Mads Kamper-Jørgensen - Academia.edu (original) (raw)

Papers by Mads Kamper-Jørgensen

International Journal of Epidemiology, Apr 19, 2017

Background: It has been proposed that childhood vaccinations protect against acute lymphoblastic ... more Background: It has been proposed that childhood vaccinations protect against acute lymphoblastic leukaemia (ALL) in children by modulation of future responses to common infections in childhood. However, the available studies provide inconsistent findings, and population-based cohort studies with longitudinal information on vaccinations are lacking. Methods: In a register-based cohort of all children born in Denmark from 1 January 1990 to 31 December 2008, followed up until age 15 years or 31 December 2009 (n ¼ 1 225 404), we evaluated exposure to childhood vaccination and risk of childhood ALL, including information on ALL subtypes. Using Cox regression, we estimated hazard ratios (HRs) comparing vaccinated with unvaccinated children. Results: Childhood ALL was diagnosed in 490 children during 10 829 194 person-years of follow-up. Neither the total number of vaccine doses received nor exposure to each vaccination given in childhood was associated with altered risk of ALL, including the following: (i) Haemophilus influenzae type b [HR, 1.04; 95% confidence interval (CI), 0.68-1.61]; ii) measles, mumps and rubella (HR, 1.01; 95% CI, 0.76-1.34); iii) whole-cell pertussis (HR, 1.10; 95% CI, 0.51-2.39); and iv) diphtheria, tetanus and inactivated polio (HR, 1.14; 95% CI, 0.42-3.13). Analyses conducted according to ALL subtypes defined by immunophenoand karyotypes showed no association with childhood vaccination. Conclusions: This nationwide cohort study provides no support of the proposed protective effect of childhood vaccination against childhood ALL.

Journal of Investigative Dermatology, Jun 1, 2014

Serum gastrin-releasing peptide levels correlate with pruritus in patients with atopic dermatitis.

Transfusion, 2010

BACKGROUND: Various blood safety initiatives have ensured a historically low risk of infection tr... more BACKGROUND: Various blood safety initiatives have ensured a historically low risk of infection transmission through blood transfusion. Although further prevention of infection transmission is possible through, for example, nucleic acid testing and future introduction of pathogen inactivation, such initiatives are very costly in relation to the benefit they offer. Although estimation of the cost-effectiveness requires detailed information about the survival of transfusion recipients, previous cost-effectiveness analyses have relied on incorrect survival assumptions. STUDY DESIGN AND METHODS: Based on empirical data of more than 1 million Scandinavian transfusion recipients followed for up to 20 years, we present two new survival functions. In a fictitious example we assessed the impact of survival assumptions on the estimated costs per quality-adjusted life-year (QALY) gained, by using the survival functions of three previous cost-effectiveness analyses along with the two new survival functions. CONCLUSIONS: We conclude that despite considerable costs, previous cost-effectiveness studies may have underestimated the costs per QALY gained by as much as 44%.

Gynecologic Oncology, Nov 1, 2016

Coverage of the Greenlandic cervical screening program was low during 1997-2011 (highest rate of ... more Coverage of the Greenlandic cervical screening program was low during 1997-2011 (highest rate of 54% in 2011). • Substantial changes in the incidence of cervical lesions was found according to calendar period and age. • These findings suggest that improvements in the Greenlandic screening program are warranted.

International Journal of Epidemiology, Feb 17, 2020

Background: Reduced risk of ovarian cancer is commonly ascribed to reduced exposure to endogenous... more Background: Reduced risk of ovarian cancer is commonly ascribed to reduced exposure to endogenous hormones during pregnancy, using oral contraceptives or not using hormone replacement therapy. However, exposure to hormones alone account for less than half of all cases. Many women carry small amounts of male cells-known as male origin microchimerism-in their circulation and remarkable impacts of these cells on women's health are being published. Here, we pursue the possibility that male origin microchimerism has a role in reducing ovarian cancer risk. Methods: We conducted a prospective case-cohort study using blood samples and questionnaire data from 700 women participating in the Danish Diet, Cancer, and Health cohort. Blood samples were analysed for Y chromosome presence as a marker of male microchimerism. We evaluated the association between male microchimerism and ovarian cancer, using weighted Cox regression models reporting hazard ratios (HRs) and corresponding 95% confidence intervals (CIs). Results: Male microchimerism was detected in 46% of cases and 65.9% of controls. Women testing positive for male microchimerism had a reduced hazard rate of ovarian cancer compared with women testing negative (HR ¼ 0.44, 95% CI: 0.29-0.68). We found no evidence of interaction with measures of hormonal exposures (P ¼ 0.50). Conclusions: For the first time we report that women who test positive for male microchimerism in their circulation have reduced rates of ovarian cancer compared with women who test negative. Although the underlying mechanisms are presently unknown, we believe male microchimerism is potent in preventing ovarian cancer.

Scandinavian Journal of Public Health, May 1, 2007

Rationale: To assess the impact of childcare attendance on morbidity for an entire country the Ch... more Rationale: To assess the impact of childcare attendance on morbidity for an entire country the Childcare Database was created by linking person-identifiable data from several Danish national data sources. The present paper describes the creation, characteristics, and potential of the Childcare Database. Design and measurement: Based on the unique Danish Civil Registration System (DCRS) identification number register data were linked regarding childcare attendance, child and family characteristics, childcare facility characteristics, and hospitalizations for children aged 0 to 5 years in the period from 1989 to 2004. Population and sample size: The number of children in the database increased in the period from 1989 to 1998 as more municipalities started registering childcare, whereafter it stabilized. The maximum number of children in the database was 373,142 in 2000. From 1999 to 2004 the Childcare Database covered more than 90% of all 0- to 5-year-old children in Denmark. At age 1 year 53% of children were enrolled in a childcare facility and approximately 75% were enrolled from 3 to 5 years of age. Potential: The Childcare Database offers a unique potential for epidemiological research within the area of childcare and morbidity. Future updates and linkages with other data sources will further expand the potential of the database. Due to the high quality of the linked nationwide register data, the Childcare Database enables conduction of epidemiological studies of high internal and external validity.

International Journal of Epidemiology, Dec 17, 2013

Background During pregnancy, woman and fetus exchange small quantities of cells, and their persis... more Background During pregnancy, woman and fetus exchange small quantities of cells, and their persistence at later times is termed microchimerism. Microchimerism is known to substantially impact on women's later health. This study examined the survival of women according to male microchimerism status. Methods Male microchimerism presence, measured as Y chromosome in peripheral blood samples, was determined in 272 women from the large Danish Diet, Cancer and Health cohort when aged 50-64 years during 1993-97. Women were followed up for cause-specific death in national Danish registers until the end of 2009. Survival was analysed using Cox regression. Results A total of 190 women (70%) were male microchimerism positive. During follow-up 21 women died, of whom 11 (52%) were male microchimerism positive at enrolment and 10 were negative. Of the 21 deaths, 13 (62%) were due to cancer and 5 (24%) were due to cardiovascular disease. Male microchimerism presence was associated with a reduced hazard ratio of all-cause mortality of 0.42 (95% CI 0.17-1.03). The hazard ratio of death from cancer and cardiovascular disease was 0.24 (95% CI 0.08-0.79) and 1.66 (95% CI 0.18-15.48), respectively, among male microchimerism positive compared with negative women. Conclusions Although the biological mechanisms are not precisely known, male microchimerism presence in peripheral blood of women is associated with substantially improved survival in women. The results also indicate that the association with male microchimerism may vary between different causes of death.

Pediatric Infectious Disease Journal, 2016

To identify risk factors for hospitalization for respiratory syncytial virus (RSV) infection in D... more To identify risk factors for hospitalization for respiratory syncytial virus (RSV) infection in Danish children. Population based cohort study with follow up to 24 months of age. 421,943 Danish children separated by five groups of gestational age (23-32, 33-35, 36, 37-41, 42-45 weeks). In adjusted Cox regression models, chronic disease, asthma hospitalization before the RSV infection and siblings were associated with increased risk of hospitalization for RSV infection in all children independent of gestational age. Plurality was associated with a decreased risk in children born between 23 and 36 weeks of gestation, whereas young maternal age, maternal asthma, single parenthood, maternal smoking, being born small for gestational age, Caesarian section, male gender and daycare were associated with increased risk of hospitalization for RSV infection in term children. In post-term children young maternal age, male sex, being born small for gestational age and maternal smoking were associated with increased risk of hospitalization for RSV.Asthma hospitalization before the RSV infection and siblings were associated with the highest measures of increased risk of hospitalization for RSV infection independent of gestational age. By five groups of gestational age, we provide estimates of the effects of 12 different factors, which can be regarded as add-on risk factors to those already known to increase the risk of hospitalization for RSV infection. Our study may help clinicians to precisely assess the risk-profile in the individual child.

Transfusion, Dec 1, 2008

Background Long-term survival of transfusion recipients has rarely been studied. We examined shor... more Background Long-term survival of transfusion recipients has rarely been studied. We examined short-and longterm mortality among transfusion recipients, and reported these as absolute rates and rates relative to the general population. Study design and methods Population-based cohort study of transfusion recipients in Denmark and Sweden followed for up to 20 years after their first blood transfusion. Main outcome measure was all-cause mortality. Results We identified 1,118,261 transfusion recipients of whom 62.0% were aged 65 years or older at the time of their first registered transfusion. Three months after the first transfusion, 84.3% of recipients were alive. One-, five-and twenty-year post-transfusion survival was 73.7%, 53.4% and 27.0%, respectively. Survival was slightly poorer in men than in women, decreased with increasing age, and was worst for recipients transfused at departments of internal medicine. The first three months after the first transfusion, the standardized mortality ratio (SMR) was 17.6 times higher in transfusion recipients than in the general population. One to four years after first transfusion, the SMR was 2.1 and even after 17 years the SMR remained statistically significantly 1.3-fold increased. Conclusion We characterized survival and relative mortality patterns among blood transfusion recipients with unprecedented detail and precision. Our results are relevant to assessments of the consequences of possible transfusion-transmitted disease as well as for cost-benefit estimation of new blood safety interventions.

Fertility and Sterility, May 1, 2013

Objective: To investigate the independent and combined associations between female and male body ... more Objective: To investigate the independent and combined associations between female and male body mass index (BMI) on the probability of achieving a live birth after treatments with in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) under adjustment for relevant covariates.

PLOS ONE, Dec 22, 2021

Background The risk of infectious mononucleosis (IM) is affected both by crowding and by sibship ... more Background The risk of infectious mononucleosis (IM) is affected both by crowding and by sibship structure, i.e., number and signed age differential between an index child and a sibling. Siblings provide protection against IM by preempting delayed primary Epstein-Barr virus infection with its associated high risk of IM. The association between childcare attendance and risk of IM, on the other hand, has never been studied in a large, well-characterized cohort. Methods Danish children born in July 1992 through 2016 with a completely known simple childcare attendance history before age 1.5 years (n = 908,866) were followed up for a hospital contact with an IM diagnosis at ages 1.5-26 years. Hazard ratios (HRs) of IM for an additional year of exposure were obtained from stratified Cox regression analyses, stratified by sex and year of birth, with age as the underlying time scale, adjusted for sibship structure, and sociodemographic variables including parental ethnicity and maternal age. Results An additional year of exclusively attending a daycare home (max 5 children) yielded HR = 0.90 (95% confidence interval 0.81-1.00), and similarly, each year of exclusively attending a childcare institution (e.g., crèche) yielded HR = 0.94 (0.84-1.06). Conclusions Forwarding enrollment in childcare by a year lowers the risk of IM later in life much less than having an additional sibling of comparable age and has no practical public health implications. We find our results suggestive of a random threshold for successful Epstein-Barr virus

British Journal of Cancer, Mar 1, 2016

Background: Endometrial cancer is mainly dependent on oestrogen exposure. Preeclampsia has shown ... more Background: Endometrial cancer is mainly dependent on oestrogen exposure. Preeclampsia has shown to reduce oestrogen levels hence preeclampsia may affect later endometrial cancer risk. Methods: We conducted a case-control study of 523 Danish women with endometrial cancer and 52 299 controls during 1978-2010. The association between preeclampsia and later endometrial cancer was evaluated overall and according to preeclampsia onset and type of endometrial cancer in conditional logistic regression models. Results: We observed no overall association between preeclampsia and endometrial cancer risk (OR ¼ 1.11 (95% CI 0.68-1.81)). This was true for all endometrial cancer subtypes. In an analysis of preeclampsia onset, however, we report a markedly increased risk of endometrial cancer following early-onset preeclampsia (OR ¼ 2.64 (95% CI 1.29-5.38)). Conclusions: Although we report no obvious association between preeclampsia and endometrial cancer, studying the subset of early-onset preeclampsia may prove fruitful in further understanding the aetiology of endometrial cancer.

Journal of Hepatology, Jul 1, 2004

Background/Aims: General population studies have shown a strong association between alcohol intak... more Background/Aims: General population studies have shown a strong association between alcohol intake and death from alcoholic cirrhosis, but whether this is a dose-response or a threshold effect remains unknown, and the relation among alcohol misusers has not been studied. Methods: A cohort of 6152 alcohol misusing men and women aged 15-83 were interviewed about drinking pattern and social issues and followed for 84,257 person-years. Outcome was alcoholic cirrhosis mortality. Data was analyzed by means of Cox-regression models. Results: In this large prospective cohort study of alcohol misusers there was a 27 fold increased mortality from alcoholic cirrhosis in men and a 35 fold increased mortality from alcoholic cirrhosis in women compared to the Danish population. Number of drinks per day was not significantly associated with death from alcoholic cirrhosis, since there was no additional risk of death from alcoholic cirrhosis when exceeding an average daily number of five drinks (>60 g/alcohol) in neither men nor women. Conclusions: The results indicate that alcohol has a threshold effect rather than a dose-response effect on mortality from alcoholic cirrhosis in alcohol misusers.

Scandinavian Journal of Public Health, Jul 1, 2011

Introduction: To present the work previously and presently being carried out based on the nationw... more Introduction: To present the work previously and presently being carried out based on the nationwide Childcare Database. Research topics: The Childcare Database comprises individually linked Danish register-based data on childcare attendance, childcare facility characteristics, child and family characteristics, and infectious disease hospitalisations. The database includes about 1 million children aged 0-5 years and has, since the creation, been linked with separate disease registers on atopic disease, pneumococcal disease, and childhood cancers. The present paper is a review of epidemiological studies based on the Childcare Database. Studies of childhood infections confirmed that childcare attendance dramatically increases the risk, but emphasised that the increased risk is often transient and confined to subsets of children. Studies of childhood cancers showed that early childhood infections are likely to reduce the risk of childhood leukaemia and that this risk reduction applies to all children. Conclusion: The Childcare Database is a unique data source for studying the association between childcare attendance and health outcomes. Further linkage with Danish registers is possible on an individual level. The studies based on the Childcare Database confirm and extend previous findings of an increased risk of infection associated with childcare attendance, as well as point towards a possible protective role of early infections in childhood cancer.

Alcoholism: Clinical and Experimental Research, Aug 1, 2008

Pediatrics, Oct 1, 2006

OBJECTIVES. It is well known that children attending childcare have a higher risk of acute respir... more OBJECTIVES. It is well known that children attending childcare have a higher risk of acute respiratory infections compared with children in home care; however, knowledge is sparse regarding how the excess risk of acute respiratory infection varies with age, time since enrollment, and other factors.METHODS. A national register-based study of 138821 inpatient admissions to hospital for acute respiratory infection during 3982925 person-years of follow-up in Danish children aged 0 to 5 years. Data on child and family characteristics, childcare attendance, and hospitalizations were obtained from Danish registries. The outcome of the study was inpatient admissions to hospital for acute respiratory infection. Incidence rate ratios were estimated using Poisson regression.RESULTS. In children <1 year of age, the first 6 months of enrollment in the first childcare facility were associated with a 69% higher incidence of hospitalizations for acute respiratory infection compared with children in home care. Similar figures for children aged 1, 2, and ≥3 years were 47%, 41%, and 8%, respectively. The incidence decreased after the first 6 months, and after ≥1 year in childcare the incidence was comparable with that of children in home care. Similar patterns were seen after second enrollment. For 0- to 2-year-old children living in households with no additional children <5 years, the excess incidence during the first 6 months of enrollment was 100% compared with 25% and 9% for children living with 1 and ≥2 additional children, respectively.CONCLUSIONS. The increased risk of acute respiratory infection was most pronounced among 0- to 2-year-old children living with no other children during the first 6 months of enrollment. Our findings may suggest that it would be optimal to postpone enrollment into childcare until after 1 year of age.

International Journal of Epidemiology, Nov 22, 2022

Background It has been suggested that the transiently increased infection risk following childcar... more Background It has been suggested that the transiently increased infection risk following childcare enrolment is compensated by decreased infection risk later in childhood and adolescence. We investigated how childcare enrolment affected rates of antimicrobial-treated infections during childhood and adolescence. Methods In a register-based cohort study of all children born in Denmark 1997–2014 with available exposure information (n = 1 007 448), we assessed the association between childcare enrolment before age 6 years and infection risks up to age 20 years, using antimicrobial exposure as proxy for infections. Nationwide childcare and prescription data were used. We estimated infection rates and the cumulative number of infections using adjusted Poisson regression models. Results We observed 4 599 993 independent episodes of infection (antimicrobial exposure) during follow-up. Childcare enrolment transiently increased infection rates; the younger the child, the greater the increase. The resulting increased cumulative number of infections associated with earlier age at childcare enrolment was not compensated by lower infection risk later in childhood or adolescence. Accordingly, children enrolled in childcare before age 12 months had experienced 0.5–0.7 more infections at age 6 years (in total 4.5–5.1 infections) than peers enrolled at age 3 years, differences that persisted throughout adolescence. The type of childcare had little impact on infection risks. Conclusions Early age at childcare enrolment is associated with a modest increase in the cumulative number of antimicrobial-treated infections at all ages through adolescence. Emphasis should be given to disrupting infectious disease transmission in childcare facilities through prevention strategies with particular focus on the youngest children.

Human Reproduction, 2013

Study question: how significant are the semen parameters in the second or consecutive ejaculate? ... more Study question: how significant are the semen parameters in the second or consecutive ejaculate? Summary answer: Second ejaculates shows higher rapid(a) motility, reduced volume, reduced slow(b), immotile(d) and non-progressive(c) motility, which are statistically significant. Sperm concentration was higher in the second sample but the difference was not significant. Although the volume in the consecutive sample was reduced significantly the rapid motility was high. What is known already: There are no available standard parameters regarding second ejaculate in literature, but it's used in intra-uterine insemination(IUI) and Assisted reproductive technology(ART) with successful outcomes. Consecutive ejaculates are recommended in literature only in men with anejaculation and men with oligoasthenozoospermia by the limited studies available. Two studies have shown an increase in ART by using the second ejaculate on the day of oocyte pickup which also avoids invasive sperm processing techniques. A clinical pregnancy rate of .30% was seen when second consecutive sperm ejaculate was used in Intra-cytoplastic Sperm Injection(ICSI) cycles. Only one study in English literature tried to look into the differences between the two samples and concluded that the second sample was superior especially in men who have poor or no sperm. Study design, size, duration: This is a single center prospective case series study with a population of 73 men who attended a reproductive clinic in one of the London Hospitals over a period of 1year. Individual patient's initial ejaculate served as control for the consecutive ejaculate. Sperm motility was read immediately after liquefaction in each ejaculate. Participants/materials, setting, methods: The men were requested to produce a second sperm sample within half to one hour of producing the first. Both the samples were analysed and the following parameters were compared: days of abstinence, volume, viscosity, concentration, motility, and morphology. Main results and the role of chance: The mean age was 37 years(95% CI 35-39). There was no correlation between the number of days of abstinence and semen motility, Spearman's coefficient 0.0826; p ¼ 0.4870. There is a statistically significant correlation between number of days of abstinence and ejaculate volume, Spearman's coefficient 0.45, p ¼ 0.0001. In attempting to quantify the relationship between days of abstinence and ejaculate volume, four extreme outliers were excluded and a linear regression model was fitted. For every one day increase in abstinence the corresponding increase in volume is 0.33ml(95% CI 0.15-0.5, p ¼ 0.000). The differences between median viscosities and median concentrations of the first and second samples were not statistically significant. The difference in median normal morphology was not clinically significant. Medians of slow motility, non-progressive motility, and immotile sperms were higher in sample 1 than sample 2, differences of 7 (p ¼ 0.0028), 5 (p ¼ 0.0034), 10 (p ¼ 0.000) respectively. Median rapid motility was lower in sample 1 than sample 2, difference of 25 (p ¼ 0.000). No difference seen in sperm antibodies. Limitations, reason for caution: This is a single centre study and the results may not apply to other centres and regions. The influences of factors such as age and racial background were not explored. The data were highly non-normal and hence non-parametric tests were utilized. The results would need to be replicated in a larger, multi-centre study. Wider implications of the findings: This is the first study to form baseline parameters for consecutive ejaculates yielding more rapidly moving sperms while allowing to compound the ejaculates to yield increased motile sperm numbers in IUI and In-Vitro Fertilization(IVF) procedures. By implementing routine use of second ejaculate pregnancy rates where sperm threshold are borderline, this strategy could be efficient and meaningful leading with potential to increase pregnancies as well as reducing the need for invasive sperm retrieval methods in IVF. Study funding/competing interest(s): Self-funded Trial registration number: N/A SELECTED ORAL COMMUNICATION SESSION