2.3.6 Social Cognitive Theory
Social Cognitive Theory (SCT) posits that whether a person will change a health behavior depends on (1) self-efficacy, (2) goals, and (3) outcome expectancies. If individuals have a high level of confidence, they can change even when they are faced with many obstacles. If they are not confident about the behavior in ques- tion, they will be less motivated to act or to persevere through obstacles or challenges as they arise. Important elements of SCT include reciprocal determin- ism (the interaction of the person, behavior, and the environment), behavioral capability (knowledge and skills needed to perform a particular behavior), expec- tations (the individual’s anticipated outcome of the behavior), self-efficacy (con- fidence in one’s ability to overcome the barriers encountered during behavior change), observational learning (watching the actions and outcomes of others’
behavior), and reinforcements (factors that increase or decrease the likelihood of the desired behavior)(7).
2.4 EXAMPLES OF NUTRITION INTERVENTIONS GROUNDED
Table2.2 Effectivebehavioraltheory-baseddietaryinterventionsinolderadults AuthorBehavioraltheory/modelDisease/DietaryindicatorMeanageofsubjects(years)Men/women Oldroyd,2001SCMDiabetesmellitus57.938/29 Miller,2002SCT,TML,IPMDiabetesmellitus72.2#4.3(I) 73.0#4.2(C)43/50 Chapman-Novakofski,2005SCM,SCTDiabetesmellitus63#1065/174 Toobert,2002SCT,SETDiabetesmellitus?(postmenopausal)0/279 Miura,2004SCTHypertension62#1029/28 Rankins,2005SCTHypertension55.2#6.1? Sethares,2004HBMHeartfailure75.7#12.3(I) 76.8#10.5(C)33/37 Nasser,2006(25)SCMHyperlipidemia50#1173/68 vanderVeen,2002(26)SCMCardiovasculardisease58.5#7.1(I) 58.2#6.9(C)38/105 Manios,2007(29)SCT,HBMDietquality60.0#4.80/75 SCM¼StagesofChangeModel;SCT¼SocialCognitiveTheory;TML¼TheoryofMeaningfulLearning;IPM¼InformationProcessingModel;SEM¼ SocialEcologicTheory;HBM¼HealthBeliefModel;I¼intervention;C¼control.
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the treatment goal for serum total cholesterol. In a second report from this study analyzing the effect of this intervention on changes in knowledge and skills neces- sary for diabetes management, the intervention group had greater improvement in total knowledge scores, positive outcome expectations, promoters of diabetes man- agement, and decision-making skills than the control group and greater reduction in barriers to diabetes management(13).
A community-based diabetes education program incorporating Social Cognitive Theory and Stages of Change Theory was conducted in patients with diabetes (mean age 63 years) by Chapman-Novakofski and colleagues(14). The program included three group sessions focused on meal planning and cooking demonstra- tions, with pre- and post-intervention evaluation. At posttest, significantly more participants reported positive dietary changes (such as using herbs in the place of salt, cooking with olive or canola oils, using artificial sweeteners in baking) and having more confidence in changing one’s diet, in preparing healthful meals, in using the Nutrition Facts label, and in overcoming the degree of difficulty in meal preparation than pretest.
The Mediterranean Lifestyle Trial evaluated the effects of a comprehensive life- style management intervention in postmenopausal women with type 2 diabetes (15). The intervention, based on a synthesis of Social Cognitive Theory and Social Ecologic Theory (16,1,17), was focused on dietary factors (i.e., adoption of a Mediterranean diet), physical activity, social support, and stress management.
Participants randomized to the intervention adhered to all aspects of the Mediter- ranean diet more days per week than participants randomized to the usual care condition(18). Significantly greater reductions in total fat and saturated fat and significantly greater increases in daily fruit and vegetable consumption occurred in intervention participants. Intervention participants also demonstrated significantly greater improvement in behavioral patterns related to low-fat eating. Dietary improvements in the intervention group were sustained at 24 months(19).
2.4.2 Hypertension
A multicomponent lifestyle modification intervention study was conducted in 57 subjects with hypertension (mean age 62 years) in Japan by Miura and colleagues (20). The intervention included patient-centered assessment and exercise and nutri- tion counseling based on Social Cognitive Theory. Following 24 weeks of interven- tion, systolic blood pressure was decreased to a significantly greater degree in the intervention group compared to the control group, which received no counseling.
The intervention group also experienced significantly greater reductions in urinary sodium excretion, total energy intake, and fat intake (as percent of total energy intake) and a significantly greater increase in exercise energy expenditure compared to the control group.
DASH – Dinner with Your Nutritionist, a university neighborhood health care center intervention to promote the Dietary Approaches to Stop Hypertension (DASH) diet, was tested in low-income African-American adults (mean age 55 years) with poorly controlled blood pressure(21). This weekly program followed a structured syllabus of objectives that included concepts based on Social Cognitive Theory as described by Baranowski et al.(22)and featured dinners based on the Chapter 2/ Behavioral Theories Applied to Nutritional Therapies 25
DASH diet plan. The objective of the study was blood pressure reduction, to be accomplished through the following behavioral objectives: building behavioral capability to identify DASH foods; instruction in planning, shopping for, and preparing DASH foods; instruction in using the Nutrition Facts label to select foods to meet DASH dietary goals; and building self-control by providing options for study participants to limit their intake of fat and sodium. Systolic and diastolic blood pressure was significantly lowered among participants who missed no more than two of the eight weekly sessions, while there was no change in blood pressure in participants who missed three or more sessions.
2.4.3 Heart Failure
An evaluation of a tailored message intervention addressing heart failure read- mission rates, quality of life, and health beliefs in patients (mean age 76 years) with heart failure was reported by Sethares and colleagues(23). This randomized trial compared patients hospitalized with heart failure who received a tailored message intervention based on the Health Belief Model(24)to patients hospitalized with heart failure who did not receive the intervention. Heart failure readmission rates at 3 months; quality of life at 1 month after hospital discharge; and the effect of the intervention on the perceived benefit and barrier beliefs of the treatment at 1 week and 1 month were compared. A sample benefit question related to diet was ‘‘Salty food is not good for me,’’ while a sample barrier question was ‘‘Food does not taste good on a low-salt diet.’’ Although hospital readmission rates and quality of life did not differ significantly between the treatment and control groups following the intervention period, beliefs regarding a sodium-restricted diet were positively impacted, including an increase in the perceived benefits and a reduction in the perceived barriers to following this diet.
2.4.4 Hyperlipidemia
An educational approach based on the Stages of Change Model (25,26) was compared with usual care in reducing dietary fat intake and serum lipids in indivi- duals (mean age 51 years) with hyperlipidemia(27). This randomized, controlled study included 40 stage-based tailored dietary activities for fat reduction in the Stages of Change intervention and different activities that did not incorporate the Stages of Change approach in the usual care intervention. Total cholesterol and low-density lipoprotein cholesterol decreased significantly in both groups at 4 weeks. These reductions were sustained over 40 weeks, with no differences noted between the groups.
2.4.5 Cardiovascular Disease Prevention
A randomized intervention study conducted by van der Veen and colleagues evaluated the effects of nutrition counseling delivered by a dietitian in men and women (mean age 58 years) at elevated risk of cardiovascular disease(28). Patients randomized to the intervention received nutrition information based on the Stages of Change Model(29,30). Compared to patients randomized to usual care, those
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receiving the intervention had significantly greater reductions in dietary total fat, saturated fat, and cholesterol both 6 and 12 months after the initiation of the intervention.
2.4.6 Diet Quality
Manios and colleagues evaluated the effectiveness of a nutrition education program on postmenopausal women (mean age 60 years) in a randomized clinical trial(31).Women were randomized to either a dietary intervention group and attended regular nutrition education sessions for 5 months based on a combined application of the Health Belief Model(32)and the Social Cognitive Theory or to a control group. The goal of the intervention group was to increase nutritional knowledge and self-efficacy of the subjects to adopt and maintain healthy dietary choices as assessed by the Healthy Eating Index (HEI). Subjects in the interven- tion group increased selected individual HEI scores to a significantly greater degree compared with the control group at the end of the intervention period;
however, there were no significant changes in total HEI scores between the groups.
2.5 PRACTICAL APPLICATIONS OF BEHAVIORAL THEORY