Performance of mixed effects models and generalized estimating equations for continuous outcomes in partially clustered trials including both independent and paired data.

Many clinical trials involve partially clustered data, where some observations belong to a cluster and others can be considered independent. For example, neonatal trials may include infants from single or multiple births. Sample size and analysis methods for these trials have received limited attention.

Optical coherence tomography assessment of the impact of colchicine on non-culprit coronary plaque composition after myocardial infarction.

Background: Low-dose colchicine reduces the risk of cardiovascular events after myocardial infarction (MI). The purpose of this study was to assess the effect of colchicine post-MI on coronary plaque morphology in non-culprit segments by optical coherence tomography (OCT).

Methods And Results: COCOMO-ACS was a double-blind, placebo-controlled trial that randomized 64 patients (median age 61.

Infant formula supplemented with milk fat globule membrane compared with standard infant formula for the cognitive development of healthy term-born formula-fed infants: protocol for a randomised controlled trial.

Introduction: Milk fat globule membrane (MFGM) is a complex lipid-protein structure in mammalian milk and human milk that is largely absent from breastmilk substitutes. The objective of this trial is to investigate whether providing infant formula enriched with MFGM versus standard infant formula improves cognitive development at 12 months of age in exclusively formula-fed full-term infants.

Methods And Analysis: This is a randomised, controlled, clinician-blinded, researcher-blinded and participant-blinded trial of two parallel formula-fed groups and a breastfed reference group that were recruited in the suburban Adelaide (Australia) community by a single study centre (a medical research institute).

Association of cord blood vitamin D with child neurodevelopment at 7 years of age.

Aim: The role of fetal vitamin D [25-hydroxyvitamin D (25(OH)D)], one of the nuclear steroid transcription regulators, and brain development is unclear. We previously found a weak but persistent association between cord blood 25(OH)D and child language abilities at 18 months and 4 years of age, but no association with cognition or behaviour. The aim of this study was to investigate the association between cord blood 25(OH)D and a range of neurodevelopmental outcomes in these same children at 7 years of age.

Categorisation of continuous covariates for stratified randomisation: How should we adjust?

To obtain valid inference following stratified randomisation, treatment effects should be estimated with adjustment for stratification variables. Stratification sometimes requires categorisation of a continuous prognostic variable (eg, age), which raises the question: should adjustment be based on randomisation categories or underlying continuous values? In practice, adjustment for randomisation categories is more common. We reviewed trials published in general medical journals and found none of the 32 trials that stratified randomisation based on a continuous variable adjusted for continuous values in the primary analysis.

Predictors of compliance with higher dose omega-3 fatty acid supplementation during pregnancy and implications for the risk of prematurity: exploratory analysis of the ORIP randomised trial.

Background: Intention-to-treat analyses of the Omega-3 to Reduce the Incidence of Prematurity (ORIP) trial found that omega-3 (n-3) fatty acid supplementation reduces the risk of prematurity in the subgroup of women with a singleton pregnancy and low n-3 status early in pregnancy, but not overall. However, results may have been influenced by less-than-optimal compliance.

Objectives: To identify predictors of compliance with n-3 supplementation and determine treatment effects among compliers.

Handling misclassified stratification variables in the analysis of randomised trials with continuous outcomes.

Many trials use stratified randomisation, where participants are randomised within strata defined by one or more baseline covariates. While it is important to adjust for stratification variables in the analysis, the appropriate method of adjustment is unclear when stratification variables are affected by misclassification and hence some participants are randomised in the incorrect stratum. We conducted a simulation study to compare methods of adjusting for stratification variables affected by misclassification in the analysis of continuous outcomes when all or only some stratification errors are discovered, and when the treatment effect or treatment-by-covariate interaction effect is of interest.

Identifying women who may benefit from higher dose omega-3 supplementation during pregnancy to reduce their risk of prematurity: exploratory analyses from the ORIP trial.

Objectives: The risk factors for prematurity are multifactorial and include low omega-3 status. Omega-3 supplementation in pregnancy has been found to reduce prematurity risk, particularly among women with low omega-3 levels. This study aimed to identify maternal characteristics that predict whether women with a singleton pregnancy will benefit from omega-3 supplementation to reduce their risk of prematurity.

Partially clustered designs for clinical trials: Unifying existing designs using consistent terminology.

Introduction: Clinical trial designs based on the assumption of independent observations are well established. Clustered clinical trial designs, where all observational units belong to a cluster and outcomes within clusters are expected to be correlated, have also received considerable attention. However, many clinical trials involve partially clustered data, where only some observational units belong to a cluster.

Protocol for a multicentre prospective observational study of families with full-term infants on postnatal wards and in the community to capture feeding practices across the first year of life: the Mother Infant Lactation Questionnaire (MILQ) study.

Introduction: Breastmilk is considered the gold standard for infant nutrition. Breast feeding is recommended as the sole source of nutrition between birth until around 6 months of age and should be continued beyond this age as complementary foods are introduced. While breast feeding initiation is generally high in developed countries, continuation of breast feeding appears to drop rapidly.

Conducting Clinical Trials in Twin Populations: A Review of Design, Analysis, Recruitment and Ethical Issues for Twin-Only Trials.

Although twins often participate in medical research, few clinical trials are conducted entirely in twin populations. The purpose of this review is to demonstrate the substantial benefits and address the key challenges of conducting clinical trials in twin populations, or 'twin-only trials'. We consider the unique design, analysis, recruitment and ethical issues that arise in such trials.

Translating n-3 polyunsaturated fatty acid status from whole blood to plasma and red blood cells during pregnancy: Translating n-3 status across blood fractions in pregnancy.

Women with low n-3 (omega-3) status in pregnancy can reduce their risk of early preterm birth (<34 weeks' gestation) through n-3 long chain polyunsaturated fatty acid (LCPUFA) supplementation. As investigators measure fatty acid status in different blood fractions, equations are needed to compare results across studies. Similarly, derived cut-points for defining low and replete n-3 status are needed to assist clinical interpretation during early pregnancy.

The Influence of Prenatal DHA Supplementation on Individual Domains of Behavioral Functioning in School-Aged Children: Follow-Up of a Randomized Controlled Trial.

Docosahexaenoic acid (DHA) accumulates in the fetal brain during pregnancy and is thought to have a role in supporting neurodevelopment. We conducted a multicenter, double-blind, randomized controlled trial in women with a singleton pregnancy who were <21 weeks' gestation at trial entry. Women were provided with 800 mg DHA/day or a placebo supplement from trial entry until birth.

Multiple imputation for handling missing outcome data in randomized trials involving a mixture of independent and paired data.

Randomized trials involving independent and paired observations occur in many areas of health research, for example in paediatrics, where studies can include infants from both single and twin births. Multiple imputation (MI) is often used to address missing outcome data in randomized trials, yet its performance in trials with independent and paired observations, where design effects can be less than or greater than one, remains to be explored. Using simulated data and through application to a trial dataset, we investigated the performance of different methods of MI for a continuous or binary outcome when followed by analysis using generalized estimating equations to account for clustering due to the pairs.

Associations between newborn thyroid-stimulating hormone concentration and neurodevelopment and growth of children at 18 months.

The study aimed to assess the associations between newborn thyroid-stimulating hormone (TSH) concentration, a marker of iodine nutrition in early life, and childhood neurodevelopment and growth using data collected from two pregnancy studies, one in a borderline iodine-deficient setting (DHA to Optimize Mother Infant Outcome (DOMInO) Study) and one in an iodine-sufficient setting (Pregnancy Iodine and Neurodevelopment in Kids (PINK) Study). TSH data were obtained from routine newborn screening. Neurodevelopment was assessed at 18 months using the Bayley Scales of Infant and Toddler Development, third edition (Bayley-III).

Assessment of salt intake to consider salt as a fortification vehicle for thiamine in Cambodia.

Thiamine deficiency is a public health issue in Cambodia. Thiamine fortification of salt has been proposed; however, the salt intake of lactating women, the target population, is currently unknown. We estimated salt intakes among lactating women (<6 months postpartum) using three methods: repeat observed-weighed intake records and 24-h urinary sodium excretions (n = 104), and household salt disappearance (n = 331).

Weekly iron-folic acid supplements containing 2.8 mg folic acid are associated with a lower risk of neural tube defects than the current practice of 0.4 mg: a randomised controlled trial in Malaysia.

Introduction: Weekly iron-folic acid (IFA) supplements are recommended for all menstruating women in countries where anaemia prevalence is >20%. Anaemia caused by folate deficiency is low worldwide, and the need to include folic acid is in question. Including folic acid might reduce the risk of a neural tube defect (NTD) should a woman become pregnant.

DHA supplementation in infants born preterm and the effect on attention at 18 months' corrected age: follow-up of a subset of the N3RO randomised controlled trial.

Infants born preterm miss out on the peak period of in utero DHA accretion to the brain during the last trimester of pregnancy which is hypothesised to contribute to the increased prevalence of neurodevelopmental deficits in this population. This study aimed to determine whether DHA supplementation in infants born preterm improves attention at 18 months' corrected age. This is a follow-up of a subset of infants who participated in the N3RO randomised controlled trial.

Effect of once weekly folic acid supplementation on erythrocyte folate concentrations in women to determine potential to prevent neural tube defects: a randomised controlled dose-finding trial in Malaysia.

Introduction: Folic acid (0.4 mg) taken prior to and during early pregnancy reduces the risk of neural tube defects (NTDs). Because these birth defects occur early in pregnancy, before women may know they are pregnant, many countries have mandated the addition of folic acid to food staples.

Plasma oxylipins and unesterified precursor fatty acids are altered by DHA supplementation in pregnancy: Can they help predict risk of preterm birth?

Oxidized lipids derived from omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids, collectively known as oxylipins, are bioactive signaling molecules that play diverse roles in human health and disease. Supplementation with n-3 docosahexaenoic acid (DHA) during pregnancy has been reported to decrease the risk of preterm birth in singleton pregnancies, which may be due to effects of DHA supplementation on oxylipins or their precursor n-6 and n-3 fatty acids. There is only limited understanding of the levels and trajectory of changes in plasma oxylipins during pregnancy, effects of DHA supplementation on oxylipins and unesterified fatty acids, and whether and how oxylipins and their unesterified precursor fatty acids influence preterm birth.

Thiamine dose response in human milk with supplementation among lactating women in Cambodia: study protocol for a double-blind, four-parallel arm randomised controlled trial.

Introduction: Thiamine (vitamin B1) deficiency remains a concern in Cambodia where women with low thiamine intake produce thiamine-poor milk, putting their breastfed infants at risk of impaired cognitive development and potentially fatal infantile beriberi. Thiamine fortification of salt is a potentially low-cost, passive means of combating thiamine deficiency; however, both the dose of thiamine required to optimise milk thiamine concentrations as well as usual salt intake of lactating women are unknown.

Methods And Analysis: In this community-based randomised controlled trial, 320 lactating women from Kampong Thom, Cambodia will be randomised to one of four groups to consume one capsule daily containing 0, 1.