21 research outputs found

    Early childhood growth trajectory and later cognitive ability:Evidence from a large prospective birth cohort of healthy term-born children

    Get PDF
    BACKGROUND: Most studies of associations between child growth and cognitive ability were based on size at one or two ages and a single measure of cognition. We aimed to characterize different aspects of early growth and their associations with cognitive outcomes in childhood through adolescence. METHODS: In a sample of 12 368 Belarusian children born at term, we examined associations of length/height and weight trajectories over the first 6.5 years of life with cognitive ability at 6.5 and 16 years and its change over time. We estimated growth trajectories using two random-effects models—the SuperImposition by Translation and Rotation to model overall patterns of growth and the Jenss-Bayley to distinguish growth in infancy from post infancy. Cognitive ability was measured using the Wechsler Abbreviated Scales of Intelligence at 6.5 years and the computerized NeuroTrax test at 16 years. RESULTS: Higher length/height between birth and 6.5 years was associated with higher cognitive scores at 6.5 and 16 years {2.7 points [95% confidence interval (CI): 2.1, 3.2] and 2.5 points [95% CI: 1.9, 3.0], respectively, per standard deviation [SD] increase}. A 1-SD delay in the childhood height-growth spurt was negatively associated with cognitive scores [–2.4 (95% CI: –3.0, –1.8) at age 6.5; –2.2 (95% CI: –2.7, –1.6) at 16 years]. Birth size and post-infancy growth velocity were positively associated with cognitive scores at both ages. Height trajectories were not associated with the change in cognitive score. Similar results were observed for weight trajectories. CONCLUSIONS: Among term infants, the overall size, timing of the childhood growth spurt, size at birth and post-infancy growth velocity were all associated with cognitive ability at early-school age and adolescence

    Perceived access and barriers to care among illicit drug users and hazardous drinkers: findings from the Seek, Test, Treat, and Retain data harmonization initiative (STTR).

    Get PDF
    BACKGROUND: Illicit drug use (DU) and hazardous drinking (HD) among marginalized populations may be associated with greater barriers to care. METHODS: We used baseline data on the participants of the Seek, Test, Treat, and Retain data harmonization initiative. DU includes use of any illicit drugs within the past 6 months. HD was defined as scores ≄8 for men and ≄ 7 for women on Alcohol Use Disorders Identification Test within the past 12 months. Social support scores were assigned by summing scores from individual questions related to social support. Two outcomes for multivariable regression models and mediation analysis were perceived access to care and perceived barriers to care scores, calculated from summated points from individual questions within each domain. All models were adjusted for age, gender, race/ethnicity, and social support and stratified by HIV status. RESULTS: Among 1403 illicit drug users and 4984 non-drug users, the mean age was 39.6 ± 12.2 years old, 71% were male, 57% African Americans, and 39% Hispanic/Latinos. Over 25% reported difficulties in covering medical costs and finding transportation to health care facilities and greater proportions of drug users and hazardous drinkers reported these issues than non-DU/non-HD. In multivariable models, DU and HD were both independently associated with having greater barriers to care (ÎČ: 0.49 (95% confidence interval: 0.19 to 0.79) p \u3c 0.01; 0.31 (0.18 to 0.45) \u3c 0.01) in HIV-negative participants. Neither DU nor HD was strongly associated with barriers to care for HIV-positive participants. Social support was associated with better perceived access to care and fewer barriers to care in the HIV-negative participants. CONCLUSION: The current study found that financial burdens of care, logistical difficulties in accessing care, and low social support were common challenges among individuals using illicit drugs and/or drinking hazardously. Addressing structural barriers and strengthening social support may be important strategies to improve health care among marginalized populations, regardless of HIV status

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

    Get PDF
    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Bayesian hierarchical model for the study of clustered data with cluster-level sources of measurement

    No full text
    Cluster randomized trials are an extensively used tool in health research; their main pitfall arises from within cluster correlation of responses, which prevents the use of traditional methods of design and analysis for individual randomized trials. This issue is overcome at the design stage by adjusting the sample size according to the magnitude of the intraclass correlation coefficient, and at the analysis stage by modeling clustered responses through linear and generalized linear mixed models that include random intercepts accounting for the variability due to clustering. However, there is a disadvantage that is usually overlooked when studying cluster trials, that is, when the measurement of the outcomes is naturally clustered, known as clustered measurement. For outcomes susceptible to non-random error, clustering among individuals measured by the same observer will occur if some observers tend to measure systematically differently than others. A particularly troublesome situation arises when the measurements are clustered within the same groups used as units of randomization, which we call "double clustering". The effect of both measurement issues is to increase the intraclass correlation coefficient due to the introduction of a second source of variability (due to observer) at a cluster level. None of these issues can be addressed at the design stage, and when a second set of random intercepts accounting for variation due to observer is introduced in the models at the analysis stage, the variances at cluster level cannot be estimated separately under double clustering. The Promotion of Breastfeeding Intervention Trial (PROBIT) revealed that double clustering is likely to be present in the measurement of several of its outcomes and, in fact this cluster randomized trial motivated the present research. A strategy to deal with these issues is to conduct a second set of measurements that allows us to obtain separate variance estimates and, in turn, to improve the estimation of the treatment effects; such measurements were taken in PROBIT for other reasons. We present a Bayesian hierarchical model for clustered-measured, and more emphatically for double-clustered outcomes, in which audited measurements are available. Due to the complex nature of the resulting posterior distributions, estimation is carried out through Markov Chain Monte Carlo (MCMC) methods. We conducted a simulation study under different conditions reflecting double clustering/clustered measurement severity for continuous and binary responses, to assess the performance of the treatment effect estimators in terms of bias, precision and coverage. Based on the results from this study, we conduct a comparison between double clustering and clustered measurement situations and ultimately we provide practical recommendations that allow us to design optimal cluster trials when clustered measurement or double clustering are likely to be present in the responses. We illustrate the applicability of our methods with continuous and binary variables from PROBIT.Les essais randomisĂ©s en grappes sont un outil largement utilisĂ© en recherche dans le domainede la santĂ©; leur principal faiblesse provient de la corrĂ©lation intra-grappe des variables rĂ©ponses,qui empĂȘche l'usage de mĂ©thodes traditionnelles de plani_cation et d'analyse employĂ©es dansdes essais randomisĂ©s individuels. Ce problĂšme est maĂźtrisĂ© au stade de la plani_cation selonl'ampleur du coe_cient de corrĂ©lation intra-classe, et Ă  l'Ă©tape de l'analyse en modĂ©lisantles rĂ©ponses en grappes par des modĂšles linĂ©aires et des modĂšles linĂ©aires gĂ©nĂ©ralisĂ©s mixtesqui comprennent des ordonnĂ©es Ă  l'origine alĂ©atoires tenant compte de la variabilitĂ© due auxgrappes. Par contre, il y a un dĂ©savantage qui passe souvent inaperçu lors de l'Ă©tude d'essaisen grappe, c'est-Ă -dire lorsque la mesure des rĂ©ponses est regroupĂ©e naturellement. Pourdes rĂ©ponses sujettes Ă  une erreur non-alĂ©atoire, le regroupement d'individus Ă©valuĂ©s par lemĂȘme observateur adviendra si l'Ă©valuation de certains observateurs di_Ăšre systĂ©matiquementde celle des autres. Une situation particuliĂšrement problĂ©matique advient lorsque lesmesures sont regroupĂ©es Ă  l'intĂ©rieur mĂȘme des grappes utilisĂ©es comme unitĂ©s de randomisation,un phĂ©nomĂšne que l'on appelle _doubles grappes_. L'e_et de ces problĂšmes de mesureest d'augmenter le coe_cient de corrĂ©lation intra-classe par l'introduction d'une deuxiĂšmesource de variabilitĂ© (due Ă  l'observateur) au niveau de la grappe. Aucun de ces problĂšmesde mesures ne peut ĂȘtre corrigĂ© au stade de la plani_cation, et lorsqu'un second ensembled'ordonnĂ©es Ă  l'origine alĂ©atoires tenant compte de la variation due Ă  l'observateur est inclusdans le modĂšle au stade de l'analyse, les variances au niveau des grappes ne peuventĂȘtre estimĂ©es en prĂ©sence de doubles grappes. L'Ă©tude PROBIT (Promotion of Breastfeed-ing Intervention Trial ) a rĂ©vĂ©lĂ© que la prĂ©sence de doubles grappes pour plusieurs de sesvariables rĂ©ponses est probable; cet essai randomisĂ© en grappes est la motivation pour letravail de recherche prĂ©sentĂ© ici. Une stratĂ©gie pour corriger ces problĂšmes est d'obtenirun second ensemble de mesures qui permet d'avoir des valeurs estimĂ©es sĂ©parĂ©es pour lesvariances et, ensuite, amĂ©liorer l'estimation des e_ets de traitement; de telles mesures ontĂ©tĂ© prises dans cadre de l'Ă©tude PROBIT pour d'autres raisons. Nous prĂ©sentons un mod-Ăšle bayĂ©sien hiĂ©rarchique pour des rĂ©ponses mesurĂ©es en grappes et, en particulier, pour lesrĂ©ponses Ă  doubles grappes, pour lesquelles des mesures auxiliaires sont disponibles. À causede la complexitĂ© des lois a posteriori, l'estimation est e_ectuĂ©e par des mĂ©thodes de MonteCarlo par chaĂźnes de Markov (MCMC). A_n d'Ă©valuer le comportement des estimateurs dese_ets de traitement en terme de biais, de la prĂ©cision et de la couverture des intervalles,nous avons e_ectuĂ© une Ă©tude par simulation sous di_Ă©rentes conditions re_Ă©tant la sĂ©vĂ©ritĂ©du phĂ©nomĂšne de doubles grappes et de mesures groupĂ©es pour des rĂ©ponses continues etbinaires. En fonction des rĂ©sultats de cette Ă©tude, nous faisons une comparaison entre les situationsde doubles grappes et de mesures groupĂ©es et nous formulons des recommandationspratiques pour permettre la plani_cation optimale d'essais en grappes lorsque les doublesgrappes et les mesures groupĂ©es sont probables dans la mesure des rĂ©ponses. Nous illustronsl'application de ces mĂ©thodes avec des variables continues et binaires de PROBIT

    Modeling Fetal Weight for Gestational Age: A Comparison of a Flexible Multi-level Spline-based Model with Other Approaches

    No full text
    We present a model for longitudinal measures of fetal weight as a function of gestational age. We use a linear mixed model, with a Box-Cox transformation of fetal weight values, and restricted cubic splines, in order to flexibly but parsimoniously model median fetal weight. We systematically compare our model to other proposed approaches. All proposed methods are shown to yield similar median estimates, as evidenced by overlapping pointwise confidence bands, except after 40 completed weeks, where our method seems to produce estimates more consistent with observed data. Sex-based stratification affects the estimates of the random effects variance-covariance structure, without significantly changing sex-specific fitted median values. We illustrate the benefits of including sex-gestational age interaction terms in the model over stratification. The comparison leads to the conclusion that the selection of a model for fetal weight for gestational age can be based on the specific goals and configuration of a given study without affecting the precision or value of median estimates for most gestational ages of interest.

    Perceived access and barriers to care among illicit drug users and hazardous drinkers: findings from the Seek, Test, Treat, and Retain data harmonization initiative (STTR)

    Get PDF
    Abstract Background Illicit drug use (DU) and hazardous drinking (HD) among marginalized populations may be associated with greater barriers to care. Methods We used baseline data on the participants of the Seek, Test, Treat, and Retain data harmonization initiative. DU includes use of any illicit drugs within the past 6 months. HD was defined as scores ≄8 for men and ≄ 7 for women on Alcohol Use Disorders Identification Test within the past 12 months. Social support scores were assigned by summing scores from individual questions related to social support. Two outcomes for multivariable regression models and mediation analysis were perceived access to care and perceived barriers to care scores, calculated from summated points from individual questions within each domain. All models were adjusted for age, gender, race/ethnicity, and social support and stratified by HIV status. Results Among 1403 illicit drug users and 4984 non-drug users, the mean age was 39.6 ± 12.2 years old, 71% were male, 57% African Americans, and 39% Hispanic/Latinos. Over 25% reported difficulties in covering medical costs and finding transportation to health care facilities and greater proportions of drug users and hazardous drinkers reported these issues than non-DU/non-HD. In multivariable models, DU and HD were both independently associated with having greater barriers to care (ÎČ: 0.49 (95% confidence interval: 0.19 to 0.79) p < 0.01; 0.31 (0.18 to 0.45) < 0.01) in HIV-negative participants. Neither DU nor HD was strongly associated with barriers to care for HIV-positive participants. Social support was associated with better perceived access to care and fewer barriers to care in the HIV-negative participants. Conclusion The current study found that financial burdens of care, logistical difficulties in accessing care, and low social support were common challenges among individuals using illicit drugs and/or drinking hazardously. Addressing structural barriers and strengthening social support may be important strategies to improve health care among marginalized populations, regardless of HIV status
    corecore