The substantive findings presented in this manuscript make several unique and important contributions to existing multiple behavior change intervention research. This randomized clinical trial addresses obesity and diabetes and links multiple behavioral lifestyle change to positive behavioral, psychosocial, and biological outcomes in Latina patients with type 2 diabetes. This is an underserved, understudied, and growing population in the USA that is at especially high risk of coronary heart disease and that carries an especially high medical burden. The study replicates a previously successful evidence-based multiple risk factor intervention with a different setting, population, geographic location, and set of interventionists [25
Over the 12-month lifestyle change intervention, Latinas with type 2 diabetes reduced their risk for adverse diabetes outcomes by lowering hemoglobin A1c, a key biologic outcome. While the reductions in A1c may seem modest, the ¡Viva Bien! treatment condition reduced A1c by 0.8% from baseline to 6 months in complete-case analysis (8.5% – 7.7%=0.8%) and significantly more than the control condition. This reduction is comparable to the improvements in A1c demonstrated by some diabetes medications and can be expected in addition to pharmacologic interventions. Epidemiological analysis of the United Kingdom Prospective Diabetes Study data [51
] showed that for every percentage point decrease in A1c, there was a 35% reduction in risk of complications. In our study, this would translate to a 28% reduction in risk of diabetes complications and could translate over longer periods of time to improved outcomes related to heart attack and cardiac death. While the United Kingdom Prospective Diabetes Study risk assessment was not specifically validated to measure change, there is precedent in the literature for calculating 10-year cardiovascular disease risk reductions using risk equations [52
], and the variables from which the United Kingdom Prospective Diabetes Study measure is derived are appropriate for measuring change (that is, patients are considered to be making clinical progress when they modify their smoking status, systolic blood pressure, hemoglobin A1c, and cholesterol level).
The ¡Viva Bien! program was successful in promoting short-term biological improvements. The fading of effect at 12 months is instructive. This may be a direct result of the fading of the intervention. Maintenance of behavior change is an important and neglected area of health behavior research, and more research is needed to find ways to sustain health behaviors over the life course in the same way that pharmacologic therapy may be prescribed to maintain health over the long term.
Participants improved on four targeted behavioral outcomes, but not smoking prevalence. They decreased saturated fat consumption, increased physical activity and stress management practices, and increased their use of social–environmental supportive resources. Women who participated in ¡Viva Bien! improved psychosocial variables such as social support, problem solving, and self-efficacy, which have been linked to health behavior change. The improvements attributable to the ¡Viva Bien! intervention were impressive in their magnitude and diversity of outcomes. Six-month effect sizes across 12 outcomes averaged 0.48 in complete-case analyses and 0.37 in intention-to treat analyses.
The pattern of correlational findings among pychosocial, behavioral, and physiological outcomes provided evidence that the intervention operated as theorized; that is, the treatment prompted changes in psychosocial variables which were related to changes in behavioral variables, which themselves were related to changes in physiologic variables—but there were few significant relations between psychosocial variables and physiological variables directly.
¡Viva Bien! yielded effect sizes similar to those obtained in the evidence-based Mediterranean Lifestyle Program from which it was adapted. Respectively for ¡Viva Bien! and the Mediterranean Lifestyle Program, effect sizes at 6 months were 0.48 vs. 0.27 for problem solving, 0.59 vs. 0.35 for self-efficacy, 0.89 vs. 0.67 for social support, 1.00 vs. 0.67 for saturated fat intake, 0.35 vs. 0.50 for stress management practice, and 0.36 vs. 0.67 for physical activity.
Health care reform discussions increasingly recognize the need to address lifestyle changes to prevent type 2 diabetes or, for those who have diabetes, its complications, emphasizing wellness, prevention, and personal behaviors [53
]. This need may be more pronounced in populations experiencing health and health care disparities, such as Latinas. One way to reduce disparities in diabetes outcomes for Latinas is to develop and test culturally appropriate, efficacious lifestyle interventions that reach and engage them, goals that were largely achieved in this study [24
]. Just as research with men cannot necessarily be generalized to women, research with non-Hispanic Whites (with whom most studies of heart disease have been conducted) cannot be assumed to generalize to other ethnicities. The extant literature provides little guidance about whether conventional strategies (e.g., weight loss, increased physical activity, quitting smoking, culturally adapted Mediterranean diets, supportive resources) are useful for reducing heart disease risk in Latinas with type 2 diabetes. Our cultural adaptation for Latinas of the previously established Mediterranean Lifestyle Program was successful in prompting Latinas to modify heart disease risk behaviors despite their generally poor baseline dietary and physical activity habits. The ultimate goal is to demonstrate that beneficial lifestyle practices and health improvements can be maintained over time and that such programs are cost-effective.
Limitations of this study include investigation within a single managed care setting and community clinic, as well as use of several self-report measures. Our purpose in recruiting patients from two different populations (Kaiser Permanente Colorado and a community health center) rather than one was to increase the generalizability of results. Most of the self-report measures have been validated against more objective standards, but it is not known whether possible inaccuracies of self-reporting in this study influenced the observed results. Another possible limitation is that despite randomization, statistically significant baseline differences were found between the usual care and ¡Viva Bien! conditions on 3 of 17 participant characteristics tested. This sometimes occurs in randomized samples, and in the present study, the few differences in participant characteristics were accounted for in subsequent analyses. Overall, a range of older and younger, lighter and heavier participants were randomized into each group. Cost of the intervention presents a potential limitation. The cost of ¡Viva Bien!, though greater than typical diabetes education interventions, is relatively low when compared to other medical treatment options for the prevention and treatment of heart disease, such as angioplasties and stents in stable individuals [54
]. Another limitation was the use of the International Physical Activity Questionnaire (a) to calculate days/week of exercise rather than other variables using the standard scoring and (b) to measure physical activity in 16% of the study sample aged 70 years or older since the International Physical Activity Questionnaire has been validated for those aged 15–69 years. Our results regarding physical activity should therefore be read cautiously.
Attendance at ¡Viva Bien! weekly meetings declined from 58% during the first 6 months to 48% for meetings between 6 and 12 months, in part because the study sampled a broad population consisting of a number of individuals who may have found it challenging to integrate the ¡Viva Bien! principles into their daily lives. Reasons for missing meetings were systematically collected and coded, and the most frequently stated reasons for missing meetings included illnesses, work-related conflicts, vacations, and social conflicts. Qualitative data suggested, counterintuitively, that habitual attendance of a biweekly meeting was more challenging then weekly meetings. Bonding occurred between staff and participants, and participants with each other, and participants stated that they believed someone was there for them. When the meeting schedule decreased, there was a feeling of abandonment more directed to staff than other participants. Also, the perceived consequences of missing the biweekly meeting may have been greater with regard to sustained engagement and commitment to the program. Once a participant missed a session, it seemed that missing future meetings became more frequent. However, only one woman specifically offered this as a reason for missing a meeting.
We anticipated wide variations in adherence to the intervention, ranging from participants who would do nothing to participants who would fully embrace all program components. Within this context, the mean attendance rate of 58% at 6 months is reasonable. Attendance may have been higher if we had recruited a convenience sample, such as is obtained in studies relying on advertisements or individuals who proactively contact a project office, or if we had screened out all except the most highly motivated women with few real life problems or competing family demands. In a practical or clinical program, which would not involve a control group and for which participants would self-enroll, motivation and adherence would likely be greater. Those with better attendance generally had better outcomes, as found in other studies with interventions of similar intensity [56
Despite the fact that some participants attended more often than others, the intervention produced impressive and consistent changes in behavioral, psychosocial, and biologic outcomes overall, which adds weight to the findings. This is a complex community-based practical research trial that must be evaluated against standards and methodological criteria appropriate for non-pharmacologic effectiveness trials.
Strengths of the study include a reasonably large, high-risk, and underserved sample; cultural adaptation of an evidence-based program; focus on and improvement of multiple lifestyle behaviors known to reduce heart disease risk; inclusion of a number of psychosocial, behavioral, biological, and quality of life outcome measures; the randomized design; and the inclusion of both complete-case and intention-to-treat analyses.
Overall, results of this study move behavior change theory forward by demonstrating that a health intervention promoting multiple, rather than single, behavioral change is feasible and effective. Health behaviors are neither isolated nor sequential. Especially for people with chronic illnesses, such as diabetes, multiple behaviors work together to influence well-being, and behavior changes must be addressed simultaneously. The ¡Viva Bien! program succeeded in helping participants develop new skills to change multiple diabetes-related behaviors. Although not all participants engaged in all behaviors equally well, they improved their outcome expectations and their self-efficacy related to performing behaviors and managing their diabetes. These results suggest that clinicians and researchers should pursue health interventions focusing on multiple behavior, rather than single behavior, change.
Future research recommendations include examination of intervention maintenance effects beyond 12 months, identification of mediators and moderators of outcomes, and cost effectiveness analyses to determine the readiness of ¡Viva Bien! for translation into practice.