Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy



Major Professor

Bonnie L. Callen

Committee Members

Lora H. Beebe, Ralph G. Brockett, Kenneth D. Phillips, Somchit Hanuchareonkul (Courtesy Member), Abbas S. Tavakoli (Courtesy Member)


Understanding the powerful factors of sodium reduction benefits older adults by leading to reduce many health risks, lower the health care cost and diminished economic and social burden. This study had two aims: 1) to explore to what degree four factors--selected basic conditioning factors, knowledge of sodium reduction, sodium reduction self-care agency, and sodium reduction self-care behavior predict urinary sodium excretion in hypertensive seniors, 2) to test whether these variables related to sodium reduction were congruent with Orem’s Self-Care Theory.

Based on this theory, internal and external conditioning factors were proposed as either positively or negatively influencing an individual’s knowledge and capability in sodium reduction or self-care agency. These factors may have had either direct or indirect effects toward self-care behavior. If persons anticipated their knowledge and competence, they would use these clues for taking action in certain situations. These factors were expected to encourage sodium reduction self-care behavior. Later, the ultimate outcome in changing this behavior by consuming less dietary sodium was inversely represented by low urinary sodium excretion.

A cross-sectional, correlational study was conducted in 312 patients age 60 or over who had been diagnosed with hypertension. The Knowledge of Dietary Sodium Reduction Scale, the Dietary Sodium Reduction Self-Care Agency Scale, and the Dietary Sodium Reduction Self-Care Behavior Scale were used in this study along with the 24-hour urinary sodium analysis. Structural equation modeling and the Analysis of Moment Structures (AMOS) program were used to analyze the data.

The final model of sodium reduction self-care behavior and urinary sodium excretion fit the data well. Significant associations among variables were observed which were consistent with Orem’s Self-Care Theory. Sodium reduction self-care agency, knowledge of sodium reduction, rural/urban, and education accounted for 39% of the variance explaining sodium reduction self-care behavior. Additionally, sodium reduction self-care behavior, sodium reduction self-care agency, knowledge of sodium reduction, rural/urban, and education accounted for 61% of the urinary sodium excretion. Knowledge of sodium reduction and sodium reduction self-care agency were the most important variable in the sodium reduction self-care behavior model and the urinary sodium excretion model, respectively.

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