Global Burden of Disease (GBD) Comprehensive Analysis of Health Risks

The COVID-19 pandemic underscored substantial health disparities worldwide, driven by various risk factors and differences in healthcare systems. Understanding these disparities through rigorous risk factor analyses is crucial for shaping public health policies and identifying areas of progress.

The Global Burden of Disease (GBD) initiative plays a pivotal role in this by estimating relative health risks, exposure levels, and disease burden attributable to numerous risk factors. told by News Medical

While other research networks, such as the NCD Risk Factor Collaboration (NCD-RisC), provide valuable data on specific risk factors, the GBD stands out for its systematic analysis across 204 countries and territories. Between 1990 and 2021, the GBD examined 88 risk factors across these regions, including 811 subnational locations.

About the Study

The GBD 2021 study details the methods and findings related to 88 risk factors and their combinations. Using data from 54,561 distinct sources, the study produced epidemiological estimates for 631 risk-outcome pairs. These estimates were specific to sex, age, location, and year, and were calculated at regional, national, and global levels.

Relative risks (RRs) for specific outcomes were estimated for each risk factor. Summary exposure values (SEVs) measured risk-weighted exposure prevalence, while theoretical minimum risk exposure levels (TMRELs) were used to calculate the population attributable fraction (PAF). The attributable burden of a risk factor was derived from the product of PAF and disease burden, expressed in disability-adjusted life years (DALYs). as Reported by HIV

Study Findings

In 2021, particulate matter air pollution emerged as the leading contributor to the global disease burden, accounting for 8% of total DALYs. High systolic blood pressure (SBP) followed closely, contributing 7.8% to total DALYs. Other significant contributors included smoking (5.7%), low birth weight and short gestation (5.6%), and high fasting plasma glucose (FPG) (5.4%).

For children aged zero to 14, key risk factors included unsafe water, low birth weight, short gestation, poor handwashing, and inadequate sanitation. In older age groups, high body-mass index (BMI), FPG, SBP, and elevated low-density lipoprotein (LDL) cholesterol levels were major risk factors.

Between 2000 and 2021, there was a notable shift in global health challenges. All-age DALYs decreased, attributed to a 20.7% reduction in behavioral risks and a 22% reduction in environmental and occupational risks. However, there was a nearly 50% increase in DALYs due to high metabolic risks.

Age-standardized global DALY rates increased during this period, largely due to high BMI and FPG, which rose by 15.7% and 7.9%, respectively. Despite this, exposure to many other risk factors and their attributable burdens declined, even for significant risks like unsafe water and child growth failure, which saw declines of 66.3% and 71.5%, respectively, in age-standardized attributable DALYs.


The study identified several risk factors for which adequate action has not yet been taken. Linking disease burden to these risk factors is crucial for resource prioritization.

A notable limitation of the GBD 2021 was the exclusion of certain significant risk factors, such as the impact of the COVID-19 pandemic, which was not formally integrated or quantified.

Additionally, variable data quality and inconsistent availability posed challenges in estimating RRs, due to significant heterogeneities across socioeconomic factors.

Future GBD studies should expand the scope of risk factors, especially for outcomes that significantly contribute to disease burden, such as mental health disorders and musculoskeletal disorders.

Mental health disorders account for 5.4% of global DALYs, yet only 8% have been attributed to risk factors. Similarly, musculoskeletal disorders constitute 5.6% of the global burden, but only 20.5% of this burden was linked to risk factors in the current GBD analysis.