Global Burden Of 87 Risk Factors In 204 Countries And Territories, 1990–2019: A Systematic Analysis For The Global Burden Of Disease Study 2019

Abstract

Background Rigorous analysis of levels and trends in exposure to leading risk factors and quantification of their effect on human health are important to identify where public health is making progress and in which cases current efforts are inadequate. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 provides a standardised and comprehensive assessment of the magnitude of risk factor exposure, relative risk, and attributable burden of disease.

Generated Summary

The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 provides a comprehensive assessment of the magnitude of risk factor exposure, relative risk, and attributable burden of disease. This study analyzed 87 risk factors and combinations of risk factors across 204 countries and territories from 1990 to 2019. The methodology involved six analytical steps, including identifying risk-outcome pairs, estimating relative risks, assessing exposure levels, determining theoretical minimum risk exposure levels (TMREL), computing attributable deaths and DALYs, and estimating the impact of risk factor combinations. The study utilized a hierarchical list of risk factors. The findings from the GBD 2019 were compared with previous estimates to assess trends and changes. A key innovation in this study was the use of summary exposure values (SEVs) to compare risk factor exposures over time and across locations. The research team estimated the prevalence of exposure and attributable deaths, YLLs, YLDs, and DALYs for 23 age groups, males, females, and both sexes combined, and 204 countries and territories that were grouped into 21 regions and seven super-regions.

Key Findings & Statistics

• The largest declines in risk exposure from 2010 to 2019 were linked to social and economic development, including household air pollution; unsafe water, sanitation, and handwashing; and child growth failure.
• Global declines also occurred for tobacco smoking and lead exposure.
• The largest increases in risk exposure were for ambient particulate matter pollution, drug use, high fasting plasma glucose, and high body-mass index.
• In 2019, the leading Level 2 risk factor globally for attributable deaths was high systolic blood pressure, which accounted for 10.8 million (95% uncertainty interval [UI] 9.51-12-1) deaths (19.2% [16-9-21-3] of all deaths in 2019), followed by tobacco (smoked, second-hand, and chewing), which accounted for 8.71 million (8-12-9-31) deaths (15.4% [14-6-16-2] of all deaths in 2019).
• The leading Level 2 risk factor for attributable DALYs globally in 2019 was child and maternal malnutrition, which largely affects health in the youngest age groups and accounted for 295 million (253-350) DALYs (11.6% [10-3-13-1] of all global DALYs that year).
• Among children aged 0–9 years, the three leading detailed risk factors for attributable DALYs were all related to malnutrition.
• Iron deficiency was the leading risk factor for those aged 10-24 years, alcohol use for those aged 25–49 years, and high systolic blood pressure for those aged 50–74 years and 75 years and older.
• In 2019, 47.8% (95% UI 45·3–50-1) of global DALYs were attributed to present and past exposure for the 87 environmental, occupational, behavioural, and metabolic risk factors and combinations of risk factors.
• The leading Level 2 risk factor for deaths was high SBP, accounting for 10.8 million (9.51-12-1) deaths in 2019 (19.2% [16-9-21-3] of all deaths that year), followed by tobacco, with 8.71 million (8-12-9-31) deaths (15.4% [14-6-16.2] of all deaths that year).
• The leading Level 2 risk factor globally for attributable DALYs was child and maternal malnutrition, at 295 million (95% UI 253-350) DALYS in 2019 (11.6% [10-3-13-1] of all DALYs that year).
• The largest declines among the leading ten risks were for child growth failure; water, sanitation, and handwashing; and household air pollution.
• In the 25-49 years age group, alcohol use was the leading Level 4 risk factor for attributable burden, followed by high SBP and then high BMI, smoking, unsafe sex, and high FPG.
• The long-term consequences of short gestation and low birthweight also increased in importance.
• In the 25-49 years age group (figure 5D), alcohol use was the leading Level 4 risk factor for attributable burden, followed by high SBP and then high BMI, smoking, unsafe sex, and high FPG.

Other Important Findings

• There were three risks that accounted for more than 1% of DALYs and were increasing in exposure by more than 1% per year: high BMI, ambient particulate matter pollution, and high FPG.
• High FPG and high BMI are increasing in all SDI quintiles, as is alcohol use. Smoking is declining in all SDI quintiles.
• The leading risk factors for attributable DALYs had highly varied geographical patterns.
• In the low SDI quintile, the most important risk factors were malnutrition; air pollution; and water, sanitation, and handwashing.
• In the low-middle SDI quintile, malnutrition and air pollution were still the leading risk factors for attributable DALYs, but high SBP rose to third.
• In the middle to high SDI quintiles, the leading risks transitioned to tobacco, high SBP, dietary risks, high BMI, and high FPG.
• The risk transition is evident across quintiles.
• In the Caribbean and central Latin America, large increases were seen in attributable burden for high FPG, high BMI, high SBP, kidney dysfunction, dietary risks, and high LDL cholesterol.
• In seven regions, child and maternal malnutrition is the leading risk factor, and in another seven regions, tobacco is the leading risk factor.
• There were declines in unsafe sex DALYs in the second half of the study period, but due to rapid increases from 1990 to 2004, there was still a 108.3% (95% UI 78-5-140.5) increase in unsafe sex DALYs from 1990 to 2019.

Limitations Noted in the Document

• The analysis is limited by the availability and quality of primary data.
• The assessment of the joint effects of risk factors depends on the correlation of risk exposure and the estimation of the joint effects of groups of risks together.
• In general, the estimates of the prevalence of exposure were independent for each age-sex-location-year.
• The study’s estimates of risk-attributable burden is limited by several potentially important risk factors not included, such as social determinants of health.
• For protective risks, such as fruit or whole grain intake, the TMREL was set at the 85th percentile of exposure, which might lead to overestimation.
• In most cases, the relative risks as a function of exposure are assumed to be universal and applied in all locations and time periods, with exceptions such as temperature and high BMI for breast cancer.

Conclusion

Overall, the record for reducing exposure to harmful risks over the past three decades is poor. Success with reducing smoking and lead exposure through regulatory policy might point the way for a stronger role for public policy on other risks in addition to continued efforts to provide information on risk factor harm to the general public. The study highlights the increasing prevalence of metabolic risks, such as high BMI and high FPG, which contribute significantly to the global disease burden. The study’s findings underscore the need for public regulatory policy, community programs, and primary care interventions to tackle these risks more effectively. The study showed that the leading risk factors for attributable DALYs had highly varied geographical patterns. The study’s findings also suggest that, for several major risks, regulatory interventions have had a significant impact. The results also show how a combination of factors has impacted health. The marked rise of metabolic risks as a group, in particular high FPG and high BMI, and their large contribution to attributable burden is perhaps most disturbing. The study indicates the need for concerted research and policy efforts to address these trends. The results show the impact that regulatory policies, such as those targeting tobacco, can have on exposure and health outcomes. The authors note that the interplay of diet quality, caloric intake, and physical activity is crucial to current and future health. The study also emphasizes the importance of considering the nexus of diet and physical activity to tackle the growing burden of metabolic risks. Given the increasing prevalence of metabolic risks, the results suggest that these areas need urgent attention and require comprehensive interventions to reverse the negative trends. The study emphasizes the need for country-specific assessments and prevention planning. The authors conclude that a global effort is needed to address harmful environmental risks and reduce exposure to the key behavioral risk factors that contribute to the global burden of disease.