ABSTRACT: Aims Whether pregnant women with Type 1 diabetes mellitus (Type 1 DM) have an increased risk of abortions is controversial. The aim of the present Danish population-based study of 33% of the Danish population was to describe the pattern of self-reported miscarriage and stillbirths from 1304 women with Type 1 DM.Methods Data were obtained by questionnaire. The current age of the women was 20–65 years and their age at diabetes onset was 30 years or less.Results The frequency of spontaneous abortions (SA) and induced abortions (IA) reported from women diagnosed with Type 1 DM prior to pregnancy was 17.5% (95% CI 15.5–19.9%) and 18.0%. (95% CI 16.0–20.0%), respectively. No significant differences in abortion frequencies before or after 1980 were reported. Previous findings of a decreasing stillbirth-rate in diabetic pregnancies during the last decades were supported.Conclusions The reported SA frequency of 17.5% (95% CI 15.5–19.9%) in pregnant women with Type 1 DM is higher than previously reported SA rates of 10–12% in Danish nondiabetic women and the SA rate is more than twice the SA rate found in a previous Danish study from a highly specialized obstetrical centre for diabetic women. These data suggest an urgent need for further improvement in the general management of Danish pregnant women with Type 1 DM.
    Diabetic Medicine 12/2001; 16(6):472 - 476. · 3.24 Impact Factor
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    ABSTRACT: The objective of the present study was to examine the prevalence of self-reported autoimmune diseases among offspring of type 1 fathers, type 1 diabetic mothers, and non-diabetic parents. Type 1 diabetic probands (n=265; mean age=42 yr), who were ascertained from the Children's Hospital of Pittsburgh Registry for 1950-1964, recently participated in the Familial Autoimmune and Diabetes Study. Non-diabetic probands (n=96), identified from voter registration lists and matched by age, race, median income, and duration of residence in the Pittsburgh area, were also enrolled. Offspring of type 1 diabetic probands were more likely to have a reported autoimmune disease (5.8% vs. 2.4%; p=0.067) than offspring of non-diabetic probands. Half the cases in the diabetic families were disorders other than type 1 diabetes, (e.g., rheumatoid arthritis, Crohn's disease, etc.). Stratification by parental gender revealed a marginally higher risk for type 1 diabetes among offspring of type 1 diabetic fathers compared to mothers (4.9% vs. 3.4%; p=0.38, respectively, through age 20 yr). However, the risk for other autoimmune disorders was statistically significantly increased among offspring of type 1 diabetic mothers (0% vs. 6.2%; p=0.02, respectively, through age 20 yr). These data suggest that offspring of type 1 diabetic parents may be at high risk of developing other autoimmune disorders during childhood, with pediatric diabetes representing the 'tip of an autoimmune iceberg'. The observed risk differences by parental gender, which have also been reported for other autoimmune disorders, warrant further investigation.
    Pediatric Diabetes 04/2000; 1(1):17-22. · 2.08 Impact Factor
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    ABSTRACT: Whether pregnant women with Type 1 diabetes mellitus (Type 1 DM) have an increased risk of abortions is controversial. The aim of the present Danish population-based study of 33% of the Danish population was to describe the pattern of self-reported miscarriage and stillbirths from 1304 women with Type 1 DM. Data were obtained by questionnaire. The current age of the women was 20-65 years and their age at diabetes onset was 30 years or less. The frequency of spontaneous abortions (SA) and induced abortions (IA) reported from women diagnosed with Type 1 DM prior to pregnancy was 17.5% (95% CI 15.5-19.9%) and 18.0%. (95% CI 16.0-20.0%), respectively. No significant differences in abortion frequencies before or after 1980 were reported. Previous findings of a decreasing stillbirth-rate in diabetic pregnancies during the last decades were supported. The reported SA frequency of 17.5% (95% CI 15.5-19.9%) in pregnant women with Type 1 DM is higher than previously reported SA rates of 10-12% in Danish nondiabetic women and the SA rate is more than twice the SA rate found in a previous Danish study from a highly specialized obstetrical centre for diabetic women. These data suggest an urgent need for further improvement in the general management of Danish pregnant women with Type 1 DM.
    Diabetic Medicine 07/1999; 16(6):472-6. · 3.24 Impact Factor
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    ABSTRACT: To assess the offspring IDDM recurrence risk in a Danish population-based study and to investigate parental and offspring related biological variables that might influence this risk, we identified 2726 IDDM probands and their 2826 offspring from a background population of 1.725 million people (33% of the Danish population). Proband current age was 20-60 years and age at IDDM onset was 30 years or less. Offspring data were obtained by a questionnaire. The cumulative IDDM risk up to age 30 years was found significantly decreased in maternal offspring compared to paternal offspring (2.3 +/- 0.6% and 5.7 +/- 0.9%, RR = 2.40, 95% CI 1.30-4.47; Mantel Cox: p = 0.004) only if parents were diagnosed with IDDM before offspring birth. However, due to a low number of diabetic offspring of probands diagnosed with IDDM after offspring birth, this observation need to be confirmed in a larger population. Using the Cox proportional hazards model we found that among several biological variables tested separately on offspring of male and female probands, all diagnosed with IDDM before pregnancy, paternal age at IDDM onset was the only statistically significant predictor of IDDM risk in offspring. Our findings may be important for counselling families in which one parent has IDDM.
    Ugeskrift for laeger 03/1999; 161(7):953-8.
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    ABSTRACT: It has previously been observed that offspring of mothers with insulin-dependent diabetes mellitus (IDDM) have a lower risk of IDDM than offspring of IDDM affected fathers. To assess the offspring IDDM recurrence risk in a Danish population-based study and to investigate parental and offspring-related biological variables that might influence this risk, we identified 2726 IDDM probands and their 2826 offspring from a background population of 1.725 million people (33% of the Danish population). Current age of probands was 20-65 years and their age at IDDM onset was 30 years or less. Sixty-nine offspring (2.4%) were affected with IDDM. The sex difference in the parental-offspring IDDM transmission rate was confirmed. The cumulative IDDM risk up to age 30 years was found to be significantly decreased in maternal offspring compared to paternal offspring (2.3 +/- 0.6 and 5.7 +/- 0.9 %, RR = 2.40, 95% CI 1.30-4.47; p = 0.004) only if parents were diagnosed with IDDM before birth of the offspring. However, due to the low number of diabetic offspring of probands diagnosed with IDDM after offspring birth, this observation needs to be confirmed in a larger population. In a subpopulation of the 2380 offspring, whose parents were all diagnosed with IDDM before offspring birth, the recurrence risk was significantly increased in offspring of male probands diagnosed up to age 17 years compared to offspring of fathers diagnosed at older ages (8.5 +/- 1.8 and 3.6 +/- 1.0%; RR = 2.27, 95% CI 1.21-4.25; p = 0.006). No such relation was found in maternal offspring. Using the Cox proportional hazards model on this offspring subpopulation we found that paternal age at IDDM onset was the only statistically significant predictor of IDDM recurrence risk. Our findings may be important for counselling families in which one parent has IDDM.
    Diabetologia 07/1998; 41(6):666-73. · 6.49 Impact Factor
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    ABSTRACT: A CA-repeat polymorphism within the first intron of the interferon (IFN)-gamma gene was analyzed. This polymorphism was recently demonstrated to be associated with insulin-dependent diabetes mellitus (IDDM) in Japanese subjects. We typed 266 IDDM patients and 195 control subjects of Danish Caucasoid origin. No significant differences in allele or genotype frequencies between patients and control were observed. In addition, we typed 168 IDDM and 110 control subjects of Finnish origin. A significant disease association of the studied IFN-gamma allelic pattern was found (p = 0.029). Analysis of data according to HLA-DQB1 susceptibility status did not reveal heterogeneity of risk at the IFN-gamma locus in either of the populations. Fifty-five Danish and 94 Finnish IDDM multiplex families with at least two affected siblings (660 individuals) were typed to test for transmission disequilibrium (TDT). No evidence for overall transmission disequilibrium using either an allele-wise (p = 0.42; combined data) or a genotype-wise analysis (p = 0.21; combined data) could be detected. Thus, the modest significance level observed in the Finnish case-control study and the failure to replicate it by the TDT provide little support for the hypothesis that the IFN-gamma gene microsatellite is associated with IDDM.
    Journal of Interferon & Cytokine Research 02/1997; 17(2):87-93. · 3.30 Impact Factor
  • Journal of Interferon and Cytokine Research - J INTERFERON CYTOKINE RES. 01/1997; 17(2):87-93.
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    ABSTRACT: Based on studies in spontaneously non-obese diabetic (NOD) mice, it has been suggested that the Mr 65,000 isoform of glutamic acid decarboxylase (GAD65) is of major importance in the pathogenesis of insulin-dependent diabetes mellitus (IDDM). In humans, antibodies to GAD65 are present before and at onset of the disease and in vitro T cell reactivity to GAD has also been reported. To further characterize the T cell recognition of GAD65, we incubated peripheral blood mononuclear cells from 45 newly diagnosed IDDM patients with purified recombinant human islet GAD65 and correlated the proliferative response with HLA DR haplotype and the presence of GAD65 autoantibodies. Fifty healthy individuals were studied as controls. Of the patients, 49% showed proliferative responses to GAD65 in contrast to only 4% of the controls. T cell proliferation to GAD65 was significantly more frequent in patients not being HLA DR3/4 heterozygous (19/29, 66%) as compared to HLA DR3/4 heterozygous patients (3/16, 19%) (p < 0.01). The difference was most pronounced in females with 64% (9/14) of the HLA non-DR3/4 patients being positive compared to none (0/6) of the HLA DR3/4 patients (p < 0.05). The overall frequency of GAD65 autoantibodies was 71% (32/45) with a similar distribution between patients with HLA DR3/4 (10/16, 63%) and HLA non-DR 3/4 (22/29, 76%). There was no correlation between levels of the T and B cell responses to GAD65 (r = 0.24). In conclusion, we find a proliferative T cell response to GAD65 in approximately 50% of recent onset IDDM patients and unexpectedly find the majority of responders to be HLA non-DR 3/4 heterozygous patients. No difference was observed in B cell responsiveness between the two HLA groups.
    Autoimmunity 01/1995; 22(3):183-9. · 2.77 Impact Factor
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    ABSTRACT: A model of the pathogenesis of insulin-dependent diabetes mellitus, i.e. the initial phase of beta-cell destruction, is proposed: in a cascade-like fashion efficient antigen presentation, unbalanced cytokine, secretion and poor beta-cell defence result in beta-cell destruction by toxic free radicals (O2- and nitric oxide) produced by the beta cells themselves. This entire process is under polygenetic control.
    Diabetologia 10/1994; 37 Suppl 2:S82-9. · 6.49 Impact Factor
  • T Lorenzen, F Pociot, P Hougaard, J Nerup
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    ABSTRACT: Due to a short observation period previous studies may have underestimated prevalence and recurrence risk of IDDM in relatives of IDDM patients. To obtain a more exact life-time risk estimate we identified 310 probands, representative of Danish IDDM patients, characterized by current age more than 50 years, age at onset 40 years or less and diabetes duration of more than 30 years. Family data were obtained from 291 probands. Mean "observation" times (age) (+/- SD) for siblings (n = 553) and offspring (n = 359) were 59.4 +/- 16.1 years and 33.8 +/- 8.8 years, respectively. Of the probands 73 (25.1%) had at least one first-degree relative with IDDM. Seventeen percent had at least one affected sibling. An increase from 10.4% to 22.4% of having first-degree relatives with IDDM among probands with age at onset below 20 years was observed during the period from proband at age 21 years up to 1 September 1992. Among affected siblings 48% of the second cases were affected more than 10 years after the first affected sibling. Using the life-table method cumulative recurrence risks from time of birth were calculated for siblings up to age 30 years of 6.4% and up to age 60 years of 9.6%. For offspring the risk up to age 34 years was 6.3%. In addition, we present a life-table method evaluating the cumulative recurrence risk from time of onset in the proband, as this is the most relevant when giving genetic counselling. In conclusion, the long-term risks of IDDM in siblings and offspring are high compared to that shown in previous reports.
    Diabetologia 04/1994; 37(3):321-7. · 6.49 Impact Factor
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    ABSTRACT: Fifty-five Danish families with two offspring concordant for type 1 diabetes--identified through a nationwide population-based survey, and 57 "true sporadic" cases--matched with familial cases for age at onset, but with no IDDM-affected first-degree relatives and long disease duration, and 110 control subjects were typed for putative genetic susceptibility markers for type 1 diabetes identified from a pathogenetic model. The markers included MHC class I, II and III loci, the manganese superoxide dismutase (MnSOD) locus (chr. 6q), interleukin-1 beta (IL1B), the IL-1 receptor antagonist (IL1RN), and the IL-1 type 1 receptor (IL1RI) loci (each chr. 2q). No significant differences between familial and sporadic cases were found within the MHC region (including the following loci: HLA-DQ, -DR, heat shock protein (HSP) 70, tumour necrosis factor (TNF), HLA-B and -A). In both groups of patients 11% were negative for both DQA1*0301-DQB1*0302 and DQA1*0501-DQB1*0201 genotypes, and 7% of the type 1 diabetics had genotypes unable to encode a susceptibility DQ alpha beta heterodimer. Disease association was found for the IL1RN (p = 0.04) and for the IL1RI (p = 0.03). When comparing controls and only familial cases with type 1 diabetes for the IL1RN polymorphism a difference was observed (p = 0.003). For the IL1B RFLP a trend for difference was observed between familial cases and control subjects (p = 0.046), whereas no differences between sporadic cases and control subjects could be demonstrated neither at the IL1B nor at the IL1RN loci. A difference in the MnSOD pattern was observed between sporadic cases and controls (p = 0.04).
    Autoimmunity 02/1994; 19(3):169-78. · 2.77 Impact Factor
  • F Pociot, T Lorenzen, J Nerup
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    ABSTRACT: Interleukin 1 (IL-1) is selectively cytotoxic to the insulin producing beta cell of pancreatic islets. This effect may be due to IL-1 induced generation of reactive oxygen species and nitric oxide. Since beta cells contain low amounts of the superoxide radical scavenger enzyme manganese superoxide dismutase (MnSOD), this may leave beta cells more susceptible to IL-1 than other cell types. Genetic variation in the MnSOD locus could reflect differences in scavenger potential. We, therefore, studied possible restriction fragment length polymorphisms (RFLPs) of this locus in patients with insulin-dependent diabetes mellitus (IDDM) (n = 154) and control individuals (n = 178). TaqI revealed a double diallelic RFLP in patients as well as in controls. No overall difference in allelic or genotype frequencies were observed between IDDM patients and control individuals (p = 0.11) and no significant association of any particular RFLP pattern with IDDM was found. Structurally polymorphic MnSOD protein variants with altered activities have been reported. If genetic variation results in MnSOD variants with reduced activities, the MnSOD locus may still be a candidate gene for IDDM susceptibility. Whether the RFLPs reported in this study reflects differences in gene expression level, protein level and/or specific activity of the protein is yet to be studied.
    Disease markers 01/1994; 11(5-6):267-74. · 2.14 Impact Factor
  • Ugeskrift for laeger 09/1983; 145(34):2573-5.
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    ABSTRACT: It has previously been observed that offspring of mothers with insulin-dependent diabetes mellitus (IDDM) have a lower risk of IDDM than offspring of IDDM affected fathers. To assess the offspring IDDM recurrence risk in a Danish population-based study and to investigate parental and offspring-related biological variables that might influence this risk, we identified 2726 IDDM probands and their 2826 offspring from a background population of 1.725 million people (33 % of the Danish population). Current age of probands was 20–65 years and their age at IDDM onset was 30 years or less. Sixty-nine offspring (2.4 %) were affected with IDDM. The sex difference in the parental-offspring IDDM transmission rate was confirmed. The cumulative IDDM risk up to age 30 years was found to be significantly decreased in maternal offspring compared to paternal offspring (2.3 ± 0.6 and 5.7 ± 0.9 %, RR = 2.40, 95 % CI 1.30–4.47; p = 0.004) only if parents were diagnosed with IDDM before birth of the offspring. However, due to the low number of diabetic offspring of probands diagnosed with IDDM after offspring birth, this observation needs to be confirmed in a larger population. In a subpopulation of the 2380 offspring, whose parents were all diagnosed with IDDM before offspring birth, the recurrence risk was significantly increased in offspring of male probands diagnosed up to age 17 years compared to offspring of fathers diagnosed at older ages (8.5 ± 1.8 and 3.6 ± 1.0 %; RR = 2.27, 95 % CI 1.21–4.25; p = 0.006). No such relation was found in maternal offspring. Using the Cox proportional hazards model on this offspring subpopulation we found that paternal age at IDDM onset was the only statistically significant predictor of IDDM recurrence risk. Our findings may be important for counselling families in which one parent has IDDM. [Diabetologia (1998) 41: 666–673]
    Diabetologia 41(6):666-673. · 6.49 Impact Factor