Life course associations between smoking and depressive symptoms. A 30-year Finnish follow-up study.

INTRODUCTION: Relatively little is known whether the association between smoking and depressive symptoms changes with age and how the trajectories of smoking and depressive symptoms are intertwined during the life course. In this population-based study, these associations were examined from young adulthood to middle age. METHODS: Participants of a Finnish cohort study (N=1955) were assessed at the ages of 22, 32, 42, and 52 using questionnaires covering daily smoking (yes/no) and the short 13-item Beck Depression Inventory. Longitudinal latent class and longitudinal latent profile analyses were used identify life course trajectories of smoking and depressive symptoms. RESULTS: The proportions of daily smokers decreased, while levels of depressive symptoms increased among both females and males from age 22 to 52 years. Smoking was associated with higher levels of depressive symptoms from age 22 to 42, while not at 52. Associations among males prevailed when adjusting for education, marital status, and alcohol use. Four life course classes of daily smoking (non-smokers, decreasing prevalence of smoking, persistent smokers, and increasing prevalence of smoking) and four trajectories of depressive symptoms (low, increasing/moderate, decreasing/moderate, and high) were identified. In males, persistent daily smokers (RRR=4.5, 95% CI: 2.2-9.2) and those in the class with increasing smoking prevalence (RRR=3.2, 95% CI: 1.1-9.1) had an increased risk of belonging to the high depressive symptoms profile. In females these associations were non-significant. CONCLUSIONS: Compared to females, the relationship between smoking and depressive symptoms seems more robust among males during adulthood. Specifically, males smoking persistently from young adulthood to middle age have an increased risk of high depressive symptoms trajectory. IMPLICATIONS: This population-based cohort with 30 years of follow-up showed that the life course trajectories of daily smoking and depressive symptoms are associated. Persistent daily smokers and those starting late had an increased risk of belonging to the profile with constantly high levels of depressive symptoms during the life course. However, these associations were statistically significant only in males. Actions should be strengthened, especially in males, to prevent smoking initiation, to help smoking cessation and identify and treat depression in smokers with significant depressive symptoms.

A Nationally Representative Study of the Hardening Hypothesis Among Educational Groups Over Four Decades.

INTRODUCTION: As smoking prevalence has decreased, there has been debate about "hardening" (smokers are more resistant to established tobacco control measures) or "softening" (smokers are more responsive to interventions) of the remaining smoking population. Despite growing evidence to reject the "hardening" hypothesis, there is lack of long-term population-based studies to test this hypothesis by educational level. AIMS AND METHODS: Repeated cross-sectional population-based surveys during 1978-2014 and in 2018 were utilized. The target population consisted of ~5000 25-64-year-old Finns annually. The data included 109 257 respondents of which 53 351 ever-smoking individuals were included in the analyses. Response rates varied between 84% and 43%. Five hardening indicators considering smoking frequency, intensity and smoking cessation were used as the dependent variables. The main independent variable was study year (time). Statistical analyses were based on regression models using restricted cubic splines by educational level. RESULTS: Contrary to the hardening hypothesis, hardening indicators showed softening over time among all educational groups. However, educational groups differed from each other. Compared with the highly educated, the quit ratio was lower, number of cigarettes per day (CPD) was higher, the proportions of daily smokers among current smokers and heavy smokers among daily smokers were higher among the less educated. CONCLUSIONS: In accordance with growing evidence, also the Finnish smoking population has "softened" over time. Although the change has been predominantly in the same direction for all educational groups, the rate of change has been stronger among the highly educated, highlighting the continued burden of smoking among the less educated. IMPLICATIONS: Even though "softening" of smoking has occurred, lighter smoking also poses health risks. Therefore, tobacco control policies and cessation services should be developed and targeted to a greater extent also for people who smoke less than daily and for those who smoke fewer CPD. Furthermore, interventions should focus on special requirements of the lower educational groups to promote health equity.

Smoking cessation intervention prior to orthopedic surgery: A study protocol to determine patient outcomes and feasibility.

The aim of the study is to analyze the effect of smoking and smoking cessation on the incidence of complications among orthopedic and hand surgery patients, and to determine the feasibility of smoking cessation intervention, as well as factors predicting success in smoking cessation. Orthopedic and hand surgery patients will be invited to participate in the study, which will recruit 550 participants (at least 20% daily smokers). A participant will be defined as a daily smoker if he/she reports daily smoking and/or laboratory tests show active smoking. Data will be collected using a self-reported questionnaire and from medical records. Smokers will receive information about the benefits of smoking cessation and will be encouraged to quit. Medication or nicotine replacement therapy will be prescribed. Laboratory tests will be taken two weeks before and two weeks after surgery. Follow-up phone calls will be made at 3, 6, and 12 months after surgery. The primary outcome is any complication, defined as a prolonged stay in hospital or any additional visit to or measure taken by a health service during the 12 months after surgery. Data on complications are mainly obtained from personal health records and from the information received at the follow-up; the rest of the data will be collected from the register of healthcare-associated infections. Secondary outcomes are the number and types of complications. The sample (n=550) was calculated to observe a 10% difference in complications between smokers and non-smokers (5% alpha level and 80% power), considering a 10% drop-out rate. Logistic regression and log-linear models will be used for data analyses.

A genome-wide association study of total child psychiatric problems scores.

Substantial genetic correlations have been reported across psychiatric disorders and numerous cross-disorder genetic variants have been detected. To identify the genetic variants underlying general psychopathology in childhood, we performed a genome-wide association study using a total psychiatric problem score. We analyzed 6,844,199 common SNPs in 38,418 school-aged children from 20 population-based cohorts participating in the EAGLE consortium. The SNP heritability of total psychiatric problems was 5.4% (SE = 0.01) and two loci reached genome-wide significance: rs10767094 and rs202005905. We also observed an association of SBF2, a gene associated with neuroticism in previous GWAS, with total psychiatric problems. The genetic effects underlying the total score were shared with common psychiatric disorders only (attention-deficit/hyperactivity disorder, anxiety, depression, insomnia) (rG > 0.49), but not with autism or the less common adult disorders (schizophrenia, bipolar disorder, or eating disorders) (rG < 0.01). Importantly, the total psychiatric problem score also showed at least a moderate genetic correlation with intelligence, educational attainment, wellbeing, smoking, and body fat (rG > 0.29). The results suggest that many common genetic variants are associated with childhood psychiatric symptoms and related phenotypes in general instead of with specific symptoms. Further research is needed to establish causality and pleiotropic mechanisms between related traits.

Smoking remains associated with education after controlling for social background and genetic factors in a study of 18 twin cohorts.

We tested the causality between education and smoking using the natural experiment of discordant twin pairs allowing to optimally control for background genetic and childhood social factors. Data from 18 cohorts including 10,527 monozygotic (MZ) and same-sex dizygotic (DZ) twin pairs discordant for education and smoking were analyzed by linear fixed effects regression models. Within twin pairs, education levels were lower among the currently smoking than among the never smoking co-twins and this education difference was larger within DZ than MZ pairs. Similarly, education levels were higher among former smoking than among currently smoking co-twins, and this difference was larger within DZ pairs. Our results support the hypothesis of a causal effect of education on both current smoking status and smoking cessation. However, the even greater intra-pair differences within DZ pairs, who share only 50% of their segregating genes, provide evidence that shared genetic factors also contribute to these associations.

Genome-wide Association Meta-analysis of Childhood and Adolescent Internalizing Symptoms.

OBJECTIVE: To investigate the genetic architecture of internalizing symptoms in childhood and adolescence. METHOD: In 22 cohorts, multiple univariate genome-wide association studies (GWASs) were performed using repeated assessments of internalizing symptoms, in a total of 64,561 children and adolescents between 3 and 18 years of age. Results were aggregated in meta-analyses that accounted for sample overlap, first using all available data, and then using subsets of measurements grouped by rater, age, and instrument. RESULTS: The meta-analysis of overall internalizing symptoms (INToverall) detected no genome-wide significant hits and showed low single nucleotide polymorphism (SNP) heritability (1.66%, 95% CI = 0.84-2.48%, neffective = 132,260). Stratified analyses indicated rater-based heterogeneity in genetic effects, with self-reported internalizing symptoms showing the highest heritability (5.63%, 95% CI = 3.08%-8.18%). The contribution of additive genetic effects on internalizing symptoms appeared to be stable over age, with overlapping estimates of SNP heritability from early childhood to adolescence. Genetic correlations were observed with adult anxiety, depression, and the well-being spectrum (|rg| > 0.70), as well as with insomnia, loneliness, attention-deficit/hyperactivity disorder, autism, and childhood aggression (range |rg| = 0.42-0.60), whereas there were no robust associations with schizophrenia, bipolar disorder, obsessive-compulsive disorder, or anorexia nervosa. CONCLUSION: Genetic correlations indicate that childhood and adolescent internalizing symptoms share substantial genetic vulnerabilities with adult internalizing disorders and other childhood psychiatric traits, which could partially explain both the persistence of internalizing symptoms over time and the high comorbidity among childhood psychiatric traits. Reducing phenotypic heterogeneity in childhood samples will be key in paving the way to future GWAS success.

Life course associations between smoking and depressive symptoms. A 30-year Finnish follow-up study.

BACKGROUND: While the association between smoking and depressive symptoms has been studied quite extensively, only little is known whether the association changes and how the trajectories of smoking and depressive symptoms are intertwined during the life course. In this population-based study, we examined these associations from young adulthood to middle age. METHODS: Participants of a Finnish cohort study (N = 1955) were addressed at ages 22, 32, 42 and 52 using postal questionnaires including questions of daily smoking and depressive symptoms (the short 13-item Beck Depression Inventory). Linear and logistic regression analyses and longitudinal latent class and profile analyses were used. RESULTS: The percentages of daily smokers decreased, while levels of depressive symptoms increased among both women and men from age 22 to 52 years. Daily smoking was associated with higher levels of depressive symptoms between ages 22 and 42, while not at age 52. Associations among men prevailed also in the adjusted models. Four life course trajectories of daily smoking (non-smokers, quitters, persistent smokers, and late starters) and four depressive symptoms (low, increasing/moderate, decreasing/moderate, and high) were identified. In the adjusted models, persistent daily smokers and late starters had significantly higher risk of belonging to the high depressive symptoms profile in men, but not in women. CONCLUSIONS: Compared to women the associations between daily smoking and depressive symptoms seem more robust among men during adulthood. Especially those men smoking persistently from young adulthood to middle age have an increased risk of high depressive symptoms trajectory during the life course.

Cancer in twin pairs discordant for smoking: The Nordic Twin Study of Cancer.

The discordant twin pair study design is powerful to control for familial confounding. We employed this approach to investigate the associations of smoking with several cancers. The NorTwinCan study combines data from the Danish, Finnish, Norwegian and Swedish twin and cancer registries. Follow-up started when smoking status was determined and ended at cancer diagnosis confirmed by information in the cancer registry, death or end of follow-up. We classified the participants as never (n = 59 093), former (n = 21 168) or current (n = 47 314) smokers. We pooled data from twin pairs where one co-twin was diagnosed with any of the following tobacco-related cancers: esophagus, kidney, larynx, liver, oral cavity, pancreas, pharynx or urinary bladder, while their co-twin had none of those. Lung cancer was included in further analysis. We used Cox regression allowing for pair-specific baseline functions to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). For tobacco-related cancer sites, we recorded 7379 cases during median 27 years of follow-up. The analyses based on individual twins showed that former (HR 1.31, 95% CI: 1.17-1.48) and current (HR 2.14 [1.95-2.34]) smokers are at increased risk to develop one of cancers listed above, compared to never smokers. Among 109 monozygotic twin pairs discordant for cancer and smoking, the HR was 1.85 (95% CI: 1.15-2.98) among current smokers and 1.69 (1.00-2.87) among former smokers when compared to their never smoking co-twin. Thus, associations of smoking with several cancers were replicated for discordant identical twin pairs. Analyses based on genetically informative data provide evidence consistent with smoking causing multiple cancers.

Genetic and Environmental Effects on the Individual Variation and Continuity of Participation in Diverse Physical Activities.

INTRODUCTION: Participation in diverse physical activities has beneficial health effects. However, little is known on how genetic and environmental factors affect this trait. Thus, we examined to what extent these factors explain participation in diverse leisure-time physical activities from late adolescence to adulthood using a twin study design. METHODS: The participants were Finnish twins who reported their participation in diverse leisure-time physical activities at ages 17 (n = 5429) and 34 yr (n = 4246). The number of physical activities engaged in was analyzed using applications of structural linear modeling for twin data. RESULTS: On average, the total number of physical activities engaged in during leisure time was slightly over three at both ages and in both sexes, with moderate heritability estimates (40%-58%) from adolescence to adulthood. Environmental factors shared by co-twins (e.g., childhood family environment) influenced only in adolescence, being higher for women. Environmental influences unique to each co-twin explained the remaining variances (34%-57%), being higher at age 34 yr. Participation in diverse leisure-time physical activities correlated moderately between ages 17 and 34 yr (men: rtrait = 0.30, 95% confidence interval [CI] = 0.25-0.35; women: rtrait = 0.26, 95% CI = 0.22-0.31). In addition, genetic influences on participation in physical activities correlated moderately between adolescence and adulthood (rA = 0.51, 95% CI = 0.39-0.64, and 0.44, 95% CI = 0.34-0.55, respectively). These common genetic influences explained 93% of the trait correlations found in men and 85% in women. CONCLUSIONS: Genetic and unique environmental influences explain a large proportion of variation in the number of leisure-time physical activities. However, the estimates vary by age and sex. Common genetic background mainly explains the continuity of the participation in diverse leisure-time physical activities between adolescence and adulthood.

Teacher-rated aggression and co-occurring behaviors and emotional problems among schoolchildren in four population-based European cohorts.

Aggressive behavior in school is an ongoing concern. The current focus is on specific manifestations such as bullying, but the behavior is broad and heterogenous. Children spend a substantial amount of time in school, but their behaviors in the school setting tend to be less well characterized than at home. Because aggression may index multiple behavioral problems, we used three validated instruments to assess means, correlations and gender differences of teacher-rated aggressive behavior with co-occurring externalizing/internalizing problems and social behavior in 39,936 schoolchildren aged 7-14 from 4 population-based cohorts from Finland, the Netherlands, and the UK. Correlations of aggressive behavior were high with all other externalizing problems (r: 0.47-0.80) and lower with internalizing problems (r: 0.02-0.39). A negative association was observed with prosocial behavior (r: -0.33 to -0.54). Mean levels of aggressive behavior differed significantly by gender. Despite the higher mean levels of aggressive behavior in boys, the correlations were notably similar for boys and girls (e.g., aggressive-hyperactivity correlations: 0.51-0.75 boys, 0.47-0.70 girls) and did not vary greatly with respect to age, instrument or cohort. Thus, teacher-rated aggressive behavior rarely occurs in isolation; boys and girls with problems of aggressive behavior likely require help with other behavioral and emotional problems. Important to note, higher aggressive behavior is not only associated with higher amounts of other externalizing and internalizing problems but also with lower levels of prosocial behavior.

A therapist-guided smartphone app for major depression in young adults: A randomized clinical trial.

BACKGROUND: Meru Health Program (MHP) is a therapist-guided, 8-week intervention for depression delivered via smartphone. The aim was to test its efficacy in patients with clinical depression in a Finnish university student health service. METHODS: Patients (n=124, women 72.6%, mean age 25y) were stratified based on antidepressant status, and randomized into intervention group receiving MHP plus treatment as usual (TAU), and control group receiving TAU only. Depression, measured by the Patient Health Questionnaire-9 (PHQ-9) scale, was the primary outcome. After baseline (T0), follow-ups were at mid-intervention (T4), immediately post-intervention (T8); 3 months (T20), and 6 months (T32) post-intervention. RESULTS: The intervention group and control group did not have significant differences in depression outcomes throughout end of treatment and follow-up. Among secondary outcomes, increase in resilience (d=0.32, p=0.03) and mindfulness (d=0.57, p=0.002), and reduction in perceived stress (d=-0.52, p=0.008) were greater in MHP+TAU versus TAU at T32; no differences were found in anxiety, sleep disturbances, and quality of life between groups. Post-hoc comparisons of patients on antidepressants showed significantly greater reduction in depression at T32 for MHP+TAU versus TAU (d=-0.73, p=0.01); patients not on antidepressants showed no between-group differences. LIMITATIONS: Limitations include unknown characteristics of TAU, potential bias from patients and providers not being blinded to treatment group, and failure to specify examination of differences by antidepressant status in the protocol. CONCLUSIONS: Most outcomes, including depression, did not significantly differ between MHP+TAU and TAU. Exploratory analysis revealed intervention effect at the end of the 6-month follow-up among patients on antidepressant medication.

Factors contributing to psychological distress in the working population, with a special reference to gender difference.

BACKGROUND: Psychological distress refers to non-specific symptoms of stress, anxiety and depression, and it is more common in women. Our aim was to investigate factors contributing to psychological distress in the working population, with a special reference to gender differences. METHODS: We used questionnaire data from the nationally representative Finnish Regional Health and Well-being Study (ATH) collected in the years 2012-2016 (target population participants aged 20 +, n = 96,668, response rate 53%), restricting the current analysis to those persons who were working full-time and under 65 of age (n = 34,468). Psychological distress was assessed using the Mental Health Inventory-5 (MHI-5) (cut-off value <=52). We studied the following factors potentially associated with psychological distress: sociodemographic factors, living alone, having children under18 years of age, lifestyle-related factors, social support, helping others outside of the home and work-related factors. We used logistic regression analysis to examine association between having work-family conflict with the likelihood for psychological distress. We first performed the models separately for men and women. Then interaction by gender was tested in the combined data for those independent variables where gender differences appeared probable in the analyses conducted separately for men and women. RESULTS: Women reported more psychological distress than men (11.0% vs. 8.8%, respectively, p < 0.0001). Loneliness, job dissatisfaction and family-work conflict were associated with the largest risk of psychological distress. Having children, active participation, being able to successfully combine work and family roles, and social support were found to be protective factors. A significant interaction with gender was found in only two variables: ignoring family due to being absorbed in one's work was associated with distress in women (OR 1.30 (95% CI 1.00-1.70), and mental strain of work in men (OR 2.71 (95% CI 1.66-4.41). CONCLUSIONS: Satisfying work, family life and being able to successfully combine the two are important sources of psychological well-being for both genders in the working population.

The associations of smoking dependence motives with depression among daily smokers.

AIMS: To investigate how strongly smoking dependence and smoking dependence motives are associated with depressive symptoms among daily smokers and if these associations are independent of measured confounders and shared familial factors. DESIGN: Cross-sectional individual-based and within-pair analyses. SETTING: Fourth wave of the population-based Finnish Twin Cohort conducted in 2011. PARTICIPANTS: 918 daily smokers born 1945-1957 (48% men), mean age 59.5 years including 38 twin pairs discordant for depression. MEASUREMENTS: Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression scale with a cut off value ≥20 for depression. Smoking dependence was assessed using the Fagerström Test for Cigarette Dependence (FTCD) and smoking dependence motives with three subscales from the multi-dimensional Brief Wisconsin Inventory of Smoking Dependence Motives (WISDM): primary dependence motives (PDM), affective enhancement (AE), and Taste. Logistic regressions, using standardized scores of independent variables and adjusted for multiple confounders with correction for sampling as twin pairs, were used in the individual-based analyses. Conditional logistic regression was used to control for shared familial factors in discordant twin pairs. FINDINGS: Prevalence of depression was 18% (n = 163: 61 [14%] in men, n = 102 [22%] in women). Higher smoking dependence measured by the FTCD (OR 1.45; 95% CI 1.20, 1.75), and dependence motives measured by the PDM (1.56; 1.30, 1.87) and the AE (1.54; 1.28, 1.85) were associated with higher odds of depression. The associations remained after adjusting for individual confounders, except for neuroticism, which attenuated all associations. FTCD, PDM, and AE showed associations with depression within depression-discordant monozygotic pairs, suggesting an association independent of familial factors. CONCLUSIONS: Depression appears to be associated with smoking dependence and smoking dependence motives related to heavy, automatic use and use to regulate affective states. The associations appear to be confounded or mediated by neuroticism but are independent of shared familial influences.

DNA methylation signatures of aggression and closely related constructs: A meta-analysis of epigenome-wide studies across the lifespan.

DNA methylation profiles of aggressive behavior may capture lifetime cumulative effects of genetic, stochastic, and environmental influences associated with aggression. Here, we report the first large meta-analysis of epigenome-wide association studies (EWAS) of aggressive behavior (N = 15,324 participants). In peripheral blood samples of 14,434 participants from 18 cohorts with mean ages ranging from 7 to 68 years, 13 methylation sites were significantly associated with aggression (alpha = 1.2 × 10-7; Bonferroni correction). In cord blood samples of 2425 children from five cohorts with aggression assessed at mean ages ranging from 4 to 7 years, 83% of these sites showed the same direction of association with childhood aggression (r = 0.74, p = 0.006) but no epigenome-wide significant sites were found. Top-sites (48 at a false discovery rate of 5% in the peripheral blood meta-analysis or in a combined meta-analysis of peripheral blood and cord blood) have been associated with chemical exposures, smoking, cognition, metabolic traits, and genetic variation (mQTLs). Three genes whose expression levels were associated with top-sites were previously linked to schizophrenia and general risk tolerance. At six CpGs, DNA methylation variation in blood mirrors variation in the brain. On average 44% (range = 3-82%) of the aggression-methylation association was explained by current and former smoking and BMI. These findings point at loci that are sensitive to chemical exposures with potential implications for neuronal functions. We hope these results to be a starting point for studies leading to applications as peripheral biomarkers and to reveal causal relationships with aggression and related traits.

Genome-wide association meta-analysis of nicotine metabolism and cigarette consumption measures in smokers of European descent.

Smoking behaviors, including amount smoked, smoking cessation, and tobacco-related diseases, are altered by the rate of nicotine clearance. Nicotine clearance can be estimated using the nicotine metabolite ratio (NMR) (ratio of 3'hydroxycotinine/cotinine), but only in current smokers. Advancing the genomics of this highly heritable biomarker of CYP2A6, the main metabolic enzyme for nicotine, will also enable investigation of never and former smokers. We performed the largest genome-wide association study (GWAS) to date of the NMR in European ancestry current smokers (n = 5185), found 1255 genome-wide significant variants, and replicated the chromosome 19 locus. Fine-mapping of chromosome 19 revealed 13 putatively causal variants, with nine of these being highly putatively causal and mapping to CYP2A6, MAP3K10, ADCK4, and CYP2B6. We also identified a putatively causal variant on chromosome 4 mapping to TMPRSS11E and demonstrated an association between TMPRSS11E variation and a UGT2B17 activity phenotype. Together the 14 putatively causal SNPs explained ~38% of NMR variation, a substantial increase from the ~20 to 30% previously explained. Our additional GWASs of nicotine intake biomarkers showed that cotinine and smoking intensity (cotinine/cigarettes per day (CPD)) shared chromosome 19 and chromosome 4 loci with the NMR, and that cotinine and a more accurate biomarker, cotinine + 3'hydroxycotinine, shared a chromosome 15 locus near CHRNA5 with CPD and Pack-Years (i.e., cumulative exposure). Understanding the genetic factors influencing smoking-related traits facilitates epidemiological studies of smoking and disease, as well as assists in optimizing smoking cessation support, which in turn will reduce the enormous personal and societal costs associated with smoking.

Cervical Cancer Screening Participation among Women of Russian, Somali, and Kurdish Origin Compared with the General Finnish Population: A Register-Based Study.

Migrant-origin women are less prone to cervical screening uptake compared with host populations. This study examined cervical cancer screening participation and factors associated with it in the Finnish mass screening program during 2008-2012 in women of Russian, Somali and Kurdish origin compared with the general Finnish population (Finns) in Finland. The study population consists of samples from the Finnish Migrant Health and Well-being Study 2010-2012 and Health 2011 Survey; aged 30-64 (n = 2579). Data from the Finnish screening register linked with other population-based registry data were utilized. For statistical analysis we employed logistic regression. Age-adjusted screening participation rates were Russians 63% (95% CI: 59.9-66.6), Somalis 19% (16.4-21.6), Kurds 69% (66.6-71.1), and Finns 67% (63.3-69.8). In the multiple-adjusted model with Finns as the reference; odds ratios for screening were among Russians 0.92 (0.74-1.16), Somalis 0.16 (0.11-0.22), and Kurds 1.37 (1.02-1.83). Among all women, the substantial factor for increased screening likelihood was hospital care related to pregnancy/birth 1.73 (1.27-2.35), gynecological 2.47 (1.65-3.68), or other reasons 1.53 (1.12-2.08). Screening participation was lower among students and retirees. In conclusion, screening among the migrant-origin women varies, being significantly lowest among Somalis compared with Finns. Efforts using culturally tailored/population-specific approaches may be beneficial in increasing screening participation among women of migrant-origin.

Association of subclinical psychosis with suicidal ideation: A twin study.

Subclinical psychosis, including schizotypal indicators and psychotic experiences, predicts future suicidal ideation. This relationship may reflect unmeasured confounding from environmental factors, genetic factors, or both. We used a genetically-informative twin design to understand if the association between subclinical psychosis and suicidal ideation is independent of shared genetic and environmental factors. We analysed cross-sectional associations of age-22 self-reported subclinical psychosis (positive, negative, and disorganised features) with suicidal ideation in twins participating in the FinnTwin12 study (maximum n = 1213). Then, we analysed the reverse association of age-14 suicidal ideation with age-22 subclinical psychosis. Associations were studied first among individuals and then within monozygotic (MZ) and dizygotic (DZ) pairs. Individual-level analyses showed that all subclinical psychosis factors were associated with suicidal ideation. In within-pair analyses, estimates of associations were lower for MZ pairs than DZ pairs, except for the negative schizotypy-suicidal ideation association where estimates were consistent across individual-level and within-pair analyses. Findings provide evidence that the association between negative features and suicide ideation is not explained by familial factors and may be causal, though the possibility of confounding by individual-specific environmental factors and reverse causation cannot be ruled out. The relationships of positive and disorganised subclinical psychosis features with suicidal ideation cannot be explained by confounding due to environmental factors shared between siblings, but their associations may be due to shared genetic factors.

Correlates and genetics of self-reported sleep and awake bruxism in a nationwide twin cohort.

BACKGROUND: Sleep bruxism (SB) and awake bruxism (AB) have been considered different entities, although co-occurrence between them has been shown. While genetic factors have a marked influence on phenotypic variance in liability to SB, this remains unclear for AB. AIM: To examine the degree of co-occurrence of SB and AB, and whether they have common correlates and also twin similarity of SB and AB bruxism traits by zygosity and sex. METHODS: A questionnaire was mailed to all twins born 1945-1957 in Finland in 2012 (n = 11 766). Age and sex adjusted logistic regression models were used. Twin similarity was assessed using polychoric correlations, and crosstwin-crosstrait correlations were computed. RESULTS: The response rate was 72% (n = 8410). Any SB was reported by 14.8% and ≥ 3 nights weekly by 5.0%. Percentages for any AB were 18.4% and 6.3%, respectively. There was substantial co-occurrence (29.5%) between SB and AB, and several shared correlates were found. For SB, the polychoric intra-class correlation was 0.366 in monozygotic (MZ) and 0.200 in dizygotic (DZ) pairs, without gender difference. A twofold crosstwin-crosstrait correlation was observed in MZ twins compared to DZ twins. CONCLUSIONS: The risk factor profiles of SB and AB were largely but not entirely similar. The higher correlation in MZ than in DZ pairs suggests the influence of genetic factors on both SB and AB. The higher crosstwin-crosstrait correlation in MZ than in DZ pairs suggests some degree of genetic influences shared by SB and AB.

Depressive symptoms predict smoking cessation in a 20-year longitudinal study of adult twins.

Depression has been suggested to hinder smoking cessation, especially when co-occurring with nicotine dependence. The study aimed to examine the longitudinal association of depressive symptoms with smoking cessation among daily smokers. The study utilized adult Finnish twin cohort where 1438 daily smokers (mean age: 38.3, range: 33-45) in 1990 were re-examined for their smoking status in 2011. We assessed baseline depressive symptoms with the Beck Depression Inventory, and the self-reported smoking status at follow-up. The methods included multinomial logistic regression and time to event analyses, adjusted for multiple covariates (age, sex, marital status, social class, heavy drinking occasions, and health status) and smoking heaviness at baseline assessed by cigarettes per day (CPD). Additionally, within-twin-pair analyses were conducted. Results indicated that moderate/severe depressive symptoms at baseline were associated with a lower likelihood of smoking cessation two decades later. Adjusting for covariates, those with moderate/severe depressive symptoms (vs. no/minimal depressive symptoms) had 46% lower likelihood of quitting (relative risk ratio, RRR = 0.54, 95% CI: 0.30-0.96). After including CPD, the association of depressive symptoms with smoking cessation attenuated modestly (RRR = 0.62, 95% CI: 0.34-1.12). Further, time to event analysis for quitting year since baseline yielded similar findings. In the within-pair analysis, depressive symptoms were not associated with quitting smoking. The results suggest that reporting more depressive symptoms is associated with a lower likelihood of smoking cessation during a 20-year period. The baseline amount of smoking and familial factors partly explain the observed association. Smoking cessation programs should monitor depressive symptoms.

Harmonizing behavioral outcomes across studies, raters, and countries: application to the genetic analysis of aggression in the ACTION Consortium.

BACKGROUND: Aggression in children has genetic and environmental causes. Studies of aggression can pool existing datasets to include more complex models of social effects. Such analyses require large datasets with harmonized outcome measures. Here, we made use of a reference panel for phenotype data to harmonize multiple aggression measures in school-aged children to jointly analyze data from five large twin cohorts. METHODS: Individual level aggression data on 86,559 children (42,468 twin pairs) were available in five European twin cohorts measured by different instruments. A phenotypic reference panel was collected which enabled a model-based phenotype harmonization approach. A bi-factor integration model in the integrative data analysis framework was developed to model aggression across studies while adjusting for rater, age, and sex. Finally, harmonized aggression scores were analyzed to estimate contributions of genes, environment, and social interaction to aggression. The large sample size allowed adequate power to test for sibling interaction effects, with unique dynamics permitted for opposite-sex twins. RESULTS: The best-fitting model found a high level of overall heritability of aggression (~60%). Different heritability rates of aggression across sex were marginally significant, with heritability estimates in boys of ~64% and ~58% in girls. Sibling interaction effects were only significant in the opposite-sex twin pairs: the interaction effect of males on their female co-twin differed from the effect of females on their male co-twin. An aggressive female had a positive effect on male co-twin aggression, whereas more aggression in males had a negative influence on a female co-twin. CONCLUSIONS: Opposite-sex twins displayed unique social dynamics of aggressive behaviors in a joint analysis of a large, multinational dataset. The integrative data analysis framework, applied in combination with a reference panel, has the potential to elucidate broad, generalizable results in the investigation of common psychological traits in children.