Severe Obesity in Young Women and Reproductive Health: The Danish National Birth Cohort

Background

Little is known about reproductive health in severely obese women. In this study, we present associations between different levels of severe obesity and a wide range of health outcomes in the mother and child.

Methods

From the Danish National Birth Cohort, we obtained self-reported information about prepregnant body mass index (BMI) for 2451 severely obese women and 2450 randomly selected women from the remaining cohort who served as a comparison group. Information about maternal and infant outcomes was also self-reported or came from registers. Logistic regression was used to estimate the association between different levels of severe obesity and reproductive outcomes.

Principal Findings

Subfecundity was more frequent in severely obese women, and during pregnancy, they had an excess risk of urinary tract infections, gestational diabetes, preeclampsia and other hypertensive disorders which increased with severity of obesity. They tended to have a higher risk of both pre- and post-term birth, and risk of cesarean and instrumental deliveries increased across obesity categories. After birth, severely obese women more often failed to initiate or sustain breastfeeding. Risk of weight retention 1.5 years after birth was similar to that of other women, but after adjustment for gestational weight gain, the risk was increased, especially in women in the lowest obesity category. In infants, increasing maternal obesity was associated with decreased risk of a low birth weight and increased risk of a high birth weight. Estimates for ponderal index showed the same pattern indicating an increasing risk of neonatal fatness with severity of obesity. Infant obesity measured one year after birth was also increased in children of severely obese mothers.

Conclusion

Severe obesity is correlated with a substantial disease burden in reproductive health. Although the causal mechanisms remain elusive, these findings are useful for making predictions and planning health care at the individual level.     

Incidence of Otitis Media in a Contemporary Danish National Birth Cohort

Objectives

In recent years welfare in Denmark has increased which might be expected to reduce otitis media (OM) incidence. We examined the age-specific incidence of OM in a nation-wide cohort of children aged 0–7 years born in 1996–2003 (Danish National Birth Cohort, DNBC). Only selection was ability to understand and speak Danish.

Methods

Information of OM and ventilation tubes (VT) was collected through three maternal interviews at 6-month, 18-month and 7-years of age and based on this age-specific and cumulative incidence of OM was calculated. As different numbers of the total population answered the different interviews, the calculations are done with different denominators. The information in DNBC was validated against two population based registries containing information of VT insertions.

Results

Cumulative incidence of OM at 7 years was 60.6% (31,982/52,755). For children with OM, 16.2% (7143/44194) had their first OM episodes between 0–6 months of age, 44.3% (19579/44194) between 7–18 months, and 39.5% (17472/44194) between 19 months and 7 years. Four or more OM episodes before 7 years were reported by 39.5% (12620/31982) and by 64.0% (2482/3881) of those who had their OM debut between 0–6 months; by 48.2% (4998/10378) with debut between 7–18 months; and by 28.7% (4996/17344) with debut between 19 months and 7 years. These figures are essentially unchanged from earlier figures from Denmark. VT insertion at least once was reported by 26,1% in the 7-year interview. Assuming recordings in the Danish National Patient Registry to be gold standard, maternal self-reportings in DNBC of insertion of VT showed high sensitivity (96.4%), specificity (98.2%), and positive (94.8%) and negative predictive values (98.8%).

Conclusion

OM affects nearly 2/3 of preschool children in Denmark despite reduction in known OM risk factors.     

Characterization of Dietary Patterns in the Danish National Birth Cohort in Relation to Preterm Birth

Background

Dietary patterns better reflect eating habits as opposed to single dietary components. However, the use of dietary pattern analysis in nutritional epidemiology has been hampered by the complexity of interpreting and presenting multidimensional dietary data.

Methods

This study extracts and visualizes dietary patterns from self-reported dietary data collected in mid-pregnancy (25^th week of gestation) from nearly 60,000 mother-child pairs part of a prospective, longitudinal cohort (Danish National Birth Cohort) and further examines their associations with spontaneous and induced preterm birth (gestational age<259 days (<37 weeks)).

Results

A total of seven dietary patterns were extracted by principal component analysis, characterized and visualized by color-coded spider plots, and referred to as: Vegetables/Prudent, Alcohol, Western, Nordic, Seafood, Candy and Rice/Pasta/Poultry. A consistent dose-response association with preterm birth was only observed for Western diet with an odds ratio of 1.30 (95% CI: 1.13, 1.49) comparing the highest to the lowest quintile. This association was primarily driven by induced preterm deliveries (odds ratio = 1.66, 95% CI: 1.30, 2.11, comparing the highest to the lowest quintile) while the corresponding odds ratio for spontaneous preterm deliveries was more modest (odds ratio = 1.18, 95% CI: 0.99, 1.39). All based on adjusted analyses.

Conclusions

In conclusion, this study presented a simple and novel framework for visualizing correlation structures between overall consumption of foods group and their relation to nutrient intake and maternal characteristics. Our results suggest that Western-type diet, high in meat and fats and low in fruits and vegetables, is associated with increased odds of induced preterm birth.     

Anemia and Dental Caries in Pregnant Women: a Prospective Cohort Study

The objective was to evaluate the effect of anemia during pregnancy on the risk of dental caries development in pregnant women. A prospective cohort including a sample of pregnant women in a prenatal care unit of São Luís, Brazil, was done. The incidence of dental caries during pregnancy, according to Nyvad’s criteria, was the outcome. The main independent variables were serum iron, ferritin, hemoglobin, erythrocyte, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW). Pregnant women (n = 121) were evaluated at two moments: up to 16th week of gestational age (T1) and in the last trimester of pregnancy (T2). Crude and adjusted associations were estimated by the incidence ratio risk (IRR) and respective 95% confidence intervals (95%CI). After adjustment, higher serum concentrations of ferritin (IRR = 0.97, 95%CI 0.95–0.99) in T1, and Fe (IRR = 0.99, 95%CI 0.98–0.99), ferritin (IRR = 0.99, 95%CI 0.98–0.99), erythrocyte (IRR = 0.71, 95%CI 0.50–0.99), hemoglobin (IRR = 0.84, 95%CI 0.73–0.96), hematocrit (IRR = 0.93, 95%CI 0.88–0.98), MCV (IRR = 0.91, 95%CI 0.86–0.96), and MCH (IRR = 0.83, 95%CI 0.74–0.93) in T2, were associated with fewer incidence of dental caries in pregnant women. Iron deficiency anemia during pregnancy is a risk factor for the incidence of dental caries in these women.     

Vitamin D Status and the Risk for Hospital-Acquired Infections in Critically Ill Adults: A Prospective Cohort Study

Introduction

To identify patient characteristics associated with low serum 25-hydroxyvitamin D (25(OH)D) concentrations in the medical intensive care unit (ICU) and examine the relationship between serum 25(OH)D and the risk for hospital-acquired infections.

Methods

This is a prospective observational cohort of adult patients admitted to the medical ICU at an urban safety net teaching hospital in Atlanta, Georgia from November 1, 2011 through October 31, 2012 with an anticipated ICU stay ≥ 1 day. Phlebotomy for serum 25(OH)D measurement was performed on all patients within 5 days of ICU admission. Patients were followed for 30 days or until death or hospital discharge, whichever came first. Hospital-acquired infections were determined using standardized criteria from review of electronic medical record.

Results

Among the 314 patients analyzed, 178 (57%) had a low vitamin D at a serum 25(OH)D concentration < 15 ng/mL. The patient characteristics associated with low vitamin D included admission during winter months (28% vs. 18%, P = 0.04), higher PaO2/FiO2 (275 vs. 226 torr, P = 0.03) and a longer time from ICU admission to study phlebotomy (1.8 vs. 1.5 days, P = 0.02). A total of 36 (11%) patients were adjudicated as having a hospital-acquired infection and in multivariable analysis adjusting for gender, alcohol use, APACHE II score, time to study phlebotomy, ICU length of stay and net fluid balance, serum 25(OH)D levels < 15 ng/mL were not associated with risk for hospital-acquired infections (HR 0.85, 95% CI 0.40-1.80, P = 0.7).

Conclusions

In this prospective, observational cohort of adults admitted to a single-center medical ICU, we did not find a significant association between low 25(OH)D and the risk for hospital-acquired infections.     

Prospective Validation of a Prognostic Model for Respiratory Syncytial Virus Bronchiolitis in Late Preterm Infants: A Multicenter Birth Cohort Study

Objectives

This study aimed to update and validate a prediction rule for respiratory syncytial virus (RSV) hospitalization in preterm infants 33–35 weeks gestational age (WGA).

Study Design

The RISK study consisted of 2 multicenter prospective birth cohorts in 41 hospitals. Risk factors were assessed at birth among healthy preterm infants 33–35 WGA. All hospitalizations for respiratory tract infection were screened for proven RSV infection by immunofluorescence or polymerase chain reaction. Multivariate logistic regression analysis was used to update an existing prediction model in the derivation cohort (n = 1,227). In the validation cohort (n = 1,194), predicted versus actual RSV hospitalization rates were compared to determine validity of the model.

Results

RSV hospitalization risk in both cohorts was comparable (5.7% versus 4.9%). In the derivation cohort, a prediction rule to determine probability of RSV hospitalization was developed using 4 predictors: family atopy (OR 1.9; 95%CI, 1.1–3.2), birth period (OR 2.6; 1.6–4.2), breastfeeding (OR 1.7; 1.0–2.7) and siblings or daycare attendance (OR 4.7; 1.7–13.1). The model showed good discrimination (c-statistic 0.703; 0.64–0.76, 0.702 after bootstrapping). External validation showed good discrimination and calibration (c-statistic 0.678; 0.61–0.74).

Conclusions

Our prospectively validated prediction rule identifies infants at increased RSV hospitalization risk, who may benefit from targeted preventive interventions. This prediction rule can facilitate country-specific, cost-effective use of RSV prophylaxis in late preterm infants.     

The Novel 10-Item Asthma Prediction Tool: External Validation in the German MAS Birth Cohort

Background

A novel non-invasive asthma prediction tool from the Leicester Cohort, UK, forecasts asthma at age 8 years based on 10 predictors assessed in early childhood, including current respiratory symptoms, eczema, and parental history of asthma.

Objective

We aimed to externally validate the proposed asthma prediction method in a German birth cohort.

Methods

The MAS-90 study (Multicentre Allergy Study) recorded details on allergic diseases prospectively in about yearly follow-up assessments up to age 20 years in a cohort of 1,314 children born 1990. We replicated the scoring method from the Leicester cohort and assessed prediction, performance and discrimination. The primary outcome was defined as the combination of parent-reported wheeze and asthma drugs (both in last 12 months) at age 8. Sensitivity analyses assessed model performance for outcomes related to asthma up to age 20 years.

Results

For 140 children parents reported current wheeze or cough at age 3 years. Score distribution and frequencies of later asthma resembled the Leicester cohort: 9% vs. 16% (MAS-90 vs. Leicester) of children at low risk at 3 years had asthma at 8 years, at medium risk 45% vs. 48%. Performance of the asthma prediction tool in the MAS-90 cohort was similar (Brier score 0.22 vs. 0.23) and discrimination slightly better than in the original cohort (area under the curve, AUC 0.83 vs. 0.78). Prediction and discrimination were robust against changes of inclusion criteria, scoring and outcome definitions. The secondary outcome ‘physicians’ diagnosed asthma at 20 years'' showed the highest discrimination (AUC 0.89).

Conclusion

The novel asthma prediction tool from the Leicester cohort, UK, performed well in another population, a German birth cohort, supporting its use and further development as a simple aid to predict asthma risk in clinical settings.     

Umbilical Serum Copper Status and Neonatal Birth Outcomes: a Prospective Cohort Study

Our study aimed to assess the distribution of copper (Cu) in umbilical cord serum and estimated the association between umbilical serum Cu status and neonatal birth outcomes in a Chinese population. Through the Ma’anShan Birth Cohort Study, 2689 maternal-singleton pairs with detailed birth records and available serum samples were identified. The tertile levels of ln-transformed Cu were used to define low, medium, and high levels for serum Cu. The median for umbilical cord serum Cu was 298.2 μg/L with a range of 123.1–699.6 μg/L in this study population. Our study found a positive association between the concentration of serum Cu in the umbilical cord and the duration of gestation. Compared with medium Cu levels, we found that infants with low Cu levels had a significant higher risk of preterm birth (OR = 5.06, 95% CI 2.74, 9.34) and early-term birth (OR = 1.36, 95% CI 1.10, 1.69) in the crude model. We also found that infants with high Cu levels had a significant higher risk of late- or post-term birth (OR = 1.47, 95% CI 1.11, 1.95). A significant higher risk of preterm, early-term, and late- or post-term birth still remained, even after adjustment for potential confounding factors. Our findings suggested that both Cu deficiency and Cu overload had an adverse effect on neonatal birth outcomes.     

Relationship of Urinary Phthalate Metabolites with Serum Thyroid Hormones in Pregnant Women and Their Newborns: A Prospective Birth Cohort in Taiwan

Background

The purpose of this study was to examine the relationship of phthalates exposure with thyroid function in pregnant women and their newborns.

Methods

One hundred and forty-eight Taiwanese maternal and infant pairs were recruited from E-Da hospital in southern Taiwan between 2009 and 2010 for analysis. One-spot urine samples and blood samples in the third trimester of pregnant women and their cord blood samples at delivery were collected. Nine phthalate metabolites in urine were determined by triple quadrupole liquid chromatography tandem mass spectrometry, whereas serum from pregnant women and their cord blood were used to measure thyroid profiles (thyroid-stimulating hormone [TSH], thyroxine, free thyroxine, and triiodothyronine) by radioimmunoassay.

Results

Median levels of urinary mono-n-butyl phthalate, mono-ethyl phthalate, and mono-(2-ethyl-5-oxohexyl) phthalate (μg/g creatinine) were the three highest phthalate metabolites, which were 37.81, 34.51, and 21.73, respectively. Using Bonferroni correction at a significance of < 0.006, we found that urinary mono-benzyl phthalate (MBzP) levels were significantly and negatively associated with serum TSH in cord blood (β = -2.644, p = 0.003).

Conclusions

Maternal urinary MBzP, of which the parental compound is butylbenzyl phthalate, may affect TSH activity in newborns. The alteration of thyroid homeostasis by certain phthalates in the early life, a critical period for neurodevelopment, is an urgent concern.     

Clinical Disorders in a Post War British Cohort Reaching Retirement: Evidence from the First National Birth Cohort Study

Background

The medical needs of older people are growing because the proportion of the older population is increasing and disease boundaries are widening. This study describes the distribution and clustering of 15 common clinical disorders requiring medical treatment or supervision in a representative British cohort approaching retirement, and how health tracked across adulthood.

Methods and Findings

The data come from a cohort of 2661 men and women, 84% of the target sample, followed since birth in England, Scotland and Wales in 1946, and assessed at 60–64 years for: cardio and cerebro-vascular disease, hypertension, raised cholesterol, renal impairment, diabetes, obesity, hypothyroidism, hyperthyroidism, anaemia, respiratory disease, liver disease, psychiatric problems, cancers, atrial fibrillation on ECG and osteoporosis. We calculated the proportions disorder-free, with one or more disorders, and the level of undiagnosed disorders; and how these disorders cluster into latent classes and relate to health assessed at 36 years. Participants had, on average, two disorders (range 0–9); only 15% were disorder-free. The commonest disorders were hypertension (54.3%, 95% CI 51.8%–56.7%), obesity (31.1%, 28.8%–33.5%), raised cholesterol (25.6%, 23.1–28.26%), and diabetes or impaired fasting glucose (25.0%, 22.6–27.5%). A cluster of one in five individuals had a high probability of cardio-metabolic disorders and were twice as likely than others to have been in the poorest health at 36 years. The main limitations are that the native born sample is entirely white, and a combination of clinical assessments and self reports were used.

Conclusions

Most British people reaching retirement already have clinical disorders requiring medical supervision. Widening disease definitions and the move from a disease-based to a risk-based medical model will increase pressure on health services. The promotion of healthy ageing should start earlier in life and consider the individual''s ability to adapt to and self manage changes in health.     

Development and Validation of a Risk Score for Chronic Kidney Disease in HIV Infection Using Prospective Cohort Data from the D:A:D Study

Background

Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice.

Methods and Findings

A total of 17,954 HIV-positive individuals from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study with ≥3 estimated glomerular filtration rate (eGFR) values after 1 January 2004 were included. Baseline was defined as the first eGFR > 60 ml/min/1.73 m2 after 1 January 2004; individuals with exposure to tenofovir, atazanavir, atazanavir/ritonavir, lopinavir/ritonavir, other boosted protease inhibitors before baseline were excluded. CKD was defined as confirmed (>3 mo apart) eGFR ≤ 60 ml/min/1.73 m². Poisson regression was used to develop a risk score, externally validated on two independent cohorts.In the D:A:D study, 641 individuals developed CKD during 103,185 person-years of follow-up (PYFU; incidence 6.2/1,000 PYFU, 95% CI 5.7–6.7; median follow-up 6.1 y, range 0.3–9.1 y). Older age, intravenous drug use, hepatitis C coinfection, lower baseline eGFR, female gender, lower CD4 count nadir, hypertension, diabetes, and cardiovascular disease (CVD) predicted CKD. The adjusted incidence rate ratios of these nine categorical variables were scaled and summed to create the risk score. The median risk score at baseline was −2 (interquartile range –4 to 2). There was a 1:393 chance of developing CKD in the next 5 y in the low risk group (risk score < 0, 33 events), rising to 1:47 and 1:6 in the medium (risk score 0–4, 103 events) and high risk groups (risk score ≥ 5, 505 events), respectively. Number needed to harm (NNTH) at 5 y when starting unboosted atazanavir or lopinavir/ritonavir among those with a low risk score was 1,702 (95% CI 1,166–3,367); NNTH was 202 (95% CI 159–278) and 21 (95% CI 19–23), respectively, for those with a medium and high risk score. NNTH was 739 (95% CI 506–1462), 88 (95% CI 69–121), and 9 (95% CI 8–10) for those with a low, medium, and high risk score, respectively, starting tenofovir, atazanavir/ritonavir, or another boosted protease inhibitor.The Royal Free Hospital Clinic Cohort included 2,548 individuals, of whom 94 individuals developed CKD (3.7%) during 18,376 PYFU (median follow-up 7.4 y, range 0.3–12.7 y). Of 2,013 individuals included from the SMART/ESPRIT control arms, 32 individuals developed CKD (1.6%) during 8,452 PYFU (median follow-up 4.1 y, range 0.6–8.1 y). External validation showed that the risk score predicted well in these cohorts. Limitations of this study included limited data on race and no information on proteinuria.

Conclusions

Both traditional and HIV-related risk factors were predictive of CKD. These factors were used to develop a risk score for CKD in HIV infection, externally validated, that has direct clinical relevance for patients and clinicians to weigh the benefits of certain antiretrovirals against the risk of CKD and to identify those at greatest risk of CKD.     

Risk of Inflammatory Bowel Disease According to Self-Rated Health,Pregnancy Course,and Pregnancy Complications: A Study within the Danish National Birth Cohort

Background

Poor self-rated health (SRH) has been connected to immunological changes, and pregnancy complications have been suggested in the etiology of autoimmune diseases including inflammatory bowel disease (IBD). We evaluated the impact of self-rated pre-pregnancy health and pregnancy course, hyperemesis, gestational hypertension, and preeclampsia on risk of IBD.

Methods

Information was collected by questionnaires from The Danish National Birth Cohort (enrolment 1996–2002) at 16^th and 30^th week of pregnancy and 6 months postpartum. A total of 55,699 women were followed from childbirth until development of IBD (using validated National Hospital Discharge Register diagnoses), emigration, death, or end of follow-up, 31^st of October, 2011. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated using Cox proportional hazards models adjusting for age and evaluating pre-pregnancy BMI, parity, alcohol and tobacco consumption, and socio-occupational status as potential confounders.

Results

Risk of IBD increased with decreasing level of self-rated pre-pregnancy health (p = 0.002) and was elevated in women with poor self-rated pregnancy course (HR, 1.61, 95% CI 1.22–2.12). Associations persisted for more than 5 years postpartum. Hyperemesis and preeclampsia were not significantly associated with risk of IBD.

Conclusions

This is the first prospective observational study to suggest that poor self-rated health – in general and in relation to pregnancy – is associated with increased risk of IBD even in the long term though results needs further confirmation. Symptoms of specific pregnancy complications were, on the other hand, not significantly associated with risk of IBD.     

Breastfeeding and Snoring: A Birth Cohort Study

Objective

To investigate the relationship between breastfeeding and snoring in childhood.

Methods

In a cohort of children with a family history of asthma who were recruited antenatally we prospectively recorded data on infant feeding practices throughout the first year of life. Snoring status and witnessed sleep apnea were measured at age 8 years by parent-completed questionnaire. Associations were estimated by logistic regression with, and without, adjustment for sets of confounders designed to exclude biasing effects.

Results

Habitual snoring was reported in 18.8% of the sample, and witnessed apnea in 2.7%. Any breastfeeding for longer than one month was associated with a reduced risk of habitual snoring at age 8 (adjusted OR 0.48, 95% CI 0.29 to 0.81) and duration of breastfeeding was inversely associated with the prevalence of habitual snoring (adjusted OR 0.79, 95% CI 0.62 to 1.00). Any breastfeeding for longer than 1 month was associated with a lower risk of witnessed sleep apnea (adjusted OR 0.17, 95% CI 0.04 to 0.71). The protective associations were not mediated by BMI, current asthma, atopy or rhinitis at age 8 years.

Conclusions

Breastfeeding for longer than one month decreases the risk of habitual snoring and witnessed apneas in this cohort of children with a family history of asthma. The underlying mechanism remains unclear but the finding would be consistent with a beneficial effect of the breast in the mouth on oropharyngeal development with consequent protection against upper airway dysfunction causing sleep-disordered breathing.     

Development and Validation of a Risk-Score Model for Type 2 Diabetes: A Cohort Study of a Rural Adult Chinese Population

Some global models to predict the risk of diabetes may not be applicable to local populations. We aimed to develop and validate a score to predict type 2 diabetes mellitus (T2DM) in a rural adult Chinese population. Data for a cohort of 12,849 participants were randomly divided into derivation (n = 11,564) and validation (n = 1285) datasets. A questionnaire interview and physical and blood biochemical examinations were performed at baseline (July to August 2007 and July to August 2008) and follow-up (July to August 2013 and July to October 2014). A Cox regression model was used to weigh each variable in the derivation dataset. For each significant variable, a score was calculated by multiplying β by 100 and rounding to the nearest integer. Age, body mass index, triglycerides and fasting plasma glucose (scores 3, 12, 24 and 76, respectively) were predictors of incident T2DM. The model accuracy was assessed by the area under the receiver operating characteristic curve (AUC), with optimal cut-off value 936. With the derivation dataset, sensitivity, specificity and AUC of the model were 66.7%, 74.0% and 0.768 (95% CI 0.760–0.776), respectively. With the validation dataset, the performance of the model was superior to the Chinese (simple), FINDRISC, Oman and IDRS models of T2DM risk but equivalent to the Framingham model, which is widely applicable in a variety of populations. Our model for predicting 6-year risk of T2DM could be used in a rural adult Chinese population.     

The Association between Nonylphenols and Sexual Hormones Levels among Pregnant Women: A Cohort Study in Taiwan

Background

Nonylphenol (NP) has been proven as an endocrine disrupter and had the ability to interfere with the endocrine system. Though the health effects of NP on pregnant women and their fetuses are sustained, these negative associations related to the mechanisms of regulation for estrogen during pregnancy need to be further clarified. The objective of this study is to explore the association between maternal NP and hormonal levels, such as estradiol, testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH), and progesterone.

Methods

A pregnant women cohort was established in North Taiwan between March and December 2010. Maternal urine and blood samples from the first, second, and third trimesters of gestation were collected. Urinary NP concentration was measured by high-performance liquid chromatography coupled with fluorescent detection. A mixed-effects model using a generalised estimating equation (GEE) was applied to assess the associations between maternal NP concentration and plasma hormones throughout the three trimesters.

Results

In total, 162 singleton pregnant women completed this study through delivery. The geometric mean of creatinine-adjusted urinary NP concentrations were 4.27, 4.21, and 4.10 µg/g cre. in the first, second, and third trimesters respectively. A natural log-transformation of urinary NP concentrations were significantly associated with LH in the GEE model (β = −0.23 mIU/ml, p<0.01).

Conclusion

This perspective cohort study demonstrates that negative association occurs between maternal NP exposure and plasma LH levels. The estrogen-mimic effect of NP might influence the negative feedback on LH during pregnancy.     

National Cohort Study of Suicidality and Violent Criminality among Danish Immigrants

Background

Immigrant populations in western societies have grown in their size and diversity yet evidence is incomplete for their risks of suicidality and criminal violence. We examined these correlated harmful behaviours in a national cohort.

Aims

(i) Compare absolute risk between first and second generation immigrants, foreign-born adoptees and native Danes by plotting cumulative incidence curves to onset of early middle age; (ii) estimate sex-specific relative risks for these immigrant type subgroups vs. native Danes; (iii) examine effect modification by higher vs. lower socio-economic status.

Methods

In a cohort of over two million persons, attempted suicides and violent crimes were investigated using data from multiple interlinked registers. We plotted sex-specific cumulative incidence curves and estimated incidence rate ratios.

Results

In the whole study cohort, 1414 people died by suicide, 46,943 attempted suicide, and 51,344 were convicted of committing a violent crime. Among all immigrant subgroups combined, compared with native Danes, relative risk of attempted suicide was greater in female immigrants (incidence rate ratio, 1.59; 95% confidence interval: CI 1.54-1.64) than in male immigrants (1.26; CI 1.20-1.32), and vice versa for relative risk of violent offending in male immigrants (2.36; CI 2.31-2.42) than in female immigrants (1.74; CI 1.62-1.87). Risk for both adverse outcomes was significantly elevated in virtually every gender-specific immigrant type subgroup examined. Violent crime risk was markedly raised in first generation immigrant males and in the Danish born male children of two immigrant parents. However, male immigrants of lower social status had lower risk of attempted suicide than their native Danish peers.

Conclusion

Young immigrants of both first and second generation status face serious challenges and vulnerabilities that western societies need to urgently address. Relative risk patterns for these adverse outcomes vary greatly between the genders and also by socioeconomic status. This high degree of heterogeneity points to the existence of modifiable factors that are amenable to positive change and a potential for effective intervention.     

Vitamin D Status and Cause-Specific Mortality: A General Population Study

Background

Vitamin D deficiency is associated with an increased risk of all-cause mortality in observational studies. The specific causes of death underlying this association lack clarity. We investigated the association between vitamin D status and cause-specific mortality.

Methods

We included a total of 9,146 individuals from the two population-based studies, Monica10 and Inter99, conducted in 1993–94 and 1999–2001, respectively. Vitamin D status was assessed as serum 25-hydroxyvitamin D. Information on causes of death was obtained from The Danish Register of Causes of Death until 31 December 2009. There were a total of 832 deaths (median follow-up 10.3 years).

Results

Multivariable Cox regression analyses with age as underlying time axis and vitamin D quartiles showed significant associations between vitamin D status and death caused by diseases of the respiratory system, the digestive system, and endocrine, nutritional and metabolic diseases with hazard ratios (HRs) 0.26 (p_trend = 0.0042), 0.28 (p_trend = 0.0040), and 0.21 (p_trend = 0.035), respectively, for the fourth vitamin D quartile compared to the first. We found non-significantly lower HRs for death caused by mental and behavioural diseases and diseases of the nervous system, but no association between vitamin D status and death caused by neoplasms or diseases of the circulatory system.

Conclusion

The associations of vitamin D status and cause-specific mortality suggest that we also look elsewhere (than to cardiovascular disease and cancer) to explain the inverse association between vitamin D status and mortality.