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K Helweg-Larsen

Publications and source records attributed to K Helweg-Larsen.

At least 19 recordsLinked to original sources
PubMed1998

[Induced abortion and risk of breast cancer].

It has been hypothesized that an interrupted pregnancy might increase the risk of breast cancer, because proliferation of breast cells will take place without the protective effect of subsequent differentiation. In a cohort of 1.5 million women (28.5 million person-years) we identified 370,715 induced abortions in 280,965 women (2.7 million person-years) and 10,246 women with breast cancer. After adjustment for other risk factors, induced abortion was not associated with the risk of breast cancer (relative risk: 1.00; 95 percent confidence interval 0.94 to 1.06). However, the relative risk of breast cancer increased with increasing gestational age of the most recently induced abortion: < 7 weeks: 0.81; 7 to 8 weeks; 1.01; 9 to 10 weeks: 1 (reference); 11 to 12 weeks: 1.12; 13 to 14 weeks: 1.13; 15 to 18 weeks: 1.23; > 18 weeks: 1.89; P(trend) = 0.016. On a population basis, induced abortion was not associated with an increased risk of breast cancer. An increase was only seen for the special group of late second trimester abortions, but this finding was based on small numbers.

Abortion, Induced↗
PubMed1998

[The trend in induced abortions in Denmark until 1995. Illustrated by the relation to other data sources, preventive campaigns during the last years and the stage of pregnancy].

This study presents a review of the trend in the Danish abortion rate, with a view to prevention campaigns and introduction of electronic registration of abortions through the National Patient Registry. The number of induced abortions has been decreasing steadily since 1975; abortion on demand up to the end of 12th gestational week has been permitted by law in Denmark since 1973. The lowest number ever was registered in 1994 and 1995, corresponding to a rate of 13.7 per 1,000 women aged 15-49 years. The number per 1,000 liveborn decreased from 277 in 1993 to 253 in 1994. The relative number of abortions was highest among women aged 20-29 years, and in the capital area. Since 1993 the health authorities have strengthened campaigns to reduce the number of unplanned pregnancies, primarily focusing on younger women and with special programs in the capital area. The reduction for these groups could point to a success of the prevention campaigns, although the rates of terminated pregnancies might be influenced by many other factors.

Abortion, Legal↗
PubMed1998

Sociodemographic risk factors for sudden infant death syndrome: associations with other risk factors. The Nordic Epidemiological SIDS Study.

The aim of this study was to investigate associations between sudden infant death syndrome (SIDS) and social factors in the Nordic countries. A case-control study was conducted in Denmark, Norway and Sweden: The Nordic Epidemiological SIDS Study. Parents of 244 SIDS infants and 869 control infants matched on gender, age at death and place of birth filled in questionnaires. The dataset was analysed by conditional logistic regression. In univariate analysis, the following sociodemographic factors were associated with an increased risk of SIDS: low maternal age [odds ratio (OR) 7.8; 2.8-21.5], high birth order (OR 4.4; 2.5-7.5), single motherhood (OR 2.9; 1.7-5.0), low maternal education (OR 4.5; 2.8-7.1), low paternal education (OR 3.0; 1.9-4.7), maternal unemployment (OR 2.4; 1.8-3.4) and paternal unemployment (OR 4.0; 2.7-5.9). In a multivariate analysis where maternal smoking was also included, only paternal unemployment, young maternal age and high birth order remained significantly associated with SIDS. Housing conditions were not associated with SIDS. However, the risk of SIDS was high if the family had lived in their present home for only a few years (OR 2.3; 1.3-4.1). Sociodemographic differences remain a major concern in SIDS in a low-incidence situation and even in an affluent population with adequate health services.

Case-Control Studies↗
PubMed1998

Sudden unexpected death in infancy: epidemiologically determined risk factors related to pathological classification.

Infants that died suddenly and unexpectedly were studied as part of the European Concerted Action on sudden infant death syndrome (SIDS). Three paediatric pathologists, first independently of each other and later in a consensus meeting, classified 63 cases into 3 groups: SIDS (19 cases), borderline SIDS (30 cases) and non-SIDS (14 cases). The interobserver agreement among the pathologists before the consensus meeting was moderate (Kappa = 0.41) and jointly it was higher (Kappa = 0.83). The distribution of epidemiologically determined risk factors was studied over these three groups. Maternal smoking after birth, low socioeconomic status and thumb sucking were found more often in SIDS than in the other cases. Inexperienced prone sleeping was a determinant for SIDS, but not for non-SIDS. Previous hospital admission, low birthweight and/or short gestation were associated with borderline SIDS. Non-SIDS cases received more breastfeeding, the parents hardly smoked during pregnancy and after birth, a firm mattress had been used, and more often signs of illness had been reported by the parents, compared with the SIDS and borderline SIDS cases. Bedding factors and both primary and secondary prone sleeping were equally distributed over the three groups which supports the hypothesis that, in SIDS and borderline SIDS, as well as in non-SIDS cases, some similar external and preventable factors might influence the events leading to death. Research should therefore focus on all sudden unexpected deaths, after which subgroups such as SIDS cases can be separately analysed. The postmortem is an essential part of the whole work-up of each case and the results should be interpreted with all other available data to arrive at a sound evaluation of cases and thus form the basis for the prevention of all sudden unexpected infant death.

Bedding and Linens↗
PubMed1998

A case-control study of smoking and sudden infant death syndrome in the Scandinavian countries, 1992 to 1995. The Nordic Epidemiological SIDS Study.

AIM: To establish whether smoking is an independent risk factor for sudden infant death syndrome (SIDS), if the effect is mainly due to prenatal or postnatal smoking, and the effect of smoking cessation. METHODS: The analyses were based on data from the Nordic epidemiological SIDS study, a case-control study with 244 cases and 869 controls. Odds ratios were computed by conditional logistic regression analysis. RESULTS: Smoking emerged as an independent risk factor for SIDS, and the effect was mainly mediated through maternal smoking in pregnancy (crude odds ratio 4.0 (95% confidence interval 2.9 to 5.6)). Maternal smoking showed a marked dose-response relation. There was no effect of paternal smoking if the mother did not smoke. Stopping or even reducing smoking was beneficial. SIDS cases exposed to tobacco smoke were breast fed for a shorter time than non-exposed cases, and feeding difficulties were also more common. CONCLUSIONS: Smoking is an independent risk factor for SIDS and is mainly mediated through maternal smoking during pregnancy. Stopping smoking or smoking less may be beneficial in reducing the risk of SIDS.

Breast Feeding↗
PubMed1997

[Reporting of induced abortions in 1994. A comparison between the data in the Registry of Legally Induced Abortions and the National Patient Registry].

Up to 31st December 1994 all cases of legally induced abortions were notified by the physician responsible for the operation to the National Board of Health and recorded in the Register of Induced Abortions. Following this data, abortion statistics will rely on data concerning induced abortions in the Danish National Patient Register, which includes information based upon the unique personal number of all patients admitted to hospitals. The completeness of the Register of Induced Abortions and the National Patient Register as to induced abortions in 1994 was assessed to evaluate the impact of the change in method of monitoring on trends in the national and regional abortion rate. The complete number of induced abortions was estimated to be the sum of the number recorded in both registers, cases recorded only in the Register of Induced Abortions, cases recorded only in the National Patient Register, and the missing number of registration of induced abortions calculated by capture-recapture methods. Of these 18,429 abortions 96.4% were registered in the National Patient Register and 93.5% in the Register of Induced Abortions. There were some regional variations. In some counties more abortions were registered in the Register of Induced Abortions and in others in the National Patient Register. Considering the change from 1995 in sources of the statistics of induced abortions, analyses of trends in the abortion rate in the early 1990s in Denmark must be evaluated with prudence.

Abortion, Legal↗
PubMed1997

Induced abortion and the risk of breast cancer.

BACKGROUND: It has been hypothesized that an interrupted pregnancy might increase a woman's risk of breast cancer because breast cells could proliferate without the later protective effect of differentiation. METHODS: We established a population-based cohort with information on parity and vital status consisting of all Danish women born from April 1, 1935, through March 31, 1978. Through linkage with the National Registry of Induced Abortions, information on the number and dates of induced abortions among those women was combined with information on the gestational age of each aborted fetus. All new cases of breast cancer were identified through linkage with the Danish Cancer Registry. RESULTS: In the cohort of 1.5 million women (28.5 million person-years), we identified 370,715 induced abortions among 280,965 women (2.7 million person-years) and 10,246 women with breast cancer. After adjustment for known risk factors, induced abortion was not associated with an increased risk of breast cancer (relative risk, 1.00; 95 percent confidence interval, 0.94 to 1.06). No increases in risk were found in subgroups defined according to age at abortion, parity, time since abortion, or age at diagnosis of breast cancer. The relative risk of breast cancer increased with increasing gestational age of the fetus at the time of the most recent induced abortion: <7 weeks, 0.81 (95 percent confidence interval, 0.58 to 1.13); 7 to 8 weeks, 1.01 (0.89 to 1.14); 9 to 10 weeks, 1.00 >12 weeks, 1.38 (1.00 to 1.90) (reference category, 9 to 10 weeks). CONCLUSIONS: Induced abortions have no overall effect on the risk of breast cancer.

Abortion, Induced↗
PubMed1997

The decline in the incidence of SIDS in Scandinavia and its relation to risk-intervention campaigns. Nordic Epidemiological SIDS Study.

A prospective case-control study of sudden infant death syndrome (SIDS) in Norway, Denmark and Sweden between September 1, 1992 and August 31, 1995 comprised 244 cases and 869 matched controls. After the introduction of risk-intervention campaigns, the SIDS incidence decreased from 2.3/1000 live births in Norway, 1.6 in Denmark and 1.0 in Sweden to 0.6/1000 or fewer in all the Scandinavian countries in 1995. The decrease paralleled a decline in the prone sleeping position and there was an accompanying parallel fall in total postneonatal mortality in all three countries. Thus, the risk-reducing campaigns for SIDS have been successful not only in Norway and Denmark, starting from relatively high incidences, but also in Sweden, starting from a low incidence. During the study period, a gradual increase was observed for the effects of prone sleeping, smoking and bottle-feeding as risk factors for SIDS.

Case-Control Studies↗
PubMed1997

Combined effects of sleeping position and prenatal risk factors in sudden infant death syndrome: the Nordic Epidemiological SIDS Study.

OBJECTIVE: Prone sleeping is a strong risk factor for sudden infant death syndrome (SIDS). We investigated whether the combined effect of prone sleeping position and prenatal risk factors further increased the SIDS risk. METHODS: In the Nordic Epidemiological SIDS Study, parents of SIDS victims in Denmark, Norway, and Sweden completed a questionnaire on potential risk factors for SIDS. Forensic pathologists verified the SIDS diagnosis. Four controls of the same gender, age, and place of birth were selected. This matched case-control study, which included 244 SIDS cases and 869 controls from 1992 to 1995, was analyzed by conditional logistic regression. RESULTS: Odds ratios (ORs) for prone and side sleeping compared with supine sleeping for the last sleep were 13.9 (95% confidence interval 8.2-24) and 3.5 (2.1-5.7). Infants 13 to 24 weeks old had particularly high risk in prone and side sleeping, at 28.5 (7.9-107) and 5.9 (1.6-22). OR for prone sleeping was higher in girls, at 30.4 (11-88), than in boys, 10.3 (5.5-19). We found strong combined effects of sleeping position and prenatal risk factors (more than multiplicative). The OR for prone and side sleeping was increased for infants with birth weight <2500 g, at 83 (25-276) and 36.6 (13-107); for preterm infants, at 48.8 (19-128) and 40.5 (14-115); and for intrauterine growth retarded, at 38.8 (14-108) and 9.6 (4.3-22), compared with supine position in infants without these prenatal factors. The combined effect of nonsupine positions and intrauterine growth retarded was highest among 13- to 24-week-old infants. Effects of combined presence of nonsupine sleeping positions and each of the factors of smoking in pregnancy, young maternal age, higher parity, low level of maternal education, and single motherhood were more than additive. Attributable fractions in the population for prone and side sleeping were 18.5% and 26.0%. CONCLUSIONS: Both prone and side sleeping increased the risk of SIDS. The risk was increased further in low birth weight infants, preterm infants, and infants at the age of 13 to 24 weeks, suggesting that SIDS may be triggered by nonsupine sleeping in infants with prenatal risk factors during a vulnerable period of postnatal development.

Age Factors↗
PubMed1996

[Perinatal mortality in Denmark. An analysis of development assessed in connection with medically induced abortion during the period 1980-1993].

Based upon data from the Danish National Register of Causes of Deaths, the Birth Register and registers on induced abortions and congenital malformations the article analyses the trend in the Danish perinatal mortality and the impact of abortions induced on medical grounds during the period 1980-1993. Estimating that half of the induced abortions might have led to a perinatal death it is concluded that the perinatal mortality would still have been significantly reduced from the late 1980s to 1990-1993. It is stressed that the impact of induced abortions be included in analyses of trends in perinatal mortality. The perinatal deaths are classified in nine categories by which a grouping into non-avoidable (unexplained intrauterine deaths and deaths due to congenital birth defects) and avoidable deaths (all other categories) was possible. The classification mixed pathoanatomical, obstetrical and paediatric criteria and facilitated an evaluation of the trend in mortality in relation to health care. The recent decrease in the overall perinatal mortality to 7.5 per 1.000 born was both due to a fall in deaths caused by prematurity and in deaths due to congenital birth defects. The deaths due to prematurity were not significantly linked to maternal smoking during pregnancy and no differences could be found in the overall prenatal screening between mothers who lost a baby due to malformations and all mothers.

Abortion, Spontaneous↗
PubMed1996

[Infant mortality among children of 35-39 year-old mothers. An analysis of development of death cause categories and among multiple pregnancies during the period 1980-1993].

The perinatal mortality in Denmark decreased significantly from the late 1980's to 1990-1993 but increased among births by mothers aged 35-39 years, from 9.7 in 1985-1989 to 11.0 per 1000 born in 1990-1993. No increase was observed among infants of teen-age mothers or mothers older than 40 years. Based upon data from the Danish National Register of Causes of Death and the Birth Register all perinatal deaths in 1980-1993 were classified in nine categories including pathoanatomical, obstetrical and paediatric criteria. The increase in perinatal mortality in infants born to mothers aged 35-39 years was because of more deaths due to congenital birth defects, intra-partum events and foeto-placental dysfunction, while mortality due to prematurity decreased. The rate of multiple pregnancies and of primiparas increased significantly among 35-39 year-old mothers. With reference to international literature, the article discusses the possible impact of in-vitro fertilisation and other fertility treatments upon the special trend in perinatal mortality in this mother age-group. A national Danish IVF-register was first established in 1994 and will in the future allow concrete analyses of the outcome of IVF-pregnancies.

Adult↗
PubMed1994

[Overheating and sudden infant death. Temperature regulation in relation to the prone position, the possible pathogenesis of sudden infant death].

The incidence of sudden infant death syndrome (SIDS) in Denmark varied in the period 1982-1991 between 1.5 and 1.9 per 1000 livebirths. In December 1991 recommendations concerning infants' sleeping position were published by The Danish National Board of Health in order to reduce the risk of SIDS. Babies were recommended to be placed in the supine or side position when sleeping. Parents have followed the guidelines. Most Danish infants are now sleeping on their back or in the side position. Simultaneously, the number of SIDS dropped from about 110 to 40 per year. The incidence decreased to 1.2 in 1992 and was further reduced in 1993 to 0.6 per 1000 live births. Referring to our knowledge of the infant's temperature regulation we discuss why the prone position is a risk factor for SIDS. The head is the site of up to 85% of heat loss in an infant in bed. Placed in the prone position, the infant is more likely to suffer a rise in body temperature, especially if this is combined with having a cold, being heavily wrapped and sleeping in a heated room. Preceding sudden death many infants are reported to have suffered from minor viral infections. These might per se increase the body temperature. Parents often wrap infants that have an infection too heavily, which in an infant sleeping in the prone position might increase the body temperature to a higher level than if sleeping supine. The body temperature influences the production of toxins from normal intestinal flora and from pathogenic bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Temperature Regulation↗
PubMed1993

Sudden death and human insulin: is there a link?

Case reports from the United Kingdom (UK) in 1989 have suggested that the introduction of human insulin in 1985 was associated with an increased risk of sudden death in insulin-treated diabetic patients. If human insulin increases the risk of sudden death, the number of these should have increased during the period where human insulin was introduced. We therefore identified all cases of sudden death in Denmark in younger insulin-treated diabetic patients, age at death below 50 years. During this period the consumption of human insulin went from 0.2% to 70% of the total consumption in Denmark. The total number of cases fulfilling the inclusion criteria was 226, and the annual number of sudden deaths did not change during the study period (p = 0.14). The number of deaths due to hypoglycaemia and cases with unexplained cause of death also remained constant (test for trend: p = 0.44). Chronic alcohol abuse or acute alcohol intoxication was found in 50% of the 135 patients dying from hypoglycaemia, ketoacidosis or unknown cause of death (including found dead in bed), while this was the case in only 16% of the remaining 91 cases dying from other natural causes. We conclude that introduction of human insulin in Denmark was not followed by an increase in sudden deaths among younger insulin-treated diabetic patients.

Adolescent↗
PubMed1993

Sudden natural death in childhood. A review of forensic autopsy protocols in cases of sudden death between the ages of one and five years, 1982-1991, with a special view to sudden unexplained death.

All cases of sudden death of individuals between the ages of one and five years examined at the Forensic Institute, Copenhagen, in a 10-year period were identified to assess the impact of sudden unexplained death in this age group. Of a total of 68 cases, 27 cases were due to accidents, there were 13 cases of homicide, 27 cases were sudden natural deaths and in 1 case the manner of death was uncertain. The autopsy records and histological sections in the 27 cases of natural death were reviewed; the cause of death was not explained in 11 of these cases (40%). Seven cases were previously considered to be caused by infectious disease or aspiration. Criteria for classification are discussed.

Accidents↗