Associations of types of grains and lifestyle with all-cause mortality among Chinese adults aged 65 years or older: a prospective cohort study

Little is known on the association of types of grains with mortality and the moderating effect of lifestyle on this association. This study aims to evaluate the single or joint associations of types of grains and lifestyle with all-cause mortality among Chinese older adults. Data were derived from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) from 1998 to 2018. Subjects aged ≥ 65 years were eligible. The types of grains included wheat, total rice, and coarse cereals. Lifestyle was derived using smoking, alcohol consumption, physical activity, and dietary pattern. All-cause mortality was the primary outcome. This study included 30275 participants with a mean age 87 ± 11 years and documented 19261 deaths during a mean follow-up of 4.8 years. Compared to wheat, in those with healthy and intermediate lifestyle, total rice was associated with a 13% (HR: 0.87, 95% CI 0.80, 0.93) and 6% (HR: 0.94, 95% CI 0.90, 1.00) lower risk of mortality, respectively, and coarse cereals were associated with a 14% (HR: 0.86, 95% CI 0.74, 1.00) and 12% (HR: 0.88, 95% CI 0.79, 0.97) lower risk of mortality, respectively. Meanwhile, an increase per SD in intakes of wheat and coarse cereals was associated with a 10% (HR: 1.10, 95% CI 1.03, 1.18) and 25% (HR: 1.25, 95% CI 1.08, 1.44) higher mortality rate in those with healthy lifestyle, and a 13% (HR: 1.13, 95% CI 1.08, 1.19) and 29% (HR: 1.29, 95% CI 1.17, 1.44) higher mortality in females but not males. In addition, a U-shaped association of intake of total grains with all- cause mortality was observed (P for non-linearity = 0.002), and a J-shaped association of intake of total rice with all- cause mortality was observed (P for non-linearity = 0.003). Specific types of grains and lifestyle were separately or jointly associated with all-cause mortality. Compared to wheat, total rice and coarse cereals were advanced grains for participants with a relatively healthy lifestyle. Intake of total rice was related to all-cause mortality in a dose-response manner. Therefore, a combination of intermediate intake of total rice and healthy lifestyle should be encouraged in older adults.