Burden and temporal trends of non-communicable diseases from 1990 to 2021 and prediction to 2035 in the group of twenty countries: a systematic analysis of the Global Burden of Disease Study 2021

Background: Non-communicable diseases (NCDs) represent a major global public health threat, closely linked to disruptions in host-microbe symbiosis and metabolic homeostasis. The Group of Twenty (G20) comprises the world's major economic powers with diverse developmental stages, yet the NCD burden and its potential implications for host and ecosystem resilience remain poorly characterized across these nations. This study aimed to systematically estimate the burden, temporal trends, and future projections of NCDs from 1990 to 2021 and up to 2035 in G20 countries. Methods: Using data from the Global Burden of Disease Study 2021 (GBD2021), we analyzed mortality and years of life lost (YLL) attributable to NCDs among G20 states, stratified by age, sex, and country. Temporal trends were assessed using joinpoint regression to identify inflection points in annual percentage changes. Socioeconomic health inequalities were quantified using the slope index of inequality (SII) and concentration index. Future burden trajectories to 2035 were projected using Bayesian age-period-cohort (BAPC) modeling. Results: Compared to 1990, the burden of the NCDs across G20 countries in 2021 showed a downward trend. However, the age-standardized mortality and YLL rates from NCDs in G20 countries accounting for 72.21 and 62.56% of all-cause mortality and YLL rates, respectively, markedly surpassing global averages. Specific countries including Indonesia, Russia, Saudi Arabia, and South Africa demonstrated persistently higher burdens compared to regional averages. Males had a higher burden than females. When examining level 2 and level 3 causes of NCDs specifically, trends in burden changes varied across different NCDs at the national levels. Cardiovascular diseases remained the leading contributor to premature mortality, though neurological disorders emerged as the fastest-growing threat. Inequality assessments revealed concentrated burdens in low-sociodemographic index (SDI) region among G20 nations. BAPC model predictions suggested that the burden of NCDs will continue to decline in the future. Conclusion: Despite an overall reduction in NCD burden, G20 countries face persistent sex disparities and divergent trends between dominant cardiovascular diseases and rapidly rising neurological disorders. These patterns reflect imbalances in host resilience, metabolic stability, and population-level ecosystem health. Targeted interventions are needed to strengthen cardiovascular prevention, enhance neurological care, and mitigate socioeconomic inequalities, with potential implications for restoring host-microbe symbiosis and improving population resilience.