The epidemiology of multiple sclerosis in the Isle of Man: 2006-2011

BACKGROUND

We sought to determine the prevalence of MS on the Isle of Man in 2006 and 2011, and the incidence and mortality rates over this interval.

METHODS

Cases were identified by hospital medical record review, General Practitioners and the local MS Society. The significance of the change in prevalence over time and the significance of differences in frequencies by sex and place of birth were assessed by Poisson regression.

RESULTS

The 2006 prevalence was 153.64 per 100,000 persons and the 2011 prevalence was 179.89. The prevalence was higher among females and persons born in the Isle of Man at both time points. The 2006-2011 incidence rate was 6.86 per 100,000 person-years, much higher among females and persons born in the Isle of Man. The prevalence sex ratios in 2006 and 2011, 2.77 and 2.59, respectively, and the incidence sex ratio, 2.19, are similar to others found in the region. The mortality rate over the study period was 2.84 per 100,000 person-years, this solely among persons born overseas.

CONCLUSIONS

This is the first study of MS epidemiology in the Isle of Man, finding this area to be of high prevalence and to have one of the highest incidence rates in the UK region.

Modulating effects of WT1 on interferon-β-vitamin D association in MS

OBJECTIVE

To investigate whether those genes involved in the vitamin D pathway modulate the relationship between 25-hydroxyvitamin D (25(OH)D) and IFN-β, the relationship between IFN-β and sun in predicting 25(OH)D, and the interaction between IFN-β and 25(OH)D in modulating relapse risk in patients with MS.

METHODS

Prospective cohort study of 169 participants with MS and genotype data followed 2002-2005. Gene-IFN-β and gene-IFN-β-sun interactions predicting 25(OH)D evaluated by multilevel mixed-effects linear regression. Gene-IFN-β interactions with 25(OH)D in modulating in relapse risk assessed using survival analysis.

RESULTS

The cohort was 71.6% female and of mean age 47.8. Two-independent intronic genotyped SNPs (rs10767935 and rs5030244) in WT1 significantly modified the IFN-β-25(OH)D association after adjustment (P(interaction) = 0.001, 0.0002; P(adj) = 0.003, 0.006, respectively). There was a marked difference in the interaction between self-reported sun exposure and IFN-β in predicting 25(OH)D by level of rs10767935, although this did not reach statistical significance. No SNPs modified the interaction between IFN-β and 25(OH)D in predicting relapse.

CONCLUSIONS

We have demonstrated that two-independent SNPs (rs10767935 and rs5030244) in WT1 modified the IFN-β-25(OH)D association in patients with MS. Some evidence was shown for a difference in the sun-IFN-β-25(OH)D association by level of rs10767935. These findings indicate that WT1 variants may play a role in altering the effects of IFN-β on vitamin D in MS.

Lung function in African infants: a pilot study

BACKGROUND

The burden of childhood respiratory illness is large in low and middle income countries (LMICs). Infant lung function (ILF) testing may provide useful information about lung growth and susceptibility to respiratory disease. However, ILF has not been widely available in LMICs settings where the greatest burden of childhood respiratory disease occurs.

AIM

To implement and evaluate a pilot study of ILF testing in a semi-rural setting in South Africa.

METHOD

Infant lung function testing was established at a community hospital in South Africa. All measures were done in unsedated infants during sleep. Measurements, made with the infant quietly breathing through a face mask and bacterial filter, included tidal breathing (TBFVL), exhaled nitric oxide (eNO), and sulphur hexafluoride multiple breath washout (MBW) measures using an ultrasonic flow meter and chemoluminescent NO analyzer.

RESULTS

Twenty infants, mean age of 7.7 (SD 2.9) weeks were tested; 8 (40%) were Black African and 12 (60%) were mixed race. Five (25%) infants were preterm. There were 19 (95%) successful TBFVL and NO tests and 18 (90%) successful MBW tests. The mean tidal volume was 30.5 ml (SD 5.9), respiratory rate 50.2 breaths per minute (SD 8.7), and eNO 10.4 ppb (SD 7.3). The mean MBW measures were: functional residual capacity 71 ml (SD 13) and the lung clearance index 7.6 (SD 0.5). The intra-subject coefficient of variations (CV) of lung function measures were similar to published normative data for Caucasian European infants.

CONCLUSION

In this study we demonstrate that unsedated infant lung function measures of tidal breathing, MBW, and eNO are feasible in a semi-rural African setting with rates comparable to those reported from high income countries.

EBV & HHV6 reactivation is infrequent and not associated with MS clinical course

BACKGROUND

Among the environmental factors associated with multiple sclerosis (MS) causation, some of the strongest associations are with Epstein-Barr virus (EBV), and to a lesser extent human herpesvirus 6 (HHV6). Associations with clinical course are less conclusive, however.

METHODS

We evaluated serum anti-EBV-EA-R IgG and anti-HHV6 IgM, and EBV and HHV6 viral load (VL) for their associations with relapse, disability, and progression in disability in a prospective cohort of 198 participants with clinically definite MS.

RESULTS

Anti-EBV-EA-R IgG was detected in 81.8% of cases at study entry, and titers remained essentially unchanged during the study. Anti-HHV6 IgM was detected in only one participant, and EBV-VL (29%) and HHV6-VL (1.8%) were detected in a minority of samples, and where detected levels were low. Our previously demonstrated association between anti-HHV6 IgG and relapse hazard was not affected by adjustment for parameters of reactivation. We found no evidence that any of the viral markers were associated with disability or progression in disability. In relation to relapse, only EBV-VL was positively associated, although this was strongly influenced by a single individual.

CONCLUSION

Using a prospective cohort design, we found no convincing evidence that reactivation parameters of EBV or HHV6 were associated with subsequent MS relapse hazard or progression in disability, confirming previous findings, and indicating that herpesvirus reactivation is not an important driver of relapse or disability in this established MS population.

Higher levels of reported sun exposure, and not vitamin D status, are associated with less depressive symptoms and fatigue in multiple sclerosis

OBJECTIVE

Insufficient sun exposure and vitamin D deficiency have both been associated with increased risk of multiple sclerosis (MS). Depressi on, anxiety, fatigue and cognitive impairment are prevalent and disabling symptoms in MS. Our objective was to examine the associations between personal sun exposure and serum 25-hydroxyvitamin D (25(OH)D), and depression, anxiety, fatigue and cognition.

METHODS

A total of 198 participants with multiple sclerosis were followed prospectively for an average of 2.3 years. Assessments of serum 25(OH)D, sun exposure, depression, anxiety and fatigue were carried out biannually; cognition was assessed annually.

RESULTS

Personal reported sun exposure was inversely associated with depression scores (β -0.26 (95%CI -0.40, -0.12);P ≤ 0.001) and fatigue scores (β -0.65 (95%CI -1.23, -0.07); P = 0.028). Only high levels of 25(OH)D (>80 nm) were inversely associated depression scores (β -0.64 (95%CI -1.15, -0.13); P = 0.015), but this was not significant after adjustment for reported sun exposure. No associations were seen between reported sun exposure or serum 25(OH)D levels and anxiety or cognition scores.

CONCLUSION

We found that higher levels reported sun exposure, rather than 25(OH)D levels, were associated with less depressive symptoms and levels of fatigue. The role of UV or light therapy will need to be evaluated in randomized controlled trials to confirm an effect on these symptoms in MS.

5 DISRUPTION OF THE HIGH MOBILITY GROUP AT-HOOK 2 (HMGA2) GENE IN SWINE REDUCES POSTNATAL GROWTH

The high mobility group AT-hook 2 (HMGA2) protein has been shown to be a crucial gene for cell growth, proliferation, and apoptosis; HMGA2 is also a strong biological candidate for growth, because mutations in this gene alter body size in mice and humans. Compared with wild-type controls, adult mice lacking HMGA2 are 60% smaller, and adult heterozygous mutants are 20% smaller. In humans, HMGA2 has been associated with adult and childhood height without any other deleterious effect. Additionally, a microdeletion in the HMGA2 gene in a human patient resulted in short stature, with no dysmorphologies and normal puberty. In order to determine the effect of HMGA2 on fetal and adult growth in pigs, a transgenic pig line deficient in HMGA2 expression was generated by gene targeting in fetal fibroblasts (FF). Using a targeting vector carrying a reporter gene, and homology arms specific to HMGA2, heterozygous mutant cell lines were generated. The cell lines were then used to generate 6 heterozygous females by somatic cell nuclear transfer (SCNT). Bodyweights and lengths from snout to base of tail were measured every 2 weeks for a year for mutant (n = 6) and wild-type farm gilts (n = 6). Data were analysed by one-way ANOVA. As in mice, disruption of one allele of the HMGA2 gene resulted in 25% reduction in weight (P < 0.0001) and 14% reduction in length (P < 0.0001). Early in postnatal growth (2 months), weights of mutants were not different than wild-type. However, mutants were 20 to 35% lighter (P < 0.05) during mid stages (6 months) and 25 to 30% (P < 0.0001) in late stages (3 months). The same insertional mutation generated 8 heterozygous male clones by SCNT. In addition, 7 nontransgenic males from the same FF line were generated as SCNT controls. Bodyweights and lengths were measured every 2 weeks for 30 weeks for HMGA2 heterozygous mutants (n = 8), control SCNT (n = 7) and wild-type farm boars (n = 5). The weight curve of boars showed similar pattern as for mutant gilts. At 30-week postnatal stage, mutants were 17% (P < 0.05) and 16% (P < 0.05) lighter in weight compared with littermate and wild-type animals, respectively. We are presently developing homozygous HMGA2 mutant lines. Currently, 3 of 6 heterozygous gilts have been bred with heterozygous boars, with 1 confirmed pregnancy. The expectation is that the homozygous animals will, like mice, be 60% smaller than the wild-type animals. The approach described here will result not only in a valuable large-animal model of dwarfism, but also in a tool to reduce the size of existing transgenic and nontransgenic swine lines. This, in turn, will increase the receptivity of valuable transgenic lines by the biomedical community. Funding for this work was provided by NIH grant R21-OD010553 to JP.

Kagome-like lattice of π–π stacked 3-hydroxyphenalenone on Cu(111)

Three-dimensional arrangement of 3-HPLN on a 2D surface, involving π–π stacking and perpendicular molecule attachment, results in a Kagome lattice.

Meta-analyses to investigate gene-environment interactions in neuroepidemiology

BACKGROUND

Most chronic neurological diseases are caused by a combination of multiple genetic and environmental factors. Increasingly, gene-environment interactions (GxE) are being examined, providing opportunities to combine studies systematically using meta-analysis.

METHODS

Systematic review of the literature on how to examine GxE using observational study designs, and how to conduct a meta-analysis of studies on GxE.

RESULTS

Most methods and challenges related to a standard meta-analysis apply to a GxE meta-analysis. There are, however, some substantive differences. With GxE, there is the capability of using a case-only design. Research on GxE interactions may be more prone to publication bias, since interactions are usually not the primary hypothesis and only 'exciting' significant GxE findings are reported out of a range of secondary analyses. In disease aetiology research, there has been debate whether to measure interaction on a multiplicative or additive scale. There are some significant challenges associated with measuring interaction on an additive scale, and thus the uptake of the measures of additive interaction has been limited. As a result, the methods of analysing interaction have been less consistent and reporting has been highly variable. We suggest using the STROBE/STREGA reporting guidelines to allow evaluation of interaction on both scales.

CONCLUSIONS

We identified a number of differences of a GxE meta-analysis over a standard meta-analysis. Awareness of these issues is important. Using established reporting guidelines for GxE studies is recommended. The development of consortia for neurological disorders that include both genetic and environmental data might offer benefits for GxE meta-analyses in the future.

White matter microstructural abnormality in children with hydrocephalus detected by probabilistic diffusion tractography

BACKGROUND AND PURPOSE

Hydrocephalus is a severe pathologic condition in which WM damage is a major factor associated with poor outcomes. The goal of the study was to investigate tract-based WM connectivity and DTI measurements in children with hydrocephalus by using the probabilistic diffusion tractography method.

MATERIALS AND METHODS

Twelve children with hydrocephalus and 16 age-matched controls were included in the study. Probabilistic diffusion tractography was conducted to generate tract-based connectivity distribution and DTI measures for the genu of the corpus callosum and the connectivity index. Tract-based summary measurements, including the connectivity index and DTI measures (fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity), were calculated and compared between the 2 study groups.

RESULTS

Tract-based summary measurement showed a higher percentage of voxels with lower normalized connectivity index values in the WM tracts in children with hydrocephalus. In the genu of the corpus callosum, the left midsegment of the corticospinal tract, and the right midsegment of the corticospinal tract, the normalized connectivity index value in children with hydrocephalus was found to be significantly lower (P < .05, corrected). The tract-based DTI measures showed that the children with hydrocephalus had significantly higher mean diffusivity, axial diffusivity, and radial diffusivity in the genu of the corpus callosum, left midsegment of the corticospinal tract, and right midsegment of corticospinal tract and lower fractional anisotropy in the genu of the corpus callosum (P < .05, corrected).

CONCLUSIONS

The analysis of WM connectivity showed that the probabilistic diffusion tractography method is a sensitive tool to detect the decreased continuity in WM tracts that are under the direct influence of mechanical distortion and increased intracranial pressure in hydrocephalus. This voxel-based connectivity method can provide quantitative information complementary to the standard DTI summary measures.

Comparative safety and effectiveness of sitagliptin in patients with type 2 diabetes: retrospective population based cohort study

OBJECTIVE

To determine if the use of sitagliptin in newly treated patients with type 2 diabetes is associated with any changes in clinical outcomes.

DESIGN

Retrospective population based cohort study.

SETTING

Large national commercially insured US claims and integrated laboratory database.

PARTICIPANTS

Inception cohort of new users of oral antidiabetic drugs between 2004 and 2009 followed until death, termination of medical insurance, or December 31 2010.

MAIN OUTCOME MEASURE

Composite endpoint of all cause hospital admission and all cause mortality, assessed with time varying Cox proportional hazards regression after adjustment for demographics, clinical and laboratory data, pharmacy claims data, healthcare use, and time varying propensity scores.

RESULTS

The cohort included 72,738 new users of oral antidiabetic drugs (8032 (11%) used sitagliptin; 7293 (91%) were taking it in combination with other agents) followed for a total of 182,409 patient years. The mean age was 52 (SD 9) years, 54% (39,573) were men, 11% (8111) had ischemic heart disease, and 9% (6378) had diabetes related complications at the time their first antidiabetic drug was prescribed. 14,215 (20%) patients met the combined endpoint. Sitagliptin users showed similar rates of all cause hospital admission or mortality to patients not using sitagliptin (adjusted hazard ratio 0.98, 95% confidence interval 0.91 to 1.06), including patients with a history of ischemic heart disease (adjusted hazard ratio 1.10, 0.94 to 1.28) and those with estimated glomerular filtration rate below 60 mL/min (1.11, 0.88 to 1.41).

CONCLUSIONS

Sitagliptin use was not associated with an excess risk of all cause hospital admission or death compared with other glucose lowering agents among newly treated patients with type 2 diabetes. Most patients prescribed sitagliptin in this cohort were concordant with clinical practice guidelines, in that it was used as add-on treatment.

Diffusion tensor imaging properties and neurobehavioral outcomes in children with hydrocephalus

BACKGROUND AND PURPOSE

White matter structural alterations and the correlation with neuropsychological deficits in children with hydrocephalus have not been well investigated. In this prospective study, the objectives were the following: 1) to apply DTI to detect in vivo white matter alterations based on diffusion properties in children with acute hydrocephalus, 2) to quantify early neuropsychological deficits, and 3) to explore the correlation between potential neuropsychological deficits and abnormalities in functionally related white matter.

MATERIALS AND METHODS

A total of 44 children, 24 with hydrocephalus and 20 controls, were enrolled in the study. DTI indices, FA, MD, AD, and RD, were evaluated in the gCC, sCC, PLIC, and ALIC. The ABAS-II was used as a broad screener of development, including conceptual, social, practical, and motor skills. The correlation between the Motor Scale and DTI indices in the PLIC was analyzed.

RESULTS

DTI analyses showed that the gCC and sCC in children with hydrocephalus had lower FA and higher MD, driven by the increased RD with statistical significance (P < .05) or trend-level significance (P = .06). The PLIC and ALIC had significantly higher AD in children with hydrocephalus (P < .05). On the ABAS-II, parent ratings of general adaptive skills, conceptual skills, and motor skills were significantly lower in children with hydrocephalus (all at P < .05). The MD and RD values in the PLIC were found to have trend-level or significant correlation with the Motor Scale (P = .057, .041, respectively).

CONCLUSIONS

DTI reveals alterations in the white matter structure in children with hydrocephalus with preliminary findings suggesting correlation with clinical motor deficits.

Exploring child maltreatment and its relationship to alcohol and cannabis use in selected Latin American and Caribbean countries

OBJECTIVES

Research from developed countries shows that child maltreatment increases the risk for substance use and problems. However, little evidence on this relationship is available from developing countries, and recognition of this relationship may have important implications for substance demand reduction strategies, including efforts to prevent and treat substance use and related problems. Latin America and the Caribbean is a rich and diverse region of the world with a large range of social and cultural influences. A working group constituted by the Inter-American Drug Abuse Control Commission and the Center for Addiction and Mental Health in June, 2010 identified research on this relationship as a priority area for a multinational research partnership.

METHODS

This paper examines the association between self-reported child maltreatment and use in the past 12 months of alcohol and cannabis in 2294 university students in seven participating universities in six participating countries: Colombia, El Salvador, Jamaica, Nicaragua, Panama and Uruguay. The research also considers the possible impact of religiosity and minimal psychological distress as factors contributing to resiliency in these samples.

RESULTS

The results showed that experience of maltreatment was associated with increased use of alcohol and cannabis. However, the effects differed depending on the type of maltreatment experienced. Higher levels of religiosity were consistently associated with lower levels of alcohol and cannabis use, but we found no evidence of an impact of minimal psychological distress on these measures.

CONCLUSIONS

This preliminary study shows that the experience of maltreatment may increase the risk of alcohol and cannabis use among university students in Latin American and Caribbean countries, but that higher levels of religiosity may reduce that risk. More work to determine the nature and significance of these relationships is needed.

Detection of temporal lobe seizures and identification of lateralisation from audified EEG

OBJECTIVE

To investigate the accuracy of human listeners in identifying epileptic seizures and seizure lateralisation from audified EEG signals.

METHODS

EEG data from 17 temporal lobe epilepsy patients (9 male, 8 female; aged 23-55) was converted to audio format by 60× time compression. Using a subset of 19% of the data, five auditory participants (2 female, 3 male; aged 23-58) were trained to identify seizures and their lateralisation by listening to audified EEG signals from difference electrodes P3-T5 and P4-T6. Following training, seizure detection performance of the auditory participants was tested using the remaining data.

RESULTS

Allowing a 5s auditory time margin for successful detection, the mean sensitivity of the five auditory participants was 89.6% (SD 8.3%) with a false detection rate of only 0.0068/h (SD 0.0077/h). The mean accuracy of seizure lateralisation identification was 77.6% (SD 7.1%).

CONCLUSIONS

With a limited amount of training, humans can detect seizures and seizure lateralisation from audified EEG signals of electrodes P3-T5 and P4-T6 with accuracy comparable to visual assessment of full EEG traces (21 electrodes) by an expert encephalographer.

SIGNIFICANCE

A more efficient and accurate clinical tool for assessing EEG data based on audification may be developed, which will improve diagnosis and treatment of epilepsy.

Celiac disease in children: an old disease with new features

Celiac disease is an underdiagnosed condition in children with variable manifestations. Presenting symptoms in children are changing over time, are impacted by age and geography, and are distinct from those of adults with this disease. Prompt diagnosis of celiac disease in affected children may avoid growth and nutritional deficits in addition to preventing long term disease complications such as infertility and malignancy. Diagnosis and management of celiac disease in children requires expert medical and nutritional care to maximize positive outcomes.