Laust H Mortensen

IT University of Copenhagen, København, Capital Region, Denmark

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Publications (63)248.57 Total impact

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    ABSTRACT: Maternal mortality and morbidity vary substantially worldwide. It is unknown if these geographic differences translate into disparities in severe maternal morbidity among immigrants from various world regions. We assessed disparities in severe maternal morbidity between immigrant women from various world regions giving birth in three high-immigration countries. We used population-based delivery data from Victoria; Australia and Ontario, Canada and national data from Denmark, in the most recent 10-year period ending in 2010 available to each participating centre. Each centre provided aggregate data according to standardized definitions of the outcome, maternal regions of birth and covariates for pooled analyses. We used random effects and stratified logistic regression to obtain odds ratios (ORs) with 95% confidence intervals (95% CIs), adjusted for maternal age, parity and comparability scores. We retrieved 2,322,907 deliveries in all three receiving countries, of which 479,986 (21%) were to immigrant women. Compared with non-immigrants, only Sub-Saharan African women were consistently at higher risk of severe maternal morbidity in all three receiving countries (pooled adjusted OR: 1.67; 95% CI: 1.43, 1.95). In contrast, both Western and Eastern European immigrants had lower odds (OR: 0.82; 95% CI: 0.70, 0.96 and OR: 0.64; 95% CI: 0.49, 0.83, respectively). The most common diagnosis was severe pre-eclampsia followed by uterine rupture, which was more common among Sub-Saharan Africans in all three settings. Immigrant women from Sub-Saharan Africa have higher rates of severe maternal morbidity. Other immigrant groups had similar or lower rates than the majority locally born populations. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.
    The European Journal of Public Health 01/2015; DOI:10.1093/eurpub/cku230 · 2.46 Impact Factor
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    ABSTRACT: To estimate the association between educational status and alcohol-related somatic and non-somatic morbidity and mortality among full siblings in comparison with non-related individuals. Cohort study. Denmark. Approximately 1.4 million full siblings born in Denmark between 1950 and 1979 were followed from age 28 until age 58 or censoring due to alcohol-related hospitalization and mortality. Cox-regression analyses were used to estimate associations of educational status with alcohol-related outcomes. Results from cohort analyses based on non-related individuals and inter-sibling analyses were compared. A lower educational status was associated with a higher rate of alcohol-related outcomes, especially among the youngest (28-37 years of age) and individuals born 1970-1979. Compared with the cohort analyses, the associations attenuated slightly in the inter-sibling analysis. For example in the cohort analysis, females with a basic school education born 1970-1979 had an increased rate of alcohol-related non-somatic morbidity and mortality (Hazard rate ratio (HR) =4.05, CI 95% 3.27-5.02) compared to those with a vocational education. In the inter-sibling analysis, the HR attenuated (HR = 2.66, CI 95% 1.95-3.63). For alcohol-related somatic outcomes the corresponding figures were HR = 3.47 (CI 95% 2.63-4.58) and HR = 3.36 (CI 95% 2.10-5.38), respectively. In general, the associations were stronger among females than males (aged 28-37) in the analyses on alcohol-related non-somatic outcomes. Health conditions earlier in life explained only a minor part of the associations. The association between educational status and alcohol-related somatic and non-somatic morbidity and mortality is only to a small degree driven by familial factors. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Addiction 12/2014; DOI:10.1111/add.12823 · 4.60 Impact Factor
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    ABSTRACT: Independently of cardiovascular disease (CVD) risk factors, cognitive ability may account for some of the excess risk of coronary heart disease (CHD) associated with lower education. We aimed to assess how late adolescence cognitive ability and midlife CVD risk factors are associated with the educational gradient in CHD in Norway.
    Journal of Epidemiology &amp Community Health 11/2014; DOI:10.1136/jech-2014-204597 · 3.29 Impact Factor
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    ABSTRACT: The objective of this study was to describe breastfeeding practices and to compare the risk of suboptimal breastfeeding of women living in Denmark according to country of origin, and further to examine how socio-economic position and duration of stay in the country affected this risk. Information on breastfeeding of 42,420 infants born 2002-2009 and living in eighteen selected Danish municipalities was collected from the Danish Health Visitor's Child Health Database. The data was linked with data on maternal socio-demographic information from Danish population-covering registries. Suboptimal breastfeeding was defined as <4 months of full breastfeeding as described by the Danish Health and Medicines Authority. We used logistic regression to model the crude associations between suboptimal breastfeeding and country of origin, and taking maternal age and parity, and a variety of parental socio-economic measures into account. Suboptimal breastfeeding was more frequent among non-Western migrant women than among women of Danish origin. Women who were descendants of Turkish and Pakistani immigrants had a higher risk of suboptimal breastfeeding as compared to the group of women who had migrated from the same countries, suggesting that acculturation did not favor breastfeeding. For all but the group of women who had migrated from Pakistan, adjustment for socio-demographic indicators (age, parity, education, attachment to labour market, and income) eliminated the increased risk of suboptimal breastfeeding. There was no evidence for differences in the breastfeeding support provided at hospital level according to migrant status. Suboptimal breastfeeding was more frequent among women who were non-Nordic migrants and descendants of migrants than among women with Danish origin.
    Maternal and Child Health Journal 04/2014; 18(10). DOI:10.1007/s10995-014-1486-z · 2.24 Impact Factor
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    ABSTRACT: Objective To assess disparities in preeclampsia and eclampsia among immigrant women from various world regions giving birth in six industrialised countries.DesignCross-country comparative study of linked population-based databases.SettingProvincial or regional obstetric delivery data from Australia, Canada, Spain and the USA and national data from Denmark and Sweden.PopulationAll immigrant and non-immigrant women delivering in the six industrialised countries within the most recent 10-year period available to each participating centre (1995–2010).Methods Data was collected using standardised definitions of the outcomes and maternal regions of birth. Pooled data were analysed with multilevel models. Within-country analyses used stratified logistic regression to obtain odds ratios (OR) with 95% confidence intervals (95% CI).Main outcome measuresPreeclampsia, eclampsia and preeclampsia with prolonged hospitalisation (cases per 1000 deliveries).ResultsThere were 9 028 802 deliveries (3 031 399 to immigrant women). Compared with immigrants from Western Europe, immigrants from Sub-Saharan Africa and Latin America & the Caribbean were at higher risk of preeclampsia (OR: 1.72; 95% CI: 1.63, 1.80 and 1.63; 95% CI: 1.57, 1.69) and eclampsia (OR: 2.12; 95% CI: 1.61, 2.79 and 1.55; 95% CI: 1.26, 1. 91), respectively, after adjustment for parity, maternal age and destination country. Compared with native-born women, European and East Asian immigrants were at lower risk in most industrialised countries. Spain exhibited the largest disparities and Australia the smallest.Conclusion Immigrant women from Sub-Saharan Africa and Latin America & the Caribbean require increased surveillance due to a consistently high risk of preeclampsia and eclampsia.
    BJOG An International Journal of Obstetrics & Gynaecology 04/2014; 121(12). DOI:10.1111/1471-0528.12758 · 3.76 Impact Factor
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    ABSTRACT: To examine whether an excess risk of maternal mortality exists among migrant women in Western Europe. We searched electronic databases for studies published 1970 through 2013 for all observational studies comparing maternal mortality between the host country and a defined migrant population. Results were derived from a random-effects meta-analysis, and statistical heterogeneity assessed by the I (2) statistic. In sub-analyses we also calculated summary estimates stratified by direct and indirect death causes. We included 13 studies with more than 42 million women and 4,995 maternal deaths. Compared with indigenous born women, the pooled risk estimate (RR) was 2.00 with 95 % confidence interval (CI) of 1.72, 2.33. Migrant women had a non-significantly higher risk of dying from direct than indirect death causes; pooled RRs of 2.65 CI 1.88, 3.74 and 1.83 CI 1.37, 2.45. This meta-analysis provides evidence that migrant women in Western European countries have an excess risk of maternal mortality.
    Maternal and Child Health Journal 12/2013; 18(7). DOI:10.1007/s10995-013-1403-x · 2.24 Impact Factor
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    ABSTRACT: Do children born to fathers of advanced age have an increased risk of dying before the age of 5 years? Children born to fathers aged 40 years or more have an increased risk of dying in early childhood due to an excess risk of fatal congenital anomalies, malignancies and external causes. Advanced paternal age has previously been associated with adverse reproductive outcomes and some long-term health problems in the offspring. This is possibly due to specific point mutations, a condition known to increase in the sperm with increasing paternal age. A Danish population-based register study, designed as a prospective cohort study, of 1 575 521 live born children born from 1978 to 2004. The age of the child (in days) was used as the underlying time and the children entered the cohort the day they were born and were followed until 31 December 2009. The children were censored on date of turning 5 years, date of death or date of emigration, whichever occurred first. Data from population-covering registers from Statistics Denmark including the Integrated Database for Labour Market Research, the Medical Birth Registry and the Registry of Causes of Death was linked using the unique civil registry number. Hazard ratios (HR) with 95% confidence intervals (CI) were used to estimate the risk of under-five mortality. The effect of paternal age was examined using restricted cubic splines and paternal age groups. Compared with children born to fathers aged 30-34 years, a statistically significant excess risk was found for children born to fathers aged 40-44 years [HR: 1.10 (95% CI: 1.00-1.21)] and children born to fathers aged 45+ years [HR: 1.16 (95% CI: 1.02-1.32)]. When only looking at 1-5 year olds, the relative risk (HR) among children born to fathers aged 40-44 years increased to 1.24 (95% CI: 1.00-1.53) and the risk in the oldest paternal age group (45+ years) rose to 1.65 (95% CI: 1.24-2.18). The results suggest that the elevated risk for children of fathers aged 40 years or more was primarily attributed to an elevated risk of dying from congenital malformations, malignancies and external causes. Specific causes of death might be misclassified; however, this is not likely to be dependent on paternal age. In some cases, the biological father may differ from the father registered. This misclassification is most likely non-differential. The excess risk of mortality among children born to older fathers is in accordance with the literature. The association needs further attention as it can provide valuable knowledge of the etiology of genetic diseases. Also, the association could become of greater importance in the future if the proportion of fathers aged 40+ years keeps growing. None.
    Human Reproduction 12/2013; 29(2). DOI:10.1093/humrep/det399 · 4.59 Impact Factor
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    ABSTRACT: Uterine rupture is a rare but severe complication in pregnancies after a previous cesarean section. In Denmark, the monitoring of uterine rupture is based on reporting of relevant diagnostic codes to the Danish Medical Birth Registry (MBR). The aim of our study was to examine the validity of registration of uterine rupture in the MBR within the population of pregnant women with prior cesarean section by conducting a review of the medical records. We reviewed 1709 medical records within the population of singleton pregnant woman delivering at term between 1997 and 2007. We retrieved the medical records of all women in the MBR with a code for uterine rupture during labor regardless of whether or not a prior cesarean section had been reported to the registry. In addition medical records of all women with a code for previous cesarean section and delivery of a child with adverse perinatal outcome were retrieved. Among women recorded in the MBR with a previous cesarean section and uterine rupture, only 60.4% actually had a uterine rupture (partial or complete). At least 16.2% of complete uterine ruptures were not reported to the registry. Considering only complete uterine ruptures, the sensitivity and specificity of the codes for uterine rupture were 83.8% and 99.1%, respectively. During the study period the monitoring of uterine rupture in the MBR was inadequate.
    European journal of obstetrics, gynecology, and reproductive biology 11/2013; 173. DOI:10.1016/j.ejogrb.2013.10.033 · 1.97 Impact Factor
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    ABSTRACT: Objective : To examine differences in oral cleft (OC) occurrence based on maternal only and parental country of origin in Denmark from 1981 to 2002. Methods : Data on all live births from the Danish Medical Birth Register from 1981 to 2002 were linked with the Danish Facial Cleft Database. Cleft cases were categorized into isolated and nonisolated cleft lip with or without palate (CL/P) and cleft palate only (CP). Birth prevalence was calculated as cases per 1,000 live born children by maternal country of origin, world region, and mixed parental groups. Results : We identified 3094 OC cases among 1,319,426 live births. Danish-born women had an OC birth prevalence of 2.38 with a 95% confidence interval (CI) (2.29-2.47) and foreign-born women a significant lower prevalence of 2.01 (CI, 1.77-2.27). This difference was explained by a lower isolated CL/P birth prevalence among foreign-born women of 0.97 (CI, 0.81-1.16) versus 1.35 (CI, 1.28-1.41). No significant differences were seen for the remaining subtypes. Parents with the same foreign country of origin had a lower overall OC (1.63; CI, 1.35-1.94) and isolated CL/P (0.76; CI, 0.57-0.99) birth prevalence than Danish-born parents. This was not the case for any of the mixed parental groups. Overall and subtype prevalence rates varied according to maternal categories of world region. Conclusion : In this study we found differences in OC occurrence among all live births in the Danish population based on maternal country of origin from 1981 to 2002. Danish-born women had higher OC and isolated CL/P birth prevalence compared with foreign-born women.
    The Cleft Palate-Craniofacial Journal 09/2013; 51(6). DOI:10.1597/13-140 · 1.11 Impact Factor
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    ABSTRACT: The aim of this study was to investigate early life determinants of developmental coordination disorder (DCD) in 7-year-old children. The study was based on data from 33 354 women and their children who participated in the 7-year follow-up study of the Danish National Birth Cohort. Information on several potential determinants (maternal age at conception, maternal occupational status, smoking and alcohol consumption during pregnancy, child's sex, intrauterine growth restriction, degree of preterm birth, and age at walking) was obtained from population registries, from interviews during pregnancy and when the child was 18 months old. The outcome in this study was DCD at 7 years of age, measured by the validated Developmental Coordination Disorder Questionnaire. The associations between the potential determinants and DCD were estimated using logistic regression. The study population consisted of 17 065 males and 16 289 females (141 [0.4%] born very preterm [23(+0) -31(+6) wk]; 1281 [3.8%] born moderately preterm [32(+0) -36(+6) wk]; 29 044 [87.1%] were born term [37(+0) -41(+6) wk], and 2888 [8.7%] were born post-term [≥42(+0) wk]). Independently of each other, the following determinants were predictors of DCD: being a female (odds ratio [OR] 0.36 [95% confidence interval {CI} 0.31-0.41]); being born very preterm (OR 6.28 [95% CI 3.99-9.89]) or moderately preterm (OR 2.10 [95% CI 1.65-2.67]); being small for gestational age (OR 1.74 [95% CI 1.46-2.08]); being 15 months of age or more at walking attainment (OR 3.05 [95% CI 2.57-3.60]); and maternal occupational status (higher grade professionals (OR 1.28 [95% CI 1.02-1.61); economically inactive (OR 1.43 [95% CI 1.07-1.91]). Young maternal age and smoking were risk factors among term-born children. The risk of DCD increases with decreasing gestational age. Intrauterine growth restriction is also a strong risk factor, as well as delayed walking.
    Developmental Medicine & Child Neurology 08/2013; 55(11). DOI:10.1111/dmcn.12223 · 2.68 Impact Factor
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    ABSTRACT: Differences between the arms in systolic blood pressure (SBP) of ≥10 mmHg have been associated with an increased risk of mortality in patients with hypertensive and chronic renal disease. For the first time, we examined these relationships in a non-clinical population. Cohort study. Participants were 4419 men (mean age 38.37 years) from the Vietnam Experience Study. Bilateral SBP and diastolic BP (DBP), serum lipids, fasting glucose, erythrocyte sedimentation rate, metabolic syndrome, and ankle brachial index were assessed in 1986. Ten per cent of men had an interarm difference of ≥10 and 2.4% of ≥15 mmHg. A 15-year follow-up period gave rise to 246 deaths (64 from cardiovascular disease, CVD). Interarm differences of ≥10 mmHg were associated with an elevated risk of all-cause mortality (hazard ratio, HR, 1.49, 95% confidence interval, CI, 1.04-2.14) and CVD mortality (HR 1.93, 95% CI 1.01-3.69). After adjusting for SBP, DBP, lipids, fasting glucose, and erythrocyte sedimentation rate, associations between interarm differences of ≥10 mmHg and all-cause mortality (HR 1.35, 95% CI 0.94-1.95) and CVD mortality (1.62, 95% CI 0.84-3.14) were significantly attenuated. In this non-clinical cohort study, interarm differences in SBP were not associated with mortality after accounting for traditional CVD risk factors. Interarm differences might not be valuable as an additional risk factor for mortality in populations with a low risk of CVD.
    07/2013; 21(11). DOI:10.1177/2047487313496193
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    ABSTRACT: Limited data suggest that leukocytes of the elderly display ultra-short telomeres. It was reported that in some elderly persons leukocyte telomere length (LTL) shows age-dependent elongation. Using cross-sectional and longitudinal models, we characterized LTL dynamics in participants of the Longitudinal Study of Aging Danish Twins. We measured LTL by Southern blots of the terminal restriction fragment length (TRFL) in 476 individuals (73–94 years) in a cross-sectional evaluation and in a subset of this cohort comprising 80 individuals (73–81 years at baseline) who were followed–up for approximately 10 years. Based on the mean TRFL, we found that a) the average rate of LTL attrition was respectively, 27 bp/year (P < 0.001) and 31 bp/year (P < 0.001) for the cross-sectional and longitudinal evaluations, and b) mean TRFL was 180 bp (95 % CI 43, 320) longer in females than males (P < 0.010). For the TRFL distribution, which captures telomeres of all lengths in the DNA sample, we observed significant shifts with age toward shorter telomeres. Based on the measurement error of the TRFLs, we computed that in the longitudinal evaluation 10.6 % of individuals would manifest LTL elongation over 10 years, assuming a 340 bp attrition during this period. This was not significantly different from the empirical observation of 7.5 % of individuals showing LTL elongation. We conclude that accumulation of ultra-short telomeres in leukocytes of the elderly reflects a shift toward shorter telomeres in the entire telomere distribution. Measurement error is the probable explanation for LTL elongation in longitudinal studies. Electronic supplementary material The online version of this article (doi:10.1007/s10654-013-9780-4) contains supplementary material, which is available to authorized users.
    European Journal of Epidemiology 02/2013; 28(2). DOI:10.1007/s10654-013-9780-4 · 5.15 Impact Factor
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    ABSTRACT: To examine whether family factors shared by siblings explained the association between education and risk of lung, colorectal and breast cancer. We used conventional cohort and intersibling Cox regression analyses to analyse the association between education and risk of cancer. Denmark. We retrieved register data from Statistics Denmark on individuals born in Denmark 1950-1979 with at least one full sibling. The cohorts included between 391 931 and 1 381 369 individuals followed from age 28 for incident lung, colorectal and breast cancer until the end of 2009. In the cohort analysis, low education was associated with an increased risk of colorectal cancer before age 45 and lung cancer, and with a decreased risk of colorectal cancer after age 45 and breast cancer. When compared with the cohort analyses, the intersibling associations were stronger for colorectal cancer after age 45 and weaker for lung cancer. Serious health conditions in childhood/young adulthood did not explain the associations. Family factors shared by siblings confounded some of the association between education and colorectal cancer after age 45 and lung cancer, but not the associations found for colorectal cancer before age 45 or breast cancer.
    BMJ Open 01/2013; 3(3). DOI:10.1136/bmjopen-2012-002114 · 2.06 Impact Factor
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    ABSTRACT: Background:  We sought to examine whether age at immigration and length of residence were associated with preterm and small-for-gestational age (SGA) delivery among immigrant women in Denmark. Methods:  We included all live singleton deliveries from Danish-born women (1 626 880) and women from the five largest immigrant groups (68 936) from 1978 to 2007. Data from the Danish Medical Birth Registry were linked to: parental country of origin, length of residence and age at immigration. Linear and logistic regression models were used to estimate absolute and relative differences with Danish-born women as the reference group. Results:  All immigrant groups had an increased risk of SGA delivery with the highest risk among Lebanese-, Somali- and Pakistani-born women: risk differences (RDs) and 95% confidence intervals [CI] per 1000 deliveries of 50.2 [95% CI 43.7, 56.7], 70.1 [95% CI 62.2, 77.9] and 85.7 [95% CI 78.5, 92.9]. Turkish- and Pakistani-born women had increased RDs of 1.8 [95% CI 0.5, 3.1] and 2.2 [95% CI 0.1, 4.2] for very preterm and RDs of 3.5 [95% CI 0.9, 6.1] and 10.2 [95% CI 5.9, 14.5] for moderate preterm delivery. Lebanese-born women had a decreased risk of very preterm delivery, RD of -1.9 [95% CI -3.5, -0.3] and Somali-born women a lower risk of moderate preterm delivery, RD of -7.8 [-12.0, -3.6]. No differences were seen for the remaining groups. The association with length of residence for most immigrant groups was U-shaped, with highest risks among recent and long-term residents. Conclusion:  Immigration was more strongly related to SGA than to preterm delivery. Observed differences in birth outcomes varied by age at immigration and length of residency in Denmark.
    Paediatric and Perinatal Epidemiology 11/2012; 26(6):534-42. DOI:10.1111/ppe.12010 · 2.16 Impact Factor
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    ABSTRACT: OBJECTIVE: To estimate the impact family factors shared by siblings has on the association between length of education and cause-specific mortality in adulthood. METHODS: The study population (n = 871 367) was all Norwegians born 1940-59 having one or more sibling within the cohort and alive in 1990. Length of education was obtained in 1990. Follow-up of deaths was from 1991 to 2008 when participants were aged 32-68 years. RESULTS: Sixty-five per cent of participants had one or more siblings who had completed a different number of years of formal education. A one-category difference in education was associated with a 30% increase in the hazard rate of death by all causes among men in the cohort analysis and 23% in within siblings analysis, and in women, increases were 22% and 14%, respectively. For cardiovascular disease, increases were 36% and 25% in men and 51% and 36% in women. For lung cancer, they were 48% and 29% in men and 53% and 22% in women. External causes and alcohol-related causes in men were generally similar in both analyses. CONCLUSIONS: This study suggests that at least some of the educational inequalities in all-cause, cardiovascular disease and lung cancer, external and alcohol-related mortality are explained by factors shared by siblings.
    International Journal of Epidemiology 10/2012; 41(6). DOI:10.1093/ije/dys143 · 9.20 Impact Factor
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    ABSTRACT: The mechanisms behind social differences in mortality rates have been debated. The authors examined the extent to which shared family background and health in early life could explain the association between educational status and all-cause mortality rates using a sibling design. The study was register-based and included all individuals born in Denmark between 1950 and 1979 who had at least 1 full sibling born in the same time period (n = 1,381,436). All individuals were followed from 28 years of age until death, emigration, or December 2009. The authors used Cox regression analyses to estimate hazard ratios for mortality according to educational level. Conventional cohort and intersibling analyses were carried out and conducted separately for deaths occurring before and after the age of 45 years, respectively. The cohort analyses showed an inverse association between educational status and all-cause mortality that was strongest for males, increased with younger birth cohorts, and tended to be strongest in the analyses of death before 45 years of age. The associations were attenuated slightly in the intersibling analyses and after adjustment for serious health conditions in early life. Hence, health selection and confounding by factors shared by siblings explained only a minor part of the association between educational level and all-cause mortality.
    American journal of epidemiology 09/2012; 176(8):675-83. DOI:10.1093/aje/kws230 · 4.98 Impact Factor
  • Laust H Mortensen
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    ABSTRACT: A large body of literature has reported associations between socioeconomic position and adverse pregnancy outcomes even in affluent egalitarian welfare states. This study explored the nature of this relationship by examining women who changed socioeconomic position between pregnancies and women who were siblings but were different in terms of socioeconomic position. Data consisted of 471,215 live born singletons born in Denmark 1997-2007 with at least one sibling or one first cousin. We examined parental educational attainment and household income in relation to preterm birth and small for gestational age using Cox regression. Household income was only weakly related to these outcomes. Paternal education was strongly associated with the outcomes only in the cohort analyses. Maternal education was inversely associated with preterm birth only in the cohort analyses, where the least educated women had the highest risk. Maternal education was inversely associated with the risk of small for gestational age in cohort analyses, attenuated between mothers who were siblings, and not present between children who were siblings. For example, the hazard ratio of preterm birth of women with a college/university degree when compared to women with only mandatory education was 0.64 (95% confidence interval: 0.60-0.67) in the cohort analysis, 0.90 (0.78-1.04) between mothers who were siblings, and 1.01 (0.82-1.24) between children who were siblings. The corresponding hazard ratios of small for gestational age were 0.54 (0.52-0.56), 0.72 (0.63-0.83), and 1.02 (0.84-1.24). This suggests that the associations were partly explained by factors shared between mothers who are siblings. In conclusion, the early life circumstances of mothers appear to be important in understanding the association between education, preterm birth and small for gestational age.
    Social Science [?] Medicine 09/2012; 76. DOI:10.1016/j.socscimed.2012.08.021 · 2.56 Impact Factor
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    ABSTRACT: The etiology of brain tumors in children and adolescents is largely unknown, and very few environmental risk factors have been identified. The aim of this study was to examine the relationship between pre- or postnatal animal contacts or farm exposures and the risk of childhood brain tumors (CBTs), since infectious agents may pose a risk factor and a proposed mechanism is transferral of infectious agents from animals to humans. The case-control study conducted in Denmark, Norway, Sweden, and Switzerland included brain tumor cases diagnosed from 2004 to 2008 aged 7-19 years at diagnosis. Three hundred and fifty-two cases (83 % participation rate) were matched to 646 population-based controls (71 % participation rate). Conditional logistic regression was used to estimate odds ratios. Maternal farm residence during pregnancy was inversely related to all CBTs combined (adjusted odds ratio (aOR) = 0.40, 95 % confidence interval (CI) = 0.19-0.88), as was the child's farm residence but not statistically significantly so (aOR = 0.57, 95 % CI = 0.28-1.17). Exposure to animals was in general not related to CBT risk except postnatal contact with birds showing reduced aORs of all CBTs (0.67, 95 % CI = 0.46-0.97) and primitive neuroectodermal tumor (0.28, 95 % CI = 0.10-0.83). Sensitivity analyses focusing on early exposure of the child did not change the associations observed for the entire exposure period with the exception of exposure to goats and sheep which was associated with reduced risks of both all CBTs (aOR = 0.48, 95 % CI = 0.24-0.97) and astrocytomas (aOR = 0.29, 95 % CI = 0.10-0.87). Altogether, our data indicate an inverse association between the mother during pregnancy or the child living on a farm and CBT risk, which contrasts with the existing literature and merits further attention. With respect to exposure to animals, we did not observe any systematic pattern. This suggests that a potential protective effect of farm residence is mediated by some other factor than animal contact.
    Cancer Causes and Control 07/2012; 23(9):1463-73. DOI:10.1007/s10552-012-0020-0 · 3.20 Impact Factor
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    ABSTRACT: The association between microchimerism acquired primarily through pregnancy and later disease is of increasing scientific interest. Because this line of research is new and little is known about the nature of microchimerism, studies of microchimerism are potentially vulnerable to error from confounding and reverse causation. To address the issue of confounding, we conducted an analysis of predictors of male microchimerism in 272 female participants of the Danish Diet, Cancer and Health cohort. Buffy coat DNA was tested for Y chromosome presence as a marker of male microchimerism. First, we used logistic regression and thereafter random forest modeling to evaluate the ability of a range of reproductive, lifestyle, hospital or clinic visit history, and other variables to predict whether women tested positive for male microchimerism. We found some indication that current use of contraceptive pills and hormone replacement therapy reduced the odds of testing positive for male microchimerism. However, prediction of male microchimerism presence was poor based on the available variables. Studies of the possible role of male microchimerism in maternal health and disease are therefore unlikely to be heavily confounded by the variables examined in the present investigation. More research focused on acquisition, retention and clearing of male cells in the maternal circulation is needed.
    07/2012; 3(3). DOI:10.4161/chim.21968
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    ABSTRACT: The purpose of this study was to examine socio-economic differences in the risk of hospitalisation among children aged 0-5 years in Denmark from 1985 to 2004. All children born between 1985 and 2004 (n=1,278,286) were followed for hospital admissions for infectious diseases from the 29th day of life until the children reached the age of 6 years or the end of 2004, whichever came first. Information on parental socio-economic position (education, labour market attachment and household income) was gathered through record linkage with administrative registries. Infections were grouped into upper respiratory, lower respiratory, gastrointestinal, ear and fever infections. The data were analysed using Cox regression. Children of parents on sick leave or early retirement had an increased risk of being hospitalised with an infection compared with children of employed parents. A clear inverse educational gradient in risk of offspring hospitalisation was also found. From 1985 to 2004 the inverse associations between parental education and risk of hospitalisation grew stronger, whereas the comparatively weaker association between household income and risk of offspring hospitalisation decreased in magnitude. The association between socio-economic status and hospitalisation was strongest for lower respiratory, gastrointestinal and ear infections. This study documented a socially patterned hospitalisation of pre-school children in Denmark. Future studies should investigate possible explanations for the increased risk among children from families with low socio-economic status.
    Paediatric and Perinatal Epidemiology 05/2012; 26(3):226-35. DOI:10.1111/j.1365-3016.2011.01255.x · 2.16 Impact Factor

Publication Stats

755 Citations
248.57 Total Impact Points


  • 2009–2015
    • IT University of Copenhagen
      København, Capital Region, Denmark
    • University of Southampton
      • MRC Lifecourse Epidemiology Unit
      Southampton, England, United Kingdom
  • 2012–2013
    • Cardiff University
      • Centre for the Development and Evaluation of Complex Interventions for Public Health Improvement
      Cardiff, Wales, United Kingdom
    • University of Oslo
      Kristiania (historical), Oslo County, Norway
  • 2010–2013
    • University of Copenhagen
      • Section of Social Medicine
      København, Capital Region, Denmark
  • 2008–2012
    • University of Southern Denmark
      • Institute of Public Health
      Odense, South Denmark, Denmark
    • Buskerud and Vestfold University College
      Tønsberg, Vestfold county, Norway
  • 2011
    • University of Bristol
      • School of Social and Community Medicine
      Bristol, England, United Kingdom
  • 2008–2009
    • University of Glasgow
      • MRC/CSO Social and Public Health Sciences Unit
      Glasgow, SCT, United Kingdom
  • 2006–2009
    • National Institute of Public Health
      København, Capital Region, Denmark
  • 2006–2008
    • National Institute of Public Health, Denmark
      København, Capital Region, Denmark
  • 2005
    • Copenhagen University Hospital
      København, Capital Region, Denmark