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Jakob Christensen

Publications and source records attributed to Jakob Christensen.

At least 19 recordsLinked to original sources
PubMed2026

Risk of neurodevelopmental disorders associated with paternal use of valproate during spermatogenesis: a living meta-analysis-version 1.

OBJECTIVE: To evaluate the association of paternal use of valproate during spermatogenesis compared with paternal use of lamotrigine or levetiracetam on offspring risk of neurodevelopmental disorders (NDDs). METHODS: Eligibility criteria: observational, peer-reviewed studies reporting neurodevelopmental outcomes of children exposed to paternal monotherapy use of valproate vs lamotrigine or levetiracetam during spermatogenesis. INFORMATION SOURCES: the databases PubMed, Embase, Cochrane Library and Web of Science were systematically searched from January 1995 to October 2025.Synthesis of results and risk of bias: a random-effects model was used to estimate pooled HRs and 95% CI, with heterogeneity assessed using I2 statistic for any NDD.We present a meta-analysis of observational, peer-reviewed studies reporting neurodevelopmental outcomes of children exposed to paternal monotherapy use of valproate versus lamotrigine or levetiracetam during spermatogenesis. Given the major regulatory implications of paternal valproate safety, the recent emergence of new population-based data, and the expectation of further large studies, we designed this work as a living systematic review and meta-analysis that will be updated as new eligible evidence becomes available. RESULTS: We identified three eligible studies based on data from (1) Norway and Sweden, (2) Norway and Taiwan and (3) Denmark. As two studies included Norwegian data, their results are referred to as 'Norway 1' and 'Norway 2' for clarity. In the meta-analysis of data from Denmark, Sweden and Norway 1, the pooled HR of offspring NDDs was 1.05 (95% CI 0.87 to 1.27; I2=0.0%), and in meta-analysis of data from Denmark, Sweden and Norway 2, it was 1.03 (95% CI 0.85 to 1.24; I2=0.0%).In the meta-analysis including Taiwan, Denmark, Sweden and Norway 1, the pooled HR was 1.06 (95% CI 0.88 to 1.27; I2=0.0%), and when including data from Taiwan, Denmark, Sweden and Norway 2, the pooled HR was 1.04 (95% CI 0.87 to 1.25; I2=0.0%). CONCLUSIONS: In this living meta-analysis, we found no evidence that paternal exposure to valproate compared with lamotrigine/levetiracetam during spermatogenesis was associated with increased risk of NDDs in offspring.

Humans↗
PubMed2007

Use of phenytoin, phenobarbital, or diazepam during pregnancy and risk of congenital abnormalities: a case-time-control study.

PURPOSE: Case-control studies are often used to examine putative teratogenic drug effects during organogenesis but these studies are subject to confounding by indication, recall, and participation bias. The case-time-control approach is less susceptible to these sources of bias. We studied congenital abnormalities following exposure to phenytoin, phenobarbital, and diazepam in early pregnancy, i.e., second and third month, compared to mid-pregnancy, i.e., fifth and sixth month of pregnancy. METHODS: We analyzed data from the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1996) in a case-time-control study. RESULTS: The study included 22 843 children with congenital abnormalities (cases) and 38 151 children with no abnormalities (controls). Overall, odds ratio (OR) for congenital abnormalities after exposure to one of the three drugs in early pregnancy was 1.2 (95% confidence interval (CI): 1.0-1.4). Among children exposed to phenytoin OR for congenital abnormalities was 3.7 (95%CI: 0.3-49.6), for children exposed to phenobarbital the OR was 1.1 (95%CI 0.7-1.7), and for diazepam, OR for congenital abnormalities was 1.2 (95%CI: 1.0-1.4). CONCLUSIONS: The associations we found between the drugs examined and congenital abnormalities were either only borderline significant or not statistically significant. The case-time-control study provides an interesting way of using existing case-control data to study rare side effect of drugs taken during pregnancy.

Abnormalities, Drug-Induced↗
PubMed2006

Epilepsy and febrile seizures in children of treated and untreated subfertile couples.

BACKGROUND: Only few studies have addressed the long-term neurological outcomes of children born by subfertile couples. We studied the risk of epilepsy and febrile seizures in children of treated and untreated subfertile couples. METHODS: The study included 83 194 live singletons born by mothers who took part in the Danish National Birth Cohort (DNBC). Information on time to pregnancy (TTP) and infertility treatment was reported by the mothers in computer-assisted telephone interviews. Data on epilepsy and febrile seizures were extracted from the Danish National Hospital Register. RESULTS: Overall, children of subfertile couples (TTP > 12 months) had a 51% higher risk of epilepsy [incidence rate ratio (IRR): 1.51; 95% confidence interval (95% CI): 1.17-1.94] compared with children of couples with a TTP of 0-5 months. The corresponding estimates were 1.71 (95% CI: 1.21-2.42) if the couples had received infertility treatment and 1.38 (95% CI: 1.00-1.89) if they conceived spontaneously. Children of subfertile couples did not have a higher risk of febrile seizures except for those who received hormonal treatment (HT) with or without intrauterine insemination (IRR = 1.37; 95% CI: 1.14-1.66). CONCLUSIONS: Children of subfertile couples had a slightly increased risk of epilepsy, and the risk tended to be higher for children of couples who received infertility treatment. Whether this reflects side effects of treatment or severity of subfecundity is not known.

Child↗
PubMed2006

[Danish clinical guidelines for epilepsy].

Danish clinical guidelines provide evidence-based recommendations for the diagnosis, treatment and care of patients with epilepsy. Clinical problems are evaluated by conducting a systematic search for literature followed by critical reading and methodological assessment of the literature found. Recommendations are made based on the evidence. Some of the important recommendations are as follows: A detailed history taken from the individual and an eyewitness is the most important tool in the diagnosis of epilepsy. EEG should be performed to aid diagnosis and classification of suspected epilepsy. MRI should be used to identify structural abnormalities in focal epilepsy unless there is clear evidence of benign focal epilepsy. The choice of antiepileptic drug depends on the type of epilepsy and the tolerability profile of the drug. Newer antiepileptic drugs are in general better tolerated than older drugs, but not more effective. In the case of diagnostic uncertainty or uncontrolled seizures, the patient should be referred to a more specialised department in a timely manner. The specialist service should include a multidisciplinary team. Epilepsy surgery should be considered early in patients with refractory focal epilepsy.

Adult↗
PubMed2006

Apgar scores and long-term risk of epilepsy.

BACKGROUND: Low Apgar scores are associated with high risk of neonatal death, cerebral palsy, and mental retardation, but the association between Apgar scores and long-term risk of epilepsy remains unresolved. METHODS: We carried out a population-based cohort study of 1,538,732 live newborns in Denmark between 1 January 1978 and 31 December 2002 by using national registers. The Apgar scores at 1 or 5 minutes were recorded by midwives following standardized procedures. We obtained information on epilepsy by linking the cohort with the National Hospital Register. Cohort members were followed from birth until onset of epilepsy, death, emigration, or 31 December 2002, whichever came first. RESULTS: The incidence rate of epilepsy increased consistently with decreasing Apgar scores. The incidence rate of epilepsy was 628 per 100,000 person-years for those with 5-minute Apgar scores of 1 to 3 and 86 per 100,000 person-years for those with a score of 10; the resulting incidence rate ratio was 7.1 (95% confidence interval = 5.8-8.8). The incidence rate ratios of epilepsy associated with low Apgar scores were particularly high in early childhood but remained high into adulthood. The association did not change after excluding children with cerebral palsy, congenital malformations, or a parental history of epilepsy. CONCLUSIONS: Neonates with a suboptimal Apgar score have a higher risk of epilepsy that lasts into adult life. These findings suggest that prenatal or perinatal factors play a larger role in the etiology of epilepsy than has previously been recognized.

Adult↗
PubMed2005

The Danish National Hospital Register is a valuable study base for epidemiologic research in febrile seizures.

BACKGROUND AND OBJECTIVES: We examined the quality and completeness of the discharge diagnosis of febrile seizures in the Danish National Hospital Register (DNHR). METHODS: We invited all children born at the Department of Obstetrics, Aarhus University Hospital, Denmark, between January 1990 and April 1992, to participate in the study. We collected information on febrile seizures in March 2001 by mailing a questionnaire to the mothers. Reported febrile seizures were verified by telephone interviews or review of medical records. We linked the cohort to the DNHR by means of a unique civil registry number assigned to all Danish citizens at birth. Overall, 6,624 (73%) children participated in the study. RESULTS: We found that 323 (4.9%) children in the cohort had had febrile seizures, and 231 of those were registered in the DNHR (completeness: 71.5%, 95% CI: 66.3-76.4). Furthermore, we confirmed the diagnosis in 231 of 249 children registered with febrile seizures in the DNHR (predictive value of a positive registration: 92.8%, 95% CI: 88.8-95.7). CONCLUSION: The Danish National Hospital Register is a valuable tool for epidemiologic research in febrile seizures.

Child↗
PubMed2005

Chemometric exploration of an amperometric biosensor array for fast determination of wastewater quality.

Four wastewater samples of different treatment qualities; untreated, alarm, alert and normal, from a Swedish chemi-thermo-mechanical pulp mill and pure water were investigated using an amperometric bio-electronic tongue in a batch cell. The aim was to explore enzymatically modified screen-printed amperometric sensors for the discrimination of wastewater quality and to counteract the inherent drift. Seven out of eight platinum electrodes on the array were modified with four different enzymes; tyrosinase, horseradish peroxidase, acetyl cholinesterase and butyryl cholinesterase. At a constant potential the current intensity on each sensor was measured for 200s, 100s before injection and 100s after injection of the sample. The dynamic biosensor response curves from the eight sensors were used for principal component analysis (PCA). A simple baseline and sensitivity correction equivalent to multiplicative drift correction (MDC), using steady state intensities of reference sample (catechol) recordings, was employed. A clear pattern emerged in perfect agreement with prior knowledge of the samples explaining 97% of the variation in the data by two principal components (PCs). The first PC described the treatment quality of the samples and the second PC described the difference between treated and untreated samples. Horseradish peroxidase and pure platinum sensors were found to be the determinant sensors, while the rest did not contribute much to the discrimination. The wastewater samples were characterized by the chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC), inhibition of nitrification, inhibition of respiration and toxicity towards Vibrio fischeri using Microtox, the freshwater alga Pseudokirchneriella subcapita and the freshwater crustacean Daphnia magna.

Algorithms↗
PubMed2005

Febrile seizures and risk of schizophrenia.

BACKGROUND: Febrile seizure is a benign condition for most children, but experiments in animals and neuroimaging studies in humans suggest that some febrile seizures may damage the hippocampus, a brain area of possible importance in schizophrenia. METHODS: A population-based cohort of all children born in Denmark between January 1977 and December 1986 was followed until December 2001 by using data from nationwide registries. RESULTS: We followed 558,958 persons including 16,429 with a history of febrile seizures for 2.8 million person-years and identified 952 persons who were diagnosed with schizophrenia. A history of febrile seizures was associated with a 44% increased risk of schizophrenia [relative risk (RR)=1.44; 95% confidence interval (CI), 1.07-1.95] after adjusting for confounding factors. The association between febrile seizures and schizophrenia remained virtually unchanged when restricting the analyses to people with no history of epilepsy. A history of both febrile seizures and epilepsy was associated with a 204% increased risk of schizophrenia (RR=3.04; 95% CI, 1.36-6.79) as compared with people with no such history. CONCLUSIONS: We found a slightly increased risk of schizophrenia among persons with a history of febrile seizures. The association may be due to a damaging effect of prolonged febrile seizures on the developing brain, shared etiological factors, or confounding by unmeasured factors.

Child↗
PubMed2005

Gender differences in epilepsy.

PURPOSE: The aim of this study was to look at gender differences in unselected populations of patients with epilepsy classified according to the 1989 International League Against Epilepsy (ILAE) criteria. METHODS: Data were obtained from two sources: (a) the EpiBase database at the outpatient clinic at the Department of Neurology, Aarhus University Hospital, Denmark, confined to adults with epilepsy (n=2,170), and (b) the Danish Twin Registry (n=318). RESULTS: In localization-related epilepsy, no overall gender difference was found in either the EpiBase population (n=1,511; w=750 (50%), m=761 (50%); p=0.80) or in the twin population (n=172; w=86 (50%), m=86 (50%); p=1.00). However, in the EpiBase population, localization-related symptomatic epilepsies were more frequent in men (n=939; w=426 (45%), m=513 (55%); p=0.005); and cryptogenic localization-related epilepsies were more frequent in women (n=572; w=324 (57%), m=248 (43%); p=0.002). In generalized epilepsy, more women than men were diagnosed in both populations [EpiBase: n=480, w=280 (58%), m=200 (42%); p<0.001; twin population: n=105, w=63 (60%), m=42 (40%); p=0.05]. The difference was confined to idiopathic generalized epilepsy [EpiBase: n=437, w=259 (59%), m=178 (41%); p<0.001; twin population: n=94, w=60 (64%), m=34 (36%); p=0.01]. CONCLUSIONS: More women than men were diagnosed with idiopathic generalized epilepsy in two epilepsy populations. Overall, no gender difference was found in localization-related epilepsy, but localization-related symptomatic epilepsies were more frequent in men, and cryptogenic localization-related epilepsies were more frequent in women The results suggest a gender susceptibility to the development of specific epilepsy subtypes.

Adolescent↗
PubMed2005

Comparison of methods for assessing reverse osmosis membrane treatment of shrimp process water.

Interest in reuse of process water from the food industry has reinforced the importance of controlling and monitoring the effectiveness and reliability of treatment systems regarding removal of organic matter and microorganisms. The ability of adenosine triphosphate bioluminescence, conductivity, turbidometry, absorbance, and multichannel fluorescence spectroscopy for indirectly monitoring the integrity of a reverse osmosis membrane when treating process water recovered from peeling in a shrimp processing line was evaluated. This study demonstrated that reverse osmosis was capable of removing bacteria (ca. 7 log CFU ml(-1)) to the levels required by the regulatory authorities for water recycling within the same food unit operation. Adenosine triphosphate and turbidometry showed a higher sensitivity for detecting compromising conditions at the treatment system (0.1% concentration of feed in permeate) and a better correlation with the aerobic count at lower levels than the other methods investigated. The sensitivity for assessing membrane integrity of conductivity and multichannel fluorescence was 1% of feed in permeate. Impact of feed variations was best leveled out in the permeates for turbidity measurements. Multichannel fluorescence spectroscopy may require laborious calibration procedures and expertise regarding data analysis and interpretation of results, which are not always available in food industries. Absorbance did not respond to changes in membrane integrity and was not well correlated to the aerobic count because of the poor sensitivity of this method for these purposes.

Animals↗
PubMed2004

Multivariate analysis to separate the signal given by cross-reactants in immunoassay with sample matrix dilution.

This paper describes a new approach to achieve selectivity in an immunoassay by separating the signals given by two cross-reactive compounds present simultaneously in a complex sample matrix. The method is based on the sequential dilution of the sample containing a mixture of the two analytes, spiking each diluted sample with a reference compound, and the detection by enzyme-linked immunosorbent assay (ELISA). The obtained multivariate response was used for the individual calibrations of the assay for each of the two cross-reactants simultaneously by using principal component analysis (PCA) and partial least squares regression (PLSR) data modeling. The calibration models showed that the signal separation due the analytes 2,4-dinitrophenol (2,4-DNP) and 4-nitrophenol (4-NP) was possible with a prediction concentration error of 1.4 microM and 72 microM, respectively.

2,4-Dinitrophenol↗
PubMed2003

Randomized, concentration-controlled trial of topiramate in refractory focal epilepsy.

OBJECTIVE: To establish the concentration response of topiramate in patients with refractory focal epilepsy. METHODS: Sixty-five patients with more than eight seizures during an 8-week baseline were randomized to three prespecified plasma levels (low, 6 micromol/L [2 mg/L]; medium, 31 micromol/L [10.5 mg/L]; and high, 56 micromol/L [19 mg/L]). Topiramate treatment was titrated to one of the prespecified plasma levels during an 8-week titration period, followed by a 12-week observation period. RESULTS: The overall median (25th to 75th percentile) reduction in seizures during the observation compared with baseline was 50% (9.5 to 90%). In the individual groups, the median reduction was as follows: low, 39% (13 to 70%); medium, 85% (41 to 96%); and high, 39% (2.0 to 81%). The primary outcome of the trial was the comparison of seizure reduction (Mann-Whitney U test) between the low and the medium group (p = 0.03). Comparisons between the other groups were as follows: medium vs high (p = 0.05) and low vs high (p = 0.81). Psychiatric adverse events and adverse events related to the CNS were the most frequently encountered. Most adverse events showed concentration response, particularly between low and medium levels. CONCLUSIONS: Patients assigned to the medium plasma level (31 micromol/L [10.5 mg/L]) had the best seizure outcome. Patients in the medium and high groups experienced more adverse events than patients in the low group. Optimal treatment response is thus most likely found at plasma concentrations higher than 6 micromol/L (2 mg/L), but no further increase in efficacy seems to occur at concentrations above 31 micromol/L (10.5 mg/L).

Adult↗
PubMed2003

Oral contraceptives reduce lamotrigine plasma levels.

The mean steady-state plasma concentration of lamotrigine (LTG) was 13 micro mol/L in 22 women taking LTG in combination oral contraceptives (OC) compared with 28 micro mol/L among 30 women on LTG who did not take OC (p < 0.0001). The LTG dose/body weight/plasma concentration was 2.1 L/kg/day in women on OC compared with 0.8 L/kg/day in women without OC (p < 0.0001), indicating that LTG plasma levels are reduced by >50% during OC co-medication. It is advisable to monitor LTG plasma levels in conjunction with initiation or withdrawal of OC in women on LTG therapy.

Adolescent↗
PubMed2003

Monitoring chemical changes of dry-cured Parma ham during processing by surface autofluorescence spectroscopy.

Parma hams at various processing stages were investigated by surface autofluorescence spectroscopy. Fluorescence "landscapes" of raw meat and salted (3 months), matured (11 and 12 months), and aged (15 and 18 months) Parma hams were obtained, and a three-dimensional data array (sample x emission x excitation) was used to develop a PARAFAC model including five components, which all exhibited characteristics of pure fluorophores regarding both excitation and emission spectra. The relative amount of each component related strongly to the processing stage, and sample age showed good correlation to fluorescence data (R = 0.98), with a relative error of prediction of approximately 1 month. Fluorescence measurements from samples of either semimembranosus or biceps femoris were used to predict chemical or sensory reference data, yielding good correlation for biceps femoris data, thereby enabling moisture content, sensory and instrumental color, and proteolysis value to be fairly well predicted. Overall, surface autofluorescence of Parma hams proved to hold relevant information, relating to major chemical/physical changes during processing. It is concluded that fluorescence spectroscopy has potential as an innovative method of quality control in dry-cured ham.

Animals↗