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High blood pressure and tobacco are the top risk factors for death worldwide

Global burden of 87 risk factors in 204 countries and territories, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019.

Overview

GBD 2019 Risk Factors Collaborators. Lancet 2020 · PMID 33069327 · DOI 10.1016/S0140-6736(20)30752-2

In 2019, high blood pressure was linked to 10.8 million and tobacco to 8.7 million deaths.

Does the study support the specific claim? No · Methodological quality: moderate

Original publication

Plain-language summary

Study explained simply

What did the researchers want to find out?: Rank risk factors.
How was the study done?: GBD 2019.
How many people, animals or samples were studied?: 204 countries.
What was actually found?: High blood pressure and tobacco lead; dietary risks rank among the top five; all 87 risks together explain 47.8% of global disease burden.
How large was the observed effect?: 19.2% and 15.4% of deaths.
What do the results mean in everyday life?: Check blood pressure; avoid tobacco; diet is one lever.
What are the study's limitations?: Modelling.
What does it say about Elawady's specific claim?: Multiple causes.
Do the results apply to Germany and Europe?: High.
What can explicitly not be concluded from this study?: Individual risk.

Scientific in-depth review

1. Full reference

Authors: GBD 2019 Risk Factors Collaborators
Journal: Lancet
Year: 2020
Identifier: PMID 33069327 DOI 10.1016/S0140-6736(20)30752-2
Verification: verified – PubMed esummary + efetch 2026-10-25
Retracted: no
Corrections: none
Extent checked: full text
Conflicts of interest and funding: Bill & Melinda Gates Foundation (plus Bloomberg Philanthropies and multiple national bodies); funders had no role. Several collaborators report pharmaceutical/industry fees or grants outside the submitted work (e.g. AstraZeneca, Pfizer, Novo Nordisk, Unilever, AB InBev Foundation contract); others none.

2. Research question

Attributable burden of 87 risk factors.

3. Study design and population

Study design: Risk assessment – Comparative risk assessment within GBD 2019 (systematic reviews/meta-regression for relative risks, Bayesian exposure modelling, TMREL counterfactual, population attributable fractions with mediation adjustment)
Population: Global
Country: Global
Period: 1990-2019
Sample size: 30,652 data sources; 560 risk-outcome pairs; 87 risks/clusters; 204 countries and territories
Inclusion and exclusion criteria: Risk-outcome pairs meeting World Cancer Research Fund criteria for convincing or probable evidence and p<0.05 after accounting for bias (exclusion of previously included pairs if p>0.1); 12 GBD 2017 pairs excluded, 47 added

4. Methods and endpoints

Exposure / intervention: 87 risks
Comparator: Theoretical minimum risk
Endpoints: Deaths, DALYs
Statistical methods: PAF by age-sex-location-year with 1000 draws propagating uncertainty (95% UI); summary exposure values; spatiotemporal Gaussian process regression, DisMod-MR 2.1; non-linear meta-regression for 147 pairs, log-linear for 218; mediation matrix for joint effects

5. Actual results

Results: 2019 Level 2 risks for deaths: high SBP 10.8 million (95% UI 9.51-12.1; 19.2% of deaths), tobacco 8.71 million (8.12-9.31; 15.4%). Females: high SBP 5.25 million (20.3%), dietary risks 3.48 million (13.5%), high FPG 3.09 million (11.9%), air pollution 2.92 million, high BMI 2.54 million. Males: tobacco 6.56 million (21.4%), high SBP 5.60 million (18.2%), dietary risks 4.47 million (14.6%), air pollution 3.75 million, high FPG 3.14 million. Leading Level 2 risk for DALYs: child and maternal malnutrition 295 million (253-350; 11.6%); dietary risks were fifth for DALYs. All 87 risks combined explained 47.8% (45.3-50.1) of global DALYs. Exposure rising >0.5%/year: ambient PM, alcohol, drug use, childhood sexual abuse, bullying, high FPG, high SBP, high BMI; metabolic risk exposure +1.46%/year 2010-19. Diet-attributable DALYs in 2017 were 29.7% lower in GBD 2019 than in GBD 2017. Combined diet quality, physical inactivity and high BMI: 11.9% (9.6-14.5) of DALYs.
Absolute risks: Attributable counts: high SBP 10.8 million deaths, tobacco 8.71 million; dietary risks 3.48 million (female) and 4.47 million (male) deaths; 47.8% of DALYs attributable to all included risks
Authors' conclusion: The record of reducing exposure to harmful risks over three decades is poor; metabolic risks are rising; regulatory success with smoking and lead suggests a stronger role for public policy.

6. Strengths

Comprehensive standardised method across 204 locations and 30 years
Explicit evidence-inclusion rules and uncertainty propagation
Mediation adjustment for joint effects
Diet TMRELs re-estimated with new systematic reviews

7. Weaknesses

Model-based; sparse and self-reported exposure data in many locations (authors)
Uncertainty intervals do not reflect differences in evidence strength or risk of bias across risk-outcome pairs (authors)
Relative risks assumed universal across locations; log-linear assumptions for many pairs
TMREL for protective factors set at arbitrary 85th percentile
Independence of exposures and multiplicative joint effects assumed
Important determinants omitted (education, poverty, stress, sleep, noise, UV, heavy metals); attributable not equal to avoidable burden
Large revisions between GBD rounds (diet -29.7%, PM +44.6%)

8. Risk of bias

Orienting tool: none applicable (comparative risk assessment/modelling; structured judgement)
Type of assessment: structured assessment based on the full text by a single reviewer (no formal double review)
Full formal assessment: no
Overall risk of bias: some concerns
Rationale: Overall unchanged (some_concerns): appropriate for ranking population-level burden, but estimates are model-dependent and revised substantially between GBD rounds. Single-reviewer structured judgement from the full text; a complete formal assessment requires two independent reviewers and the review/study protocol.

8. Risk of bias
Domain	Judgement	Rationale
Input evidence on relative risks	some concerns	Mostly observational cohorts; WCRF convincing/probable criteria applied, but evidence strength varies widely (e.g. smoking-lung cancer vs omega-3-IHD) and is not reflected in UIs.
Exposure data	some concerns	Non-uniform data availability, self-report; crosswalk corrections applied.
Model assumptions	some concerns	Universal RRs, log-linearity for 218 pairs, independence of exposures, multiplicative joint effects, arbitrary TMREL percentile.
Completeness of risk set	some concerns	Social determinants and several environmental risks not included; 52% of DALYs not attributed.
Reporting / transparency	low	Methods and appendices extensive; GATHER-compliant; funders no role.

Full-text review (25 October 2026): Added evidence-inclusion rules, model details, sex-specific death counts incl. dietary risks (3.48M female, 4.47M male), 47.8% of DALYs attributable to all risks combined, 29.7% downward revision of diet burden vs GBD 2017, authors' limitations (UIs ignore evidence strength, universal RRs, omitted social determinants), detailed funding/COI. Bias overall unchanged (some_concerns).

9. Assessment of the statistical interpretation

Attributable burden is a counterfactual model estimate, not observed causation per person. Less than half (47.8%) of global DALYs is attributable to all 87 included risks combined. Dietary risks are a major Level 2 risk (2nd for female deaths, 3rd for male deaths, 5th for DALYs), and part of diet's effect is mediated through high SBP, BMI and FPG, which are themselves counted as separate risks; rankings depend on the aggregation used.

10. Relevance to the specific claim

Shows chronic disease has multiple causes; measurable markers (blood pressure, fasting glucose) are themselves causal risk factors.

11. Independent contrary findings

I-SYS-01 ranks diet top under a different aggregation.

12. Transferability to Germany and Europe

High.

13. Overall methodological judgement

Key context: chronic disease has multiple measurable causes; diet is one leading risk but not the single leading Level 2 risk in GBD 2019, and its estimated burden was revised down versus GBD 2017.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	moderate
Directness	direct
Reproducibility	replicated
Consistency with the overall evidence	consistent
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable

14. Open questions

Avoidable (vs attributable) burden; incorporation of evidence-strength scoring and Mendelian randomisation; inclusion of social determinants.

15. Linked fact checks

Food is the first (leading) cause of modern (non-communicable) diseases. – Studies contradicting or limiting the claim
Chronic disease is mostly a cumulative reaction to what enters the body daily - contaminated food, medicines and cosmetics - not a fate that comes from outside. – Studies contradicting or limiting the claim
Laboratory values (blood glucose, acetone, HDL/LDL, urea, creatinine, electrolytes) only indicate a change of the body's strategy under stress; there is no proof they cause symptoms, and linking them to the type of food is '100% wrong'. – Studies contradicting or limiting the claim