Best (but oft-forgotten) practices: sample size and power calculation for a dietary intervention trial with episodically consumed foods

doi:10.1093/ajcn/nqaa176

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	Best (but oft-forgotten) practices: sample size and power calculation for a dietary intervention trial with episodically consumed foods
	Zhang, Wei 1; Liu, Aiyi 2; Zhang, Zhiwei 3; Nansel, Tonja 4; Halabi, Susan 5
	2020-10-01
发表期刊	AMERICAN JOURNAL OF CLINICAL NUTRITION
ISSN	0002-9165
卷号	112 期号:4 页码:920-925
摘要	Dietary interventions often target foods that are underconsumed relative to dietary guidelines, such as vegetables, fruits, and whole grains. Because these foods are only consumed episodically for some participants, data from such a study often contains a disproportionally large number of zeros due to study participants who do not consume any of the target foods on the days that dietary intake is assessed, thus generating semicontinuous data. These zeros need to be properly accounted for when calculating sample sizes to ensure that the study is adequately powered to detect a meaningful intervention effect size. Nonetheless, this issue has not been well addressed in the literature. Instead, methods that are common for continuous outcomes are typically used to compute the sample sizes, resulting in a substantially under- or overpowered study. We propose proper approaches to calculating the sample size needed for dietary intervention studies that target episodically consumed foods. Sample size formulae are derived for detecting the mean difference in the amount of intake of an episodically consumed food between an intervention and a control group. Numerical studies are conducted to investigate the accuracy of the sample size formulae as compared with the ad hoc methods. The simulation results show that the proposed formulae are appropriate for estimating the sample sizes needed to achieve the desired power for the study. The proposed method for sample size is recommended for designing dietary intervention studies targeting episodically consumed foods.
关键词	dietary intervention trials episodic consumption power sample size type I error
DOI	10.1093/ajcn/nqaa176
收录类别	SCI
语种	英语
资助项目	Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
WOS研究方向	Nutrition & Dietetics
WOS类目	Nutrition & Dietetics
WOS记录号	WOS:000581138300008
出版者	OXFORD UNIV PRESS
引用统计
文献类型	期刊论文
条目标识符	http://ir.amss.ac.cn/handle/2S8OKBNM/52419
专题	中国科学院数学与系统科学研究院
通讯作者	Liu, Aiyi
作者单位	1.Chinese Acad Sci, Acad Math & Syst Sci, Beijing, Peoples R China 2.Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, Biostat & Bioinformat Branch, NIH, Bethesda, MD 20892 USA 3.NCI, Biostat Branch, Div Canc Treatment & Diagnost, NIH, Bethesda, MD 20892 USA 4.Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, Social & Behav Sci Branch, NIH, Bethesda, MD USA 5.Duke Univ, Dept Biostat & Bioinformat, Durham, NC USA
推荐引用方式 GB/T 7714	Zhang, Wei,Liu, Aiyi,Zhang, Zhiwei,et al. Best (but oft-forgotten) practices: sample size and power calculation for a dietary intervention trial with episodically consumed foods[J]. AMERICAN JOURNAL OF CLINICAL NUTRITION,2020,112(4):920-925.
APA	Zhang, Wei,Liu, Aiyi,Zhang, Zhiwei,Nansel, Tonja,&Halabi, Susan.(2020).Best (but oft-forgotten) practices: sample size and power calculation for a dietary intervention trial with episodically consumed foods.AMERICAN JOURNAL OF CLINICAL NUTRITION,112(4),920-925.
MLA	Zhang, Wei,et al."Best (but oft-forgotten) practices: sample size and power calculation for a dietary intervention trial with episodically consumed foods".AMERICAN JOURNAL OF CLINICAL NUTRITION 112.4(2020):920-925.