Introduction:
Obesity and weight fluctuations across adulthood are well-documented risk factors for cardiovascular diseases (CVDs), while serum uric acid has emerged as a potential metabolic intermediary influencing cardiovascular health (CVH). However, limited research has explored the life-stage-specific relationships between weight changes, uric acid levels, and CVH trajectories, particularly the mediating role of uric acid in these associations.

Material and methods:
Multivariate linear regression was used to evaluate the associations between weight changes, uric acid levels, and CVH score patterns among 1,257 participants in NHANES cycles (2013–2018). Mediation analysis via bootstrap tests was conducted to investigate the role of uric acid in BMI‒CVH relationships across life stages, with stratified analysis by sex.

Results:
Obesity in early and middle adulthood was significantly associated with lower CVH scores in later adulthood. Weight changes exceeding 2.5 kg and stable obesity from middle to late adulthood were linked to increased cardiovascular risk. Serum uric acid levels were negatively associated with CVH scores and positively correlated with BMI and weight gain across all life stages. Uric acid mediated the relationship between BMI and CVH, with the mediating effect being most pronounced in early adulthood. Notably, this mediation effect showed gender differences, with a consistent effect across all stages in women but being significant only in late adulthood in men.

Conclusions:
These findings underscore the complex interplay between weight, uric acid, and cardiovascular health. Maintaining a stable weight and effectively managing uric acid levels, with consideration of sex-specific differences, are critical strategies for improving cardiovascular outcomes across the lifespan.