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Jørn Olsen

Publications and source records attributed to Jørn Olsen.

At least 37 records · Page 2Linked to original sources
PubMed2006

Genetic and environmental correlates of semen quality: a twin study.

BACKGROUND: The influences of environmental factors on the male reproductive system have been much debated over the last 3 decades. We studied the impact of genes and environment on semen quality, sex hormone levels, and sperm chromatin stability by using a twin design. METHODS: The study population consisted of monozygotic and dizygotic twins from the population-based Danish Twin Registry and a random selection of pairs of singleton brothers from the Danish Civil Registration System. All men were 20 to 45 years of age. The study population comprised 100 monozygotic twin brothers (50 pairs), 102 dizygotic twins (51 pairs), and 102 single-born brothers (51 pairs). A semen sample and blood sample were collected from all participants. RESULTS: Heritability was estimated to account for 20% (95% confidence interval = 0% to 68%) of the variation in sperm density. A higher heritability was found for the hormones reflecting Sertoli cell function (inhibin B, 76% [36% to 84%] and follicle-stimulating hormone, 81% [40% to 88%]) and for percent morphologic normal cells (41% [0% to 60%] and sperm chromatin parameters (mean alphaT, 68% [34% to 81%] and COMP alphaT, 72% [25% to 82%], respectively). CONCLUSION: Our study indicates a substantial hereditary component in plasma levels of hormones reflecting Sertoli cell function and in sperm cell chromatin stability and morphology. The environmental contribution (including the prenatal environment) appeared to be largest for sperm count.

Adult↗
PubMed2006

Occupational exposure to pesticides and pregnancy outcomes in gardeners and farmers: a study within the Danish National Birth Cohort.

OBJECTIVE: We conducted a follow-up study to examine whether exposure to pesticides during pregnancy had an adverse effect on pregnancy outcomes among Danish gardeners and farmers. METHODS: Using data from the National Birth Cohort in Denmark, we identified 226 pregnancies of gardeners and 214 pregnancies of farmers during 1997 through 2003. Work activities and exposure to pesticides were reported in an interview (around 16 weeks of gestation). Totally, 62,164 other workers in the cohort served as a reference group. Pregnancy outcomes were obtained by linkage to the national registers. Cox regression was applied to analyze late fetal loss and congenital malformations, and logistic regression was used to analyze preterm birth and small for gestational age. RESULTS: There were no significant differences in the studied pregnancy outcomes between gardeners or farmers and all other workers, except for an increased risk of very preterm birth for gardeners and a favorable birth weight for farmers. With the exception of biologic approach used in gardening, neither work activities nor exposure to pesticides showed a significant increased risk of adverse birth outcomes among gardeners or farmers. CONCLUSIONS: Our data suggest little effect of occupational exposures to pesticides on pregnancy outcomes among gardeners or farmers in Denmark. The results may not apply to other countries.

Adult↗
PubMed2006

Quality of life and depression in a population of occupational hand eczema patients.

Occupational hand eczema (OHE) is the most frequently recognized occupational disease in Denmark, and despite governmental attempts to reduce exposure to harmful occupational allergens, the number of new cases has remained almost unchanged since the mid-1990s. Some studies have indicated that OHE has considerable impact on quality of life (QoL) and may lead to depression. The aims of the study were to determine risk factors for low QoL, the frequency and severity of depression among OHE patients and changes in QoL and depression after 12 months of follow up. The study population, 758 patients, comprised all new recognized cases from the Danish National Board of Industrial Injuries Registry between October 2001 and November 2002. All patients received a questionnaire to determine impairment of QoL and depressive symptoms. A similar follow-up questionnaire was posted after 1 year. The response rate was 82% at baseline and 91% at follow up. The mean Dermatology Life Quality Index total score was 5.5 for all patients and 7.8 for severe OHE cases. Severe OHE cases and lower socioeconomic status were independently associated with low QoL. The prevalence of moderate-to-severe depression was 9%. Only minor changes in QoL and depressive symptoms were found after 12 months of follow up.

Adolescent↗
PubMed2006

Pregnancy outcomes among female hairdressers who participated in the Danish National Birth Cohort.

OBJECTIVES: The Danish National Birth Cohort (DNBC) was used to examine pregnancy outcomes among female hairdressers and neurodevelopment in their offspring. METHODS: A population-based cohort study was conducted of 550 hairdressers and 3216 shop assistants (reference group) by using data from the Danish National Birth Cohort between 1997 and 2003. Information on job characteristics was reported by the women in the first interview (around 17 weeks of gestation). Pregnancy outcomes were obtained by linkage to the national registers. Developmental milestones were reported by the mother at the fourth interview, when the child was approximately 19 months old. Cox regression was applied to analyze fetal loss and congenital malformation. Logistic regression was used to analyze other pregnancy outcomes and developmental milestones. RESULTS: We found no significant differences in fetal loss, multiple births, gender ratio, preterm birth, small-for-gestational age, congenital malformations, or achievement of developmental milestones among the children of hairdressers and shop assistants. CONCLUSIONS: The results do not indicate that children of hairdressers in Denmark currently have a high risk of fetal impairment or delayed psychomotor development.

Abortion, Spontaneous↗
PubMed2006

Determinants of acute respiratory infections in Soweto--a population-based birth cohort.

BACKGROUND: Acute respiratory infections (ARIs) are an important cause of infant morbidity in both developing and developed countries, and they are the leading cause of death in poorer parts of the world. Respiratory viruses appear to be the most frequent microbiological pathogens, especially respiratory syncytial virus. It has been suggested that factors such as being male, overcrowding, poor access to medical care, low level of maternal education, and passive smoking are associated with contracting ARIs. DESIGN: A fixed birth cohort of 571 children was followed from birth to 1 year of age. The children were monitored for symptoms of ARIs during regular home visits. SETTING: An urban low-income setting in Soweto, a township outside Johannesburg with an estimated 1.2 million inhabitants, including an estimated 45,000 children under 2 years of age. SUBJECTS: A total of 571 children were observed for 118,650 days. OUTCOME MEASURES: The incidence rate of ARIs. The determinants birth weight, breastfeeding, gender, crowding, passive smoking, indoor pollution, and sanitary facilities were analysed. RESULTS: A total of 489 episodes of coughing or coughing and nasal discharge combined were recorded. Only the father's level of education and the number of people living in the household remained significant in the multivariate analyses. The incidence of severe ARIs was reduced among breastfed infants. CONCLUSIONS: Our study supports previous observations suggesting that crowding and communal living conditions are important determinants of ARIs. Breastfeeding seemed protective against severe ARI. The lack of association with well-described risk factors such as low level of maternal education, gender and passive smoking could be due to lack of statistical power in this rather uniform population.

Acute Disease↗
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

Coffee and fetal death: a cohort study with prospective data.

The authors conducted a cohort study within the Danish National Birth Cohort to determine whether coffee consumption during pregnancy is associated with late fetal death (spontaneous abortion and stillbirth). A total of 88,482 pregnant women recruited from March 1996 to November 2002 participated in a comprehensive interview on coffee consumption and potentially confounding factors in pregnancy. Information on pregnancy outcome was obtained from the National Hospital Discharge Register and medical records. The authors detected 1,102 fetal deaths. High levels of coffee consumption were associated with an increased risk of fetal death. Relative to nonconsumers of coffee, the adjusted hazard ratios for fetal death associated with coffee consumption of 1/2-3, 4-7, and > or =8 cups of coffee per day were 1.03 (95% confidence interval (CI): 0.89, 1.19), 1.33 (95% CI: 1.08, 1.63), and 1.59 (95% CI: 1.19, 2.13), respectively. Reverse causation due to unrecognized fetal demise may explain the association between coffee intake and risk of fetal death prior to 20 completed weeks' gestation but not the association with fetal loss following 20 completed weeks' gestation. Consumption of coffee during pregnancy was associated with a higher risk of fetal death, especially losses occurring after 20 completed weeks of gestation.

Abortion, Spontaneous↗
PubMed2005

[Should the sensible drinking limits for adults be changed?].

The sensible drinking limits may be too high depending on sex, age, genetic variation and other factors. Recent research on the alcohol-related risk of breast cancer and the impact of drinking patterns on health calls for an update of the literature. We focus on studies of the effect of alcohol on morbidity and mortality and conclude that the maximum of 21 drinks per week for men and 14 for women may be maintained. We emphasize that episodic intake of alcohol increases the risk of death and that the beneficial effect of alcohol is reached at an intake of one drink per day. We also specify groups for whom the drinking limits are not valid.

Adult↗
PubMed2005

Paternal age and congenital malformations.

BACKGROUND: Spontaneous mutations in germ cells increase with male age, but an association between paternal age and congenital malformations is not well established. We conducted a population-based cohort study to estimate this association. METHODS: A study population of couples and their firstborn children were identified in the Danish Fertility Database between 1980 and 1996 (n = 71937). Diagnoses of congenital malformations in children were obtained by linkage to the nationwide hospital register (1980-1999). RESULTS: Overall, there were no differences in the prevalence of malformations as a function of paternal age. However, the prevalence of malformations of extremities and syndromes of multiple systems, as well as Down's syndrome, increased with increasing paternal age. For example, in comparison with fathers age 20-29 years, adjusted hazard ratio of syndromes of multiple systems was 1.15 [95% confidence interval (CI) 0.81-1.65] for age 35-39 years, 1.33 (95% CI 0.79-2.25) for age 40-44 years, 1.73 (95% CI 0.82-3.65) for age 45-49 years, and 3.20 (95% CI 1.37-7.48) for age > or = 50 years (test for trend P = 0.01). CONCLUSIONS: Our data suggest that advanced paternal age may be associated with an excess occurrence of some specific malformations. The association could be caused by mutations of the gametes in men induced by biological or environmental factors.

Abnormalities, Multiple↗
PubMed2005

Male reproductive disorders in humans and prenatal indicators of estrogen exposure. A review of published epidemiological studies.

Male reproductive disorders in humans and prenatal indicators of estrogen exposure. A review of published epidemiological studies. Reports of an increase in male reproductive disorders in several countries led to the hypothesis that estrogens during fetal life may cause reduced sperm counts, cryptorchidism, hypospadias and testicular cancer. So far the hypothesis is based on animal studies and reports from the wild life. We systematically searched the epidemiological literature for evidence linking indicators of prenatal serum levels of maternal estrogens with sperm density, hypospadias, cryptorchidism and testicular cancer in humans. Indicators of fetal estrogen exposure included direct measurements, recorded intake of hormones (diethylstilbestrol (DES), oral contraceptives (OCs) and estrogens), pregnancy conditions with known deviant estrogen level as for instance twin pregnancies and some environmental exposures. Among 425 papers we reviewed 81 publications with appropriate information. With the possible exception of testicular cancer there is no strong epidemiological evidence to indicate that prenatal exposure to estrogen are linked to disturbed development of the male reproductive organs.

Cryptorchidism↗
PubMed2005

Cancer risk in persons with oral cleft--a population-based study of 8,093 cases.

The authors conducted a nationwide study of the occurrence of cancer among 8,093 Danish oral cleft cases born in 1936 through 1998 and followed in the Danish Cancer Registry from 1968 through 1998, a total of 175,863 person-years, to assess a possible association between cancer and oral clefts. Observed and expected numbers of cancers among oral cleft cases were summarized as the overall and as 52 site-specific standardized incidence ratios. The expected overall number of all cancers was 131, but 140 incident cancers were found, corresponding to a standardized incidence ratio of 1.07 (95% confidence interval (CI): 0.90, 1.26). Analyses of the 52 sites for all oral cleft cases and analyses stratified for three cleft subgroups and the two sexes revealed only a few significant associations: an increased occurrence of breast cancer among females born with cleft lip and/or cleft palate (standardized incidence ratio (SIR) = 1.52, 95% CI: 1.05, 2.14), primary brain cancer among females born with cleft palate (SIR = 3.11, 95% CI: 1.14, 6.78), and primary lung cancer among males born with both cleft lip and cleft palate (SIR = 2.49, 95% CI: 1.00, 5.14). The results do not provide evidence for an increased overall cancer risk for individuals born with oral clefts.

Adolescent↗
PubMed2005

Hospitalization for mental illness among parents after the death of a child.

BACKGROUND: The loss of a child is considered one of the most stressful events in the life of a parent. We hypothesized that parental bereavement increases the risk of hospital admission for a psychiatric disorder, especially for affective disorders. METHODS: We studied a cohort of 1,082,503 persons identified from national registers in Denmark who were born between 1952 and 1999 and had at least one child under 18 years of age during the follow-up period, from 1970 to 1999. Parents who lost a child during follow-up were categorized as "bereaved" from the date of death of the child. RESULTS: As compared with parents who did not lose a child, parents who lost a child had an overall relative risk of a first psychiatric hospitalization for any disorder of 1.67 (95 percent confidence interval, 1.53 to 1.83). Bereaved mothers had a higher relative risk of being hospitalized for any psychiatric disorder than bereaved fathers (relative risks, 1.78 [95 percent confidence interval, 1.60 to 1.98] and 1.38 [95 percent confidence interval, 1.17 to 1.63], respectively; P value for interaction, 0.01). The relative risks of hospitalization specifically for affective disorders were 1.91 (95 percent confidence interval, 1.59 to 2.30) and 1.61 (95 percent confidence interval, 1.15 to 2.27) for bereaved mothers and fathers, respectively. Among mothers, the relative risk of being hospitalized for any psychiatric disorder was highest during the first year after the death of the child but remained significantly elevated five years or more after the death. CONCLUSIONS: The risk of psychiatric hospitalization was increased among parents, especially mothers, who lost a child.

Adult↗
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

European multi-centre case-control study on risk factors for rare cancers of unknown aetiology.

To search for occupational risk factors, we conducted a case-control study in nine European countries of cancers of the small intestine, male gall bladder, thymus, bone, male breast, melanoma of the eye, and mycosis fungoides. Recruitment was population based in Denmark, Latvia, France, Germany, Italy, and Sweden, from hospital areas in Spain and Portugal, and from one United Kingdom (UK) hospital. We recruited 1457 cases (84% interviewed). Numbers identified corresponded to those in the EUROCIM database for Denmark, but were below those observed for France, Italy and Sweden in the database. We recruited 3374 population (61% interviewed) and 1284 colon cancer controls (86% interviewed). It was possible to undertake this complicated study across Europe, but we encountered three main problems. It was difficult to ensure complete case ascertainment, for population controls, we found a clear divide in the response rate from 75% in the South to only 55% in the North, and a somewhat selective recruitment was noted for the colon cancer controls. The study showed there is a clear dose-response relationship between alcohol intake and the risk of male breast cancer, and an excess risk of mycosis fungoides among glass formers, pottery and ceramic workers. Further data are expected.

Adult↗