Volume 25, Issue 5 pp. 448-459

Realignment and multiple imputation of longitudinal data: an application to menstrual cycle data

Sunni L. Mumford

Corresponding Author

Sunni L. Mumford

Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD

Dr Sunni L. Mumford, Epidemiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, 7B03M, Rockville, MD 20852, USA. E-mail: [email protected]Search for more papers by this author
Enrique F. Schisterman

Enrique F. Schisterman

Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD

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Audrey J. Gaskins

Audrey J. Gaskins

Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD

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Anna Z. Pollack

Anna Z. Pollack

Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD

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Neil J. Perkins

Neil J. Perkins

Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD

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Brian W. Whitcomb

Brian W. Whitcomb

Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts at Amherst, Amherst, MA

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Aijun Ye

Aijun Ye

Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD

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Jean Wactawski-Wende

Jean Wactawski-Wende

Department of Social and Preventive Medicine, University at Buffalo, State University of New York, Buffalo, NY, USA

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First published: 14 June 2011
Citations: 30

Summary

Mumford SL, Schisterman EF, Gaskins AJ, Pollack AZ, Perkins NJ, Whitcomb BW, Ye A, Wactawski-Wende J. Realignment and multiple imputation of longitudinal data: an application to menstrual cycle data. Paediatric and Perinatal Epidemiology 2011; 25: 448–459.

Reproductive hormone levels are highly variable among premenopausal women during the menstrual cycle. Accurate timing of hormone measurement is essential, especially when investigating day- or phase-specific effects. The BioCycle Study used daily urine home fertility monitors to help detect the luteinising hormone (LH) surge in order to schedule visits with biologically relevant windows of hormonal variability. However, as the LH surge is brief and cycles vary in length, relevant hormonal changes may not align with scheduled visits even when fertility monitors are used. Using monitor data, measurements were reclassified according to biological phase of the menstrual cycle to more accurate cycle phase categories. Longitudinal multiple imputation methods were applied after reclassification if no visit occurred during a given menstrual cycle phase. Reclassified cycles had more clearly defined hormonal profiles, with higher mean peak hormones (up to 141%) and reduced variability (up to 71%). We demonstrate the importance of realigning visits to biologically relevant windows when assessing phase- or day-specific effects and the feasibility of applying longitudinal multiple imputation methods. Our method has applications in settings where missing data may occur over time, where daily blood sampling for hormonal measurements is not feasible, and in other areas where timing is essential.

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