The analyses were performed on 2225 people for whom data on 20 m walking speed and dietary intake were available. For the 2225 subjects, we used all available observations. This gave us for the analysis 2225 cases with a total of 8358 (70%) available observations. During the 5 time points, the cohort had shrunk and the percentage of cases contributing a measurement at each point is 100%, 85%, 77%, 61%, and 54%. We compared the profile of cases missing walking speed information at later follow-up times and found that they had somewhat different demographic characteristics (older, more White females, more smokers, and less educated) and on average, they had more depressive symptoms with lower cognitive score.
Descriptive and health characteristics of our participants across MedDiet adherence categories are presented in . Significant differences were shown in gender, marital status, smoking prevalence, BMI, energy intake, body fat percent, and weekly physical activity. Participants in the highest vs. the lowest MedDiet adherence groups were more likely to be men and non-smokers, with lower BMI, higher energy-intake, and physical activity, and a lower use of medications. No difference was shown in the distribution of age, race, education, subjective health status, cognitive function, and depression score. The prevalence of chronic diseases did not differ by MedDiet score, except for a higher prevalence of heart disease among the higher MedDiet score group. Levels of CRP were significantly lower among the highest MedDiet adherence group. The same trend was shown in the IL6 levels.
Baseline demographic, clinical, and dietary characteristics and functional performance by categories of MedDiet score (N =2225).
presents the daily dietary intake of antioxidants, servings of MedDiet components, and glycemic index by MedDiet score. As expected, the dietary intake of the MedDiet components was significantly higher among the highest MedDiet group except for milk and dairy. The dietary intake of antioxidants (vitamin E and carotenoids) was significantly higher among the highest MedDiet score group, whereas the daily glycemic index of the diet was slightly higher.
Daily dietary intake of selected nutrients and servings by MedDiet score.
depicts baseline differences in walking ability measured by different methods across the MedDiet score. Both usual and rapid 20 m walking speed were significantly higher among the highest MedDiet score participants. People in the highest MedDiet score group tended to be more physically active, with a significantly higher percent walking over 150 minutes per week and fewer reporting difficulty walking a quarter of a mile.
Gait speed and walking ability at baseline by MedDiet score.
presents the results of GEE models to predict decline in usual and rapid walking speed over time by MedDiet score. Both usual and rapid 20 m walking speed declined over time in all models (p<0.01). The first model was adjusted for age, race, gender, education, site, smoking status, and a time by MedDiet score interaction term; in the second and third models we showed a significant difference in the usual walking speed across MedDiet scores (p=0.013, p=0.012, and p=0.049, respectively). However, in model 4 when total body fat percent was added, the difference in walking speed was attenuated (p=0.134). Similar results were observed for the association between MedDiet adherence score and rapid 20 m walking speed (p=0.01, p=0.003, and p<0.001, respectively); however, the association remained significant after adjustment for total body fat percent (p<0.012). In all models, the MedDiet by time interaction term was not significant. The best fitting models were chosen to be presented.
Usual and rapid 20m walking speed by 3 levels of adherence to the MedDiet over 8 years (N=2225) using 4 mixed models
depict the final mixed-models of the decline in usual () and rapid () 20 m walking speed across MedDiet score adjusted for age, race, gender, education, site, smoking status, time by MedDiet score interaction term, physical activity, energy intake, health status, depression, cognition, and total body fat percent (p=0.134 for the difference in usual 20 m walking speed and p=0.012 for rapid 20 m walking speed). We repeated the analyses for participants for whom data were available on their 20m usual and rapid walking speed at year 10 (survivors). Among this group (n=1207), no association was found between usual walking speed and the MedDiet adherence category, while a strong relationship was detected between rapid walking speed and MedDiet in all models (p=0.005, 0.002, 0.004, and 0.016 for models 1–4, respectively).
Usual and rapid 20m walking speed by 3 levels of adherence to the MedDiet over 8 years (N=2225)