An epigenome-wide association study meta-analysis of educational attainment.

The epigenome is associated with biological factors, such as disease status, and environmental factors, such as smoking, alcohol consumption and body mass index. Although there is a widespread perception that environmental influences on the epigenome are pervasive and profound, there has been little evidence to date in humans with respect to environmental factors that are biologically distal. Here we provide evidence on the associations between epigenetic modifications-in our case, CpG methylation-and educational attainment (EA), a biologically distal environmental factor that is arguably among the most important life-shaping experiences for individuals. Specifically, we report the results of an epigenome-wide association study meta-analysis of EA based on data from 27 cohort studies with a total of 10 767 individuals. We find nine CpG probes significantly associated with EA. However, robustness analyses show that all nine probes have previously been found to be associated with smoking. Only two associations remain when we perform a sensitivity analysis in the subset of never-smokers, and these two probes are known to be strongly associated with maternal smoking during pregnancy, and thus their association with EA could be due to correlation between EA and maternal smoking. Moreover, the effect sizes of the associations with EA are far smaller than the known associations with the biologically proximal environmental factors alcohol consumption, body mass index, smoking and maternal smoking during pregnancy. Follow-up analyses that combine the effects of many probes also point to small methylation associations with EA that are highly correlated with the combined effects of smoking. If our findings regarding EA can be generalized to other biologically distal environmental factors, then they cast doubt on the hypothesis that such factors have large effects on the epigenome.

Registered Replication Report: Rand, Greene, and Nowak (2012).

In an anonymous 4-person economic game, participants contributed more money to a common project (i.e., cooperated) when required to decide quickly than when forced to delay their decision (Rand, Greene & Nowak, 2012), a pattern consistent with the social heuristics hypothesis proposed by Rand and colleagues. The results of studies using time pressure have been mixed, with some replication attempts observing similar patterns (e.g., Rand et al., 2014) and others observing null effects (e.g., Tinghög et al., 2013; Verkoeijen & Bouwmeester, 2014). This Registered Replication Report (RRR) assessed the size and variability of the effect of time pressure on cooperative decisions by combining 21 separate, preregistered replications of the critical conditions from Study 7 of the original article (Rand et al., 2012). The primary planned analysis used data from all participants who were randomly assigned to conditions and who met the protocol inclusion criteria (an intent-to-treat approach that included the 65.9% of participants in the time-pressure condition and 7.5% in the forced-delay condition who did not adhere to the time constraints), and we observed a difference in contributions of -0.37 percentage points compared with an 8.6 percentage point difference calculated from the original data. Analyzing the data as the original article did, including data only for participants who complied with the time constraints, the RRR observed a 10.37 percentage point difference in contributions compared with a 15.31 percentage point difference in the original study. In combination, the results of the intent-to-treat analysis and the compliant-only analysis are consistent with the presence of selection biases and the absence of a causal effect of time pressure on cooperation.

Cloning, purification and characterization of non-human primate 12/15-lipoxygenases.

The enzyme 15-lipoxygenase-1 (15-LO-1) possesses mainly 15-LO activity and has so far only been described in human cells and rabbit reticulocytes. The animal ortholog, except rabbit reticulocytes, is an enzyme with predominantly a 12-lipoxygenase activity, commonly referred to as 12/15-LO. We describe herein the characterization of the 12/15-LOs in Macaca mulatta (rhesus monkey) and in Pongo pygmaeus (orang-utan). The rhesus and the orang-utan enzymes have mainly 12-lipoxygenase and 15-lipoxygenase activity, respectively, and they display 94% and 98% identity to the human 15-LO-1 protein. The rhesus enzyme was functionally different from the human enzyme with respect to substrate utilization in that anandamide was used differently and that the rhesus enzymes positional specificity could be affected by the substrate concentration. Furthermore, genomic data indicate that chimpanzees express an enzyme with mainly 15-lipoxygenase activity whereas marmosets express an enzyme with mainly 12-LO activity. Taken together, the switch during evolution from a 12-lipoxygenating enzyme in lower primates to a 15-lipoxygenating enzyme in higher primates and man might be of importance for the biological function of this enzyme.

Consensus on the use and interpretation of cystic fibrosis mutation analysis in clinical practice.

It is often challenging for the clinician interested in cystic fibrosis (CF) to interpret molecular genetic results, and to integrate them in the diagnostic process. The limitations of genotyping technology, the choice of mutations to be tested, and the clinical context in which the test is administered can all influence how genetic information is interpreted. This paper describes the conclusions of a consensus conference to address the use and interpretation of CF mutation analysis in clinical settings. Although the diagnosis of CF is usually straightforward, care needs to be exercised in the use and interpretation of genetic tests: genotype information is not the final arbiter of a clinical diagnosis of CF or CF transmembrane conductance regulator (CFTR) protein related disorders. The diagnosis of these conditions is primarily based on the clinical presentation, and is supported by evaluation of CFTR function (sweat testing, nasal potential difference) and genetic analysis. None of these features are sufficient on their own to make a diagnosis of CF or CFTR-related disorders. Broad genotype/phenotype associations are useful in epidemiological studies, but CFTR genotype does not accurately predict individual outcome. The use of CFTR genotype for prediction of prognosis in people with CF at the time of their diagnosis is not recommended. The importance of communication between clinicians and medical genetic laboratories is emphasized. The results of testing and their implications should be reported in a manner understandable to the clinicians caring for CF patients.

Guidelines for the management of pregnancy in women with cystic fibrosis.

Women with cystic fibrosis (CF) now regularly survive into their reproductive years in good health and wish to have a baby. Many pregnancies have been reported in the literature and it is clear that whilst the outcome for the baby is generally good and some mothers do very well, others find either their CF complicates the pregnancy or is adversely affected by the pregnancy. For some, pregnancy may only become possible after transplantation. Optimal treatment of all aspects of CF needs to be maintained from the preconceptual period until after the baby is born. Clinicians must be prepared to modify their treatment to accommodate the changing physiology during pregnancy and to be aware of changing prescribing before conception, during pregnancy, after birth and during breast feeding. This supplement offers consensus guidelines based on review of the literature and experience of paediatricians, adult and transplant physicians, and nurses, physiotherapists, dietitians, pharmacists and psychologists experienced in CF and anaesthetist and obstetricians with experience of CF pregnancy. It is hoped they will provide practical guidelines helpful to the multidisciplinary CF teams caring for pregnant women with CF.

Genetics of autoimmune diseases: a multistep process.

It has so far been difficult to identify genes behind polygenic autoimmune diseases such as rheumatoid arthritis (RA), multiple sclerosis (MS), and type I diabetes (T1D). With proper animal models, some of the complexity behind these diseases can be reduced. The use of linkage analysis and positional cloning of genes in animal models for RA resulted in the identification of one of the genes regulating severity of arthritis in rats and mice, the Ncf1 gene. The Ncf1 gene encodes for the Ncf1 protein that is involved in production of free oxygen radicals through the NADPH oxidase complex, which opens up a new pathway for therapeutic treatment of inflammatory diseases. In most cases, however, a quantitative trait locus (QTL) is the sum effect of several genes within and outside the QTL, which make positional cloning difficult. Here we will discuss the possibilities and difficulties of gene identification in animal models of autoimmune disorders.

Composition of nasal airway surface liquid in cystic fibrosis and other airway diseases determined by X-ray microanalysis.

The ionic composition of the airway surface liquid (ASL) in healthy individuals and in patients with cystic fibrosis (CF) has been debated. Ion transport properties of the upper airway epithelium are similar to those of the lower airways and it is easier to collect nasal ASL from the nose. ASL was collected with ion exchange beads, and the elemental composition of nasal fluid was determined by X-ray microanalysis in healthy subjects, CF patients, CF heterozygotes, patients with rhinitis, and with primary ciliary dyskinesia (PCD). In healthy subjects, the ionic concentrations were approximately isotonic. In CF patients, CF heterozygotes, rhinitis, and PCD patients, [Na] and [Cl] were significantly higher compared when compared with those in controls. [K] was significantly higher in CF and PCD patients compared with that in controls. Severely affected CF patients had higher ionic concentrations in their nasal ASL than in patients with mild or moderate symptoms. Female CF patients had higher levels of Na, Cl, and K than male patients. As higher salt concentrations in the ASL are also found in other patients with airway diseases involving chronic inflammation, it appears likely that inflammation-induced epithelial damage is important in determining the ionic composition of the ASL.

Gene expression profiling of arthritis using a QTL chip reveals a complex gene regulation of the Cia5 region in mice.

One of the major quantitative trait loci (QTLs) associated with arthritis in crosses between B10.RIII and RIIIS/J mice is the Cia5 on chromosome 3. Early in the congenic mapping process it was clear that the locus was complex, consisting of several subloci with small effects. Therefore, we developed two novel strategies to dissect a QTL: the partial advanced inter-cross (PAI) strategy, with which we recently found the Cia5 region to consist of three loci, Cia5, Cia21 and Cia22, and now we introduce the QTL-chip strategy, where we have combined congenic mapping with a QTL-restricted expression profiling using a novel microarray design. The expression of QTL genes was compared between parental and congenic mice in lymph node, spleen and paw samples in five biological replicates and in dye-swapped experiments at three time points during the induction phase of arthritis. The QTL chip approach revealed 4 genes located in Cia21, differently expressed in lymph nodes, and 14 genes in Cia22, located within two clusters. One cluster contains six genes, differently expressed in spleen, and the second cluster contains eight genes, differently expressed in paws. We conclude the QTL-chip strategy to be valuable in the selection of candidate genes to be prioritized for further investigation.

Identification of epistasis through a partial advanced intercross reveals three arthritis loci within the Cia5 QTL in mice.

Identification of genes controlling complex diseases has proven to be difficult; however, animal models may pave the way to determine how low penetrant genes interact to promote disease development. We have dissected the Cia5/Eae3 susceptibility locus on mouse chromosome 3 previously identified to control disease in experimental models of multiple sclerosis and rheumatoid arthritis. Congenic strains showed significant but small effects on severity of both diseases. To improve the penetrance, we have now used a new strategy that defines the genetic interactions. The QTL interacted with another locus on chromosome 15 and a partial advanced intercross breeding of the two congenic strains for eight generations accumulated enough statistical power to identify interactions with several loci on chromosome 15. Thereby, three separate loci within the original QTL could be identified; Cia5 affected the onset of arthritis by an additive interaction with Cia31 on chromosome 15, whereas the Cia21 and Cia22 affected severity during the chronic phase of the disease through an epistatic interaction with Cia32 on chromosome 15. The definition of genetic interactions was a prerequisite to dissect the Cia5 QTL and we suggest the partial advanced intercross strategy to be helpful also for dissecting other QTL controlling complex phenotypes.

Genetic heterogeneity of autoimmune disorders in the nonobese diabetic mouse.

The nonobese diabetic mouse is highly susceptible not only to diabetes but to several autoimmune diseases, and one might suspect that these are controlled by a shared set of genes. However, based on various gene-segregation experiments, it seems that only a few loci are shared and that each disorder is influenced also by a unique set of genes.

Exhaled carbon monoxide is not elevated in patients with asthma or cystic fibrosis.

Increased levels of exhaled carbon monoxide (fractional concentration of CO in expired gas (FE,CO)), measured with an electrochemical sensor, have been reported in patients with inflammatory airway disorders, such as asthma, rhinitis and cystic fibrosis. This study aimed to evaluate these findings by using a fast-response nondisperse infrared (NDIR) analyser, and to compare these measurements with the fractional concentration of nitric oxide in exhaled air (FE,NO). Thirty-two steroid-naïve asthmatics, 24 steroid-treated asthmatics (16 patients with allergic rhinitis, nine patients with cystic fibrosis), and 30 nonsmoking healthy controls were included. CO measurements with the NDIR analyser were performed simultaneously with nitric oxide (NO) analysis (chemiluminescence technique). After 15 s of breath-hold, single-breath exhalations over 10 s were performed at two flow rates and end-tidal plateau concentrations were registered. An electrochemical CO sensor was used independently with an exhalation to residual volume, after a 15 s breath-hold. None of the two CO analysers gave a significant increase in FE,CO in the groups of patients with inflammatory airway disorders compared to controls. FE,NO was significantly elevated in steroid-naïve asthmatics and subjects with allergic rhinitis, but not in steroid-treated asthmatics and subjects with cystic fibrosis. Reducing exhalation flow rate by 50% gave a two-fold increase in FE,NO, while FE,CO was unaffected. A significant increase was seen in FE.CO, but not in FE,NO, when comparing with and without a 10 s breath-hold. In conclusion, the fractional concentration of carbon monoxide in expired gas was not increased in any of the patient groups, while the fractional concentration of nitric oxide in expired gas was significantly elevated in patients with steroid-naïve asthma and allergic rhinitis. Moreover, carbon monoxide was unaffected by flow rate but increased with breath-hold, suggesting an origin in the alveoli rather than the conducting airways.

Predictors of deterioration of lung function in cystic fibrosis.

The severity of lung disease in cystic fibrosis (CF) may be related to the type of mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and to environmental and immunological factors. Since pulmonary disease is the main determinant of morbidity and mortality in CF, it is important to identify factors that can explain and predict this variation. The aim of this longitudinal study of the whole Swedish CF population over age 7 years was to correlate genetic and clinical data with the rate of decline in pulmonary function. The statistical analysis was performed using the mixed model regression method, supplemented with calculation of relative risks for severe lung disease in age cohorts.The severity of pulmonary disease was to some extent predicted by CFTR genotype. Furthermore, the present investigation is the first long-term study showing a significantly more rapid deterioration of lung function in patients with concomitant diabetes mellitus. Besides diabetes mellitus, pancreatic insufficiency and chronic Pseudomonas colonization were found to be negative predictors of pulmonary function. In contrast to several other reports, we found no significant differences in lung function between genders. Patients with pancreatic sufficiency have no or only a slight decline of lung function with age once treatment is started, but an early diagnosis in this group is desirable.

Genetic control of collagen-induced arthritis in a cross with NOD and C57BL/10 mice is dependent on gene regions encoding complement factor 5 and FcgammaRIIb and is not associated with loci controlling diabetes.

The nonobese diabetic (NOD) mouse spontaneously develops autoimmune-mediated diseases such as diabetes and Sjögren's syndrome. To investigate whether NOD genes also promote autoimmune-mediated arthritis we established a NOD strain with an MHC class II fragment containing the A(q) class II gene predisposing for collagen induced arthritis (NOD.Q). However, this mouse was resistant to arthritis in contrast to other A(q) expressing strains such as B10.Q and DBA/1. To determine the major resistance factor/s, a genetic analysis was performed. (NOD.Q x B10.Q)F1 mice were resistant, whereas 27% of the (NOD.Q x B10.Q)F2 mice developed severe arthritis. Genetic mapping of 353 F2 mice revealed two loci associated with arthritis. One locus was found on chromosome 2 (LOD score 9.8), at the location of the complement factor 5 (C5) gene. The susceptibility allele was from B10.Q, which contains a productive C5 encoding gene in contrast to NOD.Q. The other significant locus was found on chromosome 1 (LOD score 5.6) close to the Fc-gamma receptor IIb gene, where NOD carried the susceptible allele. An interaction between the two loci was observed, indicating that they operate on the same or on interacting pathways. The genetic control of arthritis is unique in comparison to diabetes, since none of these loci have been identified in analysis of diabetes susceptibility.

Influence of CD4 or CD8 deficiency on collagen-induced arthritis.

The role of T cells in the mouse collagen-induced arthritis (CIA) model for rheumatoid arthritis is not clarified, and different results have been reported concerning the role of CD4 and CD8 T cells. To address this issue, we have investigated B10.Q mice deficient for CD4 or CD8. The mice lacking CD4 were found to be less susceptible to disease, but not completely resistant, whereas the CD8 deficiency had no significant impact on the disease. No difference in the development of late occurring relapses was noted. Interestingly, the CD4-deficient mice had a severely reduced response to the glycosylated form of the immunodominant type II collagen (CII) 256-270 peptide whereas the response to the non-glycosylated peptide was not significantly different. Furthermore, CD4-deficient mice had lower antibody responses to CII, explaining the lower disease susceptibility. In comparison with previously reported results, it is apparent that the lack of CD4 molecules has a different impact on CIA if present on different genetic backgrounds, findings that could possibly be related to the occurrence of different disease pathways of CIA in different mouse strains.

At what coronary risk level is it cost-effective to initiate cholesterol lowering drug treatment in primary prevention?

BACKGROUND: The entire risk factor profile should be taken into account when considering initiating cholesterol lowering drug treatment. Recent treatment guidelines are therefore based on the absolute risk of coronary heart disease. We estimated at what coronary risk it is cost-effective to initiate cholesterol lowering drug treatment in primary prevention for men and women of different ages in Sweden. METHODS: The cost-effectiveness was estimated as the incremental cost per quality-adjusted life-year (QALY) gained of cholesterol lowering drug treatment. Treatment was assumed to lower the risk of coronary heart disease by 31%. The analysis was carried out from a societal perspective including both direct and indirect costs of the intervention and morbidity, and the full future costs of decreased mortality. The coronary risk, in a Markov model of coronary heart disease, was raised until the cost per QALY gained corresponded to a specific threshold value per QALY gained. Three different threshold values were used: $40,000, $60,000 and $100,000 per QALY gained. RESULTS: The risk cut-off value for when treatment is cost-effective varied with age and gender. If society is willing to pay $60,000 to gain a QALY it was cost-effective to initiate treatment if the 5-year-risk of coronary heart disease exceeded 2.4% for 35-year-old men, 4.6% for 50-year-old men, and 10.4% for 70-year-old men. The corresponding risk cut-off values for women were 2.0%, 3.5% and 9.1%. CONCLUSIONS: The results can serve as a basis for treatment guidelines based on cost-effectiveness.

Hypothetical versus real willingness to pay in the health care sector: results from a field experiment.

We conducted a field experiment comparing hypothetical and real purchase decisions for a pharmacist provided asthma management program among 172 subjects with asthma. Subjects received either a dichotomous choice contingent valuation question or were given the opportunity to actually enroll in the program. Three different prices were used: US$ 15, 40, and 80. In the hypothetical group, 38% of subjects said that they would purchase the good at the stated price, but only 12% of subjects in the real group purchased the good (p = 0.000). We cannot, however, reject the null hypothesis that "definitely sure" hypothetical yes responses, as identified in a follow-up question, correspond to real yes responses. We conclude that the dichotomous choice contingent valuation method overestimates willingness to pay, but that it may be possible to correct for this overestimation by sorting out "definitely sure" yes responses.

Health-related quality of life by disease and socio-economic group in the general population in Sweden.

Measuring health-related quality of life (HRQoL) on population level, is becoming increasingly important for priority setting in health policy. In the health economics field, it is common to measure HRQoL in terms of health-state utilities or QoL weights. This study investigates the feasibility of obtaining mean QoL weights by mapping survey data to the generic HRQoL measure EQ-5D and to describe the HRQoL in terms of mean QoL weights in certain disease and socio-economic groups. Data from the 1996-1997 Survey of Living Conditions, interviews with a representative sample (16-84 years) of the Swedish population (n=11 698) were used. The mean QoL weight decreased from 0.91 among the youngest to 0.61 among the oldest, and was lower for women than for men. The QoL weight was 0.88 in the highest socio-economic group and 0.78 in the lowest socio-economic group. The QoL weight was lowest (0.38) among persons with depression and highest among persons with hypertension (0.71). The QoL weight decreased from 0.95 for persons with very good global self-rated health to 0.20 for persons with very poor global self-rated health. The results support the feasibility and validity of the mapping approach. HRQoL varies greatly between socio-economic groups and different disease groups.

Swedish population health-related quality of life results using the EQ-5D.

Health-related quality of life (HRQoL) measured on population level may be useful to guide policies for health. This study aims to describe the HRQoL; in EQ-5D dimensions, mean rating scale (RS) scores and mean EQ-5D index values, in the general population, by certain disease and socio-economic groups, in Stockholm County 1998. The EQ-5D self-classifier and a RS were included in the 1998 cross-sectional postal Stockholm County public health survey to a representative sample (n = 4950, 20-88 years), 63% response rate. Mean RS score ranged from 0.90 (20-29 years) to 0.69 (80-88 years), mean EQ-5D index value ranged from 0.89 (20-29 years) to 0.74 (80-88 years). For different diseases mean RS scores ranged from 0.80 (asthma) to 0.69 (angina pectoris), mean EQ-5D index values ranged from 0.79 (asthma) to 0.66 (low back pain). The mean health state scores (RS and EQ-5D index) were 0.06 lower in the unskilled manual group than in the higher non-manual group after controlling for age and sex (p < 0.0001). This difference was 0.03 after controlling also for different diseases (p < 0.0001). In conclusion, our results show that the HRQoL varies greatly between socio-economic and disease groups. Furthermore, after controlling for age, sex and disease, HRQoL is lower in manual than in non-manual groups.

Lung function changes in relation to menstrual cycle in females with cystic fibrosis.

Oestrogen and progesterone have been shown to have impact on cystic fibrosis transmembrane conductance regulator (CFTR) gene expression, tone of smooth muscle in the airways, immune response, exhaled nitric oxide and cytology in the tracheobronchial epithelium. The aim of this investigation was to study the influence of menstrual cyclicity on airway symptoms among cystic fibrosis (CF) females. Twelve CF women (mean age 30 years, mean Shwachman score 85) kept daily records during three menstrual cycles of lung function, sputum quality and need for intravenous antibiotics. Paired t-test was used as a statistical method to compare the airway symptoms between the time of ovulation (high levels of oestrogen and low levels of progesterone), the luteal phase (high levels of oestrogen and progesterone) and menstruation (low levels of oestrogens and progesterone). Forced expiratory volume in 1 sec (FEV1) was significantly higher during the luteal phase (66% of predicted) compared to during ovulation (63%) and menstruation (61%) (P<0.01). Forced vital capacity (FVC) showed the same pattern, being significantly higher during the luteal phase compared with during menstruation (mean 75% vs. 70%, P<0.01). In conclusion, lung function changes were found during menstrual cycles in women with cystic fibrosis. These changes are probably related to changes in progesterone levels during the menstrual cycles. This result warrants further studies to understand the complexity of CF lung disease in women.