Cardiovascular and metabolic morbidity in women with previous gestational diabetes mellitus: a nationwide register-based cohort study.

BACKGROUND: Gestational diabetes mellitus (GDM) is associated with adverse pregnancy outcomes and has maternal health implications reaching beyond the perinatal period. We aimed to investigate the incidence and severity of cardiovascular and metabolic morbidity in women with previous GDM in a Danish population and to study whether proxies of impaired beta cell function-insulin treatment during GDM pregnancy and development of subsequent manifest diabetes mellitus-influence incident risk of cardiovascular and metabolic morbidity. METHODS: A nationwide register-based cohort study was conducted on the complete cohort of 700,648 women delivering in Denmark during 1997-2018. The exposure variable was GDM and primary outcome was overall cardiovascular and metabolic morbidity. Secondary outcomes were major cardiovascular disease (ischemic heart disease, heart failure, and/or stroke/transient cerebral ischemia), hypertension, dyslipidemia, and venous thrombosis. Severity of morbidity was assessed using number of hospital contacts with diagnosis codes related to cardiovascular and metabolic morbidity and number of redemptions of prescribed medication related to cardiovascular and metabolic morbidity in women who developed cardiovascular and metabolic morbidity after pregnancy. RESULTS: The median follow-up period was 10.2-11.9 years with a total range of 0-21.9 years. GDM was associated with increased risk of any cardiovascular and metabolic morbidity (adjusted HR 2.13 [95% CI 2.07-2.20]), major cardiovascular disease (adjusted HR 1.69 [95% CI 1.55-1.84]), hypertension (adjusted HR 1.89 [95% CI 1.82-1.96], dyslipidemia (adjusted HR 4.48 [95% CI 4.28-4.69]), and venous thrombosis (adjusted HR 1.32 [95% CI 1.16-1.50]). Insulin treatment during pregnancy and subsequent development of manifest diabetes exacerbated the risk estimates. Previous GDM was associated with more hospital contacts and more redeemed prescriptions in women developing cardiovascular and metabolic morbidity (p < 0.001). CONCLUSIONS: Previous GDM was associated with significantly higher risk of cardiovascular and metabolic morbidity, especially incident dyslipidemia. Risks were exacerbated by proxies of beta cell impairment. Severity of morbidity was significantly worse if GDM preceded cardiovascular and metabolic morbidity.

Preterm birth after the introduction of COVID-19 mitigation measures in Norway, Sweden, and Denmark: a registry-based difference-in-differences study.

BACKGROUND: Although some studies have reported a decrease in preterm birth following the start of the COVID-19 pandemic, the findings are inconsistent. OBJECTIVE: This study aimed to compare the incidences of preterm birth before and after the introduction of COVID-19 mitigation measures in Scandinavian countries using robust population-based registry data. STUDY DESIGN: This was a registry-based difference-in-differences study using births from January 2014 through December 2020 in Norway, Sweden, and Denmark. The changes in the preterm birth (<37 weeks) rates before and after the introduction of COVID-19 mitigation measures (set to March 12, 2020) were compared with the changes in preterm birth before and after March 12 from 2014 to 2019. The differences per 1000 births were calculated for 2-, 4-, 8-, 12-, and 16-week intervals before and after March 12. The secondary analyses included medically indicated preterm birth, spontaneous preterm birth, and very preterm (<32 weeks) birth. RESULTS: A total of 1,519,521 births were included in this study. During the study period, 5.6% of the births were preterm in Norway and Sweden, and 5.7% were preterm in Denmark. There was a seasonal variation in the incidence of preterm birth, with the highest incidence during winter. In all the 3 countries, there was a slight overall decline in preterm births from 2014 to 2020. There was no consistent evidence of a change in the preterm birth rates following the introduction of COVID-19 mitigation measures, with difference-in-differences estimates ranging from 3.7 per 1000 births (95% confidence interval, -3.8 to 11.1) for the first 2 weeks after March 12, 2020, to -1.8 per 1000 births (95% confidence interval, -4.6 to 1.1) in the 16 weeks after March 12, 2020. Similarly, there was no evidence of an impact on medically indicated preterm birth, spontaneous preterm birth, or very preterm birth. CONCLUSION: Using high-quality national data on births in 3 Scandinavian countries, each of which implemented different approaches to address the pandemic, there was no evidence of a decline in preterm births following the introduction of COVID-19 mitigation measures.

Maternal thyroid disorder in pregnancy and risk of cerebral palsy in the child: a population-based cohort study.

BACKGROUND: Cerebral palsy is the most frequent motor disability in childhood, but little is known about its etiology. It has been suggested that cerebral palsy risk may be increased by prenatal thyroid hormone disturbances. The objective of this study was to investigate whether maternal thyroid disorder is associated with increased risk of cerebral palsy. METHODS: A population-based cohort study using two study populations. 1) 1,270,079 children born in Denmark 1979-2007 identified in nationwide registers, and 2) 192,918 children born 1996-2009 recruited into the Danish National Birth Cohort and The Norwegian Mother and Child Cohort study, combined in the MOthers and BAbies in Norway and Denmark (MOBAND) collaboration cohort. Register-based and self-reported information on maternal thyroid disorder was studied in relation to risk of cerebral palsy and its unilateral and bilateral spastic subtypes using multiple logistic regression. Children were followed from the age of 1 year to the age of 6 years, and cerebral palsy was identified in nationwide registers with verified diagnoses. RESULTS: In register data, hypothyroidism was recognized in 12,929 (1.0%), hyperthyroidism in 9943 (0.8%), and unclassifiable thyroid disorder in 753 (< 0.1%) of the mothers. The odds ratio for an association between maternal thyroid disorder and bilateral spastic cerebral palsy was 1.0 (95% CI: 0.7-1.5). Maternal thyroid disorder identified during pregnancy was associated with elevated risk of unilateral spastic cerebral palsy (odds ratio 3.1 (95% CI: 1.2-8.4)). In MOBAND, 3042 (1.6%) of the mothers reported a thyroid disorder in pregnancy, which was not associated with cerebral palsy overall (odds ratio 1.2 (95% CI: 0.6-2.4)). CONCLUSIONS: Maternal thyroid disorder overall was not related to bilateral spastic cerebral palsy, but maternal thyroid disorder identified in pregnancy was associated with increased risk of unilateral spastic cerebral palsy. These findings should be replicated in studies making use of maternal blood samples.

Ten-year follow-up of fracture risk in a systematic population-based screening program: the risk-stratified osteoporosis strategy evaluation (ROSE) randomised trial.

Background: Osteoporotic fractures pose a growing public health concern. Osteoporosis is underdiagnosed and undertreated, highlighting the necessity of systematic screening programs. We aimed to evaluate the effectiveness of a two-step population-based osteoporotic screening program. Methods: This ten-year follow-up of the Risk-stratified Osteoporosis Strategy Evaluation (ROSE) randomized trial tested the effectiveness of a screening program utilizing the Fracture Risk Assessment Tool (FRAX) for major osteoporotic fractures (MOF) to select women for dual-energy x-ray absorptiometry (DXA) scan following standard osteoporosis treatment. Women residing in the Region of Southern Denmark, aged 65-80, were randomised (single masked) into a screening or a control group by a computer program prior to inclusion and subsequently approached with a mailed questionnaire. Based on the questionnaire data, women in the screening group with a FRAX value ≥15% were invited for DXA scanning. The primary outcome was MOF derived from nationwide registers. ClinicalTrials.gov: NCT01388244, status: Completed. Findings: All randomised women were included February 4, 2010-January 8, 2011, the same day as approached to participate. During follow-up, 7355 MOFs were observed. No differences in incidences of MOF were identified, comparing the 17,072 women in the screening group with the 17,157 controls in the intention-to-treat analysis (IRR 1.01, 0.95; 1.06). However, per-protocol, women DXA-scanned exhibited a 14% lower incidence of MOF (IRR 0.86, 0.78; 0.94) than controls with a FRAX value ≥15%. Similar trends were observed for hip fractures, all fractures, and mortality. Interpretation: While the ROSE program had no overall effect on osteoporotic fracture incidence or mortality it showed a preventive effect for women at moderate to high risk who underwent DXA scans. Hence the overall effect might have been diluted by those who were not at an intervention level threshold risk or those who did not show up for DXA. Using self-administered questionnaires as screening tools may be inefficient for systematic screening due to the low and differential screening uptake. Funding: INTERREG and the Region of Southern Denmark.

Excess mortality following a first and subsequent osteoporotic fracture: a Danish nationwide register-based cohort study on the mediating effects of comorbidities.

OBJECTIVES: This study aimed to examine the risk of mortality following incident and subsequent osteoporotic fractures, the effect of different fracture type combinations, and the mediating role of postfracture morbidity in a Danish population. METHODS: We used the National Patient Registry to identify patients ≥60 years with incident major osteoporotic fracture of the hip, vertebrae, wrist or humerus between 2013 and 2018, and controls matched 1:10 on age and sex. Possible mediators were identified using International Classification of Diseases, 10th Revision codes registered in the 6 months following index fracture. HRs were estimated using Cox regression analyses with 95% CIs. The effect of possible mediators was estimated using mediation analyses. RESULTS: The study included 106 303 patients and 1 062 988 controls. Mortality following index fracture was highest in the month following hip fractures (HR 10.98 (95% CI 10.23 to 11.79) in women and HR 16.40 (95% CI 15.00 to 17.93) in men). Subsequent hip fractures resulted in the highest HRs for all fracture type combinations. In women, the highest HR was observed in patients with index wrist/subsequent hip fractures (HR 2.43 (95% CI 2.12 to 2.78)). In men, the highest HR was observed in patients with index humerus/subsequent hip fractures (HR 2.69 (95% CI 2.04 to 3.54)). Pneumonia mediated the largest proportion of mortality, but dehydration, urinary tract infection and sepsis were also important factors. CONCLUSIONS: The highest mortality risk was found in the month immediately following both index and subsequent fracture. The combination of index and subsequent fractures at different skeletal sites had a substantial impact on the risk of mortality. Postfracture morbidities were found mediate the association.

Diabetes Mellitus Mediates Risk of Depression in Danish Women with Polycystic Ovary Syndrome-A National Cohort Study.

AIM: To investigate the risk of depression in Danish women with PCOS compared to controls and possible mediators for depression in PCOS. National register-based study in Danish women with PCOS (PCOS Denmark, N = 25,203) and age-matched controls (N = 112,414). PCOS Odense University Hospital (PCOS OUH, N = 998) was a sub-cohort of women with PCOS with available clinical and biochemical results. The main study outcome was depression occurring after PCOS diagnosis. Depression was defined according to hospital ICD-10 diagnosis codes and/or inferred from filled medicine prescription of antidepressants. Diabetes, medical comorbidity, infertility, hormonal anti-contraception and low family income were entered as mediators in Cox regression analyses for depression. In PCOS OUH, PCOS characteristics (age, BMI, Ferriman-Gallwey score) were entered in Cox regression analyses. The median age at cohort entry was 28 (interquartile range (IQR) 23; 35) years. The median follow-up time to incident depression or censuring was 4.8 (IQR 2.2; 8.8) years in PCOS Denmark and 5.2 (IQR 2.4; 9.2) years in controls. Women with PCOS had a 40% increased risk of depression compared to controls (Hazard Ratio 1.42 (95% CI 1.38; 1.47). In regression analyses, diabetes, medical comorbidity, infertility, hormonal anticonception, and low family income were significant mediators of depression. Mediation analyses showed that the proportion of the association explained by diabetes was 12.5% (95% CI 10.4; 14.5). In PCOS OUH, BMI, waist and Ferriman-Gallwey score predicted development of depression. CONCLUSION: The risk of depression was increased in PCOS. Diabetes was an important mediator of depression in PCOS.

Cardiovascular risk in Danish transgender persons: a matched historical cohort study.

Background: Cardiovascular risk could be increased in transgender persons, but the mechanism is undetermined. Aim: The aim of this study was to assess the risk of cardiovascular outcomes in Danish transgender persons compared to controls. Methods: The study design was a historical register-based cohort study in Danish transgenders and age-matched controls. The main outcome measure was cardiovascular diagnosis (any CVD) including medicine prescriptions for CVD during 2000-2018. The transgender cohort (n = 2671) included persons with International Classification of Diseases-10 diagnosis code of 'gender identity disorder' (n = 1583) and persons with legal sex change (n = 1088), 1270 were assigned female at birth (AFAB) and 1401 were assigned male at birth (AMAB). Controls (n = 26 710) were matched by age (n = 5 controls of same and n = 5 controls of other birth sex) of the respective transgender. Results: The median (interquartile range) age at study inclusion was 22 (18; 29) years for AFAB and 26 (21; 39) years for AMAB. The mean (s.d.) follow-up time was 4.5 (4.2) years for AFAB and 5.7 (4.8) years for AMAB. The hazard ratio (HR) for any CVD was significantly higher in transgenders vs controls of same and other birth sex, with highest adjusted HR in transgenders AFAB vs control men: 2.20 (95% CI: 1.64;2.95), P < 0.001. Gender-affirming hormone treatment (GAHT) explained part of elevated risk of CVD in transgenders AFAB, whereas GAHT did not contribute to the elevated risk of CVD in transgenders AMAB. Conclusions: The risk of cardiovascular diagnosis was increased in transgenders. The mechanism should be further investigated.

Cerebral palsy among children of immigrants in Denmark and the role of socioeconomic status.

BACKGROUND: Children of immigrants in Denmark have excess risk for some of the most well-established risk factors for cerebral palsy (CP). OBJECTIVES: To study differences in risk of CP between children of immigrants and children of Danish-born mothers, and explore whether socioeconomic status drives any potential association. METHODS: A register-based cohort study including 1,274,616 children born in Denmark between 1981 and 2007. Of these, 2807 had a validated CP diagnosis in the Danish CP Register. We estimated the risk of CP as odds ratios (OR) using logistic regression and assessed mediation through socioeconomic status using natural effect models. RESULTS: In children of Danish-born mothers, 2.2/1000 had CP overall and the prevalence was similar for children of immigrants. However, children of immigrants had lower risk of unilateral spastic CP than children of Danish native-born mothers; OR = 0.59 (95% CI:0.38-0.91) for Western and OR = 0.79 (95% CI:0.61-1.03) for Non-Western immigrants. By contrast, the risk of bilateral spastic CP was higher in children of Non-Western immigrants (OR = 1.27 (95% CI:1.05-1.53)), especially from Turkey and Pakistan compared with children of Danish native-born mothers. The mediation analysis revealed an indirect effect (through maternal educational level and household income) with an OR of 1.06 (95% CI:0.99-1.14) for children of Non-Western immigrants. CONCLUSIONS: While children of immigrants had lower risk of unilateral spastic CP than children of Danish-born mothers, the risk of bilateral spastic CP was increased in children of Non-Western immigrants. Socioeconomic status did not appear to be a significant contributor to the increased risk of bilateral spastic CP.

Parental socioeconomic status and risk of cerebral palsy in the child: evidence from two Nordic population-based cohorts.

Background: We investigated whether the risk of cerebral palsy (CP) in the child varies by parents' socioeconomic status, in Denmark and Norway. Methods: We included almost 1.3 million children born in Demark during 1981-2007 and 2.4 million children born in Norway during 1967-2007, registered in the Medical Birth registries. Data on births were linked to Statistics Denmark and Norway to retrieve information on parents' education and relationship status and, in Denmark, also income. CP diagnoses were obtained from linkage with national registries. We used multivariate log-binominal regression models to estimate relative risk (RR) of CP according to parental socioeconomic status. Results: There was a strong trend of decreasing risk of CP with additional education of both the mother and the father. These trends were nearly identical for the two parents, with a one-third reduction in risk for those with the highest education compared with parents with the lowest education. When both parents had high education, risk of CP was further reduced (RR 0.58, 0.53-0.63). Women with partners had a reduction in risk (RR 0.79, 0.74-0.85) compared with single mothers overall. Risk patterns were stable over time, across countries and within spastic bilateral and unilateral CP. Household income was not associated with risk of CP. Conclusions: Risk of CP in two Scandinavian countries was lower among educated parents and mothers with a partner, but unrelated to income. Factors underlying this stable association with education are unknown, but could include differences in potentially modifiable lifestyle factors and health behaviours.

Use of paracetamol, ibuprofen or aspirin in pregnancy and risk of cerebral palsy in the child.

Background: It has been debated whether mild analgesics, mainly paracetamol, adversely affect aspects of neurodevelopment. We examined whether mother's use of paracetamol, aspirin or ibuprofen in pregnancy is associated with increased risk of cerebral palsy (CP) in the child. Method: We included 185 617 mother-child pairs from the Danish National Birth Cohort and the Norwegian Mother and Child Cohort Study. We created harmonized definitions of analgesic use in pregnancy, as well as indications for analgesic use and other potential confounders. Children with CP were identified in nationwide registers. We estimated the average causal effect of analgesics on risk of CP using marginal structural models with stabilized inverse probability weights. Results: Paracetamol use was reported in 49% of all pregnancies, aspirin in 3% and ibuprofen in 4%. Prenatal exposure to paracetamol ever in pregnancy was associated with increased risk of overall CP [adjusted odds ratio (aOR) 1.3, 95% confidence interval (CI): 1.0-1.7] and unilateral spastic CP (aOR 1.5, 95% CI: 1.0-2.2). The association appeared to be driven by an increased risk of unilateral spastic CP in children exposed in second trimester (aOR 1.6, 95% CI: 1.0-2.5). Children ever prenatally exposed to aspirin in pregnancy had an elevated risk of bilateral spastic CP (aOR 2.4, 95% CI: 1.1-5.3) compared with unexposed. Conclusion: We observed an increased risk of spastic CP in children prenatally exposed to paracetamol and aspirin. Although we controlled for several important indications for analgesic use, we cannot exclude the possibility of confounding by underlying diseases.

Cohort profile: cerebral palsy in the Norwegian and Danish birth cohorts (MOBAND-CP).

PURPOSE: The purpose of MOthers and BAbies in Norway and Denmark cerebral palsy (MOBAND-CP) was to study CP aetiology in a prospective design. PARTICIPANTS: MOBAND-CP is a cohort of more than 210 000 children, created as a collaboration between the world's two largest pregnancy cohorts-the Norwegian Mother and Child Cohort study (MoBa) and the Danish National Birth Cohort. MOBAND-CP includes maternal interview/questionnaire data collected during pregnancy and follow-up, plus linked information from national health registries. FINDINGS TO DATE: Initial harmonisation of data from the 2 cohorts has created 140 variables for children and their mothers. In the MOBAND-CP cohort, 438 children with CP have been identified through record linkage with validated national registries, providing by far the largest such sample with prospectively collected detailed pregnancy data. Several studies investigating various hypotheses regarding CP aetiology are currently on-going. FUTURE PLANS: Additional data can be harmonised as necessary to meet requirements of new projects. Biological specimens collected during pregnancy and at delivery are potentially available for assay, as are results from assays conducted on these specimens for other projects. The study size allows consideration of CP subtypes, which is rare in aetiological studies of CP. In addition, MOBAND-CP provides a platform within the context of a merged birth cohort of exceptional size that could, after appropriate permissions have been sought, be used for cohort and case-cohort studies of other relatively rare health conditions of infants and children.