The influence of cognitive-perceptual variables on patterns of change over time in rural midlife and older women's healthy eating

Abstract

Although studies demonstrate that dietary interventions for healthy adults can result in beneficial dietary changes, few studies examine when and how people change in response to these interventions, particularly in rural populations. The purpose of this study was to examine patterns of change over time in healthy eating behaviors in midlife and older women in response to a one-year health-promoting intervention, and to examine what predictors (perceived benefits, barriers, self-efficacy, and family support for healthy eating) influence the changes during the intervention and follow-up. Data for this secondary analysis were from the Wellness for Women community-based trial. Women (N = 225) between the ages of 50-69 in rural Nebraska, U.S.A., were recruited. A repeated-measures experimental design was used with randomization of two rural counties to intervention (tailored newsletter) or comparison (standard newsletter) groups. Eating behavior was measured by the Healthy Eating Index. The predictor variables were assessed using standard measures. Data analysis was done using latent growth curve modeling. The tailored newsletter group was successful in improving their healthy eating behavior compared to the standard newsletter group during the one-year intervention, at the end of the intervention, and during the follow-up phase. Family support at the end of the intervention was positively associated with healthy eating at the end of the intervention. Perceived barriers had the strongest impact on healthy eating behavior at all time points. Compared to participants in the standard newsletter group, those in the tailored newsletter group perceived more family support and fewer barriers for healthy eating at the end of the intervention (mediation effects). Based on these findings, both family support and perceived barriers should be central components of interventions focused on healthy eating behavior in rural midlife and older women.

Figure 1. Raw Mean Values of the Healthy Eating Index by Group during the Intervention (3 to 12 months) and Maintenance (18 and 24 months) Periods (with Standard Errors)

Legend: The darker shading represents the intervention period and the lighter shading represents the maintenance period.

Figure 2. Fitted lines plotted against the mean scores of the Healthy Eating Index (HEI) at each time point

The solid lines denote raw mean scores. The dotted lines denote fitted scores. Model 06 examined simple linear change over time using all 7 time points; model 07 was a revised linear model separating change during the intervention from change during maintenance. Model 08 examined curvilinear change over time using all 7 time points; model 09 was a revised curvilinear model separating change during the intervention from change during maintenance (best statistical and theoretical fit to the data). HEI Intercept was rescaled to represent healthy eating at the end of the intervention. HEI Linear denotes the intra-individual linear change over time. HEI Curvilinear denotes the intra-individual curvilinear change over time. HEI Maintenance denotes healthy eating index scores during the maintenance period.

Figure 3. Model Building Process for Explaining Change over Time in Rural Midlife and Older Women’s Healthy Eating Behavior

Note. Standardized beta coefficients are provided for the significant values in Models 10 & 11; Models 12 & 13 were included to depict model construction. In Model 13, variance explained is by each latent construct. HEI = Healthy Eating Index (The indicators of healthy eating for the 7 assessments have been removed for clarity.) Intercept was rescaled to represent healthy eating at the end of the intervention for HEI, barriers, and family support. Linear denotes the intra-individual linear change over time. Curvilinear denotes the intra-individual curvilinear change over time. HEI maintenance: denotes the healthy eating index score during the maintenance period