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J Olsen

Publications and source records attributed to J Olsen.

At least 235 records · Page 13Linked to original sources
PubMed1997

Caffeine intake and delayed conception: a European multicenter study on infertility and subfecundity. European Study Group on Infertility Subfecundity.

The effects of caffeine consumption on delayed conception were evaluated in a European multicenter study on risk factors of infertility. Information was collected retrospectively on time of unprotected intercourse for the first pregnancy and the most recent waiting time episode in a randomly selected sample of 3,187 women aged 25-44 years from five European countries (Denmark, Germany, Italy, Poland, and Spain) between August 1991 and February 1993. The consumption of caffeinated beverages at the beginning of the waiting time was used to estimate daily caffeine intake, which was categorized as 0-100, 101-300, 301-500, and > or = 501 mg. Risk of subfecundity (> or = 9.5 months) and the fecundability ratio, respectively, were assessed by logistic regression and Cox proportional hazard analyses, adjusting for age, parity, smoking, alcohol consumption, frequency of intercourse, educational level, working status, use of oral contraceptives, and country. A significantly increased odds ratio (OR) of 1.45 (95% confidence interval (CI) 1.03-2.04) for subfecundity in the first pregnancy was observed for women drinking more than 500 mg of caffeine per day, the effect being relatively stronger in smokers (OR = 1.56, 95% CI 0.92-2.63) than in nonsmokers (OR = 1.38, 95% CI 0.85-2.23). Women in the highest level of consumption had an increase in the time leading to the first pregnancy of 11% (hazard ratio = 0.90, 95% CI 0.78-1.03). These associations were observed consistently in all countries as well as for the most recent waiting time episode. The authors conclude that high levels of caffeine intake may delay conception among fertile women.

Adult↗
PubMed1997

Glycosylated hemoglobin as predictor of adverse fetal outcome in type 1 diabetic pregnancies.

The study aimed to determine whether a consistent dose-response association can be demonstrated, after adjustment for maternal age and White classification, between glycosylated hemoglobin (HbA1c) values before conception and in the first trimester of pregnancy of insulin-dependent diabetic mothers and adverse fetal outcome (abortions and major malformations). This is a historical follow-up study based on medical records in a geographically defined catchment area. The study comprised 60 pregnancies with HbA1c determinations before pregnancy and 161 with HbA1c in the first trimester in women with type 1 diabetes admitted between 1980 and 1992. Relative risk calculations indicated a highly significant and consistent correlation between HbA1c values above 6.6% and adverse fetal outcome after adjustment for differences in maternal age and White classification. Our data support a clinically significant and consistent relationship between adverse fetal outcome and HbA1c in the first trimester of pregnancy of type 1 mothers, without any indication of a cut-off level below which further improvement in HbA1c was of minor importance.

Abortion, Spontaneous↗
PubMed1997

Time to pregnancy and preterm delivery.

OBJECTIVE: To test whether subfertile women may be at higher risk of preterm delivery. METHODS: We used data from two population-based cohort studies on risk factors and pregnancy outcome for approximately 20,000 deliveries in three major Danish obstetric departments. The Aalborg-Odense study comprised all pregnant women attending routine antenatal care at two obstetric departments from 1984 to 1987. In all, 11,850 women (86%) filled in a questionnaire at about 36 weeks' gestation. The Aarhus study addressed women at the routine visit near 16 weeks' gestation from 1989 to 1991; a study questionnaire was returned by 6857 (80%). Both studies excluded women with chronic illnesses, multiple fetuses, and inability to speak Danish. Only women with planned pregnancies were included in the analysis. In all, 8855 and 3985 women from Aalborg-Odense and Aarhus, respectively, were eligible for the analyses. In both cohorts, women were categorized according to their waiting time to pregnancy (0-6 months, 7-12 months, and greater than 1 year) and according to examination or treatment for infertility (yes, no). Preterm delivery was defined as birth before 37 completed weeks. RESULTS: Compared with women who tried for 6 months or less before they conceived, women who tried for 7-12 months had 1.3 times (95% confidence interval [CI] 0.8, 2.1) the adjusted risk of preterm delivery in both cohorts, and women with a time to pregnancy of greater than 12 months had adjusted relative risks for preterm delivery of 1.6 (95% CI 1.1, 2.2) for Aalborg-Odense and 1.7 (95% CI 1.1, 2.6) for Aarhus. The results remained similar after excluding women with infertility treatment. CONCLUSIONS: Pregnant women with subfertility and clinically defined infertility are more prone to preterm delivery, even in the absence of infertility treatment.

Adult↗
PubMed1997

Repeating episodes of low fecundability. A multicentre European study. The European Study Group on Infertility and Subfecundity.

Many reproductive failures tend to repeat themselves within the same couple. Whether fecundability (the probability of conceiving in a given number of menstrual cycles) follows the same pattern is studied using data from the European Studies on Infertility and Subfecundity (ESIS): 6630 women were interviewed on 'time to pregnancy' (TTP) and other aspects of their pregnancy history. Surveys were conducted between 1991 and 1994 in seven regions from five European countries. Furthermore, the pattern of fecundability in this population was compared with results from computer simulations based upon a population with fixed fecundability parameters. Results from ESIS speak in favour of the stability of fecundability in the relatively short reproductive life of a couple. However, a substantial proportion of couples with up to two events of subfecundability (TTP >9.5 months) became pregnant shortly after trying again. This finding calls for reservation in starting expensive and/ or unpleasant diagnostic procedures at an early stage when a couple tries to become pregnant again.

Adult↗
PubMed1997

Change in incidence of Crohn's disease and ulcerative colitis in Denmark. A study based on the National Registry of Patients, 1981-1992.

BACKGROUND: The incidence of inflammatory bowel disease (IBD) in Denmark is considered to be among the highest in Europe. However, the diseases are relatively rare and therefore it would be useful if existing registers could replace ad hoc examination in the surveillance of IBD. METHODS: The present study used the Danish National Registry of Patients to estimate incidence rates, 1981-1992. RESULTS: A total of 2806 patients with Crohn's disease (CD) and 8125 with ulcerative colitis (UC) were identified. The mean incidence for CD was 4.6 (5.4 for women and 3.7 for men) per 100,000 per year, with a peak incidence in younger women. The incidence increased in most age groups with the highest increase in older women. The mean incidence for UC was 13.2 (13.4 for women and 13.0 for men) per 100,000 per year, with the highest incidence in older men. A decreasing tendency in the incidence was present in most age groups. CONCLUSIONS: The present study found an increasing incidence for CD and a stable incidence with a tendency to decrease for UC. Comparison with ad hoc studies indicates that it is possible to use the Danish National Registry of Patients in the surveillance of IBD, especially for CD.

Adult↗
PubMed1997

Evaluation of nature-nurture impact on reproductive health using half-siblings.

Research in the field of preventive medicine will increasingly focus on the role of genetic susceptibility in disease etiology. Epidemiology plays an important role in identifying which diseases are good candidates for such research activity. Computerized population registries of unstable partner relationships and change in environmental exposure settings may provide new tools for research. We illustrate these tools using facial cleft defects as an example. The design is based upon computerized and stored data from large population samples. Data on change of partner or environment between births are used to learn about the recurrence risks for diseases that were present in their first child. The study focused on a susceptible subgroup of the population who previously had an affected child. Thus, by definition, these couples had a sufficient set of causes to initiate the disease and an increased risk of recurrence if relevant genetic or environmental factors remained unchanged. When considering recurrence risks after changes in possible genetic or nongenetic risk factors, etiologically important clues may emerge. The example confirms that genetic factors play a major role in facial cleft defects.

Cleft Palate↗
PubMed1997

Cancer mortality among man-made vitreous fiber production workers.

We have updated the follow-up of cancer mortality for a cohort study of man-made vitreous fiber production workers from Denmark, Finland, Norway, Sweden, United Kingdom, Germany, and Italy, from 1982 to 1990. In the mortality analysis, 22,002 production workers contributed 489,551 person-years, during which there were 4,521 deaths. Workers with less than 1 year of employment had an increased mortality [standardized mortality ratio (SMR) = 1.45; 95% confidence interval (CI) = 1.37-1.53]. Workers with 1 year or more of employment, contributing 65% of person-years, had an SMR of 1.05 (95% CI = 1.02-1.09). The SMR for lung cancer was 1.34 (95% CI = 1.08-1.63, 97 deaths) among rock/slag wool workers and 1.27 (95% CI = 1.07-1.50, 140 deaths) among glass wool workers. In the latter group, no increase was present when local mortality rates were used. Among rock/slag wool workers, the risk of lung cancer increased with time-since-first-employment and duration of employment. The trend in lung cancer mortality according to technologic phase at first employment was less marked than in the previous follow-up. We obtained similar results from a Poisson regression analysis limited to rock/slag wool workers. Five deaths from pleural mesothelioma were reported, which may not represent an excess. There was no apparent excess for other categories of neoplasm. Tobacco smoking and other factors linked to social class, as well as exposures in other industries, appear unlikely to explain the whole increase in lung cancer mortality among rock/slag wool workers. Limited data on other agents do not indicate an important role of asbestos, slag, or bitumen. These results are not sufficient to conclude that the increased lung cancer risk is the result of exposure to rock/slag wool; however, insofar as respirable fibers were an important component of the ambient pollution of the working environment, they may have contributed to the increased risk.

Aged↗
PubMed1997

The performance of several indicators in detecting recall bias. European Study Group on Infertility and Subfecundity.

Self-reported exposure data are vulnerable to differential recall, which threatens the internal validity and thus the credibility of the study. When a proxy measure of the exposure of interest is available, it may be possible to check for the presence of recall bias due to misclassification of the exposure information. We present a number of indicators of recall bias for case-control studies, and we describe their behavior by means of computer simulations. The indicators are all based upon a comparison between self-reported exposure data and data on job titles grouped into exposure-specific matrices. The indicators are based upon the assumption that job titles are reported without differential misclassification for cases as well as controls. We also assume that exposure data are reported with the same accuracy by workers in different jobs. Under these assumptions, the proposed indicators will provide valuable-although not conclusive-signs of recall bias. The principles elaborated in this paper can be applied to other situations in which self-reported exposure data are used.

Bias↗
PubMed1997

Gestational weight gain as a predictor of birth and placenta weight according to pre-pregnancy body mass index.

OBJECTIVE: To study the association between gestational weight gain and different birth weight indicators considering the pre-pregnancy body mass index. It was hypothesized that a high body mass index (BMI) would modify the effect of gestational weight gain and support the advice of keeping gestational weight gain at a moderate level in case of obesity. STUDY DESIGN: A follow-up study of consecutively recruited women in two well defined geographical areas in Denmark. The recruitment lasted from 1984 to 1987 and 11,850 pregnant women and newborns were included in the study. The remaining analyses were restricted to non-diabetic women who gave birth between weeks 37 and 42 of gestation for whom weight gain was reported-altogether 7,122 women. RESULTS: Birth and placenta weight were associated with gestational weight gain but with lower regression coefficients at higher BMI. The proportion of newborns with a birth weight of 4,500 grams or more increased with increasing gestational weight gain, especially in women with a BMI above 26. CONCLUSION: The potential benefit of a high gestational weight gain in obese patients should be balanced by the higher risk of giving birth to babies with a birth weight of more than 4,500 grams and the risk of exaggerating a pre-existing state of obesity.

Adult↗
PubMed1997

Cancer risk in users of calcium channel blockers.

Ca2+ channel blockers may cause cancer by inhibiting apoptosis or reducing intracellular Ca2+ in certain tissues. Recent findings suggest that drug users are at increased risk for cancer in general and for colon cancer in particular. We conducted a study in one Danish county of 17911 patients who received at least one prescription of Ca2+ channel blockers between 1 January 1991 and 31 December 1993. The patients were identified from records in the National Health Insurance Program, which refunds part of the price of such drugs. Cancer occurrence and rate were determined by use of the files of the Danish Cancer Registry and compared with county-specific incidence rates for various categories of cancer. During the follow-up period of up to 3 years, 412 cancers were observed among users of Ca2+ channel blockers, compared with 414 expected, to yield an age- and sex-standardized incidence ratio (SIR) of 1.00 (95% confidence interval, 0.90 to 1.10). There was no indication of an excess risk in the subgroup of likely long-term users or users of specific drugs. The SIR of colon cancer, a site of a priori interest, was 0.8 (95% confidence interval, 0.5 to 1.1) on the basis of 34 cases. Although the results are reassuring, the lack of association could reflect the relatively short follow-up after registration in the prescription database. Continued monitoring of cancer risk is planned.

Aged↗
PubMed1997

Inhibin B as a serum marker of spermatogenesis: correlation to differences in sperm concentration and follicle-stimulating hormone levels. A study of 349 Danish men.

Recent studies have focused on reproductive health of men in the general population. However, semen samples are difficult to obtain within sampling frames that allow comparisons. Blood samples are easier to obtain than ejaculates. Therefore, serum biomarkers of spermatogenesis are of major interest for population studies. FSH has previously been used as a marker of spermatogenesis, although it is also influenced by the hypothalamus. Serum inhibin B was recently suggested as a possible, more direct serum marker of spermatogenesis in men with testicular disorders. In a Danish nationwide collaborative study, we found an unexpected difference in semen concentration between two groups of men recruited from two different centres. We, therefore, analyzed reproductive hormones in blood, including inhibin B, to test whether the observed difference in semen concentration was reflected in the reproductive hormones. From 1992 to 1995, a total of 430 men, 20-35 yr old, who lived with a partner and who had not previously attempted to achieve a pregnancy, were recruited. The couples were enrolled into the study in one of two centres (centre A, n = 231; and centre B, n = 199) when they discontinued birth control. At enrollment, they provided a semen sample (n = 419), and a blood sample was drawn (n = 349). The semen analysis was performed in accordance with the WHO 1992 guidelines, and interlaboratory differences were tested. Inhibin B was measured in an enzyme immunometric assay, which has previously been described. All blood samples were analyzed in the same laboratory. Median sperm concentration and the percentage of morphologically normal spermatozoa were significantly higher among men from centre A (56.0 mill/mL and 42.5%), compared with men from centre B (44.8 mill/mL and 39%). Men from centre B had a significantly higher median FSH (3.42 IU/L) and a lower inhibin B (186 pg/mL) than men from centre A (3.21 IU/L and 209 pg/mL). The differences persisted after control for potentially confounding variables. A significant correlation was found between the cubic root-transformed serum FSH and inhibin B levels (r = -0.61, P < 0.001), between the cubic root-transformed serum FSH and sperm concentration (r = -0.40, P < 0.001), and between the cubic root-transformed inhibin B and sperm concentration (r = 0.38, P < 0.001). The predictive power of detecting sperm counts below 20 mill/mL among men who's inhibin B and FSH both were below 80 pg/mL and above 10 IU/L, respectively, was 100%. The unexpected significant difference in semen concentration between two groups of normal Danish men was probably caused by differences in sampling procedures in the two centres where the men were recruited, rather than geographical differences. However, similar differences in serum levels of inhibin B and FSH between centres were found. These findings suggest that a real difference in spermatogenic potential between the two groups of men existed. We suggest that serum inhibin B, in future population studies on male reproductive health, may serve as a new marker of spermatogenesis, in addition to sperm concentration and serum FSH.

Adult↗
PubMed1997

Does moderate alcohol intake reduce fecundability? A European multicenter study on infertility and subfecundity. European Study Group on Infertility and Subfecundity.

BACKGROUND AND AIM: There are plausible reasons to suggest that heavy alcohol consumption reduces male as well as female fecundability, but only a few epidemiological studies have addressed this issue, and results concerning the effect of a moderate intake are equivocal. The present studies were designed to examine the association between male and female alcohol intake at the start of the waiting time to a planned pregnancy. METHODS: Two types of studies were used-a population-based study of randomly selected women between 25 and 44 years in the different European countries from census registers and electoral rolls, and a pregnancy-based study of consecutive pregnant women (at least 20 weeks pregnant) recruited during prenatal care encounters. More than 4000 couples were included in each study, and 10 different regions in Europe took part in the data collection. Data were collected through personal interviews in all population-based samples and in all but four regions of the pregnancy study. RESULTS: The results showed no strong nor coherent association between alcohol intake and subfecundity. CONCLUSIONS: Should any causal effect be present it is restricted to females with a high intake of alcohol within the range of normal consumption reported in European countries.

Adult↗
PubMed1997

Changing trends in the incidence of non-Hodgkin's lymphoma in Europe. Biomed Study Group.

Non-Hodgkin's lymphoma (NHL) is not a uniform disease entity, and in order to investigate the reported changes in incidence we have set up a study in seven population-based cancer registries in Europe. The study is designed to look at changes in the incidence of total NHL and disease subgroups using standard definitions and methodology. The registries are based in Leeds, Dijon, Kuopio, Odense, Florence, Eindhoven, and Ragussa. The classification system we have used is based on the REAL classification and has utility for epidemiological studies. We have used it to convert data sets which have utilized both local cases and the ICD-O classification. In order to improve data reproducibility, CLL/LL, myeloma/MGUS, lymphoblastic disease, and Hodgkin's disease have been excluded because of the difficulty in defining incident cases accurately. The preliminary results of this study show that there is still an upward trend in incidence rate and that in Yorkshire this is 3% per annum in total NHL. The subgroups which are increasing are extranodal and nodal peripheral T-cell lymphoma. Similar increases in incidence have been reported for the other registries. We conclude that there is a continued upward trend in incidence of NHL, the causes of which are uncertain.

Europe↗
PubMed1996

Randomised study of screening for colorectal cancer with faecal-occult-blood test.

BACKGROUND: Case-control studies and a voluntary-based follow-up study have suggested that repeated screening with faecal-occult-blood (FOB) tests can lead to a reduction in mortality from colorectal cancer (CRC). The aim of this randomised study was to compare mortality rates after FOB tests every 2 years during a 10-year period with those of unscreened similar controls. METHODS: 140,000 people aged 45-75 years lived in Funen, Denmark, in August, 1985, and were considered for inclusion in our study. Before randomisation we excluded individuals who had CRC or precursor adenomas and those who had taken part in a previous pilot study. Randomisation of 137,485 people in blocks of 14 allocated three per 14 to the screening group (30,967), three per 14 to the control group (30,966), and eight not to be enrolled in the study (75,552). Controls were not told about the study and continued to use health-care facilities as normal. Hemoccult-II blood tests (with dietary restrictions but without rehydration) were sent to screening-group participants. Only those participants who completed the first screening round were invited for further screening--five rounds of screening during a 10-year period. Participants with positive tests were asked to attend to full examination and were offered colonoscopy whenever possible. The primary endpoint was death from CRC. FINDINGS: Of the 30,967 screening-group participants, 20,672 (67%) completed the first screening round and were invited for further screening; more than 90% accepted repeated screenings. During the 10-year study, 481 people in the screening group had a diagnosis of CRC, compared with 483 unscreened controls. There were 205 deaths attributable to CRC in the screening group, compared with 249 deaths in controls. CRC mortality, including deaths attributable to complications from CRC treatment, was significantly lower in the screening group than in controls (mortality ratio 0.82 [95% CI 0.68-0.99]) p = 0.03). INTERPRETATION: Our findings indicate that biennial screening by FOB tests can reduce CRC mortality. This study is being continued to improve its statistical power and to assess the effect of the removal of more precursor adenomas in the screening-group participants than in controls on CRC incidence.

Adenoma↗
PubMed1996

[Risk of the recurrence of cleft lip and palate after changing of partner or residence].

The aim of the present study was to determine the effect of changing residence on recurrence of congenital facial cleft defects. We identified 4189 women that had given birth to infants with a facial cleft detect by linking a database comprising facial cleft cases born between 1952 and 1987 with the Central Person Registry in Denmark. Changing municipality did not decrease the frequency of recurrence of facial cleft defects in later-born sibs. Among the 907 infants of mothers who changed municipality but not partner, 29 (3.2 percent) had a facial cleft defect, as compared with 48 (3.4 percent) of 1425 infants of mothers who changed neither municipality nor partner. However, change of partner significantly reduced the recurrence risk. Among 236 infants of mothers who changed partners, 1 (0.4 percent) had a facial cleft defect, as compared with 77 (3.3 percent) of 2350 infants of mothers who did not change partners. Recurrence of facial cleft defects is not linked to the residence of the mother, but having a different partner reduced the woman's risk of having a second infant with this defect.

Child↗