The prevalence and etiology of anemia and the association between anemia and all-cause mortality: a cohort study over a 9-year period

RESEARCH BACKGROUND: As the global population ages rapidly, anemia prevalence rises among older adults, yet its impact on quality of life and mortality in this group remains poorly understood. This study aimed to identify risk factors for anemia and examine its associations with quality of life and 9-year all-cause mortality among Chinese adults aged ≥60. METHODS: We evaluated the determinants and consequences of anemia in 5,050 participants aged ≥ 60 from the China Health and Retirement Longitudinal Study (CHARLS), a prospective cohort of community-dwelling elderly individuals ≥ 45 at baseline and followed for up to 9 years. Anemia was defined according to the World Health Organization criteria. Multinomial logistic regression was performed to assess the correlation between anemia and aging. Cox proportional hazards models were used to evaluate the impact of anemia on all-cause mortality. RESULTS: In 2011, anemia prevalence was 15.05% (95% CI, 14.00–16.06%) and increased with age. Age (OR, 1.03; 95% CI, 1.01–1.05; P < 0.01), living in rural areas (OR, 1.51; 95% CI, 1.18–1.92; P < 0.01), and hypoproliferation ((OR, 1.43; 95% CI, 1.12–1.83; P < 0.01) were positively associated with anemia.Negative associations were observed for higher hematocrit (OR, 0.93; 95% CI, 0.91–0.95; P < 0.01) , total cholesterol (OR, 1.00; 95% CI, 0.99–1.00; P = 0.03), and the creatinine clearance rate (OR, 0.99; 95% CI, 0.98–1.00; P < 0.01). During the 9 years of follow-up, 741 of the 4767 (15.54%) participants died. After adjusting for covariates, anemia remained independently associated with mortality (HR, 1.22, 95% CI, 1.02, 1.47; P=0.03) was still closely associated with mortality. Persistent anemia significantly impaired survival, and anemia was linked to reduced quality of life. CONCLUSION: This study revealed that anemia is prevalent among individuals aged ≥ 60 years in China and is related to age, residence type, hypoproliferation, hematocrit, total cholesterol and the creatinine clearance rate. Research has also confirmed that anemia is associated with worse overall survival in Chinese older adults.