Biomedical subjects

J Olsen

Publications and source records attributed to J Olsen.

At least 19 recordsLinked to original sources

PubMed2006

Wheezing, asthma, hay fever, and atopic eczema in relation to maternal occupations in pregnancy.

OBJECTIVES: To examine whether prenatal occupational exposures, especially to organic solvents, are associated with atopic diseases in childhood. METHODS: The study comprised children born in Odense or Aalborg, Denmark between 1984 and 1987. Occupational job titles were derived from questionnaires filled out by the mothers when attending midwife centres. Assessment of organic solvent exposures was based on job titles selected by occupational specialists. A follow up questionnaire to the parents provided data on medical diagnoses as well as wheezing symptoms for 7844 children aged 14-18. Multivariate logistic regression analyses were performed to estimate the cumulative risk for wheezing (early wheezing not diagnosed as asthma), asthma, hay fever, and atopic eczema during childhood by means of odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Explorative analyses by maternal job titles in pregnancy showed elevated odds ratios concerning different atopic diseases for occupational groups such as "bakers, pastry cooks, and confectionary makers", "dental assistants", "electrical and electronic assemblers", "sewers and embroiders", and "bookbinders and related workers". An excess risk ratio for hay fever (OR 2.8, CI 1.1 to 7.5) was found following maternal gestational exposure to organic solvents. Furthermore, a slightly raised odds ratio for asthma was observed in children of shift workers (OR 1.2, CI 1.0 to 1.5). CONCLUSION: The data suggest links between certain maternal occupations during pregnancy and atopic diseases, which merits further scrutiny. However, no consistent pattern was seen across the different atopic diseases.

Adolescent↗

PubMed2006

Do women give the same information on binge drinking during pregnancy when asked repeatedly?

OBJECTIVE: To study if pregnant women give the same answers to questions on frequency and timing of binge drinking when asked more than once during and after pregnancy. DESIGN: Cohort study. SETTING: The Danish National Birth Cohort. SUBJECTS: The study is based on 76 307 pregnant women with repeated information on binge drinking during the early part of pregnancy and 8933 pregnant women with information on binge drinking during pregnancy weeks 30-36, obtained while pregnant and 6 months after delivery. RESULTS: More women reported binge drinking, if the interview took place close to the period in question. As the report of binge drinking was highest in the first of two interviews referring to the same period, as well as women who participated in the first interview in pregnancy week 12 or earlier reported more binge drinking compared to women who participated in the interview later in pregnancy. CONCLUSIONS: Self-reported information on binge drinking is more frequently under-reported when the recall period is long. To improve the validity of data on binge drinking, future birth cohorts should obtain information several times during pregnancy.

Adult↗

PubMed2006

Laboratory work and pregnancy outcomes: a study within the National Birth Cohort in Denmark.

AIMS: To examine pregnancy outcomes in women doing laboratory work. METHODS: Using data from the Danish National Birth Cohort (1997-2003), the authors conducted a prospective cohort study of 1025 female laboratory technicians and 8037 female teachers (as reference). The laboratory technicians were asked about laboratory work tasks during pregnancy in an interview (at around 16 weeks of gestation). Pregnancy outcomes were obtained by linking the cohort to the national registers. Hazard ratios (HRs) of late fetal loss and diagnosing of congenital malformations were calculated by using Cox regression, and odds ratios (ORs) of preterm birth and small for gestational age were calculated by using logistic regression. RESULTS: Overall, there were no significant differences in pregnancy outcomes between laboratory technicians and teachers. However, we found that laboratory technicians working with radioimmunoassay or radiolabelling had an increased risk of preterm birth (OR = 2.2, 95% CI 0.8 to 6.2 for radioimmunoassay, and OR = 1.9, 95% CI 0.8 to 4.6 for radiolabelling) and "major" malformations (HR = 2.1, 95% CI 1.0 to 4.7 for radioimmunoassay, and HR = 1.8, 95% CI 0.9 to 3.7 for radiolabelling). The ORs of preterm birth doubled for women working with these tasks every day or several times a week. When an exposure matrix was applied, an increased risk of "major" malformations for exposure to organic solvents was seen. CONCLUSIONS: The results did not indicate any high risk of reproductive failures in laboratory technicians in general. Exposure to radioisotopes may carry a high risk of preterm birth and congenital malformations. This finding deserves further investigation.

Adult↗

PubMed2005

Using infertile patients in epidemiologic studies on subfecundity and embryonal loss.

Subfecundity is a frequent and serious problem that may sometimes be preventable, but we need to know more about its determinants. Different epidemiologic designs are available. The best of these use prospectively collected data from the population, but they are time consuming, expensive and often hampered by low-participation rates. Most patients undergoing infertility treatment are closely monitored for clinical reasons, making it feasible to use secondary data to study the period from conception to implantation and pregnancy. In spite that infertility patients are highly selected, there are specific exposure-effect relations that can be studied in cohorts of infertility patients. These patients offer a potentially useful setting for studying exposures that operate late in fertilization, whereas the designs may be inadequate to identify exposures that cause reduced sperm counts, anovulation and total occlusion. The clinical sampling and the treatment set limitations for what can be studied. In certain situations, infertile patients can, however, provide useful epidemiologic evidence for learning about the causes of subfecundity.

Abortion, Spontaneous↗

PubMed2005

Fecundability according to male serum inhibin B--a prospective study among first pregnancy planners.

BACKGROUND: New biological markers of male fecundity are needed for use in large-scale epidemiological studies. We studied the association between male inhibin B and fecundability. METHODS: Four hundred and thirty Danish couples without previous reproductive experience were followed from termination of contraception until pregnancy or for a maximum of six menstrual cycles. At enrolment we obtained semen samples (n = 418) and blood samples to measure reproductive hormones, including inhibin B (n = 343). RESULTS: The fecundability odds ratio for an increment of male inhibin B by 1 log pg/ml was 1.428 (95% confidence interval 1.022-1.994), adjusted for factors influencing the crude estimate. Only inhibin B values below 100 pg/ml were strongly related to fecundability. We designed a receiver operating characteristic curve based on the 29 males with serum inhibin B #100 pg/ml. The area under the curve (AUC) for inhibin B was 0.787 and the corresponding AUCs for sperm density and FSH were 0.913 and 0.800, respectively. CONCLUSION: Serum inhibin B may be a reliable marker of male fecundity for epidemiological research and may have some advantages over sperm density. Our findings do not support the replacement of sperm density by male inhibin B when obtaining sperm data is an option.

Adult↗

PubMed2005

Spontaneous abortion in IVF couples--a role of male welding exposure.

BACKGROUND: Fume from welding of stainless steel contains hexavalent chromium, which in animal studies can induce paternally mediated spontaneous abortion. Human studies have shown conflicting results. The best studies include early pregnancy experience, but these are expensive to conduct. In vitro fertilization (IVF) provides new design opportunities. Our aim was to study pregnancy survival in IVF treated women with respect to paternal welding exposure. METHODS: We mailed a questionnaire to 5879 couples from the Danish IVF register that covers all IVF treatments after 1993 (response ratio 68.2%). A subgroup of male metal workers received a second questionnaire on exposure to welding (n = 319 men, response ratio 77%). Information on outcome was collected from national health registers. Survival of the first hCG-positive pregnancy was analysed using Cox regression. RESULTS: The proportion of pregnancies terminated by spontaneous abortion before 28 gestational weeks was 18% (n = 91 pregnancies) and 25% (n = 128) in pregnancies with paternal exposure to stainless steel welding and mild steel welding, respectively. In the reference group of 2925 pregnancies the abortion ratio was 28%. The risk ratio for pregnancies with paternal exposure to stainless steel was 0.6 (95% CI 0.4-1.0). CONCLUSIONS: We found no increased risk of spontaneous abortion in IVF treated women, who became pregnant by a man exposed to welding of any sort. Since the process of fertilization and selection of IVF pregnancies differs from natural pregnancies the negative results need not apply to other pregnancies.

Abortion, Spontaneous↗

PubMed2005

Stress and salivary cortisol during pregnancy.

The purpose of this study was to determine whether exposure to stressful life events was associated with changes in levels of circulating cortisol during pregnancy in a population of 603 pregnant women. The participating pregnant women filled out a questionnaire and collected a morning and evening sample of saliva in early pregnancy (median 14th gestational week) and in late pregnancy (median and 30th gestational week). They were asked to report the number of life events experienced during first and second trimester, respectively, and were asked to rate the intensity of the experienced events. Complications related to the pregnancy such as vaginal bleeding and suspected growth retardation were registered and the women were asked about concerns about their pregnancy. The salivary samples were analyzed for cortisol and the levels were higher in late than in early pregnancy. In late pregnancy women exposed to more than one life event or were concerned about pregnancy complications during second trimester had a higher evening cortisol level, whereas morning values were unaffected. After adjustment for smoking women who experienced more than one very stressful life event had 27% higher evening cortisol concentrations (95% confidence intervals: 1-59%). Women with worries about pregnancy complications had 27% (95% confidence intervals: 2-57%) higher levels. In early pregnancy women reporting stressful life events did not have higher evening cortisol levels, but tended to have a blunted morning HPA response. In conclusion, we found differences in the associations between chronic stress in early and late pregnancy and cortisol levels indicating that the response to chronic stress is dependent on the stage of the pregnancy.

Adult↗

PubMed2005

The intrauterine origin of male breast cancer: a birth order study in Denmark.

First pregnancies are known to have higher oestrogen levels than later ones and first-born women are at increased breast cancer risk compared with later-born women. We hypothesized that a birth order effect might be even more evident in male breast cancer patients, in whom oestrogens in adult life are generally low. In a population-based study in Denmark involving 77 male breast cancer patients and 288 population controls, first-born men compared with later-born men had a relative risk of 1.71 for the disease (95% confidence interval (CI) 1.00-2.92). This result is in line with that seen in female breast cancer cases and indicates that male breast cancer may have roots in the intrauterine life, oestrogens being a likely mediator.

Birth Order↗

PubMed2005

Relation between diagnoses on severity, sick leave and loss of job among patients with occupational hand eczema.

BACKGROUND: Epidemiological studies indicate that occupational hand eczema (OHE) often is associated with persistent dermatitis and prolonged sick leave, which may lead to unemployment. Previous studies suggest that OHE caused by allergic contact dermatitis and atopic dermatitis (AD) carries the worst prognosis. OBJECTIVES: To evaluate and compare the severity and consequences of recognized OHE in different diagnostic and subdiagnostic groups. METHODS: Between October 2001 and November 2002, all new cases of recognized OHE were identified from the Danish National Board of Industrial Injuries Registry (758 cases). Severity was graded from 0 to 2 depending on the intensity of skin response and the frequency of relapse. To supplement the information from the Registry, we surveyed the study population using a postal questionnaire which included questions about disease duration, sick leave, current occupation and loss of job. RESULTS: The overall response rate to the questionnaire was 82%. We observed substantially greater severity among those with occupational irritant contact dermatitis (ICD) and AD than for any other diagnoses. Age above 50 years was also associated with increased severity of OHE. Prolonged sick leave due to OHE was reported by 19.9% and was associated with AD and severe OHE. We found a higher proportion of prolonged sick leave among those in food-related occupations (27.2%) compared with those in wet occupations (20.1%) and other occupations (16.5%). Twenty-three per cent reported that they had lost their job at least once during the past 12 months due to OHE. The only strong association with loss of job was food-related occupations. CONCLUSIONS: Occupational ICD and AD appear to be strongly associated with severity of OHE. AD and severity of OHE were independently associated with prolonged sick leave. Having a food-related occupation appears to be associated with increased risk of loss of job.

Adolescent↗

PubMed2005

Relation between patients' and physicians' severity assessment of occupational hand eczema.

BACKGROUND: Severity assessment of occupational hand eczema (OHE) is important not only in clinical settings but also in research. Questionnaires with self-rated assessment of severity may be an attractive tool for assessing severity because of their cost efficiency in comparison with expensive clinical examinations. OBJECTIVES: To evaluate the relation between self-rated severity and severity assessment based on standardized medical certificates issued by dermatologists in a population of patients with OHE. METHODS: Between October 2001 and November 2002 (58 weeks) we identified all new cases of recognized OHE from the Danish National Board of Industrial Injuries (DNBII) registry. Each patient was examined by a dermatologist, who issued a standardized medical certificate. The severity assessment in the DNBII registry was based on this medical certificate, which comprised information on morphology and extent of eczema, and frequency of eruptions. All participants received a self-administered questionnaire and were asked to classify severity of their OHE on a visual analogue scale from 0 to 10. The relation between DNBII-assessed and self-rated severity was illustrated by a receiver operating characteristic analysis. RESULTS: Of 758 patients included in the study, 621 returned the questionnaire and 602 (79%) provided information on self-rated severity. The proportion of severe cases was significantly higher among patients' assessments compared with the rating by the DNBII. Almost 18% were categorized as severe cases by the DNBII while 40% of patients had assessed themselves as having severe eczema. The optimal cut-off point had a sensitivity and specificity of self-rated severity according to the DNBII assessment of 65% and 66%, respectively. The positive predictive value was 29% and the negative predictive value was 90%. CONCLUSIONS: The low positive predictive value suggests major differences in the criteria for self-rated severity vs. DNBII-rated severity. We recommend researchers to include ratings from both patients and physicians in future investigations of severity. The methods may address different aspects of OHE.

Adolescent↗

PubMed2005

Wheezing, asthma, hayfever, and atopic eczema in childhood following exposure to tobacco smoke in fetal life.

BACKGROUND: Prenatal maternal smoking has been associated with adverse respiratory effects in childhood such as lung deficits and wheezing, but results concerning asthma, hayfever, and atopic eczema are inconsistent. OBJECTIVE: In the present study, we investigate the effects of maternal smoking in pregnancy on asthma, hayfever, atopic eczema, and wheezing in the offspring up to the age of 14-18. METHODS: The study was based on a cohort of mothers enrolled during midwife visits around the 36th week of gestation in Odense and Aalborg, Denmark, 1984-1987. Singleton, live born children (n = 11,144) were followed-up in 2002 to obtain a childhood history of atopic diseases, by means of questionnaires to the parents. Multivariate logistic regression analyses for medical diagnoses of asthma, hayfever, atopic eczema, and symptoms of wheezing before the age of 3, were carried out on 7844 children. RESULTS: After adjustment for confounders, late prenatal smoke exposure was associated with wheezing, with an odds ratio (OR) of 1.2, and a 95% confidence interval (CI) of 1.1-1.5. Furthermore, slightly reduced estimates for hayfever (OR 0.8, CI 0.7-1.0) and atopic eczema (OR 0.8, CI 0.7-0.9) were obtained for children exposed in late pregnancy compared with non-exposed. CONCLUSION: Late gestational smoke exposure was associated with wheezing but not with asthma, while null or even protective estimates were indicated for hayfever and atopic eczema. However, lack of control options for hereditary factors may have affected the results.

Adolescent↗

PubMed2005

Hospitalization because of diabetes and bereavement: a national cohort study of parents who lost a child.

AIMS: To examine whether parents who lost a child have an increased risk of hospitalization because of Type 1 or Type 2 diabetes. METHODS: We identified all parents who lost a child in Denmark from 1980 to 1996 (stress exposed), and compared them with parents randomly selected from all other parents in the country at that time without such a bereavement. Fifteen non-bereaved families were matched to each bereaved family for family size and the age of the children. First hospitalizations for Type 1 or Type 2 diabetes were monitored in these two groups up to 18 years after the bereavement. There were 21 062 parents in the bereaved cohort and 293 745 parents in the non-bereaved cohort. The study was based upon linkage of several national registers, and first-time hospitalization with diabetes (Type 1 or Type 2) was the end point. RESULTS: Five hundred and fifty-one cases were hospitalized because of Type 1 diabetes and 1569 cases because of Type 2 diabetes. There was a 29% higher risk of hospitalization because of Type 1 diabetes [95% CI -5 to 75%; corresponding to a relative risk (RR) of 1.29; 95% CI 0.95-1.75] and a 44% higher risk of hospitalization because of Type 2 diabetes (95% CI 21-71%; corresponding to an RR of 1.44; 95% CI 1.21-1.71) in the bereaved cohort. The high risk of hospitalization because of Type 2 diabetes following bereavement was only statistically significant for mothers. CONCLUSIONS: Psychological stress may be a contributing cause of, or have prognostic importance for, both Type 1 and Type 2 diabetes, but a statistically significant association was only seen for Type 2 diabetes.

Adaptation, Psychological↗

PubMed2005

The threat to scientific integrity in environmental and occupational medicine.

Over the last century, environmental and occupational medicine has played a significant role in the protection and improvement of public health. However, scientific integrity in this field has been increasingly threatened by pressure from some industries and governments. For example, it has been reported that the tobacco industry manipulated eminent scientists to legitimise their industrial positions, irresponsibly distorted risk and deliberately subverted scientific processes, and influenced many organisations in receipt of tobacco funding. Many environmental whistleblowers were sued and encountered numerous personal attacks. In some countries, scientific findings have been suppressed and distorted, and scientific advisory committees manipulated for political purposes by government agencies. How to respond to these threats is an important challenge for environmental and occupational medicine professionals and their societies. The authors recommend that professional organisations adopt a code of ethics that requires openness from public health professionals; that they not undertake research or use data where they do not have freedom to publish their results if these data have public health implications; that they disclose all possible conflicts; that the veracity of their research results should not be compromised; and that their research independence be protected through professional and legal support. The authors furthermore recommend that research funding for public health not be directly from the industry to the researcher. An independent, intermediate funding scheme should be established to ensure that there is no pressure to analyse data and publish results in bad faith. Such a funding system should also provide equal competition for funds and selection of the best proposals according to standard scientific criteria.

Conflict of Interest↗

PubMed2004

High-speed horizontal-path atmospheric turbulence correction with a large-actuator-number microelectromechanical system spatial light modulator in an interferometric phase-conjugation engine.

Results of atmospheric propagation for a high-speed, large-actuator-number adaptive optics system are presented. The system uses a microelectromechanical system- (MEMS-) based spatial light modulator correction device with 1024 actuators. Tests over a 1.35-km path achieved correction speeds in excess of 800 Hz and Strehl ratios close to 0.5. The wave-front sensor was based on a quadrature interferometer that directly measures phase. This technique does not require global wave-front reconstruction, making it relatively insensitive to scintillation and phase residues. The results demonstrate the potential of large-actuator-number MEMS-based spatial light modulators to replace conventional deformable mirrors.

Journal Article↗

PubMed2004

Performance of a phase-conjugate engine implementing a finite-bit phase correction.

The achievable Strehl ratio when a finite-bit correction to an aberrated wave front is implemented is examined. The phase-conjugate engine used to measure the aberrated wave front consists of a quadrature interferometric wave-front sensor, a liquid-crystal spatial light modulator, and computer hardware-software to calculate and apply the correction. A finite-bit approximation to the conjugate phase is calculated and applied to the spatial light modulator to remove the aberrations from the optical beam. The experimentally determined Strehl ratio of the corrected beam is compared with analytical expressions for the expected Strehl ratio and shown to be in good agreement with those predictions.

Journal Article↗

PubMed2004

Pesticide exposure in male farmers and survival of in vitro fertilized pregnancies.

BACKGROUND: Male-mediated spontaneous abortion is well described among animals, but less well documented in humans. Studies that include early pregnancy experience are expensive to conduct, but IVF provides new opportunities. MATERIALS AND METHODS: The Danish IVF register covers all IVF treatments performed after 1993. We mailed a questionnaire to 5879 women (response rate 68.2%). A subgroup of exposed male partners received a questionnaire on specific exposure to pesticides and growth retardants (n = 128 men, response rate 81.3%). Information on outcome was collected from national health registers. Survival of the first HCG-positive pregnancy was analysed using Cox regression. RESULTS: The proportion of pregnancies terminated by spontaneous abortion before 28 gestational weeks was 19.7% (n = 66 pregnancies), 19.7% (n = 61), 21.3% (n = 47) and 22.2% (n = 18) in pregnancies with paternal exposure to herbicides, fungicides, pesticides and growth retardants. respectively. In the reference group of 2925 pregnancies, the abortion rate was 28.4%. The differences in survival were not statistically significant. CONCLUSIONS: We found no increased risk of spontaneous abortion in IVF-treated women attributable to paternal agricultural application of pesticides and growth retardants. Exposure to potentially harmful pesticides in Denmark is relatively low, and the findings are restricted to countries with similar standards of protection.

Abortion, Spontaneous↗

PubMed2004

Having children with different men and subsequent cancer risk. A nationwide study in Denmark.

The more men by whom a woman has children, the more diverse will be the foetal antigens of paternal origin introduced into her bloodstream, and we investigated whether this has an impact on subsequent cancer risks. By using population registries we identified 64704 women who had children with at least two different partners from 1973 to 1996 in Denmark. We compared their cancer incidence with that of women who during the same time period had at least two births with no indication of partner change, adjusting for age, parity, socioeconomic factors and residence. The overall cancer incidence was more than 50% higher in women with two or more partners. Women having children with multiple partners had a higher incidence of cancer of the cervix and corpus uteri, a lower incidence of melanoma but a similar incidence of breast and ovarian cancer. Uncontrolled differences in lifestyle factors may explain the higher cancer risk associated with having multiple partners. The strong protective effect for melanoma was unexpected and deserves further study.

Adult↗

PubMed2004

The risk of multiple sclerosis in bereaved parents: A nationwide cohort study in Denmark.

BACKGROUND: Previous studies have suggested that psychological stress may play a role in the risk of multiple sclerosis (MS), but the evidence is very limited. OBJECTIVE: To examine the association between MS and a well-defined major stressful life event: the death of a child. METHODS: In this follow-up study based on nationwide and population-based registers, all 21,062 parents who lost a child younger than 18 years from 1980 to 1996 in Denmark were included in the exposed cohort and 293,745 matched parents who did not lose a child in the unexposed cohort. The two cohorts were followed for incident MS from 1980 to 1997. Hazard ratios (HR) with 95% CI were calculated as the measure of association between the exposure and MS, using the Cox proportional hazards regression model. RESULTS: Two hundred fifty-eight MS patients were identified (28 in the exposed cohort and 230 in the unexposed cohort). The exposed parents had an increased risk of MS (HR 1.56, 95% CI 1.05 to 2.31), which is significant only when follow-up was at least 8 years. The HR for definite/probable MS was 1.42 (95% CI 0.90 to 2.24). Parents who lost a child unexpectedly had an HR of 2.13 (95% CI 1.13 to 4.03) for all MS, which is higher than that for other bereaved parents (HR 1.33; 95% CI 0.81 to 2.16). CONCLUSION: Psychological stress may play a role in the development of MS.

Adult↗