Predictors of adherence in the Women's Health Initiative Calcium and Vitamin D Trial
Department of Medicine, Division of Preventive and Behavioral Medicine
Aged; Attitude to Health; Calcium, Dietary; *Dietary Supplements; Double-Blind Method; Female; Forecasting; Humans; Longitudinal Studies; Medication Adherence; Middle Aged; Postmenopause; Risk Factors; Vitamin D; *Women's Health
Life Sciences | Medicine and Health Sciences | Women's Studies
The authors analyzed data from the Women's Health Initiative (WHI) Calcium and Vitamin D Supplementation Trial (CaD) to learn more about factors affecting adherence to clinical trial study pills (both active and placebo). Most participants (36,282 postmenopausal women aged 50-79 years) enrolled in CaD 1 year after joining either a hormone trial or the dietary modification trial of WHI. The WHI researchers measured adherence to study pills by weighing the amount of remaining pills at an annual study visit; adherence was primarily defined as taking > or = 80% of the pills. The authors in this study examined a number of behavioral, demographic, procedural, and treatment variables for association with study pill adherence. They found that relatively simple procedures (ie, phone contact early in the study [4 weeks post randomization] and direct social contact) later in the trial may improve adherence. Also, at baseline, past pill-use experiences, personal supplement use, and relevant symptoms may be predictive of adherence in a supplement trial.
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Citation: Behav Med. 2009 Winter;34(4):145-55. Link to article on publisher's site
Brunner, Robert L.; Dunbar-Jacob, Jacqueline; LeBoff, Meryl S.; Granek, I.; Bowen, Deborah J.; Snetselaar, Linda G.; Shumaker, Sally A.; Ockene, Judith K.; Rosal, Milagros C.; Wactawski-Wende, Jean; Cauley, Jane A.; Cochrane, Barbara B.; Tinker, Lesley F.; Jackson, Rebecca D.; Wang, C. Y.; and Wu, L., "Predictors of adherence in the Women's Health Initiative Calcium and Vitamin D Trial" (2009). Women’s Health Research Faculty Publications. 493.