The association between hypoalbuminemia and risk of death due to cancer and vascular disease in individuals aged 65 years and older: findings from the prospective Moli-sani cohort study

Background: Serum albumin is inversely associated with overall mortality, but its association with specific causes of death remains uncertain. This study aims to investigate whether hypoalbuminemia, defined as serum albumin levels ≤35 g/L, is associated with mortality specifically attributed to cancer and/or vascular diseases. Methods: Serum albumin levels were measured in the population-based, prospective cohort of the Moli-sani study, established between 2005 and 2010. Hypoalbuminemia was defined as serum albumin levels ≤35 g/L. Cause-specific mortality was assessed using the validated Italian mortality registry and coded according to the International Classification of Diseases, Revision 9. Over a median follow-up period of 13.1 years, the relationship between serum albumin and mortality, adjusted for covariates, was investigated using competing-risk survival analysis. Findings: The analysed cohort comprised 17,930 individuals aged ≥35 years, of whom 8445 were men (47.1%). The mean age was 54 years (standard deviation (SD) = 11 years), with 3299 individuals (18.4%) aged older than 65 years. All participants had C-reactive protein levels <10 mg/L and no history of liver, renal, cardiovascular, or cancer disease. Hypoalbuminemia was found in 406 individuals (2.3%). The study documented a total of 1428 deaths, with 574 attributed to cancer and 464 to vascular causes. Hypoalbuminemia was independently associated with mortality when compared to serum albumin >40 g/L (Hazard Ratio (HR) = 1.61, 95% Confidence Interval: 1.21-2.13). A decrease of 1-SD in serum albumin levels corresponded to HR of 1.16 (1.09-1.22), 1.16 (1.05-1.28), and 1.13 (1.03-1.23) for total, vascular and cancer mortality, respectively. Upon stratifying by age, hypoalbuminemia was associated with total mortality solely in those aged ≥65 years (HR = 1.83; 1.33-2.50) but not in the <65 years group (HR = 1.03; 0.53-2.00; P < 0.0001 for difference). Similar age-related patterns emerged for vascular death (per 1-SD decrease HR = 1.19; 1.07-1.33 in individuals ≥65 years and HR = 1.05; 0.86-1.29 in individuals <65 years) and cancer mortality (HR = 1.15; 1.02-1.30; ≥65 years and HR = 1.08; 0.96-1.23; <65 years). Interpretation: Individuals ≥65 years old with serum albumin levels ≤35 g/L are at higher risk of total, cancer, and vascular mortality. Funding: This paper was developed within the project funded by Next Generation EU-"Age-It - Ageing well in an ageing society" project (PE0000015), National Recovery and Resilience Plan (NRRP)-PE8-Mission 4, C2, Intervention 1.3.