Acoustic Enrichment of Heterogeneous Circulating Tumor Cells and Clusters from Metastatic Prostate Cancer Patients

BACKGROUND

There are important unmet clinical needs to develop cell enrichment technologies to enable unbiased label-free isolation of both single cell and clusters of circulating tumor cells (CTCs) manifesting heterogeneous lineage specificity. Here, we report a pilot study based on the microfluidic acoustophoresis enrichment of CTCs using the CellSearch CTC assay as a reference modality.

METHODS

Acoustophoresis uses an ultrasonic standing wave field to separate cells based on biomechanical properties (size, density, and compressibility), resulting in inherently label-free and epitope-independent cell enrichment. Following red blood cell lysis and paraformaldehyde fixation, 6 mL of whole blood from 12 patients with metastatic prostate cancer and 20 healthy controls were processed with acoustophoresis and subsequent image cytometry.

RESULTS

Acoustophoresis enabled enrichment and characterization of phenotypic CTCs (EpCAM+, Cytokeratin+, DAPI+, CD45-/CD66b-) in all patients with metastatic prostate cancer and detected CTC-clusters composed of only CTCs or heterogeneous aggregates of CTCs clustered with various types of white blood cells in 9 out of 12 patients. By contrast, CellSearch did not detect any CTC clusters, but detected comparable numbers of phenotypic CTCs as acoustophoresis, with trends of finding a higher number of CTCs using acoustophoresis.

CONCLUSION

Our preliminary data indicate that acoustophoresis provides excellent possibilities to detect and characterize CTC clusters as a putative marker of metastatic disease and outcomes. Moreover, acoustophoresis enables the sensitive label-free enrichment of cells with epithelial phenotypes in blood and offers opportunities to detect and characterize CTCs undergoing epithelial-to-mesenchymal transitioning and lineage plasticity.

Acetaminophen Use During Pregnancy and Children's Risk of Autism, ADHD, and Intellectual Disability

Importance

Several studies suggest that acetaminophen (paracetamol) use during pregnancy may increase risk of neurodevelopmental disorders in children. If true, this would have substantial implications for management of pain and fever during pregnancy.

Objective

To examine the associations of acetaminophen use during pregnancy with children's risk of autism, attention-deficit/hyperactivity disorder (ADHD), and intellectual disability.

Design, Setting, and Participants

This nationwide cohort study with sibling control analysis included a population-based sample of 2 480 797 children born in 1995 to 2019 in Sweden, with follow-up through December 31, 2021.

Exposure

Use of acetaminophen during pregnancy prospectively recorded from antenatal and prescription records.

Main Outcomes and Measures

Autism, ADHD, and intellectual disability based on International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision codes in health registers.

Results

In total, 185 909 children (7.49%) were exposed to acetaminophen during pregnancy. Crude absolute risks at 10 years of age for those not exposed vs those exposed to acetaminophen were 1.33% vs 1.53% for autism, 2.46% vs 2.87% for ADHD, and 0.70% vs 0.82% for intellectual disability. In models without sibling control, ever-use vs no use of acetaminophen during pregnancy was associated with marginally increased risk of autism (hazard ratio [HR], 1.05 [95% CI, 1.02-1.08]; risk difference [RD] at 10 years of age, 0.09% [95% CI, -0.01% to 0.20%]), ADHD (HR, 1.07 [95% CI, 1.05-1.10]; RD, 0.21% [95% CI, 0.08%-0.34%]), and intellectual disability (HR, 1.05 [95% CI, 1.00-1.10]; RD, 0.04% [95% CI, -0.04% to 0.12%]). To address unobserved confounding, matched full sibling pairs were also analyzed. Sibling control analyses found no evidence that acetaminophen use during pregnancy was associated with autism (HR, 0.98 [95% CI, 0.93-1.04]; RD, 0.02% [95% CI, -0.14% to 0.18%]), ADHD (HR, 0.98 [95% CI, 0.94-1.02]; RD, -0.02% [95% CI, -0.21% to 0.15%]), or intellectual disability (HR, 1.01 [95% CI, 0.92-1.10]; RD, 0% [95% CI, -0.10% to 0.13%]). Similarly, there was no evidence of a dose-response pattern in sibling control analyses. For example, for autism, compared with no use of acetaminophen, persons with low (<25th percentile), medium (25th-75th percentile), and high (>75th percentile) mean daily acetaminophen use had HRs of 0.85, 0.96, and 0.88, respectively.

Conclusions and Relevance

Acetaminophen use during pregnancy was not associated with children's risk of autism, ADHD, or intellectual disability in sibling control analysis. This suggests that associations observed in other models may have been attributable to familial confounding.

Mode of delivery and subsequent self-perceived sexual life satisfaction: a population-based cohort study

BACKGROUND

The potential association between mode of obstetrical delivery and subsequent sexual outcomes of the birthing parent remains uncertain and has not been well investigated from the perspective of positive sexual life satisfaction.

OBJECTIVE

This study aimed to investigate if there was any association between mode of delivery and subsequent sexual life satisfaction of the birthing parent. A secondary aim was to assess the extent to which this association changed when stratified by time elapsed since delivery.

STUDY DESIGN

The study matched participants in the Stockholm Public Health Cohort with deliveries recorded in the Swedish Medical Birth Register. Any deliveries recorded in the registry before the participation in the Stockholm Public Health Cohort were included (n=46,078). The length of time from delivery to outcome assessment varied from 1 month to 41 years (mean, 18 years [±10.8]). Mode of delivery was retrieved from the same registry, whereas self-perceived sexual life satisfaction was retrieved from the Stockholm Public Health Cohort Questionnaires where participants had assessed their sexual life satisfaction as 1 out of 5 mutually exclusive options. Multinomial logistic regression was used to test for any association between mode of delivery (cesarean, instrumental, and spontaneous vaginal delivery) and sexual life satisfaction, both overall and stratified by time elapsed since delivery.

RESULTS

After adjusting for covariates, no statistically significant (P < .05) difference in subsequent sexual life satisfaction of the birthing parent between modes of delivery was identified. Adjusted odds ratios for assessing sexual life satisfaction as the lowest level ("very unsatisfactory") were 1.11 (95% confidence interval, 0.98-1.25) for cesarean delivery and 1.16 (95% confidence interval, 0.99-1.35) for instrumental delivery, compared with spontaneous vaginal delivery. The difference in covariate-adjusted prevalence of the lowest level of sexual life satisfaction among the different groups categorized by time since delivery was small: 4.0% (95% confidence interval, 2.4%-5.6%) for cesarean delivery as opposed to 2.8% (95% confidence interval, 2.1%-3.6%) for spontaneous vaginal delivery within 2 years since delivery.

CONCLUSION

These findings do not support any impact of mode of delivery on the subsequent self-perceived sexual life satisfaction among birthing people, either overall or across different time periods since delivery.

Trends and patterns of antiseizure medication prescribing during pregnancy between 1995 and 2018 in the United Kingdom: A cohort study

OBJECTIVE

To examine antiseizure medication (ASM) prescription during pregnancy.

DESIGN

Population-based drug utilisation study.

SETTING

UK primary and secondary care data, 1995-2018, from the Clinical Practice Research Datalink GOLD version.

POPULATION OR SAMPLE

752 112 completed pregnancies among women registered for a minimum of 12 months with an 'up to standard' general practice prior to the estimated start of pregnancy and for the duration of their pregnancy.

METHODS

We described ASM prescription across the study period, overall and by ASM indication, examined patterns of prescription during pregnancy including continuous prescription and discontinuation, and used logistic regression to investigate factors associated with those ASM prescription patterns.

MAIN OUTCOME MEASURES

Prescription of ASMs during pregnancy and discontinuation of ASMs before and during pregnancy.

RESULTS

ASM prescription during pregnancy increased from 0.6% of pregnancies in 1995 to 1.6% in 2018, driven largely by an increase in women with indications other than epilepsy. Epilepsy was an indication for 62.5% of pregnancies with an ASM prescription and non-epilepsy indications were present for 66.6%. Continuous prescription of ASMs during pregnancy was more common in women with epilepsy (64.3%) than in women with other indications (25.3%). Switching ASMs was infrequent (0.8% of ASM users). Factors associated with discontinuation included age ≥35, higher social deprivation, more frequent contact with the GP and being prescribed antidepressants or antipsychotics.

CONCLUSIONS

ASM prescription during pregnancy increased between 1995 and 2018 in the UK. Patterns of prescription around the pregnancy period vary by indication and are associated with several maternal characteristics.

Maternal intrahepatic cholestasis of pregnancy and neurodevelopmental conditions in offspring: A population-based cohort study of 2 million Swedish children

BACKGROUND

Intrahepatic cholestasis of pregnancy (ICP) is the most common obstetric liver disorder and is associated with an increased risk of iatrogenic preterm birth and adverse infant outcomes. Hence, there are several plausible pathways through which ICP could affect offspring neurodevelopment. However, to the best of our knowledge, no studies have investigated these associations. Thus, we aimed to determine whether ICP is associated with offspring neurodevelopmental conditions.

METHODS AND FINDINGS

In this Swedish register-based cohort study, we included singleton non-adopted children born in Sweden between the 1st of January 1987 and the 31st of December 2010, who were resident in Sweden >5 years, with no missing covariate information, which we followed until the 31st of December 2016. Maternal ICP diagnosis and the date of the initial diagnosis during pregnancy were obtained from the National Patient Register. Offspring diagnoses of attention deficit/hyperactivity disorder (ADHD), autism, or intellectual disability were obtained from the National Patient Register, and the dispensation of ADHD medications were obtained from the Prescribed Drug Register. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression while controlling for observed confounders and unobserved confounders shared among full siblings and maternal full cousins. A total of 2,375,856 children were included in the study; 81.6% of them were of Nordic origin, and 51.4% were male. Of these, 10,378 (0.44%) were exposed to ICP. During a median of 18 years follow-up (interquartile range 11 to 24), 143,746 (6.05%) of children were diagnosed with a neurodevelopmental condition. After adjusting for child's sex, birth year, birth month, maternal age, highest parental education level, maternal birth country, birth order, maternal psychiatric history, ICP was associated with increased odds of offspring neurodevelopmental conditions (OR 1.22, 95% CI 1.13 to 1.31), particularly among those exposed to early-onset ICP (OR 2.38, 95% CI 1.71 to 3.30) as compared to ICP diagnosed after reaching term (≥37 weeks of gestation) (OR 1.08, 95% CI 0.97 to 1.20). The findings of early-onset ICP were consistent in family-based analyses. Within-family comparisons of full maternal cousins yielded an OR of 2.99 (95% CI 1.48 to 6.04), and comparisons of full siblings showed an OR of 1.92 (95% CI 0.92 to 4.02), though the latter was less precise. The findings were consistent across specific neurodevelopmental conditions and different analytical approaches. The primary limitations of this study included its observational design, the absence of data on ICP therapeutics, and the lack of bile acid measures.

CONCLUSIONS

In this study, we observed that exposure to ICP during gestation is associated with an increased likelihood of neurodevelopmental conditions in offspring, particularly in cases of early-onset ICP. Further studies are warranted to better understand the role of early-ICP in offspring neurodevelopment.

Acoustic enrichment of heterogenous circulating tumor cells and clusters from patients with metastatic prostate cancer

Background

There are important unmet clinical needs to develop cell enrichment technologies to enable unbiased label-free isolation of both single cell and clusters of circulating tumor cells (CTCs) manifesting heterogeneous lineage specificity. Here, we report a pilot study based on microfluidic acoustophoresis enrichment of CTCs using the CellSearch CTC assay as a reference modality.

Methods

Acoustophoresis uses an ultrasonic standing wave field to separate cells based on biomechanical properties (size, density, and compressibility) resulting in inherently label-free and epitope-independent cell enrichment. Following red blood cell lysis and paraformaldehyde fixation, 6 mL of whole blood from 12 patients with metastatic prostate cancer and 20 healthy controls were processed with acoustophoresis and subsequent image cytometry.

Results

Acoustophoresis enabled enrichment and characterization of phenotypic CTCs (EpCAM+, Cytokeratin+, DAPI+, CD45-/CD66b-) in all patients with metastatic prostate cancer and detected CTC-clusters composed of only CTCs or heterogenous aggregates of CTCs clustered with various types of white blood cells in 9 out of 12 patients. By contrast, CellSearch did not detect any CTC-clusters, but detected comparable numbers of phenotypic CTCs as acoustophoresis, with trends of finding higher number of CTCs using acoustophoresis.

Conclusion

Our preliminary data indicate that acoustophoresis provides excellent possibilities to detect and characterize CTC-clusters as a putative marker of metastatic disease and outcomes. Moreover, acoustophoresis enables sensitive label-free enrichment of cells with epithelial phenotype in blood and offers opportunities to detect and characterize CTCs undergoing epithelial-to-mesenchymal transitioning and lineage plasticity.

The Association Between Tobacco Use and Risk of COVID-19 Infection and Clinical Outcomes in Sweden: A Population-Based Study

Background: The association between tobacco use and COVID-19 is controversial. During the early course of the pandemic, limited testing prevented studying a wide spectrum of clinical manifestations. Objective: To examine the potential causal association between tobacco use and COVID-19 during the second wave (1 October 2020-30 June 2021) of the pandemic in Stockholm, Sweden. Methods: A population-based cohort study was conducted in the Stockholm region of Sweden, with information on tobacco use collected prior to the pandemic. Adjusted relative risks (RR) of COVID-19 and 95% confidence intervals (CI) were calculated, contrasting current smokers and snus users to non-users of tobacco. Results: Compared with non-users of tobacco, current smokers had a lower risk of COVID-19 (RR 0.78, 95% CI = 0.75-0.81) and of hospitalisation for the disease. Current snus users had a higher risk of COVID-19. Heavy smokers and snus users had longer hospital stays than non-users of tobacco. Conclusion: Tobacco use may have a different impact on the risk of being infected with SARS-CoV-2 and the risk of developing severe clinical manifestations. Further research is needed to determine the underlying mechanisms.

Prevalence of cannabis use among young adults in Sweden comparing randomized response technique with a traditional survey

BACKGROUND AND AIMS

The prevalence of cannabis use based on self-reports is likely to be underestimated in population surveys, especially in contexts where its use is a criminal offence. Indirect survey methods ask sensitive questions ensuring that answers cannot be identified with an individual respondent, therefore potentially resulting in more reliable estimates. We aimed to measure whether the indirect survey method 'randomized response technique' (RRT) increased response rate and/or increased disclosure of cannabis use among young adults compared with a traditional survey.

DESIGN

We conducted two parallel nation-wide surveys during the spring and the summer of 2021. The first survey was a traditional questionnaire-based one (focusing on substance use and gambling). The second survey applied an indirect survey method known as 'the cross-wise model' to questions related to cannabis use. The two surveys employed identical procedures (e.g. invitations, reminders and wording of the questions) SETTING AND PARTICIPANTS: The participants were young adults (aged 18-29 years) living in Sweden. The traditional survey had 1200 respondents (56.9% women) and the indirect survey had 2951 respondents (53.6% women).

MEASUREMENTS

In both surveys, cannabis use was assessed according to three time-frames: life-time use; use during the past year; and use during the past 30 days.

FINDINGS

The estimated prevalence of cannabis use was two- to threefold higher on all measures when estimated using the indirect survey method compared with the traditional survey: use during life-time (43.2 versus 27.3%); during the past year (19.2 versus 10.4%); and during the past 30 days (13.2 versus 3.7%). The discrepancy was larger among males and individuals with an education shorter than 10 years, who were unemployed, and who were born in non-European countries.

CONCLUSIONS

Indirect survey methods may provide more accurate estimates than traditional surveys on prevalence of self-reported cannabis use.

Bias amplification of unobserved confounding in pharmacoepidemiological studies using indication-based sampling

PURPOSE

Estimating causal effects in observational pharmacoepidemiology is a challenging task, as it is often plagued by confounding by indication. Restricting the sample to those with an indication for drug use is a commonly performed procedure; indication-based sampling ensures that the exposed and unexposed are exchangeable on the indication-limiting the potential for confounding by indication. However, indication-based sampling has received little scrutiny, despite the hazards of exposure-related covariate control.

METHODS

Using simulations of varying levels of confounding and applied examples we describe bias amplification under indication-based sampling.

RESULTS

We demonstrate that indication-based sampling in the presence of unobserved confounding can give rise to bias amplification, a self-inflicted phenomenon where one inflates pre-existing bias through inappropriate covariate control. Additionally, we show that indication-based sampling generally leads to a greater net bias than alternative approaches, such as regression adjustment. Finally, we expand on how bias amplification should be reasoned about when distinct clinically relevant effects on the outcome among those with an indication exist (effect-heterogeneity).

CONCLUSION

We conclude that studies using indication-based sampling should have robust justification - and that it should by no means be considered unbiased to adopt such approaches. As such, we suggest that future observational studies stay wary of bias amplification when considering drug indications.

Does misclassification of former tobacco smokers explain the 'smoker's paradox' in the risk of COVID-19? Insights from the Stockholm Public Health Cohort

BACKGROUND

The association between tobacco smoking and the risk of COVID-19 and its adverse outcomes is controversial, as studies reported contrasting findings. Bias due to misclassification of the exposure in the analyses of current versus non-current smoking could be a possible explanation because former smokers may have higher background risks of the disease due to co-morbidity. The aim of the study was to investigate the extent of this potential bias by separating non-, former, and current smokers when assessing the risk or prognosis of diseases.

METHODS

We analysed data from 43,400 participants in the Stockholm Public Health Cohort, Sweden, with information on smoking obtained prior to the pandemic. We estimated the risk of COVID-19, hospital admissions and death for (a) former and current smokers relative to non-smokers, (b) current smokers relative to non-current smokers, that is, including former smokers; adjusting for potential confounders (aRR).

RESULTS

The aRR of a COVID-19 diagnosis was elevated for former smokers compared with non-smokers (1.07; 95% confidence interval (CI) =1.00-1.15); including hospital admission with any COVID-19 diagnosis (aRR= 1.23; 95% CI = 1.03-1.48); or with COVID-19 as the main diagnosis (aRR=1.23, 95% CI= 1.01-1.49); and death within 30 days with COVID-19 as the main or a contributory cause (aRR=1.40; 95% CI=1.00-1.95). Current smoking was negatively associated with risk of COVID-19 (aRR=0.79; 95% CI=0.68-0.91).

CONCLUSIONS

Separating non-smokers from former smokers when assessing the disease risk or prognosis is essential to avoid bias. However, the negative association between current smoking and the risk of COVID-19 could not be entirely explained by misclassification.

Current tobacco use and COVID-19 diagnoses in a cohort of adult clients of public dental clinics in Sweden

Smoking has been linked with both increased and decreased risk of COVID-19, prompting the hypothesis of a protective role of nicotine in the pathogenesis of the disease. Studies of the association between use of smokeless tobacco and COVID-19 would help refining this hypothesis. We analysed data from 424,386 residents in the Stockholm Region, Sweden, with information on smoking and smokeless tobacco (snus) use prior to the pandemic obtained from dental records. Diagnoses of COVID-19 between February and October 2020 were obtained from health-care registers. We estimated the risk of receiving a diagnosis of COVID-19 for current smokers and for current snus users relative to non-users of tobacco, adjusting for potential confounders (aRR). The aRR of COVID -19 was elevated for current snus users (1.09 ;95%CI = 0.99-1.21 among men and 1.15; 95%CI = 1.00-1.33 among women). The risk for women consuming more than 1 can/day was twice as high as among non-users of tobacco. Current smoking was negatively associated with risk of COVID-19 (aRR = 0.68; 95% CI = 0.61-0.75); including hospital admission (aRR = 0.60; 95% CI = 0.47-0.76) and intensive care (aRR = 0.43; 95% CI = 0.21-0.89). The hypothesis of a protective effect of tobacco nicotine on COVID-19 was not supported by the findings. The negative association between smoking and COVID-19 remains unexplained.

Characterization of a Clostridioides difficile outbreak caused by PCR ribotype 046, associated with increased mortality

This study describes a large nosocomial outbreak of Clostridioides difficile infections (CDI) dominated by ribotype (RT) 046 in a Swedish hospital. The present study aimed to examine the pathogenicity of this RT, explore epidemiological links by whole genome sequencing (WGS), and evaluate different interventions implemented to stop the outbreak. Clinical isolates (n =  366) collected during and after the outbreak were ribotyped and 246 isolates were subjected to WGS. Medical records of patients infected with the seven most common RTs were evaluated. RT046 was spread effectively throughout the hospital and was the most common among the 44 different RTs found (114/366 isolates). Infection with RT046 was associated with higher mortality compared to other strains (20.2% to 7.8%), although there were no differences in concomitant disease, age or antibiotic treatment. To control the outbreak, several measures were successfully implemented.

Autism and self-harm: A population-based and discordant sibling study of young individuals

OBJECTIVE

Self-harm among young autistic individuals is a clinical challenge, and the risk of premature death by suicide is strongly increased in this group. Using the advantage of total-population and family-based data, we investigated whether autism per se is a risk factor for self-harm independently of psychiatric comorbidities and how it differs from self-harm in non-autistic individuals.

METHODS

We used The Stockholm Youth Cohort, a total-population register study, including all residents in Stockholm County aged 0-17 years between 2001 and 2011.Study participants were followed from age 10 to 27 for hospital admissions because of self-harm. We used modified Poisson regression to calculate relative risks (RR) using robust standard error to derive 95% confidence intervals (CI).

RESULTS

In all, 410,732 individuals were included in the cohort (9,070 with a diagnosis of autism). Autistic individuals had a fivefold increased adjusted relative risk of self-harm (RR 5.0 [95% CI 4.4-5.6]). The risk increase was more pronounced for autism without intellectual disability and particularly high for self-cutting 10.2 [7.1-14.7] and more violent methods 8.9 [5.2-15.4]. The association between autism and self-harm was independent of, but clearly exacerbated by comorbid psychiatric conditions. It was of similar magnitude as risks linked to these conditions per se, and not explained by shared familial factors.

CONCLUSION

Self-harm severe enough to present to medical services is as common in autistic youth as in those with depression or ADHD. Potentially more lethal methods are more likely to be used of autistic self-harmers.

Molecular epidemiology of community- and hospital-associated Clostridioides difficile infections in Jönköping, Sweden, October 2017 - March 2018

Clostridioides difficile infections (CDIs) in Sweden are mostly hospital-associated (HA) with limited knowledge regarding community-associated (CA) infections. Here, we investigated the molecular epidemiology of clinical isolates of CA-CDI and HA-CDI in a Swedish county. Data and isolates (n = 156) of CDI patients (n = 122) from Jönköping county, October 2017-March 2018, were collected and classified as CA (without previous hospital care or onset ≤2 days after admission or >12 weeks after discharge from hospital) or HA (onset >3 days after hospital admission or within 4 weeks after discharge). Molecular characterization of isolates included PCR ribotyping (n = 156 isolates) and whole genome sequencing with single nucleotide polymorphisms (SNP) analysis (n = 53 isolates). We classified 47 patients (39%) as CA-CDI and 75 (61%) as HA-CDI. Between CA-CDI and HA-CDI patients, we observed no statistically significant differences regarding gender, age, 30-day mortality or recurrence. Ribotype 005 (RR 3.1; 95% CI: 1.79-5.24) and 020 (RR 2.5; 95% CI: 1.31-4.63) were significantly associated with CA-CDI. SNP analysis identified seven clusters (0-2 SNP difference) involving 17/53 isolates of both CA-CDI and HA-CDI. Molecular epidemiology differed between CA-CDI and HA-CDI and WGS analysis suggests transmission of CDI within and between hospitals and communities.

Long-term mortality from birth in individuals with and without isolated congenital aortic stenosis: a nationwide, register-based cohort study

Background

Congenital aortic valve stenosis (CAVS) accounts for almost 5% of congenital heart defects. Increased survival has been reported in patients with complex congenital heart defects over the last decade. However, data on the long-term outcomes of simple defects such as in isolated CAVS, are still limited.

Purpose

The present study aimed to investigate the risk of mortality in patients with isolated CAVS over the last half century in Sweden.

Methods

We used data from the Swedish National Patient and Cause of Death Register to identify patients with isolated CAVS born between 1970 and 2017. Each CAVS was matched with 10 controls without congenital heart disease from the Total Population Register, according to sex and birth year. The maximal follow-up time was from birth up to 47.5 years of age. We estimated mortality rates for cases and controls, and the 95% confidence interval (CI) of their ratio. Kaplan-Meier curves were used to estimate the survival for cases and controls under the follow-up.

Results

A total of 1,258 patients with isolated CAVS and 12,550 matched controls were included in the study. The median follow-up was 24.5 years (interquartile range (IQR):18.0) for cases and 25.5 years (IQR: 17.6) for controls respectively. The overall risk of mortality was more than three times higher for patients with isolated CAVS, compared with matched controls, hazard ratio (HR) 3.1 (95%, CI 2.1–4.5). Survival at 47.5 years of age was 94.1% for cases and 97.3% for controls. Within the first year of life, the mortality risk in patients with isolated CAVS was more than 19 times higher (95%, CI 8.8–43.6) than controls. By contrast, when diagnosed with isolated CAVS above the age of 10 years, the risk of mortality was 2.1 times higher (95%, CI 1.1–3.5) compared to controls.

Conclusions

The mortality in patients with isolated CAVS was more than three times higher compared with matched controls. The highest mortality was found in patients with a diagnosis of isolated CAVS diagnosed within the first year after birth, verifying the critical form of the disease. Furthermore, patients diagnosed with isolated CAVS later in life (hence clinically assumed as a mild form of valvulopathy) have a mortality risk twice as high as controls, highlighting the need for follow-up and lifetime management, even in the mild forms of valvulopathies.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swedish state under an agreement between the Swedish Government and county Councils (ALF)

Abstract 5994: Separating cancer cells from neutrophils by gradient acoustic focusing

Introduction: A subset of aggressive prostate cancers (PCa) progress to invade surrounding tissue to form distant metastases and shed of circulating tumor cells (CTCs). However, due to a scarcity of CTC among the millions of nucleated blood cells, there is an unmet need to improve CTC assays. Acoustophoresis uses standing ultrasound waves in a flow-through microfluidic chamber to discriminate cells based on the size, density, and compressibility. The technique is label-free as opposed to assays that rely on the cell surface marker EpCAM to detect CTCs. We will use label-free two-step acoustophoresis method as the initial separation step followed by a density medium purging step, to obtain efficient recovery of CTC of very high purity.

Experimental procedure: Acoustic cell separation of CTCs from blood is challenging in reference to overlap of acoustic properties between small-sized CTCs and densely granular WBC. To obtain high recovery of CTC, we must apply a sufficiently large acoustic focusing amplitude which leads to a contaminating cell population comprising 2% white blood cells, (WBCs) that mainly contain eosinophil cells. To obtain high purity cancer cell fractions there is a critical need for an additional cleaning step. Therefore, we used the density medium iodixanol in a purging step where the optimal iodixanol medium concentration is intended to provide one cell type with positive, and the other with negative acoustic contrast.

Preliminary results: show that the granulocytes can be transferred by the ultrasound field into the high-density medium (iodixanol) and can thereby be removed through a first outlet. The cancer cells do not transfer into the iodixanol medium and will be collected in a pure PCa cell fraction in the low-density medium through a second outlet. The samples were processed at a flow rate of 75 μl/min. The limiting factor regarding flow rate when purging the sample from granulocytes is overheating caused by the ultrasound transducer. The separation efficiency for cancer cells was 99.5% with 2.2% contaminating granulocytes. Theoretically, by combining the two separation steps only 0,044% of the WBC would remain in the cancer cell fraction.

Conclusion: It is unclear which are the functional properties that enable a primary tumor to shed CTCs, and comprehensive characterization is urgently needed to identify key features of these processes. CTC fractions of high purity will enable single cell analysis with validated Fluidigm-based RT-PCR panels, mass spectrometry, and RNA-sequencing. We propose to use a two-step acoustic separation method, with a primary acoustic separation step and a second high-density medium purging step.

Citation Format: Cecilia Magnusson, Mahdi Rezayati Charan, Hans Lilja, Per Augustsson. Separating cancer cells from neutrophils by gradient acoustic focusing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5994.

Two-Step Acoustophoresis Separation of Live Tumor Cells from Whole Blood

There is an unmet clinical need to extract living circulating tumor cells (CTCs) for functional studies and in vitro expansion to enable drug testing and predict responses to therapy in metastatic cancer. Here, we present a novel two-step acoustophoresis (A²) method for isolation of unfixed, viable cancer cells from red blood cell (RBC) lysed whole blood. The A² method uses an initial acoustofluidic preseparation step to separate cells based on their acoustic mobility. This acoustofluidic step enriches viable cancer cells in a central outlet, but a significant number of white blood cells (WBCs) remain in the central outlet fraction due to overlapping acoustophysical properties of these viable cells. A subsequent purging step was employed to remove contaminating WBCs through negative selection acoustophoresis with anti-CD45-functionalized negative acoustic contrast particles. We processed 1 mL samples of 1:1 diluted RBC lysed whole blood mixed with 10 000 DU145 cells through the A² method. Additional experiments were performed using 1000 DU145 cells spiked into 1.5 × 10⁶ WBCs in 1 mL of buffer to further elucidate the dynamic range of the method. Using samples with 10 000 DU145 cells, we obtained 459 ± 188-fold depletion of WBC and 42% recovery of viable cancer cells. Based on spiked samples with 1000 DU145 cells, our cancer cell recovery was 28% with 247 ± 156-fold WBC depletion corresponding to a depletion efficacy of ≥99.5%. The novel A² method provides extensive elimination of WBCs combined with the gentle recovery of viable cancer cells suitable for downstream functional analyses and in vitro culture.

Migration and risk of intellectual disability with and without autism: A population-based cohort study

OBJECTIVE

To investigate whether parental migration, parental region of origin, timing of child's birth in relation to maternal migration and parental reason for migration are associated with intellectual disability (ID) with and without autism.

METHODS

We used a register-based cohort of all individuals aged 0-17 years in Stockholm County during 2001-2011. General estimating equation logistic model and additionally sibling comparison were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). The models were adjusted for child's sex and birth year and parental age at child's birth, and additionally for migrant-specific variables in the analyses including only children with migrant parent(s).

RESULTS

Within the eligible sample of 670,098 individuals, 3781 (0.6%) had ID with autism, and 5076 (0.8%) had ID without autism. Compared with children with Swedish-born parents, children with both parents born abroad had an increased risk of ID with autism (OR = 1.6, CI 1.5-1.8) and ID without autism (OR = 1.9, CI 1.7-2.0). Among these children with both parents born abroad, it was protective of ID with autism when the child's birth occurred before and later than four years after maternal migration, which was replicated in the sibling comparison. The associations with both conditions were more pronounced with parental origin in regions comprising low- and middle-income countries and with reasons other than work or study.

CONCLUSIONS

Parental migration is associated with ID regardless of co-occurrence of autism. Our results indicate an association between environmental factors during pregnancy related to migration and offspring ID with autism, although further confirmative studies are needed.

Parental alcohol use and self-reported health among Swedish adolescents aged 10-18 years

Background

Including harm that is inflicted upon the drinker's social environment is vital when calculating the cost of harmful alcohol use to society. Knowledge about the true damage of alcohol is important in order to implement adequate public health responses. Research on children of alcoholics has demonstrated that parental alcohol misuse may affect offspring negatively in several ways. Studies on the general youth population have found that parental drinking is associated with offspring alcohol use. However, the links to offspring health are less explored. The aim of the study was to examine the associations between parental drinking and children's psychological complaints, somatic complaints, and perceived stress.

Methods

Data were obtained from the nationally representative Swedish Level-of Living survey of 2010. Parents and children (aged 10-18) living together completed surveys independently. The study sample consisted of 905 children, with information from at least one parent, in 627 households. Children's self-reports of psychological complaints, somatic complaints, and perceived stress were coded into binary measures and used as dependent variables. Based on self-reports of frequency and quantity of alcohol use, parents were categorised into abstainers, low consumers, moderate drinkers, and heavy drinkers. Gender, family structure, and parent-reported socioeconomic conditions were included as control variables. Binary logistic regression analyses were performed.

Results

In the fully adjusted models, children with heavy drinking parents were more likely to report psychological complaints (OR 2.52, p &lt; 0.01), somatic complaints (OR 1.96, p &lt; 0.01), and feeling stressed (OR 1.68, p &lt; 0.05), compared to children whose parents were classified as moderate drinkers.

Conclusions

The study showed that children living with heavy drinking parents were more likely to report adverse health. Implementing policies that aim to protect these children may be beneficial.

Key messages

Children living with heavy drinking parents were more likely to report psychological complaints, somatic complaints, and perceived stress. Living with heavy drinking parents may affect children’s health negatively, and measures to mitigate the harms these children experience ought to be considered.

Problematic alcohol use in the family and adolescents’ stress-related complaints

Background

A non-negligible proportion of children grow up in families where problematic alcohol use is present. From a resilience perspective and for the implementation of effective interventions, it is relevant to examine to what extent favourable conditions in other contexts may buffer against such family adversities. The aim of the current study was to examine the relationship between problematic familial alcohol use and offspring stress-related complaints. Another aim was to explore whether teacher ratings of the school's degree of student focus can buffer against negative health consequences of problem drinking at home.

Methods

Data were drawn from four cross-sectional surveys conducted in 2014 and in 2016 among 8,728 students (∼15-16 years) and 2,024 teachers in 147 Stockholm senior-level school units, with linked school-level register information. Stress-related complaints were measured from students' reports on the weekly co-occurrence of stomach-ache and headache. Teachers' ratings of the school's student focus were measured by an index based on four items which was aggregated to the school level. Student-level sociodemographic characteristics were included as control variables along with the schools' composition and student-teacher ratio. Two-level binary logistic regression analyses were performed.

Results

Problematic familial alcohol use was associated with an increased likelihood of stress-related complaints among students (OR 1.74, 95% CI 1.44-2.10). The cross-level interaction revealed that this association was weaker among students in schools with higher levels of student focus.

Conclusions

The study showed that the association between problematic familial alcohol use and students' stress-related complaints was less pronounced in schools with higher teacher ratings of student focus. This finding indicates that favourable conditions in schools can buffer against problematic conditions in the family, thus serving a compensatory role.

Key messages

Students reporting problematic familial alcohol use were more likely to suffer from stress-related complaints. High teacher ratings of the school’s student focus buffered against the association between problematic familial alcohol use and stress-related complaints.

HMG-CoA reductase inhibitors and COVID-19 mortality in Stockholm, Sweden: A registry-based cohort study

BACKGROUND

The relationship between statin treatment and Coronavirus Disease 2019 (COVID-19) mortality has been discussed due to the pleiotropic effects of statins on coagulation and immune mechanisms. However, available observational studies are hampered by study design flaws, resulting in substantial heterogeneity and ambiguities. Here, we aim to determine the relationship between statin treatment and COVID-19 mortality.

METHODS AND FINDINGS

This cohort study included all Stockholm residents aged 45 or older (N = 963,876), followed up from 1 March 2020 until 11 November 2020. The exposure was statin treatment initiated before the COVID-19-pandemic, defined as recorded statin dispensation in the Swedish Prescribed Drug Register between 1 March 2019 and 29 February 2020. COVID-19-specific mortality was ascertained from the Swedish Cause of Death Registry. Hazard ratios (HRs) were calculated using multivariable Cox regression models. We further performed a target trial emulation restricted to initiators of statins. In the cohort (51.6% female), 169,642 individuals (17.6%) were statin users. Statin users were older (71.0 versus 58.0 years), more likely to be male (53.3% versus 46.7%), more often diagnosed with comorbidities (for example, ischemic heart disease 23.3% versus 1.6%), more frequently on anticoagulant and antihypertensive treatments, less likely to have a university-level education (34.5% versus 45.4%), and more likely to have a low disposable income (20.6% versus 25.2%), but less likely to reside in crowded housing (6.1% versus 10.3%). A total of 2,545 individuals died from COVID-19 during follow-up, including 765 (0.5%) of the statin users and 1,780 (0.2%) of the nonusers. Statin treatment was associated with a lowered COVID-19 mortality (adjusted HR, 0.88; 95% CI, 0.79 to 0.97, P = 0.01), and this association did not vary appreciably across age groups, sexes, or COVID-19 risk groups. The confounder adjusted HR for statin treatment initiators was 0.78 (95% CI, 0.59 to 1.05, P = 0.10) in the emulated target trial. Limitations of this study include the observational design, reliance on dispensation data, and the inability to study specific drug regimens.

CONCLUSIONS

Statin treatment had a modest negative association with COVID-19 mortality. While this finding needs confirmation from randomized clinical trials, it supports the continued use of statin treatment for medical prevention according to current recommendations also during the COVID-19 pandemic.

Caesarean section and its relationship to offspring general cognitive ability: a registry-based cohort study of half a million young male adults

Background

A relationship between caesarean section and offspring cognitive ability has been described, but data are limited, and a large-scale study is needed.

Objective

To determine the relationship between mode of delivery and general cognitive ability.

Methods

A cohort of 579 244 singleton males, born between 1973 and 1987 who conscripted before 2006, were identified using the Swedish population-based registries. Their mode of delivery was obtained from the Swedish Medical Birth registry. The outcome measure was a normalised general cognitive test battery (mean 100, SD 15) performed at military conscription at around age 18.

Findings

Males born by caesarean section performed poorer compared with those born vaginally (mean score 99.3 vs 100.1; adjusted mean difference −0.84; 95% CI −0.97 to −0.72; p<0.001). Both those born by elective (99.3 vs 100.2; −0.92; 95% CI −1.24 to −0.60; p<0.001) and non-elective caesarean section (99.2 vs 100.2; −1.03; 95% CI −1.34 to −0.72; p=0.001), performed poorer than those born vaginally. In sibling analyses, the association was attenuated to the null (100.9 vs 100.8; 0.07; 95% CI −0.31 to 0.45; p=0.712). Similarly, neither elective nor non-elective caesarean section were associated with general cognitive ability in sibling analyses.

Conclusion

Birth by caesarean section is weakly associated with a lower general cognitive ability in young adult males. However, the magnitude of this association is not clinically relevant and seems to be largely explained by familial factors shared between siblings.

Clinical implication

Clinicians and gravidas ought not to be concerned that the choice of mode of delivery will impact offspring cognitive ability.

Work ability and psychological distress in a working population: results from the Stockholm Public Health Cohort

AIMS

Psychological distress is a global public health concern with individual and societal implications causing work-related disability and loss of productivity. It is less known how much work ability contributes to the development of psychological distress. This study aimed to assess the association between self-perceived physical and mental work ability in relation to job demands, and the incidence of psychological distress in a Swedish working population.

METHODS

Data were obtained from three subsamples of the Stockholm Public Health Cohort with baseline in 2010 and follow-up in 2014, based on a working population in Stockholm County aged 18-60 years, with no or mild psychological distress at baseline (n=29,882). Self-perceived physical and mental work ability in relation to job demands were assessed at baseline with a subscale from the Work Ability Index. Study participants scoring 4 or more on the General Health Questionnaire 12 at follow-up were classified as having developed psychological distress during the study period. Poisson log linear regression was used to calculate crude and adjusted rate ratios with 95% confidence intervals.

RESULTS

At follow-up, 2543 participants (12%) had developed psychological distress. Reporting poor physical and/or poor mental work ability in relation to job demands at baseline was associated with an almost doubled rate ratio of psychological distress at follow-up, compared to reporting good work ability (rate ratio 1.8; 95% confidence interval 1.6-2.0).

CONCLUSIONS

Poor work ability is associated with a higher incidence of future psychological distress compared to good work ability.

Migration or ethnic minority status and risk of autism spectrum disorders and intellectual disability: systematic review

BACKGROUND

There is an emerging evidence that the migration and the ethnic minority status are associated with the risks of autism spectrum disorder (ASD) and intellectual disability (ID). This systematic review aimed to investigate whether associations are specific to ASD or ID; whether and which migration-related or ethnically determined factors are associated with the risk of ASD and ID; and what mechanisms may explain these risks.

METHODS

A systematic literature search was conducted using Embase, Medline and PsycINFO for studies reporting on the risks of ASD and/or ID among migrants, descendants of migrants and/or ethnic minorities. Risks of any ASD, ASD + ID, ASD - ID and any ID were reviewed in relation to migration and ethnic minority status, with consideration to the study quality. In addition, possible underlying mechanisms suggested in the included studies were summarized.

RESULTS

Thirty-five studies were included. The summarized evidence indicated an increased risk of ASD + ID and a decreased risk of ASD - ID in migrants, descendants of migrants and ethnic minorities. These associations appeared more pronounced among children of migrant mothers, with origin in low-income countries, and among descendants of migrants. Data on ID were scarce. Suggested mechanisms explaining the increased risks of ASD + ID included environmental factors acting in utero and genetic factors (including consanguinity), while ascertainment bias was proposed to account for the lowered risks of diagnosed ASD - ID.

CONCLUSION

Migration-related factors acting in utero and/or associated with origin in low-income countries may be important in the ASD + ID aetiology, although further confirmative studies are needed.

Swedish snus use is associated with mortality: a pooled analysis of eight prospective studies

BACKGROUND

The health consequences of the use of Swedish snus, including its relationship with mortality, have not been fully established. We investigated the relationship between snus use and all-cause and cause-specific mortality (death due to cardiovascular diseases, cancer diseases and all other reasons, respectively) in a nationwide collaborative pooling project.

METHODS

We followed 169 103 never-smoking men from eight Swedish cohort studies, recruited in 1978-2010. Shared frailty models with random effects at the study level were used in order to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) of mortality associated with snus use.

RESULTS

Exclusive current snus users had an increased risk of all-cause mortality (aHR 1.28, 95% CI 1.20-1.35), cardiovascular mortality (aHR 1.27, 95% CI 1.15-1.41) and other cause mortality (aHR 1.37, 95% CI 1.24-1.52) compared with never-users of tobacco. The risk of cancer mortality was also increased (aHR 1.12, 95% CI 1.00-1.26). These mortality risks increased with duration of snus use, but not with weekly amount.

CONCLUSIONS

Snus use among men is associated with increased all-cause mortality, cardiovascular mortality, with death from other causes and possibly with increased cancer mortality.

Maternal smoking and smokeless tobacco use during pregnancy and offspring development: sibling analysis in an intergenerational Swedish cohort

Background

The association between maternal smoking in pregnancy and offspring intellectual disability (ID) is less well understood than that of smoking and fetal growth restriction. As fetal growth and cognitive development may share similar confounding structures, comparison of the two associations may improve understanding of the causal nature of the association with ID. Furthermore, comparisons of smoking with smokeless tobacco use may aid identification of mechanisms of action.

Methods

This was a cohort study of all Swedish births between 1999 and 2012 (n = 1 070 013), with prospectively recorded data. We assessed the association between maternal smoking during pregnancy and offspring outcomes ID and born small for gestational age (SGA). Analyses were repeated for snus use in pregnancy. Using a sibling design, we estimated within-family effects that control for shared sibling characteristics.

Results

Those exposed to maternal smoking in pregnancy had increased odds of ID [odds ratio (OR) = 1.24, 95% confidence interval (CI): 1.16-1.33] and SGA (OR = 2.19, 95% CI: 2.11-2.27) after confounder adjustment. Within-family effects were found for SGA (OR = 1.44, 95% CI: 1.27-1.63) but not ID (OR = 0.92, 95% CI: 0.74-1.14). For snus use, the results for ID were similar to smoking. We found increased odds of offspring SGA among mothers who used snus in pregnancy in sensitivity analyses but not in primary analyses.

Conclusions

Our findings are consistent with a causal effect of maternal smoking in pregnancy on risk of offspring born SGA but not on risk of ID. We found no evidence for a causal effect of snus use in pregnancy on ID and inconclusive evidence for SGA.

Faecalibacterium prausnitzii increases following fecal microbiota transplantation in recurrent Clostridioides difficile infection

OBJECTIVE

Fecal microbiota transplantation (FMT) is a highly effective treatment for Clostridioides difficile infection (CDI). However, the fecal transplant's causal components translating into clearance of the CDI are yet to be identified. The commensal bacteria Faecalibacterium prausnitzii may be of great interest in this context, since it is one of the most common species of the healthy gut microbiota and produces metabolites with anti-inflammatory properties. Although there is mounting evidence that F. prausnitzii is an important regulator of intestinal homeostasis, data about its role in CDI and FMT are relatively scarce.

METHODS

Stool samples from patients with recurrent CDI were collected to investigate the relative abundance of F. prausnitzii before and after FMT. Twenty-one patients provided fecal samples before the FMT procedure, at 2 weeks post-FMT, and at 2-4 months post-FMT. The relative abundance of F. prausnitzii was determined using quantitative polymerase chain reaction.

RESULTS

The abundance of F. prausnitzii was elevated in samples (N = 9) from donors compared to pre-FMT samples (N = 15) from patients (adjusted P<0.001). No significant difference in the abundance of F. prausnitzii between responders (N = 11) and non-responders (N = 4) was found before FMT (P = 0.85). In patients with CDI, the abundance of F. prausnitzii significantly increased in the 2 weeks post-FMT samples (N = 14) compared to the pre-FMT samples (N = 15, adjusted P<0.001). The increase persisted 2-4 months post-FMT (N = 15) compared to pre-FMT samples (N = 15) (adjusted P<0.001).

CONCLUSIONS

FMT increases the relative abundance of F. prausnitzii in patients with recurrent CDI, and this microbial shift remains several months later. The baseline abundance of F. prausnitzii in donors or recipients was not associated with future treatment response, although a true predictive capacity cannot be excluded because of the limited sample size. Further studies are needed to discern whether F. prausnitzii plays an active role in the resolution of CDI.

Labour market position of young people and premature mortality in adult life: A 26-year follow-up of 569 528 Swedish 18 year-olds

BACKGROUND

Throughout the industrialized world, demand for low skilled labour is falling. The length of schooling is increasing in response, but so is the proportion of individuals not finishing upper secondary school. The objective of this study was to evaluate the associations between labour market positions at age 18 and all-cause and suicide- and accident-specific mortality in later adulthood.

METHODS

Labour market positions at age 18 were categorized for all Swedes born 1972-77 (n=630 959) into four main groups: employed, successful students, students not about to qualify (SNAQs), and individuals not in employment, education or training (NEETs). Cox proportional hazard models were fitted to assess all-cause, suicide and accident mortality up to 2016 (ages 39-44), adjusting for high school grades, parental and own prior psychiatric diagnoses, and childhood socioeconomic status.

FINDINGS

SNAQs had substantially increased all-cause (men: HR=2.10; 95% CI 1.92-2.28, women: HR=1.64; 95% CI: 1.44-1.86), suicide (men: HR=2.16; CI: 1.86-2.51, women: HR=2.10; 95% CI 1.64-2.69), and accident specific (men: HR=2.08; 95% CI 1.77-2.44, women: 1.87; 95% CI 1.33;2.62) mortality risks compared to successful students. The risks were similar for NEETs. There was no increased risk among full-time employed compared to successful students.

INTERPRETATION

Expanding the educational system may be a natural response to falling demand for low skilled labour but not by far one that corrects the major societal challenge of it. Unless educational systems adequately respond to this challenge, only more inequality is to be expected ahead.

FUNDING

This work was supported by a grant to FR and AL from the Swedish Research Council for Health, Working Life, and Welfare with contract number (2014-2009).

Prediction of a time-sensitive condition among patients with dizziness assessed by the emergency medical services

BACKGROUND

Dizziness is a relatively common symptom among patients who call for the emergency medical services (EMS).

AIM

To identify factors of importance for the early identification of a time-sensitive condition behind the symptom of dizziness among patients assessed by the EMS.

METHODS

All patients assessed by the EMS and triaged using Rapid Emergency Triage and Treatment (RETTS) for adults code 11 (=dizziness) in the 660,000 inhabitants in the Municipality of Gothenburg, Sweden, in 2016, were considered for inclusion. The patients were divided into two groups according to the final diagnosis (a time-sensitive condition, yes or no).

RESULTS

There were 1536 patients who fulfilled the inclusion criteria, of which 96 (6.2%) had a time-sensitive condition. The majority of these had a stroke/transitory ischaemic attack (TIA). Eight predictors of a time-sensitive condition were identified. Three were associated with a reduced risk: 1) the dizziness was of a rotatory type, 2) the dizziness had a sudden onset and 3) increasing body temperature. Five were associated with an increased risk: 1) sudden onset of headache, 2) a history of head trauma, 3) symptoms of nausea or vomiting, 4) on treatment with anticoagulants and 5) increasing systolic blood pressure.

CONCLUSION

Among 1536 patients who were triaged by the EMS for dizziness, 6.2% had a time-sensitive condition. On the arrival of the EMS, eight factors were associated with the risk of having a time-sensitive condition. All these factors were linked to the type of symptoms or to clinical findings on the arrival of the EMS or to the recent clinical history.

Developmental vitamin D and autism spectrum disorders: findings from the Stockholm Youth Cohort

Animal studies indicate that early life vitamin D is crucial for proper neurodevelopment. Few studies have examined whether maternal and neonatal vitamin D concentrations influence risk of autism spectrum disorders (ASD). Participants were sampled from the Stockholm Youth Cohort, a register-based cohort in Sweden. Concentrations of total 25-hydroxyvitamin D (25OHD) were assessed from maternal and neonatal biosamples using a highly sensitive liquid chromatography tandem mass spectrometry method. The maternal sample consisted of 449 ASD cases and 574 controls, the neonatal sample: 1399 ASD cases and 1607 controls; and the paired maternal-neonatal sample: 340 ASD cases and 426 controls. Maternal 25OHD was not associated with child ASD in the overall sample. However, in Nordic-born mothers, maternal 25OHD insufficiency (25 - <50 nmol/L) at ~11 weeks gestation was associated with 1.58 times higher odds of ASD (95% CI: 1.00, 2.49) as compared with 25OHD sufficiency (≥50 nmol/L). Neonatal 25OHD < 25 nmol/L was associated with 1.33 times higher odds of ASD (95% CI: 1.02, 1.75) as compared with 25OHD ≥ 50 nmol/L. Sibling-matched control analyses indicated these associations were not likely due to familial confounding. Children with both maternal 25OHD and neonatal 25OHD below the median had 1.75 (95% CI: 1.08, 2.86) times the odds of ASD compared with children with maternal and neonatal 25OHD both below the median. Our results are consistent with an increasing body of evidence suggesting that vitamin D concentrations in early life may be associated with increased risk of neurodevelopmental disorders including ASD.

Suicide risk among refugees compared with non-refugee migrants and the Swedish-born majority population

BACKGROUND

It has been hypothesised that refugees have an increased risk of suicide.

AIMS

To investigate whether risk of suicide is higher among refugees compared with non-refugee migrants from the same areas of origin and with the Swedish-born population, and to examine whether suicide rates among migrants converge to the Swedish-born population over time.

METHOD

A population-based cohort design using linked national registers to follow 1 457 898 people born between 1 January 1970 and 31 December 1984, classified by migrant status as refugees, non-refugee migrants or Swedish-born. Participants were followed from their 16th birthday or date of arrival in Sweden until death, emigration or 31 December 2015, whichever came first. Cox regression models estimated adjusted hazard ratios for suicide by migrant status, controlling for age, gender, region of origin and income.

RESULTS

There were no significant differences in suicide risk between refugee and non-refugee migrants (hazard ratio 1.28, 95% CI 0.93-1.76) and both groups had a lower risk of suicide than Swedish born. During their first 5 years in Sweden no migrants died by suicide; however, after 21-31 years their suicide risk was equivalent to the Swedish-born population (hazard ratio 0.94, 95% CI 0.79-1.22). After adjustment for income this risk was significantly lower for migrants than the Swedish-born population.

CONCLUSIONS

Being a refugee was not an additional risk factor for suicide. Our findings regarding temporal changes in suicide risk suggest that acculturation and socioeconomic deprivation may account for a convergence of suicide risk between migrants and the host population over time.

DECLARATION OF INTEREST

None.

Qualification for upper secondary education in individuals with autism without intellectual disability: Total population study, Stockholm, Sweden

This study used the Stockholm Youth Cohort, a total population cohort (N = 364,957), to describe patterns and predictors of qualification for upper secondary education, defined by passing graduation grades in core compulsory school subjects in contemporary young individuals diagnosed with autism spectrum disorders without intellectual disability (n = 6138). At the expected age for graduation, 16 years, 29% (adjusted rate difference 95% confidence interval (28.0–30.0)) fewer autistic than non-autistic individuals were qualified for upper secondary education (57% and 86%, respectively). Comorbid attention-deficit hyperactivity disorder further increased this difference. Within the group of autistic students without intellectual disability, female sex and lower family income were associated with non-qualification for upper secondary education. The proportion of students with autism without intellectual disability who qualified for upper secondary education increased at age 20. These findings underline the need for improved support for students with a diagnosis of autism without intellectual disability in mainstream education.

The association between birth by cesarean section and adolescent cardiorespiratory fitness in a cohort of 339,451 Swedish males

Birth by cesarean section is increasing worldwide and associates with offspring morbidities capable of adversely impacting cardiorespiratory fitness later in life. Whether birth by cesarean section associates with lower levels of cardiorespiratory fitness later in life is unknown and is of interest to public health. Four Swedish national registers were linked to follow 339,451 singleton males, born between 1973–1987 until December 31 2005, for Watt-maximum achieved on a cycle ergometer test at conscription into the Swedish military. Main exposure was birth by cesarean section which was compared to vaginal birth. A sub-population of 45,999 males born between 1982–1987 was identified to explore differentiated associations between elective and non-elective cesarean section with Watt-maximum. Within-family analyses of 34,252 families with 70,632 biological male siblings, who conscripted during the study period, were performed to explore the role of familial confounding on Watt-maximum. Swedish males born by cesarean section achieved lower mean Watt-maximum (− 2.32 W, 95%C.I. − 2.90 to − 1.75) and displayed excess odds of low cardiorespiratory fitness (aOR = 1.08, 95%C.I. 1.05 to 1.11) at conscription in the eighteenth life-year compared to males born vaginally after adjusting for birth characteristics, maternal morbidities and parental socioeconomic position. In the sub-population, males born 1982–1987, there was a greater negative association of elective cesarean section with cardiorespiratory fitness (− 4.42 W, 95%C.I. − 6.27 to − 2.57, p < 0.001) than non-elective cesarean sections (− 1.96 W, 95%C.I. − 3.77 to − 0.16, p = 0.033) as compared to vaginal births. No associations between modes of cesarean delivery and cardiorespiratory fitness levels persisted in the within-family analyses where biological male siblings were compared whilst controlling for factors shared within families. Males born by cesarean section had lower levels of cardiorespiratory fitness eighteen years later compared to males born vaginally. These findings appear to be largely explained by factors of familial confounding.

The Familial Risk of Autism Spectrum Disorder with and without Intellectual Disability

Autism spectrum disorder (ASD) is highly heritable, yet how its familial risk and heritability may vary by cognitive ability is not well understood. In this population‐based cohort study, we examined the familial risk and heritability of ASD with and without co‐occurring intellectual disability (ID). We estimated odds ratios and heritability of ASD with ID (ASD+ID) and ASD without ID (ASD−ID) using register‐based diagnosis data of 567,436 index persons born in 1984–2009 in Stockholm County, Sweden, and their parents, siblings, cousins, aunts, and uncles. The familial risk profile exhibited differences between ASD−ID and ASD+ID, most notably for index persons with affected parents. For example, for an index person who had at least one parent with ASD, the child's odds of ASD−ID and ASD+ID (95% confidence interval (CI)) increased by 16.2 (14.2–18.6) and 7.4 (5.5–10.0) folds, respectively. The more closely related a family member with ASD was, the greater the observed risk was of ASD in the index person, especially for ASD−ID. The broad‐sense heritability (95% CI) for ASD − ID and ASD+ID were 64.6% (46.0–100.0%) and 33.4% (14.4–58.4%), respectively. Familial risk and heritability of ASD may vary by intellectual ability, which implies that risk factors between these ASD phenotypes may differ. Our findings from the heritability analysis and familial risk analysis suggest that ASD−ID may have a greater genetic basis than ASD+ID, although this should be verified in future studies.

Lay Summary

Autism spectrum disorder (ASD) is highly heritable, yet how its familial risk and heritability may vary by cognitive ability is not well‐understood. In a population‐based cohort study on families of 567,436 index persons using Swedish registers data, we found that the familial risk profile differed between ASD with and without intellectual disability. Our findings from the heritability analysis and familial risk analysis suggest that ASD−ID may have a greater genetic basis than ASD+ID, although this should be verified in future studies.

Preschool environment and preschool teacher's physical activity and their association with children's activity levels at preschool

Objective

The aim of this study was to investigate the association between preschool playground size, formalized physical activity (PA) policies, time spent outdoors and preschool teacher’s levels of PA and children’s objectively assessed levels of PA and sedentary time (ST) during preschool hours.

Methods

In total, 369 children and 84 preschool teachers from 27 preschools in Södermalm municipally, Stockholm Sweden wore an Actigraph GT3X+ accelerometer during 7 consecutive days. Preschool environmental and structural characteristics were measured via the Environment and Policy Evaluation Self-Report (EPAO-SR) instrument and time in- and outdoors was recorded by preschool teachers during the PA measurements. Weight and height of children were measured via validated scales and parents filled out a questionnaire on demographical and descriptive variables. Linear mixed models, nested on preschool level, were used to assess the association between predictors and outcomes.

Results

The mean child age was 4.7 years (SD 0.8) and 45% were girls. We found that children were more active in preschools with a formalized PA policy, compared to preschools without such a policy, but not less sedentary. The association between policy and activity seemed to be more pronounced when accounting for other environmental factors. Similar associations were found in children spent most time outdoors (uppermost quartile) compared with children spent least time outdoors (Lowermost quartile). Preschool teachers’ light PA (LPA) (ß = 0.25, P = 0.004) and steps (ß = 0.52, P<0.001) were associated with children’s LPA and steps while the preschool playground size showed no association with PA in children, when accounting for other environmental factors.

Conclusion

The current study showed that preschool structural characteristics such as formalized PA policies and more time spent outdoors were positively associated with children’s PA. These findings suggest that formalized PA policies and time outdoors may be of importance for promoting children’s PA during preschool hours.

Risk factors for subarachnoid haemorrhage: a nationwide cohort of 950 000 adults

BACKGROUND

Subarachnoid haemorrhage (SAH) is a devastating disease, with high mortality rate and substantial disability among survivors. Its causes are poorly understood. We aimed to investigate risk factors for SAH using a novel nationwide cohort consortium.

METHODS

We obtained individual participant data of 949 683 persons (330 334 women) between 25 and 90 years old, with no history of SAH at baseline, from 21 population-based cohorts. Outcomes were obtained from the Swedish Patient and Causes of Death Registries.

RESULTS

During 13 704 959 person-years of follow-up, 2659 cases of first-ever fatal or non-fatal SAH occurred, with an age-standardized incidence rate of 9.0 [95% confidence interval (CI) (7.4-10.6)/100 000 person-years] in men and 13.8 [(11.4-16.2)/100 000 person-years] in women. The incidence rate increased exponentially with higher age. In multivariable-adjusted Poisson models, marked sex interactions for current smoking and body mass index (BMI) were observed. Current smoking conferred a rate ratio (RR) of 2.24 (95% CI 1.95-2.57) in women and 1.62 (1.47-1.79) in men. One standard deviation higher BMI was associated with an RR of 0.86 (0.81-0.92) in women and 1.02 (0.96-1.08) in men. Higher blood pressure and lower education level were also associated with higher risk of SAH.

CONCLUSIONS

The risk of SAH is 45% higher in women than in men, with substantial sex differences in risk factor strengths. In particular, a markedly stronger adverse effect of smoking in women may motivate targeted public health initiatives.

Risk of transition from occasional neck/back pain to long-duration activity limiting neck/back pain: a cohort study on the influence of poor work ability and sleep disturbances in the working population in Stockholm County

OBJECTIVES

The prevalence of neck/back pain (NBP) is high worldwide. Limited number of studies have investigated workers with occasional NBP regarding the risk of developing long-duration activity limiting NBP (LNBP). The objectives were to assess (1) the effect of poor work ability and sleep disturbances in persons with occasional NBP on the risk of LNBP, and (2) the interaction effect of these exposures.

DESIGN

Cohort study based on three subsamples from the Stockholm Public Health Cohort.

SETTINGS

The working population in Stockholm County.

PARTICIPANTS

Persons aged 18-60 years, reporting occasional NBP the past 6 months at baseline year 2010 (n=16 460).

MEASURES

Work ability was assessed with items from the Work Ability Index, perceived mental and/or physical work ability. Sleep disturbances were self-reported current mild/severe disturbances. The outcome in year 2014 was reporting NBP the previous 6 months, occurring ≥couple of days per week and resulting in decreased work ability/restricted other daily activities. The additive effect of having both poor work ability and sleep disturbances was modelled with a dummy variable, including both exposures. Poisson log-linear regression was used to calculate risk ratios (RRs) and 95% CIs.

RESULTS

At follow-up, 9% had developed LNBP. Poor work ability and sleep disturbances were independent risk factors for LNBP; adjusted RR 1.7 (95% CI: 1.4 to 2.0) and 1.4 (95% CI: 1.2 to 1.5), respectively. No additive interaction was observed.

CONCLUSION

Workers with occasional NBP who have poor work ability and/or sleep disturbances are at risk of developing LNBP. Having both conditions does not exceed additive risk.

No association between moist oral snuff (snus) use and oral cancer: pooled analysis of nine prospective observational studies

Aims: Worldwide, smokeless-tobacco use is a major risk factor for oral cancer. Evidence regarding the particular association between Swedish snus use and oral cancer is, however, less clear. We used pooled individual data from the Swedish Collaboration on Health Effects of Snus Use to assess the association between snus use and oral cancer. Methods: A total of 418,369 male participants from nine cohort studies were followed up for oral cancer incidence through linkage to health registers. We used shared frailty models with random effects at the study level, to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for confounding factors. Results: During 9,201,647 person-years of observation, 628 men developed oral cancer. Compared to never-snus use, ever-snus use was not associated with oral cancer (adjusted HR 0.90, 95% CI: 0.74, 1.09). There were no clear trends in risk with duration or intensity of snus use, although lower intensity use (⩽ 4 cans/week) was associated with a reduced risk (HR 0.65, 95% CI: 0.45, 0.94). Snus use was not associated with oral cancer among never smokers (HR 0.87, 95% CI: 0.57, 1.32). Conclusions: Swedish snus use does not appear to be implicated in the development of oral cancer in men.

Birth Weight and Cardiorespiratory Fitness Among Young Men Born at Term: The Role of Genetic and Environmental Factors

Background Preterm delivery and low birth weight are prospectively associated with low cardiorespiratory fitness (CRF). However, whether birth weight, within the at-term range, is associated with later CRF is largely unknown. Thus, the aim of the current study was to examine this issue and whether such association, if any, is explained by shared and/or nonshared familial factors. Methods and Results We conducted a prospective cohort study, including 286 761 young male adults and a subset of 52 544 siblings born at-term. Objectively measured data were retrieved from total population registers. CRF was tested at conscription and defined as the maximal load obtained on a cycle ergometer. We used linear and nonlinear and fixed-effects regression analyses to explore associations between birth weight and CRF. Higher birth weight, within the at-term range, was strongly associated with increasing CRF in a linear fashion. Each SD increase in birth weight was associated with an increase of 7.9 (95% CI, 7.8-8.1) and 6.6 (95% CI; 5.9-7.3) Wmax in the total and sibling cohorts, respectively. The association did not vary with young adulthood body mass index. Conclusions Birth weight is strongly associated with increasing CRF in young adulthood among men born at-term, across all categories of body mass index. This association appears to be mainly driven by factors that are not shared between siblings. Hence, CRF may to some extent be determined already in utero. Prevention of low birth weight, also within the at-term-range, can be a feasible mean of increasing adult CRF and health.

Neighborhood Socioeconomic Characteristics and Utilization of ADHD Medication in Schoolchildren: A Population Multilevel Study in Stockholm County

Objective: To examine the effects of neighborhood socioeconomic disadvantage and ethnic composition on the utilization of ADHD medication in schoolchildren after accounting for individual- and family-level characteristics. Method: A cohort of all schoolchildren living in Stockholm County was prospectively followed for new prescriptions of ADHD medication (N = 276,955). Three-level logistic regression models were used with individual/family characteristics (e.g., immigrant background) at the first level and small area market statistics (SAMS) and municipality characteristics (i.e., socioeconomic disadvantage and ethnic composition) at the second and third level. Results: SAMS socioeconomic disadvantage was associated with increased utilization of ADHD medication. The utilization of ADHD medication was lower among immigrant children as compared with natives, and their odds of not utilizing medication increased as the degree of concentration of foreign-born increased. Conclusion: These results suggest that interventions at the neighborhood level may offer an additional route for the prevention of the disorder and/or alleviation of its consequences.

Elective and nonelective cesarean section and obesity among young adult male offspring: A Swedish population-based cohort study

BACKGROUND

Previous studies have suggested that cesarean section (CS) is associated with offspring overweight and obesity. However, few studies have been able to differentiate between elective and nonelective CS, which may differ in their maternal risk profile and biological pathway. Therefore, we aimed to examine the association between differentiated forms of delivery with CS and risk of obesity in young adulthood.

METHODS AND FINDINGS

Using Swedish population registers, a cohort of 97,291 males born between 1982 and 1987 were followed from birth until conscription (median 18 years of age) if they conscripted before 2006. At conscription, weight and height were measured and transformed to World Health Organization categories of body mass index (BMI). Maternal and infant data were obtained from the Medical Birth Register. Associations were evaluated using multinomial and linear regressions. Furthermore, a series of sensitivity analyses were conducted, including fixed-effects regressions to account for confounders shared between full brothers. The mothers of the conscripts were on average 28.5 (standard deviation 4.9) years old at delivery and had a prepregnancy BMI of 21.9 (standard deviation 3.0), and 41.5% of the conscripts had at least one parent with university-level education. Out of the 97,291 conscripts we observed, 4.9% were obese (BMI ≥ 30) at conscription. The prevalence of obesity varied slightly between vaginal delivery, elective CS, and nonelective CS (4.9%, 5.5%, and 5.6%, respectively), whereas BMI seemed to be consistent across modes of delivery. We found no evidence of an association between nonelective or elective CS and young adulthood obesity (relative risk ratio 0.96, confidence interval 95% 0.83-1.10, p = 0.532 and relative risk ratio 1.02, confidence interval 95% 0.88-1.18, p = 0.826, respectively) as compared with vaginal delivery after accounting for prepregnancy maternal BMI, maternal diabetes at delivery, maternal hypertension at delivery, maternal smoking, parity, parental education, maternal age at delivery, gestational age, birth weight standardized according to gestational age, and preeclampsia. We found no evidence of an association between any form of CS and overweight (BMI ≥ 25) as compared with vaginal delivery. Sibling analysis and several sensitivity analyses did not alter our findings. The main limitations of our study were that not all conscripts had available measures of anthropometry and/or important confounders (42% retained) and that our cohort only included a male population.

CONCLUSIONS

We found no evidence of an association between elective or nonelective CS and young adulthood obesity in young male conscripts when accounting for maternal and prenatal factors. This suggests that there is no clinically relevant association between CS and the development of obesity. Further large-scale studies are warranted to examine the association between differentiated forms of CS and obesity in young adult offspring.

TRIAL REGISTRATION

Registered as observational study at ClinicalTrials.gov Identifier: NCT03918044.

Tobacco and type 2 diabetes: is the association explained by genetic factors?

BACKGROUND

Smoking and use of Swedish smokeless tobacco (snus) are associated with increased risk of type 2 diabetes (T2D). Our aim was to estimate the unique and shared genetic components of these traits and to what extent the association is explained by shared genetic factors.

METHODS

We used twins of the Swedish Twin Registry who responded to a questionnaire between 1998 and 2006 (n = 40 247) and were followed until 2015 in the National Prescription and Patient Registries. We estimated hazard ratios (HRs) and odds ratios (ORs) for the association between smoking/snus use and T2D (n = 2130) and used structural equation models to estimate genetic and environmental variance components and genetic correlations.

RESULTS

Current smokers [HR 1.69, 95% confidence interval (CI), 1.49-1.92] and snus users (HR 1.19, 95% CI 1.01-1.41) had an increased risk of T2D. In within-pair analyses of monozygotic twins, corresponding ORs were 1.36, 95% CI 0.75-2.46 (smoking) and 1.54, 95% CI 0.80-2.99 (snus). Heritability was 43% (95% CI 36-51) for ever smoking, 58% (95% CI 44- 70) for ever snus use and 66% (95% CI 59-72) for T2D. The genetic correlation with T2D was 18% (95% CI 1-35) for smoking and -6% (95% CI -24 to 4) for snus use, indicating that only a small fraction of the genetic influence is shared.

CONCLUSIONS

We could confirm that consumers of snus and cigarettes are at increased risk of T2D. Both snus use and smoking have strong genetic components, which appears to be attributable primarily to genes that are distinct from those promoting T2D.

Family History of Mental and Neurological Disorders and Risk of Autism

IMPORTANCE

Familial aggregation of mental and neurological disorders is often observed in autism spectrum disorders (ASD), but reports have generally focused on single disorders and are limited to first-degree relatives.

OBJECTIVES

To examine family history of mental and neurological disorders among first- to fourth-degree relatives and risk of ASD with and without intellectual disability (ID) in index persons.

DESIGN, SETTING, AND PARTICIPANTS

In this population-based cohort study, 567 436 index persons were identified from the Stockholm Youth Cohort, an ongoing longitudinal register-linkage cohort study of the total population aged 0 to 17 years residing in Stockholm County, Sweden. Index persons were nonadopted singleton births born between 1984 and 2009 who were at least 2 years of age at the end of follow-up on December 31, 2011, had resided in Stockholm County for at least 2 years since birth, and could be linked to both biological parents. Data analysis was conducted from May 2017 to December 2018.

EXPOSURE

Mental and neurological diagnoses of relatives of the index persons.

MAIN OUTCOMES AND MEASURES

Diagnosis of ASD, with or without co-occurring ID, in the index persons.

RESULTS

The cohort included 567 436 index persons (291 191 [51.3%] male; mean [SD] age at the end of follow-up, 14.3 [7.5] years). The prevalence of ASD with and without ID was 0.4% and 1.5%, respectively. Positive family history of mental and neurological disorders was associated with higher odds of ASD in index persons; 6895 (63.1%) of index persons with ASD had a parent with history of mental and/or neurological disorders, compared with 252 454 (45.4%) of index persons without ASD. Family history of multiple disorders was associated with higher odds of ASD in index persons, including history of ASD (odds ratio among first-degree relatives for ASD with and without ID: 14.2, 9.0), intellectual disability (7.6, 2.3), attention-deficit/hyperactivity disorder (3.3, 4.7), obsessive compulsive disorder (1.9, 2.1), schizophrenia and other nonaffective psychotic disorders (2.1, 1.8), depression (1.4, 2.0), bipolar disorder (1.4, 2.2), personality disorder (2.1, 2.6), cerebral palsy (2.2, 1.5), and epilepsy (2.0, 1.3). The more closely related the affected family member was, the higher the odds was of ASD for the index person. ASD without intellectual disability was associated with more disorders compared to ASD with intellectual disability. ASD with intellectual disability exhibited a weaker familial association with other mental disorder diagnoses but a stronger familial association with some neurological diagnoses as compared to ASD without intellectual disability.

CONCLUSIONS AND RELEVANCE

This study suggests that family history of mental and neurological disorders is associated with increased risk of ASD. The familial component of ASD etiology may differ by presence or absence of co-occurring ID.

Proportion of adults in the general population of Stockholm County who want gender-affirming medical treatment

The number of patients presenting for care at gender clinics is increasing, yet the proportion of adults in the general population who want gender-affirming medical treatment remains essentially unknown. We measured the wish for cross-sex hormones or gender-affirming surgery, as well as other aspects of gender incongruence, among the general adult population of Stockholm County, Sweden. A population-representative sample of 50,157 Stockholm County residents ages 22 and older comprise the Stockholm Public Health Cohort. They were enrolled in 2002, 2006, and 2010 and followed-up in roughly 4-year intervals, with questions on health, lifestyle and social characteristics. In 2014, participants received the item “I would like hormones or surgery to be more like someone of a different sex.” Two additional items concerned other aspects of gender incongruence: “I feel like someone of a different sex”, and “I would like to live as or be treated as someone of a different sex.” Each item had four answer options (“Not at all correct”, “Somewhat or occasionally correct”, “Quite correct”, and “Absolutely correct”). For each item, any of the three affirmative answer choices were considered as some level of agreement. Calibration weights were used to estimate population-representative rates with 95% confidence intervals. The desire for cross-sex hormones or surgery was reported by 0.5% (95% CI, 0.4%–0.7%) of participants. Feeling like someone of a different sex was reported by 2.3% (95% CI, 2.1%–2.6%). Wanting to live as or be treated as a person of another sex was reported by 2.8% (95% CI, 2.4%–3.1%). These findings greatly exceed estimates of the number of patients receiving gender-affirming medical care. Clinicians must be prepared to recognize and care for patients experiencing discomfort due to gender incongruence and those who would like gender-affirming medical treatment.

Association Between Autism Spectrum Disorders With or Without Intellectual Disability and Depression in Young Adulthood

IMPORTANCE

Depression is a frequently occurring mental disorder and may be common in adults with autism spectrum disorders (ASD), but there is a lack of longitudinal population-based studies examining this association. Whether any increased risk of depression in ASD has a shared familial basis and whether it differs by co-occurring intellectual disability is not well known.

OBJECTIVES

To examine whether individuals with ASD are more likely to be diagnosed as having depression in adulthood than the general population and their nonautistic siblings and to investigate whether these risks differ by the presence or absence of intellectual disability.

DESIGN, SETTING, AND PARTICIPANTS

Population-based cohort study with a nested sibling comparison. The Stockholm Youth Cohort is a total population record linkage study that includes all children and young people (age range, 0-17 years) who were ever resident in Stockholm County, Sweden, between January 2001 and December 2011 (n = 735 096). Data analysis was conducted between January 5 and November 30, 2017, in Stockholm County, Sweden.

MAIN OUTCOMES AND MEASURES

Clinical diagnosis of depressive disorders was identified using the Stockholm County Adult Psychiatric Outpatient Register and the Swedish National Patient Register.

RESULTS

Participants were 223 842 individuals followed up to age 27 years by 2011, of whom 4073 had diagnosed ASD (mean [SD] age, 21.5 [2.7] years; 65.9% male; 2927 without intellectual disability and 1146 with intellectual disability) and 219 769 had no ASD (mean [SD] age, 22.1 [2.8] years; 50.9% male). By age 27 years, 19.8% (n = 808) of individuals diagnosed having ASD had a diagnosis of depression compared with 6.0% (n = 13 114) of the general population (adjusted relative risk [RR], 3.64; 95% CI, 3.41-3.88). The risk of a depression diagnosis was higher in ASD without intellectual disability (adjusted RR, 4.28; 95% CI, 4.00-4.58) than in ASD with intellectual disability (adjusted RR, 1.81; 95% CI, 1.51-2.17). Nonautistic full-siblings (adjusted RR, 1.37; 95% CI, 1.23-1.53) and half-siblings (adjusted RR, 1.42; 95% CI, 1.23-1.64) of individuals with ASD also had a higher risk of depression than the general population. Compared with their nonautistic full-siblings, individuals with ASD had more than a 2-fold risk of a depression diagnosis (adjusted odds ratio, 2.50; 95% CI, 1.91-3.27) in young adulthood.

CONCLUSIONS AND RELEVANCE

According to this study's results, ASD, particularly ASD without intellectual disability, is associated with depression by young adulthood compared with the general population. It appears that this association is unlikely to be explained by shared familial liability. Future research to identify modifiable pathways between ASD and depression may assist in the development of preventive interventions.

Moist smokeless tobacco (Snus) use and risk of Parkinson's disease

Background

Cigarette smoking is associated with a lower risk of Parkinson's disease. It is unclear what constituent of tobacco smoke may lower the risk. Use of Swedish moist smokeless tobacco (snus) can serve as a model to disentangle what constituent of tobacco smoke may lower the risk. The aim of this study was to determine whether snus use was associated with a lower risk of Parkinson's disease.

Methods

Individual participant data were collected from seven prospective cohort studies, including 348 601 men. We used survival analysis with multivariable Cox regression to estimate study-specific relative risk of Parkinson's disease due to snus use, and random-effects models to pool estimates in a meta-analysis. The primary analyses were restricted to never-smokers to eliminate the potential confounding effect of tobacco smoking.

Results

During a mean follow-up time of 16.1 years, 1199 incident Parkinson's disease cases were identified. Among men who never smoked, ever-snus users had about 60% lower Parkinson's disease risk compared with never-snus users [pooled hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.28-0.61]. The inverse association between snus use and Parkinson's disease risk was more pronounced in current (pooled HR 0.38, 95% CI 0.23-0.63), moderate-heavy amount (pooled HR 0.41, 95% CI 0.19-0.90) and long-term snus users (pooled HR 0.44, 95% CI 0.24-0.83).

Conclusions

Non-smoking men who used snus had a substantially lower risk of Parkinson's disease. Results also indicated an inverse dose-response relationship between snus use and Parkinson's disease risk. Our findings suggest that nicotine or other components of tobacco leaves may influence the development of Parkinson's disease.

Autistic Traits and Suicidal Thoughts, Plans, and Self-Harm in Late Adolescence: Population-Based Cohort Study

OBJECTIVE

To examine the hypothesis that autism spectrum disorders (ASD) diagnosis and traits in childhood are associated with suicidal thoughts, plans and self-harm at 16 years, and that any observed associations are explained by depression at 12 years.

METHOD

We examined associations between ASD diagnosis and 4 dichotomized ASD traits (social communication, pragmatic language, repetitive behavior, and sociability) with suicidal and nonsuicidal self-harm, suicidal thoughts, and suicidal plans at age 16 years in 5,031 members of the United Kingdom-based birth cohort study the Avon Longitudinal Study of Parents and Children. We assessed whether any associations were explained by depressive symptoms in early adolescence measured by the Short Moods and Feelings Questionnaire at 12 years.

RESULTS

Children with impaired social communication had a higher risk of self-harm with suicidal intent (relative risk [RR] = 2.14, 95% CI = 1.28-3.58), suicidal thoughts (RR = 1.42, 95% CI = 1.06-1.91), and suicidal plans (RR = 1.95, 95% CI = 1.09-3.47) by age 16 years as compared to those without. There was no evidence for an association between ASD diagnosis and outcomes, although these analyses were imprecise because of small numbers. There was also no evidence of an association between other autism traits and the outcomes. Approximately 32% of the total estimated association between social communication impairment and self-harm was explained by depressive symptoms at 12 years.

CONCLUSION

Social communication impairments are an important autistic trait in relation to suicidality. Early identification and management of depression may be a preventative mechanism, and future research identifying other potentially modifiable mechanisms may lead to interventions against suicidal behavior in this high-risk group.