Showing papers by "Boston University published in 2006"

Confirmatory Factor Analysis for Applied Research

Abstract: "With its emphasis on practical and conceptual aspects, rather than mathematics or formulas, this accessible book has established itself as the go-to resource on confirmatory factor analysis (CFA). Detailed, worked-through examples drawn from psychology, management, and sociology studies illustrate the procedures, pitfalls, and extensions of CFA methodology. The text shows how to formulate, program, and interpret CFA models using popular latent variable software packages (LISREL, Mplus, EQS, SAS/CALIS); understand the similarities and differences between CFA and exploratory factor analysis (EFA); and report results from a CFA study. It is filled with useful advice and tables that outline the procedures. The companion website offers data and program syntax files for most of the research examples, as well as links to CFA-related resources. New to This Edition *Updated throughout to incorporate important developments in latent variable modeling. *Chapter on Bayesian CFA and multilevel measurement models. *Addresses new topics (with examples): exploratory structural equation modeling, bifactor analysis, measurement invariance evaluation with categorical indicators, and a new method for scaling latent variables. *Utilizes the latest versions of major latent variable software packages"--

Final report of the E821 muon anomalous magnetic moment measurement at BNL

Abstract: We present the final report from a series of precision measurements of the muon anomalous magnetic moment, a(mu)=(g-2)/2. The details of the experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven National Laboratory, using nearly equal samples of positive and negative muons, were used to deduce a(mu)(Expt)=11659208.0(5.4)(3.3)x10(-10), where the statistical and systematic uncertainties are given, respectively. The combined uncertainty of 0.54 ppm represents a 14-fold improvement compared to previous measurements at CERN. The standard model value for a(mu) includes contributions from virtual QED, weak, and hadronic processes. While the QED processes account for most of the anomaly, the largest theoretical uncertainty, approximate to 0.55 ppm, is associated with first-order hadronic vacuum polarization. Present standard model evaluations, based on e(+)e(-) hadronic cross sections, lie 2.2-2.7 standard deviations below the experimental result.

Introduction to NF-kappaB: players, pathways, perspectives.

Abstract: This article serves as an introduction to the collection of reviews on nuclear factor-kappaB (NF-kappaB). It provides an overview of the discovery and current status of NF-kappaB as a research topic. Described are the structures, activities and regulation of the proteins in the NF-kappaB family of transcription factors. NF-kappaB signaling is primarily regulated by inhibitor kappaB (IkappaB) proteins and the IkappaB kinase complex through two major pathways: the canonical and non-canonical NF-kappaB pathways. The organization and focus of articles included in the following reviews are described, as well as likely future areas of research interest on NF-kappaB.

Corporate Social Responsibility, Customer Satisfaction, and Market Value

Abstract: Although prior research has addressed the influence of corporate social responsibility (CSR) on perceived customer responses, it is not clear whether CSR affects market value of the firm. This study develops and tests a conceptual framework, which predicts that (1) customer satisfaction partially mediates the relationship between CSR and firm market value (i.e., Tobin's q and stock return), (2) corporate abilities (innovativeness capability and product quality) moderate the financial returns to CSR, and (3) these moderated relationships are mediated by customer satisfaction. Based on a large-scale secondary data set, the results show support for this framework. Notably, the authors find that in firms with low innovativeness capability, CSR actually reduces customer satisfaction levels and, through the lowered satisfaction, harms market value. The uncovered mediated and asymmetrically moderated results offer important implications for marketing theory and practice.

High prevalence of vitamin D inadequacy and implications for health.

Abstract: During the past decade, major advances have been made in vitamin D research that transcend the simple concept that vitamin D is Important for the prevention of rickets in children and has little physiologic relevance for adults. Inadequate vitamin D, in addition to causing rickets, prevents children from attaining their genetically programmed peak bone mass, contributes to and exacerbates osteoporosis in adults, and causes the often painful bone disease osteomalacia. Adequate vitamin D is also important for proper muscle functioning, and controversial evidence suggests it may help prevent type 1 diabetes mellitus, hypertension, and many common cancers. Vitamin D inadequacy has been reported in approximately 36% of otherwise healthy young adults and up to 57% of general medicine inpatients in the United States and in even higher percentages in Europe. Recent epidemiological data document the high prevalence of vitamin D inadequacy among elderly patients and especially among patients with osteoporosis. Factors such as low sunlight exposure, age-related decreases in cutaneous synthesis, and diets low in vitamin D contribute to the high prevalence of vitamin D inadequacy. Vitamin D production from cutaneous synthesis or intake from the few vitamin D-rich or enriched foods typically occurs only intermittently. Supplemental doses of vitamin D and sensible sun exposure could prevent deficiency in most of the general population. The purposes of this article are to examine the prevalence of vitamin D inadequacy and to review the potential implications for skeletal and extraskeletal health.

The Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America

Abstract: Evidence-based guidelines for the management of patients with Lyme disease, human granulocytic anaplasmosis (formerly known as human granulocytic ehrlichiosis), and babesiosis were prepared by an expert panel of the Infectious Diseases Society of America. These updated guidelines replace the previous treatment guidelines published in 2000 (Clin Infect Dis 2000; 31[Suppl 1]:1-14). The guidelines are intended for use by health care providers who care for patients who either have these infections or may be at risk for them. For each of these Ixodes tickborne infections, information is provided about prevention, epidemiology, clinical manifestations, diagnosis, and treatment. Tables list the doses and durations of antimicrobial therapy recommended for treatment and prevention of Lyme disease and provide a partial list of therapies to be avoided. A definition of post-Lyme disease syndrome is proposed.

Variable Selection for Propensity Score Models

Abstract: Despite the growing popularity of propensity score (PS) methods in epidemiology, relatively little has been written in the epidemiologic literature about the problem of variable selection for PS models. The authors present the results of two simulation studies designed to help epidemiologists gain insight into the variable selection problem in a PS analysis. The simulation studies illustrate how the choice of variables that are included in a PS model can affect the bias, variance, and mean squared error of an estimated exposure effect. The results suggest that variables that are unrelated to the exposure but related to the outcome should always be included in a PS model. The inclusion of these variables will decrease the variance of an estimated exposure effect without increasing bias. In contrast, including variables that are related to the exposure but not to the outcome will increase the variance of the estimated exposure effect without decreasing bias. In very small studies, the inclusion of variables that are strongly related to the exposure but only weakly related to the outcome can be detrimental to an estimate in a mean squared error sense. The addition of these variables removes only a small amount of bias but can increase the variance of the estimated exposure effect. These simulation studies and other analytical results suggest that standard model-building tools designed to create good predictive models of the exposure will not always lead to optimal PS models, particularly in small studies.

Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence: The COMBINE Study: A Randomized Controlled Trial

Abstract: ContextAlcohol dependence treatment may include medications, behavioral therapies, or both. It is unknown how combining these treatments may impact their effectiveness, especially in the context of primary care and other nonspecialty settings.ObjectivesTo evaluate the efficacy of medication, behavioral therapies, and their combinations for treatment of alcohol dependence and to evaluate placebo effect on overall outcome.Design, Setting, and ParticipantsRandomized controlled trial conducted January 2001-January 2004 among 1383 recently alcohol-abstinent volunteers (median age, 44 years) from 11 US academic sites with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnoses of primary alcohol dependence.InterventionsEight groups of patients received medical management with 16 weeks of naltrexone (100 mg/d) or acamprosate (3 g/d), both, and/or both placebos, with or without a combined behavioral intervention (CBI). A ninth group received CBI only (no pills). Patients were also evaluated for up to 1 year after treatment.Main Outcome MeasuresPercent days abstinent from alcohol and time to first heavy drinking day.ResultsAll groups showed substantial reduction in drinking. During treatment, patients receiving naltrexone plus medical management (n = 302), CBI plus medical management and placebos (n = 305), or both naltrexone and CBI plus medical management (n = 309) had higher percent days abstinent (80.6, 79.2, and 77.1, respectively) than the 75.1 in those receiving placebos and medical management only (n = 305), a significant naltrexone × behavioral intervention interaction (P = .009). Naltrexone also reduced risk of a heavy drinking day (hazard ratio, 0.72; 97.5% CI, 0.53-0.98; P = .02) over time, most evident in those receiving medical management but not CBI. Acamprosate showed no significant effect on drinking vs placebo, either by itself or with any combination of naltrexone, CBI, or both. During treatment, those receiving CBI without pills or medical management (n = 157) had lower percent days abstinent (66.6) than those receiving placebo plus medical management alone (n = 153) or placebo plus medical management and CBI (n = 156) (73.8 and 79.8, respectively; P<.001). One year after treatment, these between-group effects were similar but no longer significant.ConclusionsPatients receiving medical management with naltrexone, CBI, or both fared better on drinking outcomes, whereas acamprosate showed no evidence of efficacy, with or without CBI. No combination produced better efficacy than naltrexone or CBI alone in the presence of medical management. Placebo pills and meeting with a health care professional had a positive effect above that of CBI during treatment. Naltrexone with medical management could be delivered in health care settings, thus serving alcohol-dependent patients who might otherwise not receive treatment.Trial Registrationclinicaltrials.gov Identifier: NCT00006206

Comorbid Psychiatric Disorders in Children with Autism: Interview Development and Rates of Disorders

Abstract: The Kiddie Schedule for Affective Disorders and Schizophrenia was modified for use in children and adolescents with autism by developing additional screening questions and coding options that reflect the presentation of psychiatric disorders in autism spectrum disorders. The modified instrument, the Autism Comorbidity Interview-Present and Lifetime Version (ACI-PL), was piloted and frequently diagnosed disorders, depression, ADHD, and OCD, were tested for reliability and validity. The ACI-PL provides reliable DSM diagnoses that are valid based on clinical psychiatric diagnosis and treatment history. The sample demonstrated a high prevalence of specific phobia, obsessive compulsive disorder, and ADHD. The rates of psychiatric disorder in autism are high and are associated with functional impairment.

Cyclophosphamide versus placebo in scleroderma lung disease.

Abstract: BACKGROUND We conducted a double-blind, randomized, placebo-controlled trial to determine the effects of oral cyclophosphamide on lung function and health-related symptoms in patients with evidence of active alveolitis and scleroderma-related interstitial lung disease. METHODS At 13 clinical centers throughout the United States, we enrolled 158 patients with scleroderma, restrictive lung physiology, dyspnea, and evidence of inflammatory interstitial lung disease on examination of bronchoalveolar-lavage fluid, thoracic highresolution computed tomography, or both. Patients received oral cyclophosphamide (≤2 mg per kilogram of body weight per day) or matching placebo for one year and were followed for an additional year. Pulmonary function was assessed every three months during the first year, and the primary end point was the forced vital capacity (FVC, expressed as a percentage of the predicted value) at 12 months, after adjustment for the baseline FVC. RESULTS Of 158 patients, 145 completed at least six months of treatment and were included in the analysis. The mean absolute difference in adjusted 12-month FVC percent predicted between the cyclophosphamide and placebo groups was 2.53 percent (95 percent confidence interval, 0.28 to 4.79 percent), favoring cyclophosphamide (P<0.03). There were also treatment-related differences in physiological and symptom outcomes, and the difference in FVC was maintained at 24 months. There was a greater frequency of adverse events in the cyclophosphamide group, but the difference between the two groups in the number of serious adverse events was not significant. CONCLUSIONS One year of oral cyclophosphamide in patients with symptomatic sclerodermarelated interstitial lung disease had a significant but modest beneficial effect on lung function, dyspnea, thickening of the skin, and the health-related quality of life. The effects on lung function were maintained through the 24 months of the study.

The Role of Corporate Social Responsibility in Strengthening Multiple Stakeholder Relationships: A Field Experiment

Abstract: This research relied on afield experiment involving a real world instance of corporate philanthropy to shed light on both the scope and limitations of the strategic returns to corporate social responsibility (CSR). In particular, the authors demonstrate that the impact of CSR in the real world is not only less pervasive than has been previously acknowledged but also more multifaceted than has been previously conceptualized. The findings indicated that contingent on CSR awareness, which was rather low, stakeholders did react positively to the focal company not only in the consumption domain but in the employment and investment domains as well. Stakeholder attributions regarding the genuineness of the company's motives moderated these effects.

Multiple Biomarkers for the Prediction of First Major Cardiovascular Events and Death

Abstract: BACKGROUND Few investigations have evaluated the incremental usefulness of multiple biomarkers from distinct biologic pathways for predicting the risk of cardiovascular events. METHODS We measured 10 biomarkers in 3209 participants attending a routine examination cycle of the Framingham Heart Study: the levels of C-reactive protein, B-type natriuretic peptide, N-terminal pro-atrial natriuretic peptide, aldosterone, renin, fibrinogen, D-dimer, plasminogen-activator inhibitor type 1, and homocysteine; and the urinary albumin-to-creatinine ratio. RESULTS During follow-up (median, 7.4 years), 207 participants died and 169 had a first major cardiovascular event. In Cox proportional-hazards models adjusting for conventional risk factors, the following biomarkers most strongly predicted the risk of death (each biomarker is followed by the adjusted hazard ratio per 1 SD increment in the log values): B-type natriuretic peptide level (1.40), C-reactive protein level (1.39), the urinary albumin-to-creatinine ratio (1.22), homocysteine level (1.20), and renin level (1.17). The biomarkers that most strongly predicted major cardiovascular events were B-type natriuretic peptide level (adjusted hazard ratio, 1.25 per 1 SD increment in the log values) and the urinary albumin-to-creatinine ratio (1.20). Persons with "multimarker" scores (based on regression coefficients of significant biomarkers) in the highest quintile as compared with those with scores in the lowest two quintiles had elevated risks of death (adjusted hazard ratio, 4.08; P<0.001) and major cardiovascular events (adjusted hazard ratio, 1.84; P=0.02). However, the addition of multimarker scores to conventional risk factors resulted in only small increases in the ability to classify risk, as measured by the C statistic. CONCLUSIONS For assessing risk in individual persons, the use of the 10 contemporary biomarkers that we studied adds only moderately to standard risk factors.

Strategies for Two Sided Markets

Abstract: When markets have different types of users that attract one another, more demand from one group can spur additional demand from the matched group in a virtuous cycle. These effects are often present in platform markets. Examples include application developers/users, credit card merchants/cardholders, and dating sites for men/women. Network effects in these two-sided markets significantly affect prices, competition, and industry concentration. Prices generally fall for the group that is the stronger attractor. Winner-take-all markets can arise depending on the strength of these network effects, economies of supply, specialization, and multihoming. Finally, when users of one platform overlap users of another, there is an opportunity for "platform envelopment" where one platform swallows a competitor. Bundling features that attract one group of the competitor's users can bring along the matching group.

Electronic properties of disordered two-dimensional carbon

Abstract: Two-dimensional carbon, or graphene, is a semimetal that presents unusual low-energy electronic excitations described in terms of Dirac fermions. We analyze in a self-consistent way the effects of localized (impurities or vacancies) and extended (edges or grain boundaries) defects on the electronic and transport properties of graphene. On the one hand, point defects induce a finite elastic lifetime at low energies with the enhancement of the electronic density of states close to the Fermi level. Localized disorder leads to a universal, disorder independent, electrical conductivity at low temperatures, of the order of the quantum of conductance. The static conductivity increases with temperature and shows oscillations in the presence of a magnetic field. The graphene magnetic susceptibility is temperature dependent (unlike an ordinary metal) and also increases with the amount of defects. Optical transport properties are also calculated in detail. On the other hand, extended defects induce localized states near the Fermi level. In the absence of electron-hole symmetry, these states lead to a transfer of charge between the defects and the bulk, the phenomenon we call self-doping. The role of electron-electron interactions in controlling self-doping is also analyzed. We also discuss the integer and fractional quantum Hall effect in graphene, the role played by the edge states induced by a magnetic field, and their relation to the almost field independent surface states induced at boundaries. The possibility of magnetism in graphene, in the presence of short-range electron-electron interactions and disorder is also analyzed.

Prediction of Lifetime Risk for Cardiovascular Disease by Risk Factor Burden at 50 Years of Age

Abstract: Background Lifetime risk for atherosclerotic cardiovascular disease (CVD) has not previously been estimated, and the effect of risk factor burden on lifetime risk is unknown. Methods and results We included all Framingham Heart Study participants who were free of CVD (myocardial infarction, coronary insufficiency, angina, stroke, claudication) at 50 years of age. Lifetime risks to 95 years of age were estimated for men and women, with death free of CVD as a competing event. We followed up 3564 men and 4362 women for 111,777 person-years; 1757 had CVD events and 1641 died free of CVD. At 50 years of age, lifetime risks were 51.7% (95% CI, 49.3 to 54.2) for men and 39.2% (95% CI, 37.0 to 41.4) for women, with median survivals of 30 and 36 years, respectively. With more adverse levels of single risk factors, lifetime risks increased and median survivals decreased. Compared with participants with > or =2 major risk factors, those with optimal levels had substantially lower lifetime risks (5.2% versus 68.9% in men, 8.2% versus 50.2% in women) and markedly longer median survivals (>39 versus 28 years in men, >39 versus 31 years in women). Conclusions The absence of established risk factors at 50 years of age is associated with very low lifetime risk for CVD and markedly longer survival. These results should promote efforts aimed at preventing development of risk factors in young individuals. Given the high lifetime risks and lower survival in those with intermediate or high risk factor burden at 50 years of age, these data may be useful in communicating risks and supporting intensive preventive therapy.

The Role of Corporate Social Responsibility in Strengthening Multiple Stakeholder Relationships: A Field Experiment:

Abstract: This research relied on a field experiment involving a real-world instance of corporate philanthropy to shed light on both the scope and limitations of the strategic returns to corporate social responsibility (CSR). In particular, the authors demonstrate that the impact of CSR in the real world is not only less pervasive than has been previously acknowledged but also more multifaceted than has been previously conceptualized. The findings indicated that contingent on CSR awareness, which was rather low, stakeholders did react positively to the focal company not only in the consumption domain but in the employment and investment domains as well. Stakeholder attributions regarding the genuineness of the company’s motives moderated these effects.

Biomarkers of cardiovascular disease: molecular basis and practical considerations.

Abstract: Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality in the United States.1 Primary prevention and secondary prevention of CVD are public health priorities.2 Substantial data indicate that CVD is a life course disease that begins with the evolution of risk factors that in turn contribute to the development of subclinical atherosclerosis.3,4 Subclinical disease culminates in overt CVD.5,6 The onset of CVD itself portends an adverse prognosis with greater risk of recurrent events, morbidity, and mortality.7,8 It is also increasingly clear that although clinical assessment is the keystone of patient management, such evaluation has its limitations.9–12 Clinicians have used additional tools to aid clinical assessment and to enhance their ability to identify the “vulnerable” patient at risk for CVD, as suggested by a recent National Institutes of Health (NIH) panel.13,14 Biomarkers are one such tool to better identify high-risk individuals, to diagnose disease conditions promptly and accurately, and to effectively prognosticate and treat patients with disease. This review provides an overview of the molecular basis of biomarker discovery and selection and the practical considerations that are a prerequisite to their clinical use. The term biomarker (biological marker) was introduced in 1989 as a Medical Subject Heading (MeSH) term: “measurable and quantifiable biological parameters (eg, specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.” In 2001, an NIH working group standardized the definition of a biomarker as “a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention” …

Linear confinement and AdS/QCD

Abstract: In a theory with linear confinement, such as QCD, the masses squared m^2 of mesons with high spin S or high radial excitation number n are expected, from semiclassical arguments, to grow linearly with S and n. We show that this behavior can be reproduced within a putative 5-dimensional theory holographically dual to QCD (AdS/QCD). With the assumption that such a dual theory exists and describes highly excited mesons as well, we show that asymptotically linear m^2 spectrum translates into a strong constraint on the INFRARED behavior of that theory. In the simplest model which obeys such a constraint we find m^2 ~ (n+S).

Toll-like receptors in systemic autoimmune disease

Abstract: Toll-like receptors (TLRs) have a crucial role in the early detection of pathogen-associated molecular patterns and the subsequent activation of the adaptive immune response. Whether TLRs also have an important role in the recognition of endogenous ligands has been more controversial. Numerous in vitro studies have documented activation of both autoreactive B cells and plasmacytoid dendritic cells by mammalian TLR ligands. The issue of whether these in vitro observations translate to an in vivo role for TLRs in either the initiation or the progression of systemic autoimmune disease is a subject of intense research; data are beginning to emerge showing that this is the case.

Testosterone Therapy in Adult Men with Androgen Deficiency Syndromes: An Endocrine Society Clinical Practice Guideline

Abstract: Objective: The objective was to provide guidelines for the evaluation and treatment of androgen deficiency syndromes in adult men Participants: The Task Force was composed of a chair, selected by the Clinical Guidelines Subcommittee of The Endocrine Society, five additional experts, a methodologist, and a professional writer The Task Force received no corporate funding or remuneration Evidence: The Task Force used systematic reviews of available evidence to inform its key recommendations The Task Force used consistent language and graphical descriptions of both the strength of recommendation and the quality of evidence, using the recommendations of the Grading of Recommendations, Assessment, Development, and Evaluation group Consensus Process: Consensus was guided by systematic reviews of evidence and discussions during three group meetings, several conference calls, and e-mail communications The drafts prepared by the panelists with the help of a professional writer were reviewed successively by Th

Age at drinking onset and alcohol dependence: age at onset, duration, and severity.

Abstract: Objective To examine whether starting to drink at an early age is associated with developing alcohol dependence at a younger age and chronic relapsing dependence, controlling for respondent demographics, smoking and illicit drug use, childhood antisocial behavior and depression, and family alcoholism history. Design Cross-sectional survey. Setting Nationwide face-to-face survey with a multistage probability sample. Participants A total of 43 093 adults were surveyed in 2001-2002. Main Outcome Measures Based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria, lifetime alcohol dependence, dependence within 10 years of starting drinking, multiple episodes, an alcohol dependence episode in the past year, episodes exceeding 1 year, and meeting 6 or 7 dependence criteria. Results Relative to respondents who began drinking at 21 years or older, those who began drinking before age 14 years were more likely to experience alcohol dependence ever and within 10 years of first drinking (adjusted hazard ratios and 95% confidence intervals [CIs], 1.78 [1.51-2.11] and 1.69 [1.38-2.07], respectively). They also more often experienced past-year dependence and multiple dependence episodes (adjusted odds ratios, 1.93 [95% CI, 1.40-2.64] and 3.09 [95% CI, 2.19-4.35], respectively). Among alcohol-dependent persons, the odds were 2.62 (95% CI, 1.79-3.84) for having at least 1 episode exceeding 1 year and 2.89 (95% CI, 1.97-4.23) for meeting 6 or 7 dependence diagnostic criteria. Conclusion There is a need to screen and counsel adolescents about alcohol use and to implement policies and programs that delay alcohol consumption.

Epidemic influenza and vitamin D.

Abstract: In 1981, R. Edgar Hope-Simpson proposed that a 'seasonal stimulus' intimately associated with solar radiation explained the remarkable seasonality of epidemic influenza. Solar radiation triggers robust seasonal vitamin D production in the skin; vitamin D deficiency is common in the winter, and activated vitamin D, 1,25(OH)2D, a steroid hormone, has profound effects on human immunity. 1,25(OH)2D acts as an immune system modulator, preventing excessive expression of inflammatory cytokines and increasing the 'oxidative burst' potential of macrophages. Perhaps most importantly, it dramatically stimulates the expression of potent anti-microbial peptides, which exist in neutrophils, monocytes, natural killer cells, and in epithelial cells lining the respiratory tract where they play a major role in protecting the lung from infection. Volunteers inoculated with live attenuated influenza virus are more likely to develop fever and serological evidence of an immune response in the winter. Vitamin D deficiency predisposes children to respiratory infections. Ultraviolet radiation (either from artificial sources or from sunlight) reduces the incidence of viral respiratory infections, as does cod liver oil (which contains vitamin D). An interventional study showed that vitamin D reduces the incidence of respiratory infections in children. We conclude that vitamin D, or lack of it, may be Hope-Simpson's 'seasonal stimulus'.

Body mass index, metabolic syndrome, and risk of type 2 diabetes or cardiovascular disease

Abstract: Context: Metabolic risk conferred by adiposity may be due to associated risk factor clustering. Objective: The objective of this study was to assess risk for diabetes or cardiovascular disease (CVD) stratified by body mass index (BMI) and the presence or absence of metabolic syndrome (MetS) or insulin resistance (IR). Design, Setting, and Participants: This was a community-based, longitudinal study of 2902 people (55% women, mean age 53 yr) without diabetes or CVD in 1989–1992 followed for up to 11 yr. We categorized subjects by normal weight (BMI 25 kg/m 2 ), overweight (25–29.9 kg/m 2 ), or obese (30 kg/m 2 ) and by the National