Healthy eating and all-cause mortality among Chinese aged 80 years or older.

Background: There is little evidence of the influence of dietary patterns on mortality risk among adults 80 years or older ("oldest-old"). We evaluated the association between the Simplified Healthy Eating index (SHE-index) and mortality among Chinese oldest-old.

Methods: Population-based cohort study from the Chinese Longitudinal Healthy Longevity Survey (CLHLS 1998-2014, n = 35 927), conducted in 22 Chinese provinces, were pooled for analysis. The first seven waves of the CLHLS (1998, 2000, 2002, 2005, 2008-09, 2011-12, and 2013-2014) were utilized, with follow-up to the last wave (2018) (range 0-21 years). The SHE-index was collected in each wave, and was constructed from intake frequency of nine dietary variables, with a higher score indicating better diet quality. Cox proportional hazards model with dietary patterns as a time-varying exposure was employed to analyze the relationship between SHE-index and mortality.

Results: At baseline, the median age of all participants was 92 years (25th percentile, 85 years; 75th percentile, 100 years). In multivariable models, the hazard ratios (95% confidence intervals) for SHE-index quartile 2, quartile 3 and quartile 4 versus quartile1 were 0.91 (0.88, 0.93), 0.89 (0.86, 0.92) and 0.82 (0.78, 0.85), respectively. Results were generally consistent for men and women and in a large number of sensitivity analyses.

Conclusions: Healthier eating patterns were associated with a significant reduction in the risk of all-cause mortality among Chinese oldest-old, lending support to the importance of life-long adherence to healthy diet into advanced old age.