Among 9,761 NHANES participants followed for a median of 7.42 years, 32.4% carried a diagnosis of metabolic dysfunction-associated steatotic liver disease (MASLD). Both allostatic load — a composite of 10 physiological stress biomarkers — and a health behaviour score (diet, nicotine exposure, physical activity, sleep) independently predicted all-cause and cardiovascular mortality. The synergistic effect was most pronounced in MASLD: individuals combining high allostatic load with poor health behaviours faced a hazard ratio of 3.33 (95% CI 1.97–5.65) for all-cause death and 3.66 (95% CI 1.31–10.23) for cardiovascular death, compared to low-stress, healthy-behaviour counterparts.
Fatty liver disease has long been framed as a metabolic and nutritional problem, but this analysis positions chronic psychophysiological stress as an independent, modifiable mortality driver — not merely a background variable. For the roughly one-in-three adults now carrying MASLD, the practical implication is that stress reduction deserves equal billing alongside dietary change and physical activity in clinical management. The finding is observational and causality cannot be confirmed; residual confounding from unmeasured socioeconomic factors is plausible, and the median follow-up of 7.4 years may undercount late cardiovascular events. Nonetheless, the large nationally representative cohort and consistent dose-response across both outcomes lend credibility. Clinicians managing MASLD patients should consider integrating stress-biomarker screening and behavioural counselling — an underutilised, low-cost lever that this data suggests could meaningfully shift mortality trajectories.