Healthy Diet and Risk of Dementia in Older Adults

Associations among multidomain lifestyles, chronic diseases, and dementia in older adults: a cross-sectional analysis of a cohort study

Background

Unhealthy lifestyles and chronic diseases are commonly seen and treatable factors in older adults and are both associated with dementia. However, the synergistic effect of the interaction of lifestyles and chronic diseases on dementia is unknown.

Methods

We determined independent associations of multidomain lifestyles and chronic diseases (cerebrovascular disease, diabetes, and hypertension) with dementia and examined their synergistic impact on dementia among older adults. The data were drawn from the Hubei Memory and Aging Cohort Study. We created a summary score of six factors for multidomain lifestyles. Dementia was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders IV. Logistic regression and multiple correspondence analyses were used to explore the relationships among multidomain lifestyles, chronic diseases, and dementia. A sensitivity analysis was performed to minimize the interference of reverse causality and potential confounders.

Results

Independent associations with dementia were found in unhealthy (OR = 1.90, 95% CI: 1.38-2.61) and intermediate healthy lifestyles (OR, 3.29, 2.32-4.68), hypertension (OR, 1.21, 1.01-1.46), diabetes (OR, 1.30, 1.04-1.63), and cerebrovascular disease (OR, 1.39, 1.12-1.72). Interactions of diabetes (p = 0.004), hypertension (p = 0.004), and lifestyles were significant, suggesting a combined impact on dementia. Sensitivity analysis supported the strong association among multidomain lifestyles, chronic diseases, and dementia prevalence.

Conclusion

An unhealthy lifestyle was associated with a higher prevalence of dementia, regardless of whether the participants had chronic diseases; however, this association was stronger in individuals with chronic diseases. Multidomain lifestyles and chronic diseases may have an enhanced impact on dementia.

Trends in Diet Quality Among Older US Adults From 2001 to 2018

IMPORTANCE

Poor diet is a major risk factor for chronic diseases, disability, and death in the US. As older adults comprise the fastest-growing population segment in the US, it is crucial to describe dietary trends among older adults to identify opportunities and challenges for improving health in old age.

OBJECTIVE

To characterize trends in overall dietary quality and key food components and nutrients among older US adults by age, sex, race and ethnicity, marital status, educational level, and income.

DESIGN, SETTING, AND PARTICIPANTS

This serial cross-sectional study used 24-hour dietary recall data from 10 837 adults aged 65 years or older in 9 National Health and Nutrition Examination Survey cycles (2001-2002 to 2017-2018). Statistical analysis was conducted from June 1 to October 1, 2021.

EXPOSURES

Calendar year and sociodemographic subgroups.

MAIN OUTCOMES AND MEASURES

Survey-weighted, energy-adjusted mean diet scores and proportions of older US adults with poor, intermediate, or ideal diet scores based on the American Heart Association (AHA) 2020 Strategic Impact Goals for diet. Additional outcomes included the AHA secondary score and the Healthy Eating Index (HEI)-2015 score.

RESULTS

A total of 10 837 individuals (5423 women [50.0%]; 6339 White participants [58.5%]; mean [SD] age, 73.9 [0.1] years) were analyzed. Overall dietary quality deteriorated from 2001 to 2018 among older adults. The mean primary AHA score (total = 50 points) decreased from 19.84 (95% CI, 19.40-20.29) to 18.28 (95% CI, 17.84-18.73; a decrease of 7.9%; P < .001 for trend). The mean secondary AHA score (total = 80 points) decreased from 34.75 (95% CI, 34.11-35.39) to 31.83 (95% CI, 31.17-32.48; a decrease of 8.4%; P < .001 for trend). The mean HEI-2015 score (total = 100 points) decreased from 47.82 (95% CI, 47.11-48.52) to 45.25 (95% CI, 44.53-45.98; a decrease of 5.4%; P < .001 for trend). Based on the primary AHA score, the proportion of US older adults with a poor diet quality significantly increased from 50.9% to 60.9%, the proportion with an intermediate diet quality significantly decreased from 48.6% to 38.7%, and the proportion with ideal diet quality remained consistently low (0.4% in both 2001-2002 and 2017-2018). Dietary variations were identified by sociodemographic subgroups. We found a significant decreasing trend in diet scores among both sexes and all age groups except for those aged 75 to 79 years.

CONCLUSIONS AND RELEVANCE

The findings of this cross-sectional study suggest that dietary quality worsened for most dietary components among older US adults between 2001 and 2018. Despite improvement in some dietary components, more than half of older US adults still have poor dietary quality.