Health Risk Factors and Non-Communicable Disease Mortality in Saudi Arabia: Autoregressive Distributed Lag (ARDL) Analysis of the Moderating Role of Health Expenditure (2000–2024)

non-communicable diseases (NCDs) remain a leading cause of premature mortality worldwide and represent a major health challenge in Saudi Arabia. Rising prevalence rates of diabetes, hypertension, and obesity have coincided with substantial increases in national health expenditure. However, the extent to which health spending modifies the relationship between these risk factors and NCD mortality has not been fully examined. This study employed annual time-series data for Saudi Arabia from 2000 to 2024 and estimated an Autoregressive Distributed Lag (ARDL) model to assess both short-run and long-run dynamics. Variables included NCD mortality, hypertension, diabetes, obesity, and current health expenditure as a share of GDP. Interaction terms were constructed to evaluate the moderating role of health spending. Stationarity, bounds testing, long-run estimation, and diagnostic checks were performed. The baseline model showed limited direct effects of the primary risk factors on NCD mortality. When interaction terms were introduced, health expenditure demonstrated a statistically significant moderating effect. The interaction with diabetes was negative in both the short and long run, indicating that higher spending reduces the mortality impact of diabetes. The interaction with hypertension was positive in the short run, consistent with improved detection, and negative in the long run, reflecting sustained treatment benefits. The error-correction term confirmed a stable adjustment toward long-run equilibrium. The findings highlight the strategic role of health expenditure in mitigating the mortality impact of major NCD risk factors. Effective and well-targeted investment in chronic disease management, early detection, and preventive care can accelerate progress toward national health objectives and support long-term system resilience.