AS286 - OPACH: Objective Physical Activity and Cardiovascular Health in Older Women

Investigator Names and Contact Information

Andrea Z. LaCroix, Principal Investigator []

For questions about this study or its data, please contact Eileen Rillamas-Sun, Staff Scientist [].


While self-reported measures of physical activity have some validity, they lack precision, may reflect over-reporting of activity, and provide only limited information on the details and patterns of physical activity.  Objectively measured physical activity allows cohort studies to address key gaps in knowledge about the health benefits of physical activity. Of specific interest are impacts on cardiovascular health as there is strong evidence that physical activity reduces the risk of cardiovascular disease.

The OPACH study was an ancillary study of the WHI Long Life Study.  Long Life Study participants who were ambulatory were concurrently invited to join the OPACH study. The goal of OPACH was to increase the understanding of the health benefits and risks of physical activity, specifically with cardiovascular events and incident falls. OPACH participants were asked to complete the following tasks: 1) wear an accelerometer (physical activity monitor) for 7 days, (2) complete a Sleep Log, (3) complete a Physical Activity Questionnaire, and (4) complete monthly Falls Calendars for a year.

For a more detailed description of the study protocol, we strongly recommend reading and becoming familiar with the OPACH study design paper (MS2965, citation provided below and copy provided in "Data Dictionaries and Study Documentation" page). This publication also provides figures describing the study samples for the accelerometer data and the falls calendar/interview data.

Specific Aims

The specific aims of the OPACH study were:

  1. To determine the associations between objective measures of physical activity and the risk of incident cardiovascular disease in older women participating in WHI.

  2. To compare the magnitude of associations between self-reported and accelerometer measures of physical activity with incident cardiovascular disease; and to determine if self-reported measures of physical activity provided unique information about risk, which was not captured by accelerometer measures.

  3. To conduct a calibration study in order to determine accelerometry thresholds for older women that distinguish sedentary from light activity and light activity from moderate to vigorous activity.

  4. To determine how level of physical activity influences risk of fall-related injuries and overall risk for any injury.

Although the focus of OPACH was cardiovascular disease, the data collected creates opportunities to examine the associations between objective measurements of physical activity and risk of mortality, breast cancer, colon cancer, type 2 diabetes, dementia, cognitive decline and physical disability.  In addition, study associations between objective physical activity and cardiovascular biomarkers measured from biospecimens that were collected at the Long Life Study home visit (lipids, glucose, insulin, C-reactive protein, creatinine) can also be examined.

Results and Findings

As of November 2018, 9 manuscripts have been published related to the OPACH study and numerous proposals have been approved. For a complete, up-to-date list of WHI papers related to this ancillary study, please use the searchable Bibliography section of this website. To search for papers by study number, access the Simple Search, and enter "AS286" in the "Related Studies" field.

Design Paper:

MS2965 - LaCroix AZ, Rillamas-Sun E, Buchner D, Evenson KR, Di C, Lee IM, Marshall S, LaMonte MJ, Hunt J, Tinker LF, Stefanick M, Lewis CE, Bellettiere J, and Herring AH. The Objective Physical Activity and Cardiovascular Disease Health in Older Women (OPACH) Study. BMC Public Health 2017 Jan;17(1):192. PMCID: PMC5307783


MS2246 - Evenson KR, Wen F, Herring AH, Di C, LaMonte MJ, Tinker LF, Lee IM, Rillamas-Sun E, LaCroix AZ, Buchner DM. Calibrating physical activity intensity for hip-worn accelerometry in women age 60 to 91 years: The Women's Health Initiative OPACH Calibration Study. Prev Med Rep. 2015 Sep;2:750-756.  PMCID: PMC4625400

MS2367 - Rillamas-Sun E, Buchner DM, Di C, Evenson KR, LaCroix AZ. Development and application of an automated algorithm to identify a window of consecutive days of accelerometer wear for large-scale studies. BMC Res Notes 2015 Jun;8:270. PMCID: PMC4482153

MS2542- LaMonte MJ, Lewis CE, Buchner DM, Evenson KR, Rillamas-Sun E, Di C, Lee IM, Bellettiere J, Stefanick ML, Eaton CB, Howard BV, Bird C, and LaCroix LZ. Both Light Intensity and Moderate-to-Vigorous Physical Activity Measured by Accelerometry Are Favorably Associated with Cardiometabolic Risk Factors in Older Women: The Objective Physical Activity and Cardiovascular Health (OPACH) Study. J Am Heart Assoc 2017 Oct;6(10): e007064. doi: 10.1161/JAHA.117.007064. PMCID: PMC5721888.

MS2683 - Bai J, Di C, Xiao L, Evenson KR, LaCroix AZ, Crainiceanu CM, and Buchner DM. An Activity Index for Raw Accelerometry Data and Its Comparison with Other Activity Metrics. PLoS One 2016 Aug;11(8): e0160644. PMCID: PMC4981309

MS2758 - Hua A, Quicksall Z, Di C, Motl R, LaCroix AZ, Schatz B, and Buchner DM. Accelerometer-based predictive models of fall risk in older women: a pilot study. npj Digital Medicine 2018 Jul; 1: 25. doi: 10.1038/s41746-018-0033-5.

MS2966 - Buchner DM, Rillamas-Sun E, Di C, LaMonte MJ, Marshall SW, Hunt J, Zhang Y, Rosenberg DE, Lee IM, Evenson KR, Herring AH, Lewis CE, Stefanick ML, and LaCroix AZ. Accelerometer-Measured Moderate to Vigorous Physical Activity and Incidence Rates of Falls in Older Women. J Am Geriatr Soc 2017 Jul 29.  doi: 10.1111/jgs.14960. [Epub ahead of print]

MS3072 - LaMonte MJ, Buchner DM, Rillamas-Sun E, Di C, Evenson KR, Bellettiere J, Lewis CE, Lee IM, Tinker LF, Seguin R, Zaslovsky O, Eaton CB, Stefanick ML, and LaCroix AZ. Accelerometer-Measured Physical Activity and Mortality in Women Aged 63 to 99. J Am Geriatr Soc 2018 May; 66(5): 886-894. PMCID: PMC5955801.

MS3301 - Bellettiere J, Healy GN, LaMonte MJ, Kerr J, Evenson KR, Rillamas-Sun E, Di C, Buchner DM, Hovell MF, and LaCroix AZ. Associations of sedentary time and diabetes in 6166 older women: The Objective Physical Activity and Cardiovascular Health Study. J Gerontol A Biol Sci Med Sci 2018 May. doi: 10.1093/gerona/gly101.