Abstract
IMPORTANCE To our knowledge, the role of overall diet quality in successful aging has not been conclusively demonstrated. OBJECTIVE To prospectively examine the association between diet quality and longevity and successful aging in a population-based cohort of older adults. DESIGN, SETTING, AND PARTICIPANTS Participants in “Mabat Zahav” (the Israeli National Health and Nutrition Survey of Older Adults), an older adult cohort (aged ≥65 years) consisting of a random sample of 1770 individuals, were recruited from July 2005 to December 2006 (time 1 [T1]). Survivors of T1 were again contacted and asked to participate in a second interview. From May 2017 to June 2019 (time 2 [T2]), an extensive face-to-face interview and a functional assessment were conducted in each participant’s home in a subsample of 604 participants from T1, representing 72.7% of 820 surviving individuals who were able to complete interviews and assessments. EXPOSURES A 24-hour dietary recall, assessed at T1, was used to calculate scores from the 2015 version of the Healthy Eating Index (HEI-2015) (scores range from 0 [worst diet] to 100 [best diet]). MAIN OUTCOMES AND MEASURES Time to death, with follow-up lasting through June 2019, and successful aging. The latter, based on T2 assessment, was defined as (objectively measured) preserved physical and cognitive function and (subjective) mental well-being and favorable self-rated health. Inverse probability weighting was used in the analysis to minimize attrition bias. RESULTS At T1, the study included 1770 participants (mean [SD] age, 74.6 [6.2] years; 943 women [53%]). On average, participants with higher HEI-2015 scores had healthier lifestyles and higher socioeconomic status at T1. During a median follow-up duration of 12.6 years (IQR, 7.6-13.2 years), 893 deaths occurred. Among the 596 T2 participants analyzed (mean [SD] age, 84.1 [4.4] years; 334 [56%] women), 242 (40%) met successful aging criteria. After adjustment for sociodemographic and lifestyle risk factors, a higher HEI-2015 score was inversely associated with mortality (hazard ratios, 0.85; 95% CI, 0.72-0.99 in the upper tertile and 0.83; 95% CI, 0.71-0.98 in the middle tertile vs the lower tertile; P = .04 for trend) and was positively associated with successful aging (odds ratios, 1.73; 95% CI, 1.10-2.72 in the upper tertile and 1.30; 95% CI, 0.83-2.03 in the middle tertile vs the lower tertile; P = .03 for trend). CONCLUSIONS AND RELEVANCE In this cohort study of older adults in Israel, improved diet quality was associated with increased longevity and successful aging in a dose-dependent manner. These data contribute to the body of literature that suggests diet quality is associated with aging in the older age group.
Generated Summary
This study, published in JAMA Network Open, presents a prospective investigation into the relationship between diet quality, longevity, and successful aging among Israeli adults aged 65 years or older. The research employed a cohort study design, drawing on data from the “Mabat Zahav” (Israeli National Health and Nutrition Survey of Older Adults). The study included 1770 participants initially recruited between July 2005 and December 2006 (Time 1, T1). A subset of 604 participants from T1, representing those who were still alive and able to participate, were re-interviewed between May 2017 and June 2019 (Time 2, T2). The primary objective was to examine how diet quality, assessed using the Healthy Eating Index (HEI-2015), correlated with both longevity (time to death) and successful aging, which was defined at T2 based on preserved physical and cognitive function, mental well-being, and self-rated health. The research utilized inverse probability weighting to address potential attrition bias, aiming to minimize any skewed results due to participants dropping out of the study. The methodology involved a 24-hour dietary recall to determine HEI-2015 scores and detailed face-to-face interviews to assess various health-related aspects. Statistical analyses were performed to determine the relationship between diet quality and the outcomes of mortality and successful aging. The study offers insights into the significance of dietary patterns and their impact on aging.
Key Findings & Statistics
The study included 1770 participants at T1, with a mean age of 74.6 (6.2) years; 943 (53%) were women. The HEI-2015 scores at baseline ranged from 13 to 94 (mean [SD], 60.0 [13.0]).
- During a median follow-up of 12.6 years, 893 deaths occurred.
- Among the 596 T2 participants, 242 (40%) met successful aging criteria.
- The HRs for mortality were 0.85 (95% CI, 0.72-0.99) in the upper tertile and 0.83 (95% CI, 0.71-0.98) in the middle tertile vs the lower tertile (P = .04 for trend) after adjusting for sociodemographic and lifestyle risk factors.
- The odds ratios for successful aging were 1.73 (95% CI, 1.10-2.72) in the upper tertile and 1.30 (95% CI, 0.83-2.03) in the middle tertile vs the lower tertile (P = .03 for trend).
- For every 10-point improvement in HEI-2015 score, a multivariable-adjusted HR of 0.95 (95% CI, 0.90-1.00) was observed.
- Baseline characteristics by HEI-2015 tertiles revealed that participants with higher HEI-2015 scores had healthier lifestyles and higher socioeconomic status at T1.
- In a comparison of baseline characteristics of T2 participants and nonparticipants, T2 participants who met the criteria for successful aging had higher levels of education, higher household income, and higher HEI-2015 scores.
- When individual successful aging components were assessed, higher HEI-2015 scores were associated with grip strength, cognitive function, self-rated health, and mental health.
- The mean (SD) age of participants at T2 was 84.1 (4.4) years, with 334 (56%) being women.
Other Important Findings
- Participants with higher HEI-2015 scores were more educated and had higher household income, better self-rated health, and fewer functional limitations.
- Higher HEI-2015 scores were inversely associated with mortality.
- The association between HEI-2015 scores and successful aging remained significant after adjusting for sociodemographic and lifestyle risk factors.
- Sensitivity analyses, including unweighted analysis and alternative definitions of successful aging, supported the main findings.
- The study found an association between higher diet quality and increased odds of successful aging.
- The study highlights the importance of diet quality for both longevity and successful aging in the older age group.
- Results suggest a dose-dependent association between diet quality and successful aging.
Limitations Noted in the Document
- The HEI-2015 score was based on a single 24-hour dietary recall which may not fully capture the usual dietary intake, potentially leading to regression-attenuation bias.
- Residual confounding is possible despite adjusting for several potential confounders.
- T2 participants differed from nonparticipants due to attrition.
- The HEI-2015 is not age specific.
- The study was conducted in a specific population (Israeli adults), which may limit the generalizability of the findings to other populations.
- There is a possibility of reverse causality, although sensitivity analyses attempted to address this.
Conclusion
The study’s findings strongly suggest a link between diet quality and successful aging, specifically in a cohort of Israeli older adults. The data supports the notion that a healthier diet, characterized by a higher HEI-2015 score, is associated with increased longevity and a greater likelihood of successful aging. The study contributes to the existing body of literature that emphasizes the role of diet quality in the aging process and confirms prior research on the association between dietary patterns and longevity. The observed dose-dependent relationship between diet quality and successful aging further underscores the importance of healthy eating habits in older populations. This emphasizes the need for interventions to promote dietary improvements as a strategy to foster better health outcomes in later life. The study’s conclusions encourage a focus on dietary guidelines, rather than a specific diet plan, and suggest that raising awareness of the advantages of healthy food choices and providing healthy alternatives could lead to better aging outcomes in the older adult population. The study underscores the value of promoting dietary improvements as a key element in strategies aimed at enhancing health in later life. The authors emphasize that public health initiatives should adopt a “never too late” approach, reinforcing the benefits of making healthy food choices at any age.