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Biomedical subjects

K Källén

Publications and source records attributed to K Källén.

At least 19 recordsLinked to original sources
PubMed2006

Impact and risk factors for early-onset group B streptococcal morbidity: analysis of a national, population-based cohort in Sweden 1997-2001.

OBJECTIVES: To study early-onset group B streptococcal (EOGBS) morbidity, mortality, and maternal risk factors. DESIGN: Observational, population-based, retrospective. Data from national registers and medical records. SETTING: Sweden, 1997-2001. POPULATION: Cohort of 640 infants with a diagnosis of GBS infection out of 435 070 live births. METHOD: Infants with diagnoses GBS sepsis (P36.0) and/or pneumonia (P23.3) were analysed. In cases with P36.0, register data were validated against infant and maternal medical records. Odds ratios (OR) were estimated by multiple logistic regression. MAIN OUTCOME MEASURES: Incidence of EOGBS morbidity, mortality, frequency of maternal risk factors and administration of intrapartum antibiotics. RESULTS: There were 319 cases with EOGBS sepsis. Blood culture verified 174 cases. There were 145 with clinical sepsis and 180 with pneumonia only. The incidences were 0.40, 0.33, and 0.41 per 1000 live births, respectively. The mortality was 7.5, 0.7, and 2.2% in respective groups. The frequencies of established maternal risk factors were: membrane rupture > or =18 hours, 44%; prematurity, 26%; temperature during labour > or =38 degrees C, 22%. Novel maternal risk factors identified in verified cases were gestational age (GA) of 37 completed weeks (OR 3.5, 1.8-6.5) and gestational diabetes (OR 3.7, 1.8-8.5). When including clinical sepsis, also epidural anaesthesia, infant large for GA, postmaturity, and high maternal age were significant risk factors. CONCLUSION: The incidence of verified EOGBS disease was 0.4 per 1000 live births with a total burden of EOGBS morbidity approximately three times higher. GA of 37 completed weeks and gestational diabetes were identified as additional significant risk factors.

Adult↗
PubMed2005

Implementation of new medical techniques: experience from the Swedish randomized controlled trial on fetal ECG during labor.

BACKGROUND: In a large Swedish multicenter randomized controlled trial (RCT) on intra partum fetal monitoring with automatic analysis of fetal ECG waveform (STAN) in combination with cardiotocography (CTG) (4966 parturients, 300 obstetricians and midwives managing the patients), interim analysis revealed protocol violations. By a post hoc analysis of the results over time, factors affecting the acceptance of the new technique were analyzed. METHODS: The rates of primary and secondary outcome measures (fetal outcome, operative deliveries) were compared in the two study groups (CTG + ST and CTG only). Changes over time were statistically evaluated using a test for homogeneity between the two periods. RESULTS: After retraining, the CTG + ST group showed the lowest rates of operative delivery for fetal distress, fetal blood sampling and admissions to neonatal intensive care unit. Operative deliveries (p = 0.02) and the number of fetal blood sampling decreased significantly over time (p = 0.001). CONCLUSIONS: Training and education probably predisposed the clinicians to a change and reinforced it when it occurred as a result of increased personal experience. The audit and feedback together with the influence of opinion leaders and inter-collegial interactions seem to have been of importance for the successively increasing acceptance of the new method during the RCT.

Cardiotocography↗
PubMed2004

Increased risk of perinatal/neonatal death in infants who were smaller than expected at ultrasound fetometry in early pregnancy.

OBJECTIVES: To investigate if there is an association between perinatal/neonatal death and a discrepancy between gestational age by ultrasound fetometry in early pregnancy (GA(U)) and gestational age by last menstrual period (GA(LMP)), and to investigate possible causes for such an association. METHODS: The Swedish Medical Birth Registry was used to identify singleton pregnancies with information available on GA(LMP) and GA(U) that were delivered in Sweden between 1990 and 2000. A total of 718 011 pregnancies was included and information on the pregnancy and delivery was obtained from the National Board of Health. RESULTS: Infants with a GA(U) at least 7 days less than the GA(LMP) were at increased risk for stillbirth (odds ratio (OR), 1.45; 95% CI, 1.32-1.58), neonatal death within 1 month (OR, 1.87; 95% CI, 1.67-2.09), Apgar score < 7 at 5 min (OR, 1.18; 95% CI, 1.11-1.24), birth weight < 2500 g (OR, 1.48; 95% CI, 1.43-1.52), and preterm birth < 37 weeks (OR, 1.45; 95% CI, 1.42-1.49). The association between a postponed expected date of delivery and perinatal/neonatal death increased with gestational length and was especially pronounced among infants who were born after at least 40 completed weeks of pregnancy (GA(U)). CONCLUSIONS: A discrepancy between GA(U) and GA(LMP) may indicate early disturbances in fetal/placental development. Furthermore, it can be speculated that, as the risk significantly increased with gestational duration, at least a part of the increased risk for poor pregnancy outcome in adjusted pregnancies was due to consequences of true post-term pregnancies not being recognized as such.

Apgar Score↗
PubMed2004

Ictal SPECT in clinical perisylvian syndrome.

In the congenital bilateral perisylvian syndrome, pseudobulbar symptoms, cognitive deficits and cortical malformations in the perisylvian region are typical features. We report two initially magnetic resonance imaging (MRI) negative patients from our epilepsy surgery program that shared the same seizure and ictal SPECT characteristics suggesting seizure onset localized in the perisylvian region. In one patient, reevaluation revealed perisylvian cortical malformation on MRI while in the other patient MRI was normal. In these patients, subtraction ictal SPECT coregistered with MRI (SISCOM) proved useful together with clinical data in diagnosing the patients with mild forms of perisylvian syndrome.

Adult↗
PubMed2003

Skewed fetal gender distribution in prolonged pregnancy: a fallacy with consequences.

OBJECTIVE: Skewed gender distribution and falsely assigned gestational age lead to unnecessary or late obstetric intervention in prolonged pregnancy. The aim of this study was to examine the consequences of a fetal gender-dependent systematic 1.5-day dating error at ultrasound fetometry. MATERIAL AND METHODS: A total of 82 484 singleton deliveries >/=37 weeks at 11 hospitals in southern Sweden from 1995 to 2000 were included. Frequencies of labor induction and Apgar scores <7 at 5 min were compared with regard to fetal gender, both before and after correction of gestational age by adding 0.75 days to female-fetus pregnancies and subtracting 0.75 days from male-fetus pregnancies. RESULTS: The uncorrected odds ratio for having a male baby at >/=42 weeks was 1.41 (95% confidence interval, 1.33-1.49). After adjusting gestational age by +/-0.75 days, the odds ratio reduced to 0.90 (95% confidence interval, 0.84-0.95). The risk for labor induction was significantly above unity in male-fetus pregnancies delivered after 41 weeks when gestational age was corrected for fetal gender, while the risk for female fetuses having a low Apgar score was not significantly increased compared to male fetuses (P = 0.087). CONCLUSION: Skewed gender distribution in prolonged pregnancy results in a higher rate of labor induction in pregnancies with male fetuses at >/=41 weeks, and the risk for newborn females having a low Apgar score in prolonged pregnancy is not significantly increased compared to boys.

Diagnostic Errors↗
PubMed2003

Caesarean section increases the risk of hospital care in childhood for asthma and gastroenteritis.

OBJECTIVE: To investigate if caesarean section (CS) increases the risk for childhood asthma and gastroenteritis with reference made to children born with vaginal delivery (VD). METHODS: Retrospective study of data from linked Swedish medical service registers--Medical Birth Registry (MBR) and Hospital Discharge Registry (HDR). Data were obtained from women without any background/perinatal morbidity noted, and from children without any neonatal complications. Children that had reached at least 1 year of age and were found in the HDR were considered as cases, whereas children not found in the HDR or hospitalized for other causes than asthma or gastroenteritis were defined as controls. Odds ratios (OR) stratified for year of birth, maternal age, parity and smoking in early pregnancy were calculated. Investigations were made comparing the risk for in hospital treatment for asthma or gastroenteritis in CS children and in VD siblings of CS children. The overall inpatient morbidity in CS and VD children were also investigated. RESULTS: The OR for asthma in CS children was 1.31 [95% confidence interval (CI) 1.23-1.40]. The same OR, 1.31, was found for gastroenteritis (95% CI 1.24-1.38). The OR for CS children having experienced both asthma and gastroenteritis was further increased (1.74, 95% CI 1.36-2.23). The risk for asthma in VD siblings of CS children was not significantly increased, whereas VD siblings experienced a slightly increased risk for gastroenteritis. CS children had an increased overall in hospital morbidity when compared to VD children. CONCLUSION: There is a significant increase of the risk for developing symptoms of asthma and/or gastroenteritis that motivates admission for hospital care in CS children older than 1 year. It is speculated that a disturbed intestinal colonization pattern in CS children may be a common pathogenic factor.

Adult↗
PubMed2002

Mid-trimester ultrasound prediction of gestational age: advantages and systematic errors.

OBJECTIVE: To detect possible sources of bias in ultrasound prediction of gestational age. SUBJECTS AND METHODS: Using the Swedish Medical Birth Registry, 571 617 women were identified who were delivered between 1990 and 1997 and who had obtainable information on last menstrual period and expected date of delivery according to ultrasound. RESULTS: Male fetuses were more likely than females to be judged older than the last menstrual period date suggested at early fetometry. The estimated magnitude of the systematic error by infant gender corresponded to 1.5 days. Similarly, the fetuses of young women, multiparous women, smokers and women with low educational level were at increased risk of being smaller than expected at ultrasound examination in early pregnancy. A strong association was seen between adjustments of expected date of delivery -7 days or more and small-for-gestational age according to ultrasound at birth. Compared to singleton pregnancies, twin pregnancies were more likely to be judged more progressed at ultrasound fetometry than the last menstrual period date suggested. CONCLUSIONS: Compared to last menstrual period estimates, routine ultrasound measurements to predict date of delivery are comparatively reliable but systematic errors are inherent in the method. The erroneous adjusted dates may be due to incorrect measurements or systematic bias (e.g. gender), but they are also likely to reflect early growth restriction (e.g. in the case of maternal smoking and small-for-gestational age). Further studies are needed to investigate whether the systematic errors in ultrasound prediction of gestational age could lead to suboptimal obstetric management in adjusted pregnancies.

Adolescent↗
PubMed2001

VATER non-random association of congenital malformations: study based on data from four malformation registers.

This study was undertaken to find a strict, unbiased epidemiological delineation of the VATER non-random association of congenital malformations and, based on registry information, to identify a group of probable VATER association infants suitable for etiological analyses. Information on 5,260 infants with multiple malformations was collected from four large registers of congenital malformations. Data were analyzed using a statistical method in which various putative confounders were controlled for. Our results indicate the existence of a distinct group of malformations corresponding to the VATER association: esophageal atresia, anal atresia, upper preaxial limb reduction defects, and costo-vertebral malformations. A subdivision into an upper and a lower group of VATER association was indicated, with heart malformations associated with the upper group and kidney malformations associated with the lower group. Restricting the inclusion criteria for VATER association to the above mentioned core malformations, few infants seem to belong to the VATER association, thus limiting the possibilities of carrying out etiological analyses. A relatively large number of infants may belong to a family of related conditions among which VATER association is a subgroup. In the search for risk factors, a strict definition of the VATER association is needed in order to not dilute the study material with irrelevant cases. The present study provides such strict inclusion criteria.

Abnormalities, Multiple↗
PubMed2001

The impact of maternal smoking during pregnancy on delivery outcome.

BACKGROUND: Maternal smoking during pregnancy is associated with pre-term birth, intrauterine growth retardation, a small head circumference, a low Apgar score at 5 min and stillbirths and neonatal deaths. This study was undertaken in order to investigate the impact of maternal smoking during pregnancy when all these outcomes were considered. METHODS: With the use of the Swedish Medical Birth Registry, infants in any one of the above mentioned outcome groups were selected from 1,413,811 infants born between 1983 and 1996 with known smoking exposure in early pregnancy. Confounders such as year of birth, maternal age, parity and educational level were controlled for. The attributable risk of maternal smoking on the various negative delivery outcomes was obtained by application of the risk estimates to population counts. RESULTS: The present study confirmed the associations between maternal smoking and the miscellaneous outcomes mentioned above with high significance. The odds ratios (with 95% confidence intervals) for maternal smoking (< 10 cigarettes/day and > or = 10 cigarettes/day) for any one of the outcomes were 1.39 (1.37-1.41) and 1.65 (1.62-1.68) respectively (dose-response p < 0.001). The number of attributable cases caused by maternal smoking was estimated at 15,000, which represents 9% of all cases and 1% of all infants born in Sweden during the study period. CONCLUSION: Maternal smoking during pregnancy accounts for a substantial part of various negative delivery outcomes.

Adult↗
PubMed2000

OEIS complex--a population study.

Using a novel method for the analysis of infants with multiple malformations, we investigated the cluster of associated malformations called the OEIS (omphalocele, bladder exstrophy, imperforate anus, spine defect) complex among 5,260 infants with multiple malformations identified in four large registers of congenital malformations, corresponding to 5.84 million births. The existence of the OEIS complex was clearly demonstrated and malformations entering it could be defined. Other than the four classical malformations, omphalocele, bladder exstrophy, imperforate anus, and spine malformation, a strong association with spina bifida and intersex was stressed. Spine malformations occurred not only in the lumbosacral level but also more cranially, and an association also with upper spina bifida could be demonstrated. No specific association with any other malformation, including cardiac defects, was apparent. The OEIS complex is an unusually clearly defined entity among the various nonrandom associations which have been described.

Abnormalities, Multiple↗
PubMed2000

Maternal smoking during pregnancy and infant head circumference at birth.

Using the Swedish Medical Birth Registry, information on 1,362,169 infants born during 1983-1996 was analyzed in order to investigate the relation between maternal smoking during pregnancy and infant head circumference at birth. Infants of smoking mothers were at an increased risk to have head circumference <32 cm, and the adjusted odds ratios (OR) with 95% confidence intervals (CI) for any smoking, smoking <10 cigarettes per day, and smoking >/=10 cigarettes per day were: 1.65 (1.62-1.68), 1.52 (1.48-1.56), and 1.86 (1.81-1.92), respectively. A highly significant association between small head circumference for gestational age and maternal smoking was also found (ORs (with 95% CI) were for any smoking, <10, and >/=10: 1.58 (1.55-1.61), 1.48 (1.45-1.51), and 1.74 (1.70-1.79), respectively). For both outcomes, the observed dose-response effects were highly significant (P<10(-6)). Even more alarming was the finding that given a certain level of growth retardation, infants of smoking mothers were at an increased risk of small head circumference for gestational age compared to infants of non-smoking mothers (OR (with 95% CI) for any smoking adjusted for 'percentage of expected birth weight': 1.08 (1.06-1.10)). Given the evidence that maternal smoking specifically affects head growth, until contradictory evidence has been found, it seems reasonable to assume that maternal smoking during pregnancy affects brain development negatively.

Birth Weight↗
PubMed2000

Multiple malformations and maternal smoking.

The Swedish health registries were used to investigate a possible effect of maternal smoking on the incidence of multiple malformations. Among 1413811 infants born in 1983-96 and with known smoking exposure in early pregnancy, 26619 with isolated malformations and 1409 with two or more malformations were selected. After controlling for year of birth, maternal age, parity and educational level, a statistically significant association between maternal smoking and multiple malformations was found (OR 1.15; 95% CI 1.02, 1.29). Among isolated malformations, the estimated OR for maternal smoking was close to unity (OR 1.02; 95% CI 0.99, 1.05), but a strong heterogeneity of the magnitude of the association between maternal smoking and the different malformations was found. Among multimalformed, no such heterogeneity was indicated. The ORs for maternal smoking were calculated for all possible pairwise combinations of 44 selected malformations, but no association between maternal smoking and any specific combination could be detected. The ORs for maternal smoking among probable cases of VATER, CHARGE or OEIS non-random associations, respectively, were estimated, but no association was indicated between maternal smoking and any of the malformation complexes. The results of the present study indicate that maternal smoking is associated with a non-specific increased risk of multiple malformations, but further research is needed before such an inference can be made.

Confidence Intervals↗
PubMed2000

Quantitative 201Tl SPET imaging in the follow-up of treatment for brain tumour: a sensitive tool for the early identification of response to chemotherapy?

The aim of this study was to establish if repeated quantitative 201Tl SPET scanning during follow-up of astrocytoma therapy can provide information that is relevant for clinical management. Sixteen consecutive patients, with histopathologically verified highly malignant astrocytoma, were followed during PCV chemotherapy. Imaging with 201Tl SPET and CT was performed repeatedly over 8-16 weeks until treatment discontinuation, with a maximum follow-up of 74 weeks. Tumour uptake volume (TUV), a measure of metabolically active tumour tissue, was calculated from the SPET images. The reliability of early identification of treatment failure, defined as > 25% tumour volume increase, following one course (week 8) and three courses (week 24) of chemotherapy, was calculated for the two imaging methods. 201Tl SPET positive patients (> 25% tumour volume increase) were compared with 201Tl SPET negative patients in terms of time to treatment discontinuation (TTD) and survival time (ST). The patients were followed with a total of 59 SPET examinations, and treatment was continued for a median 27 weeks (range 16-78 weeks). The comparative reliability of SPET and CT showed the highest sensitivity and accuracy for SPET in the early identification of astrocytoma treatment failure at the week 24 assessment. Patients with positive 201Tl SPET after three courses of chemotherapy had a significantly reduced TTD (P = 0.040) but not significantly reduced ST. Of the ten patients who received concomitant radiation and chemotherapy, five had a small (0-10 ml) TUV at the week 24 assessment. Patients with a TUV > 10 ml at this assessment had a shorter TTD (P = 0.016) and a reduced ST (P = 0.024) compared to patients with a TUV < 10 ml. In conclusion, the assessment of progressive disease by quantitative 201Tl SPET appears to provide information on treatment response, earlier and with a higher reliability than CT. Repeated 201Tl SPET scanning during follow-up of astrocytoma treatment is an alternative tool for the early identification of treatment failure.

Adult↗
PubMed1999

Maternal smoking and craniosynostosis.

To investigate a possible association between maternal smoking during pregnancy and craniosynostosis (premature closure of one or more of the cranial sutures), a study was conducted using Swedish health registries. Infants with craniosynostosis (n = 304) without a known chromosome anomaly were selected among 1,413,811 infants born between 1983-1996 with known smoking exposure in early pregnancy. A statistically significant association between maternal smoking and craniosynostosis was found (adjusted odds ratio (OR), 1.45; 95% confidence interval (CI), 1.13-1.87), but this association was only valid for isolated defects (OR, 1.67; 95% CI, 1.27-2.19). For associated craniosynostosis (malformation syndromes included), a negative (nonsignificant) association with maternal smoking was indicated instead. For isolated craniosynostosis (all types), a dose-dependent effect of maternal smoking was indicated (OR and 95% CI for smoking <10 cigarettes/day, 1.45 (1.04-2.02); OR and 95% CI for smoking >/=10 cigarettes/day, 2.12 (1.50-2.99)), but was not statistically significant. Among the different types of craniosynostosis, premature closure of the sagittal suture showed the strongest association with maternal smoking (OR, 1.48; 95% CI, 1. 02-2.14), whereas for coronal suture defects, no association with maternal smoking could be detected (OR, 1.02; 95% CI, 0.47-2.21). As no obvious confounders were detected, the present study supports an earlier report of an association between maternal smoking during pregnancy and at least some types of craniosynostosis.

Adult↗
PubMed1999

CHARGE Association in newborns: a registry-based study.

The CHARGE Association is a nonrandom occurrence of congenital malformations that has been described in clinical series. Reported patients have been selected on the basis of certain prior criteria. In this article, we try to identify a congenital malformation pattern corresponding to the CHARGE Association, using statistical methods and analyzing 5,260 infants with multiple malformations collected from four large registries of congenital malformations. Care was taken to identify a number of confounding characteristics that can influence the ascertainment and registration of specific congenital malformations. We have identified a cluster of malformations that generally agreed with the current clinical definition of the CHARGE Association and have added some further malformations (e.g., facial clefts). We demonstrate that others (e.g. , esophageal atresia) are probably not part of the pattern. Heart defects (H in the acronym) seems to be less helpful in identifying infants with the association. We suggest a method to select infants who probably represent the CHARGE Association for analyses of possible risk factors.

Abnormalities, Multiple↗
PubMed1999

Maternal smoking and congenital heart defects.

The Swedish Child Cardiology Registry (CCR) and the Swedish Medical Birth Registry (MBR) were used to investigate a possible association between maternal smoking during pregnancy and congenital heart defects. Among 1,413,811 infants born in 1983-1996 with known smoking exposure in early pregnancy, 3384 infants with congenital heart defects were selected (458 term infants with persistent ductus arteriosus (PDA) identified from MBR or CCR, and 2926 infants with other heart defects, identified from CCR). After controlling for year of birth, maternal age, parity, and educational level, a weak, statistically significant association between all heart defects and maternal smoking was found (odds ratio (OR): 1.09; 95% confidence interval (CI): 1.01-1.19). When infants with isolated PDA were removed from the case group the significance disappeared (OR: 1.07; 95% CI: 0.98-1.17). For truncus abnormalities (OR: 1.23; 95% CI: 1.02-1.49), atrial septal defects (OR: 1.63; 95% CI: 1.04-2.57), and PDA (OR: 1.30; 95% CI: 1.05-1.62), a rather strong effect of maternal smoking was indicated. The increased OR for PDA remained when gestational duration and intrauterine growth was also controlled for. Further research based on independent data sets is needed to conclude whether the risk estimates for maternal smoking are true and truly differ between the groups. The classification system used (with 24 classes) is described in enough detail to permit a repetition of the study.

Confounding Factors, Epidemiologic↗
PubMed1999

Assessment of glioma viability by estimating 201Tl SPET tumour uptake volume.

The aim of this study was to develop a quantitative method to assess viable tumour based on post-operative 201Tl single photon emission tomography (SPET). We studied 15 patients with histologically defined highly malignant gliomas in the post-operative phase before initiation of adjuvant treatment. A 201Tl index was calculated in two ways: maximal counts versus mean counts within a region of interest (ROI). The tumour uptake volume (TUV) within the lesion was calculated from the number of voxels that had 201Tl uptake above a threshold calculated from the uptake on the contralateral side. The threshold was set at three levels: A = 1.4 times the mean 201Tl uptake in a three-dimensional reference ROI + 96.7% confidence interval (the TUV was corrected by subtraction of the volume in the reference ROI that had uptake above the threshold with compensation for unequal ROI sizes); B = 1.4 times the mean reference ROI + 99% confidence interval; and C = maximum 201Tl uptake in the reference ROI. The SPET results were compared with the tumour volumes calculated from CT scans. Thirteen tumours showed high post-operative 201Tl uptake. The 201Tl index was not significantly correlated with histological grade within the group of highly malignant gliomas. 201Tl SPET tumour uptake volume method B was highly significantly correlated with CT estimated tumour volume. In conclusion, the measurement of post-operative 201Tl SPET tumour uptake volume demonstrates metabolically active glioma tissue and is an alternative method for the monitoring of glioma treatment response.

Adult↗