Laust Hvas Mortensen

Cognitive ability in early adulthood and risk of 5 specific psychiatric disorders in middle age: the Vietnam Experience Study

CONTEXT Lower cognitive ability is a risk factor for some forms of psychopathology, but much of the evidence for risk is based on individuals who required specialist care. It is unclear whether lower ability influences the risk of particular patterns of comorbidity. OBJECTIVE To examine the relation between premorbid cognitive ability in early adulthood and the risk of major depression, generalized anxiety disorder (GAD), posttraumatic stress disorder (PTSD), alcohol and other drug abuse or dependence, and comorbid forms of these conditions in midlife. DESIGN Prospective cohort study in which cognitive ability was measured on enlistment into military service at a mean age of 20.4 years and psychiatric disorder was assessed by structured diagnostic interview at a mean age of 38.3 years. SETTING The United States. PARTICIPANTS A total of 3258 male veterans, participants in the Vietnam Experience Study. MAIN OUTCOME MEASURES Major depression, GAD, PTSD, and alcohol or other drug abuse or dependence since enlistment and currently, diagnosed according to the DSM-III. RESULTS Lower cognitive ability was associated with an increased risk of depression, GAD, alcohol abuse or dependence, and PTSD and with some patterns of comorbidity. For a 1-SD decrease in cognitive ability, unadjusted odds ratios (95% confidence interval) for having these disorders currently were 1.32 (1.12-1.56) for depression, 1.43 (1.27-1.64) for GAD, 1.20 (1.08-1.35) for alcohol abuse or dependence, 1.39 (1.18-1.67) for PTSD, 2.50 (1.41-4.55) for PTSD plus GAD, 2.17 (1.47-3.22) for PTSD plus GAD plus depression, and 2.77 (1.12-6.66) for all 4 disorders. Most associations remained statistically significant after adjustment for confounders. CONCLUSIONS Lower cognitive ability is a risk factor for several specific psychiatric disorders, including some forms of comorbidity. Understanding the mechanisms whereby ability is linked to individual patterns of psychopathology may inform intervention.

Socioeconomic position and the risk of preterm birth : a study within the Danish National Birth Cohort

BACKGROUND Low socioeconomic position is generally associated with increased risk of preterm birth, but it remains unclear whether the inequality depends on the socioeconomic measure used, if the associations differ according to the degree of prematurity, and how individual level risk factors mediate the association. METHODS The hazard ratios (HR) of preterm birth associated with five different measures of socioeconomic position and three degrees of preterm birth were analysed in a dataset of 75 890 singleton pregnancies (1996-2002) from the Danish National Birth Cohort. This, and the mediating role of selected individual level risk factors (smoking, alcohol consumption, binge drinking, pre-pregnancy body mass index, gestational weight gain) were estimated, using Cox regression analyses. RESULTS Mothers with <10 years of education had an elevated risk of preterm birth compared with mothers with >12 years of education and the association interacted with parity, while income and occupation affected the risk to a lesser degree. The adjusted HR for less educated nulliparous and parous women were 1.22 (95% CI 1.04-1.42) and 1.56 (95% CI 1.31-1.87), respectively, compared with women with >12 years of education. For parous women with <10 years of education inclusion of smoking in the model decreased the HR of preterm birth to 1.43 (95% CI 1.19-1.72). CONCLUSIONS Maternal educational level was the strongest predictor of preterm birth among five socioeconomic measures and the gradient did not differ significantly according to the degree of preterm birth. For parous women smoking explained some of the educational gradient but in general the selected risk factors only reduced the relative educational gradient in preterm birth marginally.

Socio-economic inequality in preterm birth: a comparative study of the Nordic countries from 1981 to 2000

During the 1980s and 1990s, there were large social and structural changes within the Nordic countries. Here we examine time changes in risks of preterm birth by maternal educational attainment in Denmark, Finland, Norway and Sweden. Information on gestational age and maternal socio-economic position was obtained from the NorCHASE database, which includes comparable population-based register data of births from Denmark, Finland, Sweden and Norway from 1981 to 2000. The risks of very preterm birth (<32 gestational weeks) and moderately preterm birth (32-36 gestational weeks) were calculated by maternal educational attainment and analysed in 5-year intervals from 1981 to 2000. Compared with mothers with >12 years of education, mothers with <10 years of education had similarly increased risks of very, and to a lesser extent moderately, preterm birth in all four countries. The educational gradient increased slightly over time in very preterm births in Denmark, while there was a slight narrowing of the gap in Sweden. In moderately preterm births, the educational inequality gap was constant over the study period in Denmark, Norway and Sweden, but narrowed in Finland. The educational gradient in preterm birth remained broadly stable from 1981 to 2000 in all four countries. Consequently, the socio-economic inequalities in preterm birth were not strongly influenced by structural changes during the period.

Ethnic disparity in stillbirth and infant mortality in Denmark 1981–2003

Objective: Ethnic minorities constitute a growing part of the Danish population but little is known about ethnic disparity in early life mortality in this population. The aim of this study was to investigate ethnic disparities in stillbirth risk and infant mortality in Denmark from 1981 to 2003. Methods: From population-covering registries, all live and stillbirths of women from the five largest ethnic minority groups and of women from the (Danish) majority population (N = 1 333 452) were identified. The liveborn were followed up for vital status to the age of 1 year. Log-binomial regression was used to estimate relative risks according to ethnic group. The main outcome measure was stillbirth and infant death. Results: Compared with the majority population, the relative risks of stillbirth were 1.28 (95% CI: 1.07 to 1.53) for Turkish, 1.62 (1.25 to 2.09) for Pakistani and 2.11 (1.60 to 2.77) for Somali women. The relative risks of infant mortality were 1.41 (1.22 to 1.63), 1.88 (1.53 to 2.30) and 1.39 (1.03 to 1.89) for children born to Turkish, Pakistani and Somali mothers respectively. The fetal and infant mortality in offspring of Lebanese and Former Yugoslavian women was not different from the mortality in the Danish group. The differences found were, in general, not attributable to ethnic differences in socioeconomic position. Turkish, Pakistani and Somali children had an excess relative risk of infant death due to congenital malformations and the risk of death from perinatal causes was increased among the Pakistani offspring. Conclusion: Among the five largest ethnic minorities, the Turkish. Pakistani and Somali population had substantially higher fetal and infant mortality compared with the Danish majority population, while the Lebanese and Former Yugoslavian minorities were at the same level as the majority population. The excess risk was not attributable to socioeconomic conditions.

Mechanisms underlying the associations of maternal age with adverse perinatal outcomes: a sibling study of 264 695 Danish women and their firstborn offspring

BACKGROUND The mechanisms underlying the association between maternal age (both young and older maternal age) and adverse perinatal outcomes are unclear. METHODS We examined the association of maternal age at first birth with preterm birth (<37 weeks gestation) and small for gestational age (SGA) in a cohort of 264 695 Danish women, each of which had at least one sister in the cohort (n = 121 859 sibling groups). We compared cohort analyses with sister-controlled analyses. The sister-controlled analyses control for all observed and unobserved characteristics that are identical or very similar between sisters, such as childhood socio-economic characteristics-a confounder we hypothesized would exaggerate the young maternal age-adverse outcomes association but mask the older maternal age-adverse outcome association. RESULTS There was a U-shaped association of maternal age with risk of preterm birth (lowest risk age 24-30 years) and SGA (lowest risk age 26-30 years) in cohort analyses. In analyses with sister control, there was a J-shaped association of maternal age with preterm birth, with a monotonic increase in risk across the maternal age range from 24 years of maternal age. For SGA, risk increased across the age range in sister-controlled analyses, being lowest at age 15 years and highest at age 45 years (thought with wide confidence intervals at the extremes of the age distribution). CONCLUSIONS Our findings suggest that different mechanisms underlie the association of younger and older maternal age with adverse perinatal outcomes. Socio-economic position and other characteristics shared by sisters appear to explain most of the association of young maternal age with adverse perinatal outcomes, but the association of older maternal age with preterm birth, and SGA is not explained by this confounding and may even be masked by it.

Socioeconomic inequality in birth outcomes: What do the indicators tell us, and where do we find the data?

All human beings are born free and equal in dignity and rights. — Universal Declaration of Human Rights[1][1] We all know the first words in Article 1 in the United Nations Declaration of Human Rights. We also know, however, that this is more a declaration of intent than of reality, even in the

Income-related and educational inequality in small-for-gestational age and preterm birth in Denmark and Finland 1987-2003

Aims: In this paper, we examine income- and education-related inequality in small-for-gestational age (SGA) and preterm birth in Denmark and Finland from 1987 to 2003 using concentration indexes (CIXs). Methods: From the national medical birth registries we gathered information on all births from 1987 to 2003. Information on highest completed maternal education and household income in the year preceding birth of the offspring was obtained for 1,012,400 births in Denmark and 499,390 in Finland. We then calculated CIXs for income- and education-related inequality in SGA and preterm birth. Results: The mean household income-related inequality in SGA was −0.04 (95% confidence interval: −0.05, −0.04) in Denmark and −0.03 (−0.04, −0.02) in Finland. The maternal education-related inequality in SGA was −0.08 (−0.10, −0.06) in Denmark and −0.07 (−0.08, −0.06) in Finland. The income-related inequality in preterm birth was −0.03 (−0.03, −0.02) in Denmark and −0.03 (−0.04, −0.02) in Finland. The education-related inequality in preterm birth was −0.05 (−0.07, −0.04) in Denmark and −0.04 (−0.05, −0.03) in Finland. In Denmark, the income-related and education-related inequity in SGA increased over time. In Finland, the income-related inequality in SGA birth increased slightly, while education-related inequalities remained stable. Inequalities in preterm birth decreased over time in both countries. Conclusions: Denmark and Finland are examples of nations with free prenatal care and publicly financed obstetric care of high quality. During the period of study there were macroeconomic shocks affecting both countries. However, only small income- and education-related inequalities in SGA and preterm births during the period were observed.

Use of ADHD medication during pregnancy from 1999 to 2010: a Danish register‐based study

This study aimed to describe the trends in use of Attention Deficit Hyperactivity Disorders (ADHD) medication during pregnancy in Denmark from 1999 to 2010, as well as to explore characteristics of women who use ADHD medication during pregnancy and whether exposure is associated with outcome of pregnancy.

Socioeconomic differences in perinatal health and disease

Introduction: The Danish Medical Birth Register has been used extensively in conjunction with other national registers to examine different aspects of socioeconomic differences in perinatal health outcomes. Here, we review some recent findings. Research topics: Socioeconomic differences were observed in stillbirth, preterm birth, birthweight, congenital anomalies, and infant death. The patterns varied according to the health outcome and measure of socioeconomic position, but also according to the time period and the country under study. Our review also shows how many different strategies have been used to examine the influence of socioeconomic factors on perinatal health. Conclusion: Danish register data is an invaluable source of information on socioeconomic differences in perinatal health. Danish registers continue to provide excellent opportunities for research and surveillance in this area.

Parental socioeconomic position and development of overweight in adolescence: longitudinal study of Danish adolescents.

BackgroundAn inverse social gradient in overweight among adolescents has been shown in developed countries, but few studies have examined whether weight gain and the development of overweight differs among adolescents from different socioeconomic groups in a longitudinal study. The objective was to identify the possible association between parental socioeconomic position, weight change and the risk of developing overweight among adolescents between the ages 15 to 21.MethodsProspective cohort study conducted in Denmark with baseline examination in 1996 and follow-up questionnaire in 2003 with a mean follow-up time of 6.4 years. A sample of 1,656 adolescents participated in both baseline (mean age 14.8) and follow-up (mean age 21.3). Of these, 1,402 had a body mass index (BMI = weight/height2kg/m2) corresponding to a value below 25 at baseline when adjusted for age and gender according to guidelines from International Obesity Taskforce, and were at risk of developing overweight during the study period. The exposure was parental occupational status. The main outcome measures were change in BMI and development of overweight (from BMI < 25 to BMI > = 25).ResultsAverage BMI increased from 21.3 to 22.7 for girls and from 20.6 to 23.6 in boys during follow-up. An inverse social gradient in overweight was seen for girls at baseline and follow-up and for boys at follow-up. In the full population there was a tendency to an inverse social gradient in the overall increase in BMI for girls, but not for boys. A total of 13.4% developed overweight during the follow-up period. Girls of lower parental socioeconomic position had a higher risk of developing overweight (ORs between 4.72; CI 1.31 to 17.04 and 2.03; CI 1.10-3.74) when compared to girls of high parental socioeconomic position. A tendency for an inverse social gradient in the development of overweight for boys was seen, but it did not meet the significance criteriaConclusionsThe levels of overweight and obesity among adolescents are high and continue to rise. Results from this study suggest that the inverse social gradient in overweight becomes steeper for girls and emerges for boys in late adolescence (age span 15 to 21 years). Late adolescence seems to be an important window of opportunity in reducing the social inequality in overweight among Danish adolescents.