Class inequalities in physical functioning trajectories before and after retirement

Background

Longer work careers are discussed, but inequalities in health trajectories among employees facing retirement remain poorly understood. We examined social class trajectories in physical functioning among ageing female employees ten years before and after transition to old-age or disability retirement.

Methods

We used Helsinki Health Study cohort data. The baseline (2000-02) included 7168 women, aged 40-60, employed by the City of Helsinki, Finland (response 67%). Follow-ups took place in 2007, 2012 and 2017 (response 78-83%). The outcome was RAND-36 Physical Functioning subscale, range 0-100, with higher scores indicating better functioning. Social classes were upper and lower class, and covariates age, work conditions and health behaviours. Mixed-effect growth curve models were used to predict functioning scores and 95% confidence intervals (CI) 10 years before and after mandatory old-age or disability retirement.

Results

Old-age and disability retirees lacked class inequalities in functioning 10 years prior retirement. Towards retirement transition, functioning declined and inequalities emerged. Among old-age retirees, the predicted score was 86.1 (CI 85.2-86.9) for upper class and 82.2 (81.5-83.0) for lower class. Among disability retirees, the score was 70.3 (67.8-72.9) for upper class and 62.2 (60.4-63.9) for lower class. Among old-age retirees, functioning declined and inequalities slightly widened. Among disability retirees, the decline plateaued and inequalities narrowed. Physical work and BMI somewhat attenuated the inequalities.

Conclusions

Among female employees, functioning declined and class inequalities emerged towards retirement transition. Widening inequalities were seen among old-age retirees, but not among disability retirees. Preventing the decline of functioning and related inequalities would help safeguard a healthy and successful ageing among female retirees.

Key messages

• As functioning shows a constant decline before and after old-age retirement, there is a need for slowing down the pace of the decline.

• Class inequalities in functioning tend to widen among old-age retirees; egalitarian measures are needed to turn the development to narrowing inequalities.

Clustering of unhealthy behaviours and subsequent sickness absence among Finnish municipal employees

Background

Unhealthy behaviours are associated with increased sickness absence (SA), but few studies have explored these associations using person-oriented approach. We aimed to identify latent classes of unhealthy behaviours among female and male employees and examined their associations with subsequent SA.

Methods

Health behaviours (leisure-time physical activity, sedentary behaviour, fruit and vegetable [F&V] consumption, sleep, binge drinking, and use of tobacco products) were derived from the Helsinki Health Study questionnaire survey, collected in 2017 among 19-39-year-old employees of the City of Helsinki, Finland. The questionnaire data were linked to employer's SA register. Latent class analysis was used to identify underlying profiles of unhealthy behaviours and negative binomial regression was used to examine their associations with subsequent SA (≤7 days, >7 days, and all lengths) among 3228 women and 771 men. The mean follow-up time was 2.1 years.

Results

Among women, we identified 3 latent classes: 1) healthy behaviours (81% of women), 2) binge drinking and tobacco use (12%), and 3) inadequate F&V consumption and insufficient sleep (7%). Classes 2 and 3 showed increased rates for subsequent SA compared to class 1, regardless of the length of SA spells (age-adjusted rate ratios [RR] 1.37-1.42 and 1.35-1.64, respectively). Among men, we identified 3 latent classes: 1) healthy behaviours (51% of men), 2) binge drinking and tobacco use (19%), and 3) inadequate F&V consumption, binge drinking and tobacco use (30%). While classes 1 and 2 were not different in terms of subsequent SA, class 3 had increased rates of subsequent, particularly short-term SA (RR 1.24, 95% CI 1.03-1.48).

Conclusions

Preventive actions should consider simultaneously several unhealthy behaviours while aiming to reduce employees’ SA. These actions might benefit from regarding potential gender differences in the clustering of unhealthy behaviours and their associations with SA.

Key messages

• Preventive actions to reduce sickness absence should consider clustering of unhealthy behaviours among employees.

• Potential gender differences need to be regarded in these actions.

Does seeing a psychologist reduce sickness absence due to mental disorders? A quasi-experiment

Background

Mental ill-health in young adults is a major public health and work-life problem. We examined in a quasi-experimental design whether occupational psychologist appointment can reduce subsequent sickness absence due to mental disorders among young Finnish employees.

Methods

The present study was conducted among 18-39-year-old employees of the City of Helsinki using register data from the City of Helsinki and the Social lnsurance Institution of Finland. We used Wald test to compare the differences in sickness absence days due to mental disorders (ICD-10, F-diagnosed) between those treated (occupational psychologist appointment for work ability support) and the non-treated (no psychologist appointment) during a one year follow-up. The full sample (n = 2156, 84% women) consisted of employees with mental disorder diagnosed sickness absence during 2009-2014. To account for the systematic differences between the treated and non-treated, the participants were matched according to their characteristics (age, sex, occupational class, education, previous sickness absence and psychotropic medication). The matched sample included 886 participants. We excluded those with treatment before the treatment screening time (± 3 months to the end of sickness absence period), non-treated with treatment during the follow-up and those that could not be matched (lack of common support).

Results

In the full sample, the mean of sickness absence days due to mental disorders was 17.7 (95% CI, 11.4, 24.1) days for those treated (n = 240) and 23.2 (95% CI, 20.5, 25.9) days for non-treated (n = 1916), difference being non-significant. The corresponding figures in the matched sample were (16.8, 95% CI, 9.5-24.1) for those treated (n = 195) and (27.8, 95% CI, 22.6-32.9) for non-treated (n = 691), difference being statistically significant (p = 0.02).

Conclusions

This quasi-experiment suggests that seeing an occupational psychologist to support work ability may be reduce mental health related sickness absence.

Key messages

We showed that supporting work ability at an early stage may prevent sickness absence due to mental disorders. More efforts to provide early stage support for maintaining work ability may prove useful in reducing sickness absence rates in younger employees.

Characterization of the anisotropic deformation of the right ventricle during open heart surgery

Digital Image Correlation (DIC) was used for studying the anisotropic behavior of the thin walled right ventricle of the human heart. Strains measured with Speckle Tracking Echocardiography (STE) were compared with the DIC data. Both DIC and STE were used to measure longitudinal strains of the right ventricle in the beginning of an open-heart surgery as well as after the cardiopulmonary bypass. Based on the results, the maximum end-systolic strains obtained with the DIC and STE change similarly during the surgery with less than 10% difference. The difference is largely due to the errors in matching the longitudinal direction in the two methods, sensitivity of the measurement to the positioning of the virtual extensometer of in both STE and DIC, and physiological difference of the measurements as the DIC measures the top surface of the heart whereas the STE obtains the data from below. The anisotropy of the RV was measured using full field principal strains acquired from the DIC displacement fields. The full field principal strains cover the entire region of interest instead of just two points as the virtual extensometer approach used by the STE. The principal strains are not direction dependent measures, and therefore are more independent of the anatomy of the patient and the exact positioning of the virtual strain gage or the STE probe. The results show that the longitudinal strains alone are not enough to fully characterize the behavior of the heart, as the deformation of the heart can be very anisotropic, and the anisotropy changes during the surgery, and from patient to patient.

Healthy behaviours and risk of all-cause mortality

Introduction

Healthy behaviours are associated with better health in general but less is known about the combined associations of multiple healthy behaviours with mortality risk. We aimed to examine the associations of combined healthy behaviours with mortality risk over a 15-year follow-up among middle-aged employees.

Methods

Survey data, collected in 2000–2002 among 40–60-year-old employees of the City of Helsinki, Finland, was linked with complete register data on mortality from Statistics Finland (response rate 67%, written informed consent for register linkages 74%). Healthy behaviours included high leisure-time physical activity, non-smoking, no binge drinking and healthy food habits. Each healthy behaviour were dichotomized and assigned a value of one for healthy and zero for unhealthy. The number of healthy behaviours were summed together (score range 0-4). Cox regression models were fitted, and the follow-up continued until the end of 2015 (n = 6336). Confounders included age, sex, marital status, socioeconomic position and self-rated health.

Results

Of the respondents, 7% reported four healthy behaviours, 27% three, 34% two, 22% one and 9% no healthy behaviours. A total of 281 deaths occurred during the follow-up. Each healthy behaviour was individually associated with a reduced mortality risk, non-smoking having the strongest and healthy diet the weakest association. The combined association showed that those without any of the healthy behaviours (HR 2.8, 95% CI 1.51-5.29) and those with only one healthy behaviour (HR 1.89, 95% CI 1.04-3.43) had a higher mortality risk than those with four healthy behaviours. Instead, those with at least two healthy behaviours were not at an increased risk of mortality.

Conclusions

A low number of healthy behaviours predicted mortality among middle-aged employees. Efforts should be made to promote multiple healthy behaviours among the middle-aged to enhance health and prevent premature mortality.

Key messages

Almost one third of the respondents had no or only one healthy behaviour. A low number of healthy behaviours was associated with an increased risk of mortality.

Joint associations of fruit and vegetable consumption and physical activity with mortality risk

Background

Fruit and vegetable consumption (FVC) and leisure-time physical activity (LTPA) are associated with better health outcomes but less is known about their joint associations with the risk of mortality. We examined the joint associations of FVC and LTPA with premature mortality among midlife and ageing municipal employees, adjusting for key covariates.

Methods

Survey data collected in 2000–2002 among 40–60-year-old employees of the City of Helsinki, Finland, were linked with complete register data on mortality from Statistics Finland (4961 women, 1373 men; response rate 67%; written consent for register linkages 74%). FVC was dichotomised into daily or non-daily, and LTPA into high (>14 MET-hours/week including vigorous exercise) or low. Covariates included age, sex, marital status, socioeconomic position, binge drinking, smoking and self-rated health. Cox regression models were fitted. The follow-up continued until the event of death or the end of 2015.

Results

A total of 281 deaths occurred during the follow-up. The mortality rate was 7.1% in men and 3.7% in women. A gender interaction was found, showing differing associations for women and men. Men with both daily FVC and high LTPA had the lowest mortality risk (HR 0.19, 95% CI 0.06-0.63) after adjusting for covariates. Men with high LTPA and non-daily FVC also had a lower mortality risk (HR 0.51, 95% CI 0.29-0.90) compared to those with non-daily FVC and low LTPA. Women with daily FVC and high LTPA had a lower mortality risk initially, but after adjusting for covariates no statistically significant associations were observed.

Conclusions

The joint associations of FVC and LTPA with premature mortality differed between women and men. This could be related to gender differences in e.g. the causes of death, and further studies are needed to clarify this. Increasing FVC and LTPA might prevent premature mortality among men.

Key messages

Fruit and vegetable consumption jointly with physical activity decreased the risk of premature mortality among men only. Further studies are needed to clarify the gender difference which could be related to for example death causes.

Pore space extraction and characterization of sack paper using μ-CT

We show that attenuation X-ray microcomputed tomography (μ-CT) offers a route to extract the three-dimensional pore space of paper reliably enough to distinguish samples of the same kind of paper. Here, we consider two sack kraft papers for cement bags with different basis weights and thicknesses. Sample areas of approximately 5 mm² with a resolution of 1.5 μm are considered, i.e. sizes that exceed sample areas of 2 mm² for which the pore structure was previously studied in the literature. The image segmentation is based on indicator kriging as a local method that removes ambiguities in assigning voxels as pore or as fibre. The microstructures of the two samples are statistically compared in terms of descriptors such as sheet thickness, porosity, fractions of externally accessible pores and mean geodesic tortuosity. We demonstrate that a quantitative comparison of samples in terms of porosity and thickness requires a common definition of the sheet surfaces. Finally, the statistical pore space analysis based on the μ-CT scans reliably reveals structural differences between the two paper samples, but only when several descriptors are used.

LAY DESCRIPTION

This paper is a seemingly abundant material. Its intrinsic porosity enables a vast number of commercial applications. Particularly packing products, e.g. cement bags, often incorporate sack kraft paper due to its high porosity and its additional mechanical strength. A direct quantification of the porosity of sack kraft papers is, hence, particularly desirable. However, experimental quantification of paper porosity or its pore network properties is difficult and often highly indirect. A nondestructive statistical analysis of the 3D microstructure holds the promise to directly assess the pores. In particular, X-ray microcomputed tomography (μ-CT), frequently with sub-μm resolution, has been established as a method to study the fibre and pore structure of paper. The question arises, whether statistical analysis of the microstructure based on μ-CT imaging is sufficient to reliably distinguish between different sack kraft papers. Here, we explore whether the pore structure of paper can be extracted and statistically analysed for larger sample areas despite the fact that a larger sample size directly translates into a lower resolution of the μ-CT scan. We expect that a large sample size increases the region of interest on the basis of which samples can be better distinguished. A lowered resolution poses a severe challenge for the reliable identification of voxel data as pores or as fibres, because the contrast between paper fibres (made of cellulose) and air, which is established due to X-ray absorption, is weak. We show that we can reliably assign each voxel by using an indicator kriging as a two-step method. This method performs an initial voxel identification based on the overall distribution of measured grey values and refines the identification by inspecting the local environment of each voxel. For the pore space extracted in such a way, we can then compute quantities that are related to the geometry and connectivity properties of the pores. Furthermore, we address a paper-born challenge for such an analysis, i.e. we cannot always unambiguously tell whether a pore is located inside the paper sheet or at the surface of the paper. The way the paper surfaces are extracted from the microstructure decisively determines the final specifications of the predicted properties. A significant distinction of the samples is only possible when comparing the properties of the pore network.

An Optical Method for the In-Vivo Characterization of the Biomechanical Response of the Right Ventricle

The intraoperative in-vivo mechanical function of the left ventricle has been studied thoroughly using echocardiography in the past. However, due to technical and anatomical issues, the ultrasound technology cannot easily be focused on the right side of the heart during open-heart surgery, and the function of the right ventricle during the intervention remains largely unexplored. We used optical imaging and digital image correlation for the characterization of the right ventricle motion and deformation during open-heart surgery. This work is a pilot study focusing on one patient only with the aim of establishing the framework for long term research. These experiments show that optical imaging and the analysis of the images can be used to obtain similar parameters, and partly at higher accuracy, for describing the mechanical functioning of the heart as the ultrasound technology. This work describes the optical imaging based method to characterize the mechanical response of the heart in-vivo, and offers new insight into the mechanical function of the right ventricle.

Association between breastfeeding and better preserved cognitive ability in an elderly cohort of Finnish men

BACKGROUND

Being breastfed in infancy has been shown to benefit neurodevelopment. However, whether the benefits persist to old age remains unclear.

METHODS

We examined the associations between breastfeeding and its duration on cognitive ability in young adulthood and old age, and on aging-related cognitive change over five decades. In total, 931 men from the Helsinki Birth Cohort Study born in 1934-1944 in Finland took the Finnish Defence Forces Basic Intellectual Ability Test (total and verbal, arithmetic and visuospatial subtest scores) twice, at ages 20.2 and 67.9 years, and had data on breastfeeding (yes v. no) and its duration ('never breastfed', 'up to 3', '3 to 6' and '6 or more months'). Linear and mixed model regressions tested the associations.

RESULTS

At 20.2 years, breastfed men had higher cognitive ability total and visuospatial subtest scores [mean differences (MDs) ranged between 3.0-3.9, p values < 0.013], and its longer duration predicted higher cognitive ability total and arithmetic and visuospatial subtest scores (MDs ranged between 3.0 and 4.8, p values < 0.039). At 67.9 years, breastfed men had higher total cognitive ability and all subtest scores (MDs ranged between 2.6 and 3.4, p values < 0.044) and its longer duration predicted all cognitive ability scores (MDs ranged between 3.1 and 4.7, p values < 0.050). Verbal subtest scores decreased over five decades in men who were never breastfed or were breastfed for 3 months or less, and increased in those breastfed for longer than 3 months.

CONCLUSIONS

Neurodevelopmental advantages of breastfeeding and its longer duration persist into old age, and longer duration of breastfeeding may benefit aging-related change, particularly in verbal reasoning ability.

GWAS meta-analysis reveals novel loci and genetic correlates for general cognitive function: a report from the COGENT consortium

This corrects the article DOI: 10.1038/mp.2016.244.

GWAS meta-analysis reveals novel loci and genetic correlates for general cognitive function: a report from the COGENT consortium

The complex nature of human cognition has resulted in cognitive genomics lagging behind many other fields in terms of gene discovery using genome-wide association study (GWAS) methods. In an attempt to overcome these barriers, the current study utilized GWAS meta-analysis to examine the association of common genetic variation (~8M single-nucleotide polymorphisms (SNP) with minor allele frequency ⩾1%) to general cognitive function in a sample of 35 298 healthy individuals of European ancestry across 24 cohorts in the Cognitive Genomics Consortium (COGENT). In addition, we utilized individual SNP lookups and polygenic score analyses to identify genetic overlap with other relevant neurobehavioral phenotypes. Our primary GWAS meta-analysis identified two novel SNP loci (top SNPs: rs76114856 in the CENPO gene on chromosome 2 and rs6669072 near LOC105378853 on chromosome 1) associated with cognitive performance at the genome-wide significance level (P<5 × 10^-8). Gene-based analysis identified an additional three Bonferroni-corrected significant loci at chromosomes 17q21.31, 17p13.1 and 1p13.3. Altogether, common variation across the genome resulted in a conservatively estimated SNP heritability of 21.5% (s.e.=0.01%) for general cognitive function. Integration with prior GWAS of cognitive performance and educational attainment yielded several additional significant loci. Finally, we found robust polygenic correlations between cognitive performance and educational attainment, several psychiatric disorders, birth length/weight and smoking behavior, as well as a novel genetic association to the personality trait of openness. These data provide new insight into the genetics of neurocognitive function with relevance to understanding the pathophysiology of neuropsychiatric illness.

Common mental disorders in young adults born late-preterm

BACKGROUND

Results of adulthood mental health of those born late-preterm (34 + 0-36 + 6 weeks + days of gestation) are mixed and based on national registers. We examined if late-preterm birth was associated with a higher risk for common mental disorders in young adulthood when using a diagnostic interview, and if this risk decreased as gestational age increased.

METHOD

A total of 800 young adults (mean = 25.3, s.d. = 0.62 years), born 1985-1986, participated in a follow-up of the Arvo Ylppö Longitudinal Study. Common mental disorders (mood, anxiety and substance use disorders) during the past 12 months were defined using the Composite International Diagnostic Interview (Munich version). Gestational age was extracted from hospital birth records and categorized into early-preterm (<34 + 0, n = 37), late-preterm (34 + 0-36 + 6, n = 106), term (37 + 0-41 + 6, n = 617) and post-term (⩾42 + 0, n = 40).

RESULTS

Those born late-preterm and at term were at a similar risk for any common mental disorder [odds ratio (OR) 1.11, 95% confidence interval (CI) 0.67-1.84], for mood (OR 1.11, 95% CI 0.54-2.25), anxiety (OR 1.00, 95% CI 0.40-2.50) and substance use (OR 1.31, 95% CI 0.74-2.32) disorders, and co-morbidity of these disorders (p = 0.38). While the mental disorder risk decreased significantly as gestational age increased, the trend was driven by a higher risk in those born early-preterm.

CONCLUSIONS

Using a cohort born during the advanced neonatal and early childhood care, we found that not all individuals born preterm are at risk for common mental disorders in young adulthood - those born late-preterm are not, while those born early-preterm are at a higher risk. Available resources for prevention and intervention should be targeted towards the preterm group born the earliest.

Somatic, positive and negative domains of the Center for Epidemiological Studies Depression (CES-D) scale: a meta-analysis of genome-wide association studies

BACKGROUND

Major depressive disorder (MDD) is moderately heritable, however genome-wide association studies (GWAS) for MDD, as well as for related continuous outcomes, have not shown consistent results. Attempts to elucidate the genetic basis of MDD may be hindered by heterogeneity in diagnosis. The Center for Epidemiological Studies Depression (CES-D) scale provides a widely used tool for measuring depressive symptoms clustered in four different domains which can be combined together into a total score but also can be analysed as separate symptom domains.

METHOD

We performed a meta-analysis of GWAS of the CES-D symptom clusters. We recruited 12 cohorts with the 20- or 10-item CES-D scale (32 528 persons).

RESULTS

One single nucleotide polymorphism (SNP), rs713224, located near the brain-expressed melatonin receptor (MTNR1A) gene, was associated with the somatic complaints domain of depression symptoms, with borderline genome-wide significance (p discovery = 3.82 × 10-8). The SNP was analysed in an additional five cohorts comprising the replication sample (6813 persons). However, the association was not consistent among the replication sample (p discovery+replication = 1.10 × 10-6) with evidence of heterogeneity.

CONCLUSIONS

Despite the effort to harmonize the phenotypes across cohorts and participants, our study is still underpowered to detect consistent association for depression, even by means of symptom classification. On the contrary, the SNP-based heritability and co-heritability estimation results suggest that a very minor part of the variation could be captured by GWAS, explaining the reason of sparse findings.

GWAS for executive function and processing speed suggests involvement of the CADM2 gene

To identify common variants contributing to normal variation in two specific domains of cognitive functioning, we conducted a genome-wide association study (GWAS) of executive functioning and information processing speed in non-demented older adults from the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) consortium. Neuropsychological testing was available for 5429-32,070 subjects of European ancestry aged 45 years or older, free of dementia and clinical stroke at the time of cognitive testing from 20 cohorts in the discovery phase. We analyzed performance on the Trail Making Test parts A and B, the Letter Digit Substitution Test (LDST), the Digit Symbol Substitution Task (DSST), semantic and phonemic fluency tests, and the Stroop Color and Word Test. Replication was sought in 1311-21860 subjects from 20 independent cohorts. A significant association was observed in the discovery cohorts for the single-nucleotide polymorphism (SNP) rs17518584 (discovery P-value=3.12 × 10(-8)) and in the joint discovery and replication meta-analysis (P-value=3.28 × 10(-9) after adjustment for age, gender and education) in an intron of the gene cell adhesion molecule 2 (CADM2) for performance on the LDST/DSST. Rs17518584 is located about 170 kb upstream of the transcription start site of the major transcript for the CADM2 gene, but is within an intron of a variant transcript that includes an alternative first exon. The variant is associated with expression of CADM2 in the cingulate cortex (P-value=4 × 10(-4)). The protein encoded by CADM2 is involved in glutamate signaling (P-value=7.22 × 10(-15)), gamma-aminobutyric acid (GABA) transport (P-value=1.36 × 10(-11)) and neuron cell-cell adhesion (P-value=1.48 × 10(-13)). Our findings suggest that genetic variation in the CADM2 gene is associated with individual differences in information processing speed.

Late preterm birth, post-term birth, and abnormal fetal growth as risk factors for severe mental disorders from early to late adulthood

BACKGROUND

Late preterm births constitute the majority of preterm births. However, most evidence suggesting that preterm birth predicts the risk of mental disorders comes from studies on earlier preterm births. We examined if late preterm birth predicts the risks of severe mental disorders from early to late adulthood. We also studied whether adulthood mental disorders are associated with post-term birth or with being born small (SGA) or large (LGA) for gestational age, which have been previously associated with psychopathology risk in younger ages.

METHOD

Of 12 597 Helsinki Birth Cohort Study participants, born 1934-1944, 664 were born late preterm, 1221 post-term, 287 SGA, and 301 LGA. The diagnoses of mental disorders were identified from national hospital discharge and cause of death registers from 1969 to 2010. In total, 1660 (13.2%) participants had severe mental disorders.

RESULTS

Individuals born late preterm did not differ from term-born individuals in their risk of any severe mental disorder. However, men born late preterm had a significantly increased risk of suicide. Post-term birth predicted significantly increased risks of any mental disorder in general and particularly of substance use and anxiety disorders. Individuals born SGA had significantly increased risks of any mental and substance use disorders. Women born LGA had an increased risk of psychotic disorders.

CONCLUSIONS

Although men born late preterm had an increased suicide risk, late preterm birth did not exert widespread effects on adult psychopathology. In contrast, the risks of severe mental disorders across adulthood were increased among individuals born SGA and individuals born post-term.

Genetic contributions to variation in general cognitive function: a meta-analysis of genome-wide association studies in the CHARGE consortium (N=53949)

General cognitive function is substantially heritable across the human life course from adolescence to old age. We investigated the genetic contribution to variation in this important, health- and well-being-related trait in middle-aged and older adults. We conducted a meta-analysis of genome-wide association studies of 31 cohorts (N=53,949) in which the participants had undertaken multiple, diverse cognitive tests. A general cognitive function phenotype was tested for, and created in each cohort by principal component analysis. We report 13 genome-wide significant single-nucleotide polymorphism (SNP) associations in three genomic regions, 6q16.1, 14q12 and 19q13.32 (best SNP and closest gene, respectively: rs10457441, P=3.93 × 10(-9), MIR2113; rs17522122, P=2.55 × 10(-8), AKAP6; rs10119, P=5.67 × 10(-9), APOE/TOMM40). We report one gene-based significant association with the HMGN1 gene located on chromosome 21 (P=1 × 10(-6)). These genes have previously been associated with neuropsychiatric phenotypes. Meta-analysis results are consistent with a polygenic model of inheritance. To estimate SNP-based heritability, the genome-wide complex trait analysis procedure was applied to two large cohorts, the Atherosclerosis Risk in Communities Study (N=6617) and the Health and Retirement Study (N=5976). The proportion of phenotypic variation accounted for by all genotyped common SNPs was 29% (s.e.=5%) and 28% (s.e.=7%), respectively. Using polygenic prediction analysis, ~1.2% of the variance in general cognitive function was predicted in the Generation Scotland cohort (N=5487; P=1.5 × 10(-17)). In hypothesis-driven tests, there was significant association between general cognitive function and four genes previously associated with Alzheimer's disease: TOMM40, APOE, ABCG1 and MEF2C.

A genome-wide meta-analysis of association studies of Cloninger's Temperament Scales

Temperament has a strongly heritable component, yet multiple independent genome-wide studies have failed to identify significant genetic associations. We have assembled the largest sample to date of persons with genome-wide genotype data, who have been assessed with Cloninger's Temperament and Character Inventory. Sum scores for novelty seeking, harm avoidance, reward dependence and persistence have been measured in over 11,000 persons collected in four different cohorts. Our study had >80% power to identify genome-wide significant loci (P<1.25 × 10(-8), with correction for testing four scales) accounting for ≥0.4% of the phenotypic variance in temperament scales. Using meta-analysis techniques, gene-based tests and pathway analysis we have tested over 1.2 million single-nucleotide polymorphisms (SNPs) for association to each of the four temperament dimensions. We did not discover any SNPs, genes, or pathways to be significantly related to the four temperament dimensions, after correcting for multiple testing. Less than 1% of the variability in any temperament dimension appears to be accounted for by a risk score derived from the SNPs showing strongest association to the temperament dimensions. Elucidation of genetic loci significantly influencing temperament and personality will require potentially very large samples, and/or a more refined phenotype. Item response theory methodology may be a way to incorporate data from cohorts assessed with multiple personality instruments, and might be a method by which a large sample of a more refined phenotype could be acquired.

Neurocognitive abilities in young adults with very low birth weight

OBJECTIVE

Although severely preterm birth has been associated with impaired neurocognitive abilities in children, follow-up studies in adulthood are scarce. We set out to study whether adults born with very low birth weight (VLBW) (<1,500 g), either small for gestational age (SGA) (birth weight ≤-2 SD) or appropriate for gestational age (AGA), differ in a range of neurocognitive abilities and academic performance from adults born at term and not SGA.

METHODS

As part of the Helsinki Study of Very Low Birth Weight Adults, 103 VLBW (37 SGA) and 105 term-born control adults (mean age 25.0, range 21.4-29.7 years) without major neurosensory impairments participated in the follow-up study in 2007-2008. The test battery included measures of general cognitive ability as well as executive functioning and related abilities. Academic performance was self-reported.

RESULTS

With adjustment for sex and age, the VLBW group scored lower or performed slower than the control group in some indices of all tests (these mean differences ranged from 0.3 to 0.5 SD units, p ≤ 0.03) and they had received remedial education at school more frequently; however, no differences existed in self-reported academic performance. The differences were evident in both VLBW-SGA and VLBW-AGA groups. Further covariate adjustments for parental education, current head circumference, and head circumference at birth and, in tests of executive functioning and related abilities, adjustment for IQ estimate had minor effects on the results.

CONCLUSIONS

In comparison with control adults, VLBW adults scored lower on several neurocognitive tests. Poorer neurocognitive performance is associated with VLBW irrespective of the intrauterine growth pattern.

Meta-analysis of genome-wide association studies identifies common variants in CTNNA2 associated with excitement-seeking

The tendency to seek stimulating activities and intense sensations define excitement-seeking, a personality trait akin to some aspects of sensation-seeking. This trait is a central feature of extraversion and is a component of the multifaceted impulsivity construct. Those who score high on measures of excitement-seeking are more likely to smoke, use other drugs, gamble, drive recklessly, have unsafe/unprotected sex and engage in other risky behaviors of clinical and social relevance. To identify common genetic variants associated with the Excitement-Seeking scale of the Revised NEO Personality Inventory, we performed genome-wide association studies in six samples of European ancestry (N=7860), and combined the results in a meta-analysis. We identified a genome-wide significant association between the Excitement-Seeking scale and rs7600563 (P=2 × 10(-8)). This single-nucleotide polymorphism maps within the catenin cadherin-associated protein, alpha 2 (CTNNA2) gene, which encodes for a brain-expressed α-catenin critical for synaptic contact. The effect of rs7600563 was in the same direction in all six samples, but did not replicate in additional samples (N=5105). The results provide insight into the genetics of excitement-seeking and risk-taking, and are relevant to hyperactivity, substance use, antisocial and bipolar disorders.

Predictors for the efficacy of naltrexone treatment in alcohol dependence: sweet preference

AIMS

To analyse the possible associations between sweet preference and the efficacy of naltrexone treatment of alcohol dependence.

METHODS

The preference for different concentrations of sucrose was evaluated in 78 participants diagnosed with alcohol dependence after treatment for 32 weeks with naltrexone or placebo without prior detoxification.

RESULTS

A significant difference between naltrexone and placebo groups was found in the association between the preference for higher sucrose concentrations and relapses to heavy drinking. Higher sweet preference was significantly related to successful treatment measures in the naltrexone group but not in the placebo group.

CONCLUSION

Sweet preference has a strong correlation to treatment outcomes with naltrexone, and sweet preference might be used as a predictor for better treatment results in alcoholics. Our study offers one possible new explanation of the clinical observation that naltrexone is not effective for every patient.

Prenatal growth, postnatal growth and trait anxiety in late adulthood - the Helsinki Birth Cohort Study

OBJECTIVE

Trait anxiety may predispose to anxiety disorders and cardiovascular events. We tested whether prenatal growth or postnatal growth from birth to 11 years of age and in adulthood predict trait anxiety in late adulthood.

METHOD

Women (n = 951) and men (n = 753) reported trait anxiety using the Spielberger Trait Anxiety Scale at an average age of 63.4 years and growth was estimated from records.

RESULTS

Higher trait anxiety was predicted by smaller body size at birth, in infancy and in adulthood. Moreover, faster growth particularly from seven to 11 years of age and slower growth between 11 and 63 years predicted higher trait anxiety.

CONCLUSION

We found a pattern of pre- and postnatal growth that predisposed to higher trait anxiety in late adulthood. This pattern resembles that found to increase the risk of cardiovascular events and, thus, points to a shared common origin in a suboptimal prenatal and childhood developmental milieu.