Abstract:
BACKGROUND:Including twins in randomised trials leads to non-independence or clustering in the data. Clustering has important implications for sample size calculations, yet few trials take this into account. Estimates of the intracluster correlation coefficient (ICC), or the correlation between outcomes of twins, are needed to assist with sample size planning. Our aims were to provide ICC estimates for infant outcomes, describe the information that must be specified in order to account for clustering due to twins in sample size calculations, and develop a simple tool for performing sample size calculations for trials including twins. METHODS:ICCs were estimated for infant outcomes collected in four randomised trials that included twins. The information required to account for clustering due to twins in sample size calculations is described. A tool that calculates the sample size based on this information was developed in Microsoft Excel and in R as a Shiny web app. RESULTS:ICC estimates ranged between -0.12, indicating a weak negative relationship, and 0.98, indicating a strong positive relationship between outcomes of twins. Example calculations illustrate how the ICC estimates and sample size calculator can be used to determine the target sample size for trials including twins. CONCLUSIONS:Clustering among outcomes measured on twins should be taken into account in sample size calculations to obtain the desired power. Our ICC estimates and sample size calculator will be useful for designing future trials that include twins. Publication of additional ICCs is needed to further assist with sample size planning for future trials.
journal_name
Paediatr Perinat Epidemioljournal_title
Paediatric and perinatal epidemiologyauthors
Yelland LN,Sullivan TR,Collins CT,Price DJ,McPhee AJ,Lee KJdoi
10.1111/ppe.12471subject
Has Abstractpub_date
2018-07-01 00:00:00pages
380-387issue
4eissn
0269-5022issn
1365-3016journal_volume
32pub_type
杂志文章abstract::This study examines the correlation and agreement between the calculated 'gestational interval' from the date of last menstrual period (LMP) and the Ballard newborn assessment of gestational maturity. It then investigates selected maternal socio-demographic, prenatal, intrapartum and infant factors which may account f...
journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.1990.tb00628.x
更新日期:1990-04-01 00:00:00
abstract::The perinatal mortality rate (PMR) in twins was analysed using Japanese vital statistics during the period 1980-98. There was a total of 1992 twin perinatal deaths. The PMR in twins significantly decreased from 91 per 1000 births in 1980 to 31 per 1000 in 1998. The PMR was higher in males than females, but the differe...
journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1046/j.1365-3016.2001.00361.x
更新日期:2001-07-01 00:00:00
abstract:BACKGROUND:While there is evidence of an association between caesarean birth and increased asthma in children in high-income countries, it is unknown whether this association exists in low-to-middle-income countries (LMICs). We investigated whether children born through caesarean in India and Vietnam are at increased r...
journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/ppe.12324
更新日期:2017-01-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2009.01063.x
更新日期:2009-11-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.1997.tb00006.x
更新日期:1997-07-01 00:00:00
abstract::Reference data describing weight, length, and head circumference (anthropometric measurements) at birth were published by Lubchenco and Usher before 1970. Few attempts have been made to investigate whether these data are appropriate for today's cohort of preterm neonates. We analysed anthropometric data for neonates b...
journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2005.00641.x
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abstract:BACKGROUND:Studies using vital records-based maternal weight data have become more common, but the validity of these data is uncertain. METHODS:We evaluated the accuracy of prepregnancy body mass index (BMI) and gestational weight gain (GWG) reported on birth certificates using medical record data in 1204 births at a ...
journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/ppe.12120
更新日期:2014-05-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2005.00655.x
更新日期:2005-07-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2009.01038.x
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2007.00879.x
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2007.00850.x
更新日期:2007-09-01 00:00:00
abstract::Although race and preterm delivery are known to be associated with sudden infant death syndrome (SIDS), the relationships between age at death from SIDS and these factors have not been well described. To examine these relationships, we used linked infant birth and death records for the cohort of 1,204,375 White and 28...
journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.1990.tb00655.x
更新日期:1990-07-01 00:00:00
abstract::This study describes the timing of puberty in 8- to 13-year-old girls enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC) and identifies factors associated with earlier achievement of menarche. Women were enrolled during pregnancy and their offspring were followed prospectively. We analysed self-r...
journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2009.01055.x
更新日期:2009-09-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1046/j.1365-3016.2001.0376a.x
更新日期:2001-10-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2006.00737.x
更新日期:2006-07-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/ppe.12374
更新日期:2017-07-01 00:00:00
abstract:BACKGROUND:Prenatal alcohol exposure can affect neurodevelopment, but few studies have examined associations with autism spectrum disorder (ASD). METHODS:We assessed the association between maternal alcohol use and ASD in the Study to Explore Early Development, a multi-site case-control study of children born between ...
journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/ppe.12404
更新日期:2017-11-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1046/j.1365-3016.2000.00271.x
更新日期:2000-07-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2012.01314.x
更新日期:2012-09-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1046/j.1365-3016.1999.00194.x
更新日期:1999-07-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2011.01242.x
更新日期:2012-01-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2006.00759.x
更新日期:2006-11-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2011.01215.x
更新日期:2011-09-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2005.00674.x
更新日期:2005-09-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2010.01105.x
更新日期:2010-05-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.2010.01183.x
更新日期:2011-05-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/ppe.12253
更新日期:2016-03-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1046/j.1365-3016.2003.00463.x
更新日期:2003-01-01 00:00:00
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journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章,评审
doi:10.1111/ppe.12651
更新日期:2020-03-01 00:00:00
abstract::The population under study in the South African longitudinal study of urban children and their families, 'Birth to Ten' (BTT), comprised all births during a 7-week period from April to June 1990 in Soweto-Johannesburg. Specification of the population base for the cohort was hampered by a number of flaws in the notific...
journal_title:Paediatric and perinatal epidemiology
pub_type: 杂志文章
doi:10.1111/j.1365-3016.1995.tb00124.x
更新日期:1995-01-01 00:00:00