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J Olsen

Publications and source records attributed to J Olsen.

At least 253 records · Page 14Linked to original sources
PubMed1996

Smoking reduces fecundity: a European multicenter study on infertility and subfecundity. The European Study Group on Infertility and Subfecundity.

Several studies published within the past 10 years indicate that smoking reduces fecundity, but not all studies have found this effect, and smoking cessation is not used routinely in infertility treatment in Europe. The present study was designed to examine male and female smoking at the start of a couple's waiting time to a planned pregnancy. Two types of samples were used: population-based samples of women aged 25-44 years who were randomly selected in different countries from census registers and electoral rolls, in which the unit of analysis was the couple; and pregnancy-based samples of pregnant women (at least 20 weeks' pregnant) who were consecutively recruited during prenatal care visits, in which the unit of analysis was a pregnancy. More than 4,000 couples were included in each sample, and 10 different regions in Europe took part in data collection. The data were collected between August 1991 and February 1993 by personal interview in all population-based samples and in all but three regions of the pregnancy sample, where self-administered questionnaires were used. The results based on the population sample showed a remarkably coherent association between female smoking and subfecundity in each individual country and in all countries together, both with the first pregnancy (odds ratio (OR) = 1.7, 95% confidence interval (CI) 1.3-2.1, at the upper level of exposure) and during the most recent waiting time to pregnancy (OR = 1.6, 95% CI 1.3-2.1). Results based on the pregnancy sample were similar (OR = 1.7, 95% CI 1.3-2.3). No significant association was found with male smoking (in the population sample, OR = 0.9, 95% CI 0.7-1.1 (first pregnancy) and OR = 1.0, 95% CI 0.9-1.3 (most recent waiting time); in the pregnancy sample, OR = 0.9, 95% CI 0.7-1.1). The fecundity distribution among smokers appeared to be shifted toward longer waiting times without a change in the shape of the distribution. Women who have difficulty conceiving should try to stop smoking or to reduce their smoking to less than 10 cigarettes per day.

Adult↗
PubMed1996

Seasonal variation in the time to pregnancy: a secondary analysis of three Danish databases.

Three Danish databases were reanalysed to investigate seasonal variation in the time to pregnancy. Information was available on cohorts of women selected on the basis of union membership or residence in a given area: textile workers in Denmark (with 1,053 first and 1,771 second pregnancies), pharmacy assistants in Denmark (with 734 first and 725 second pregnancies) and pregnant women in the 36th week of pregnancy in two Danish cities (with 3,657 first and 3,526 second pregnancies). The influence of the season was of primary interest, because it is presumed to cause impaired ovarian function and hence a prolonged time to pregnancy. Furthermore, we studied whether the waiting time was prolonged in other situations with possibility of decreased ovarian function: in young and older women. In genera, seasonality in the time to pregnancy based on the time of conception was found with a higher chance of a prolonged waiting time before conceiving in February-April and a lower chance of a prolonged waiting time before conceiving in August-October. This association was not distorted by the age of the women or diabetes mellitus. A prolonged time to pregnancy was found in women of 30 years or older. Women of 20 years or younger did not have a prolonged waiting time, but most of them were well beyond the age of menarche and thus beyond the period of impaired ovarian function. On a population level, there was evidence for seasonality in the time to pregnancy, which is compatible with seasonal variation in pregnancy planning as well as with biological influences.

Adolescent↗
PubMed1996

Extracellular alpha-Glucosidase with Dextran-Hydrolyzing Activity from the Thermophilic Fungus, Thermomyces lanuginosus

The thermophilic fungus Thermomyces lanuginosus, which is able to use dextran as primary carbon source for growth, excreted during the early phases of growth an enzyme activity capable of degrading dextran. The activity peaked at 22 h and decreased rapidly after the culture entered the stationary phase, probably caused by protease activity. Results from growth on a number of different carbon sources showed that polymer carbohydrates yielded the highest dextranase activities. On the basis of the substrate specificity and the release of glucose in the alpha-anomeric form from the hydrolysis of maltose, it is proposed that the enzyme responsible for the necessary degradation of dextran to smaller saccharides is an alpha-glucosidase.

Journal Article↗
PubMed1996

Referral bias among health workers in studies using hospitalization as a proxy measure of the underlying incidence rate.

Contacts with health services like hospitals or general practitioners are usually the only available proxy measure of incidence of disease in studies based on secondary data and differential referrals or care-seeking behavior often bias such proxy measures. In former analyses based on the Occupational Hospitalization Register in Denmark assisting nurses had high Standardized Hospitalization Ratios for many diseases. It was, however, suspected that it fully or partly was due to a referral bias or self-selection to hospital treatment rather than exposures to occupational hazards. The aim of the present study is to evaluate the referral bias hypothesis by comparing hospitalization and mortality data for health workers for a disease category with a high mortality. Cohorts of all gainfully employed 20- to 59-year-old Danes were formed in order to compare Standardized Mortality Ratios and Standardized Hospitalization Ratios of ischemic heart disease (IHD) in occupational groups. The follow-up period was 10 years. For most of the investigated occupational groups a similar disease pattern was found whether hospitalization or death was used as the outcome measure. In "nurse assistants" a statistically significant higher risk was, however, found using hospitalization due to IHD as the end point rather than mortality. Additional analysis did not support the hypothesis that the finding could be explained by differentiated hospitalization due to social factors. The true incidence rates of the disease need not be equally well described by proxy measures such as hospitalization diagnosis or death diagnosis in all occupational groups. Differential access to medical treatment in some groups may lead to bias when hospital data are used as proxy measures for the underlying incidence rates.

Bias↗
PubMed1996

The effect of preoperative methylprednisolone on pulmonary function and pain after lung operations.

Thirty-six patients undergoing elective thoracotomy with pulmonary resection with the use of combined epidural and general anesthesia were randomized into a double-blind study to receive a single intravenous preoperative dose of methylprednisolone 25 mg/kg body weight or a placebo (saline solution). Postoperative pain relief consisted of epidural morphine 4 mg and paracetamol 1 gm three times a day for 4 days. Postoperative pulmonary function (peak expiratory flow rate, forced expiratory volume in first second, forced vital capacity) was evaluated on days 1, 2, 3, 4, and 7 and after 1 month. The value obtained after 1 month served as the control value. Pain score at rest and during cough was evaluated after 4 and 8 hours and on days 1, 2, 3, and 4. Pulmonary function was reduced after operation to the same degree in the steroid and placebo group: 42% versus 41% for forced expiratory volume in first second and 38% versus 39% for forced vital capacity, compared with control values after 1 month. Pain score was reduced in the steroid group after 4 hours and on day 1 during rest and after 4 and 8 hours and on day 2 during cough, compared with results in the placebo group (p < 0.05). In the steroid group three patients underwent reoperation because of leakage through the chest wall incision. In conclusion, administration of a single preoperative dose of methylprednisolone did not affect the postoperative reduction in pulmonary function after thoracotomy despite attenuated pain response, and the results do not warrant steroid administration before lung operation.

Adult↗
PubMed1996

A framework for evaluation of secondary data sources for epidemiological research.

BACKGROUND: As part of the development in information technology, increasing amounts of health care data are available for epidemiological research. METHODS: In this review, we discuss the following factors affecting the value of secondary data in research: 1) completeness of registration of individuals, 2) the accuracy and degree of completeness of the registered data, 3) the size of the data source, 4) the registration period, 5) data accessibility, availability and cost, 6) data format, and 7) possibilities of linkage with other data sources (record linkage). RESULTS AND CONCLUSION: The importance of these issues depends on the use of the data and on the problems they have to address. If the evaluation is satisfactory with respect to the above-mentioned factors relevant to the particular study, the data source could be a very cost-effective way of solving the research problem.

Bias↗
PubMed1996

Shift work and subfecundity: a European multicenter study. European Study Group on Infertility and Subfecundity.

Shift work has been associated with various unfavorable pregnancy outcomes (ie, pregnancy loss, spontaneous abortion, low birth weight, etc). The suggested underlying mechanism is the interference of shift work with the circadian regulation of human metabolism and, in particular, with the temporal pattern of endocrine function. To analyze the effect of shift work on fecundity, the Time of Unprotected Intercourses (TUI) has been measured in couples recruited in the European Studies on Infertility and Subfecundity, which were undertaken in seven European countries. A low (odds ratio < 2.0) but consistent excess risk of subfecundity (TUI > or = 9.4 months) has been observed both in a representative sample of the general population of women in reproductive age and in a sample of pregnant women or women who had just given birth. The excess risk was also consistently evident both in the subsample of the first pregnancies and in the subsample of the most recent pregnancies. Only the exposure of women to shift work seemed to affect a couple's fecundity; men working shift work did not modify the fecundity pattern of their own couples. No specific job title among shift workers concentrated the risk of subfecundity. No association of menstrual disorders with shift work was identified. Even though residual confounding could partly account for the results and the fact that a plausible biological explanation of the claimed effect is still lacking, data from this study are in favor of an association between shift work and prolonged waiting time to pregnancy.

Adult↗
PubMed1996

Communication Concerning the Risks of Occupational Exposures in Pregnancy.

The health professional who is involved in communicating information about reproductive risks from occupational hazards needs to consider several important aspects. Uncertainties in risk assessment, timing of exposure in relation to pregnancy, and the consequences of different preventive measures for the woman (family), as well as for the employer and other persons at the workplace are examples of such aspects. The basis for the pregnant woman's perception of risk must be recognized. The risk-communication goal is that the persons concerned fully understand the risk and its possible consequences, so that they will be able to make informed decisions about how to act. More attention should be given to risk communication in the training of health professionals.

Journal Article↗
PubMed1996

Clonal chromosome aberrations in myeloid leukemia after styrene exposure.

OBJECTIVES: The purpose of the study was to determine the risk of myeloid leukemia subclassified according to clonal chromosome aberrations in styrene-exposed workers. METHODS: A nested case-referent study was carried out on 19 myeloid leukemia patients, of which 12 showed clonal chromosome aberrations, and 57 referents ascertained within the Danish reinforced plastics industry and similar industries with no styrene exposure. RESULTS: A 2.5-fold increased risk for myeloid leukemia with clonal chromosome aberrations (95% confidence interval 0.2-25.0) was found among workers of companies with styrene exposure. CONCLUSIONS: The results suggest that styrene may cause leukemia through a clastogenic effect. But similar findings could also have been found if the exposure was associated with a specific subtype of leukemia prone to develop the chromosome aberrations in question. Due to the few observations and the lack of detailed exposure data, additional studies are needed to corroborate or refute the present suggestive findings.

Adult↗
PubMed1996

Seeking medical help for subfecundity: a study based upon surveys in five European countries.

OBJECTIVE: To study care-seeking behavior for infertility treatment in different European countries. DESIGN: Multicenter surveys of randomly selected women in the child bearing age. SETTING: Five countries participated in the study: Denmark, Germany, Italy, Poland, and Spain. Data were collected from 1991 to 1993 as part of a concerted action. PATIENTS: Population-based samples of women 25 to 44 years of age. The sample sizes ranged from 442 women in Poland to 2,729 in Italy. Participation rates ranged from 54% in Germany to 87% in Denmark. Data were collected by means of a highly structured questionnaire used at a face-to-face interview. MAIN OUTCOME MEASURES: Waiting time to pregnancy, time, and type of treatment for infertility. RESULTS: Less than half of the infertile couples seek medical help in most European countries. The lowest proportion seeking help was found in Poland and the highest in Denmark. CONCLUSION: The increasing demand for infertility treatment is expected to continue, because the potential unmet need is outspoken in most European countries.

Adult↗