Risk assessmentindependent cross-checkabstract checked★ key study I-SYS-101 in-depth review
Global causes of ill health in 2021
Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990-2021: a systematic analysis for the Global Burden of Disease Study 2021.
Overview
GBD 2021 Risk Factors Collaborators. Lancet 2024 · PMID 38762324 · DOI 10.1016/S0140-6736(24)00933-4
Air pollution, high blood pressure and smoking were the top single risks; poor diet as a group ranked fifth.
Does the study support the specific claim? Partly · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Rank risk factors worldwide.
- How was the study done?
Global modelling study.
- How many people, animals or samples were studied?
204 countries.
- What was actually found?
Air pollution and high blood pressure lead.
- How large was the observed effect?
PM 8.0%, SBP 7.8%, smoking 5.7% of DALYs.
- What do the results mean in everyday life?
Diet matters a lot but is not the only or first cause.
- What are the study's limitations?
Model-based.
- What does it say about Elawady's specific claim?
Partly contradicts 'food is the first cause'.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Exact causal shares.
Scientific in-depth review
1. Full reference
- Authors
- GBD 2021 Risk Factors Collaborators
- Journal
- Lancet
- Year
- 2024
- Identifier
- PMID 38762324 DOI 10.1016/S0140-6736(24)00933-4
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref
- Retracted
- no
- Corrections
ErratumIn: Lancet. 2024 Jul 20;404(10449):244. doi: 10.1016/S0140-6736(24)01458-2.
- Extent checked
- abstract only
- Conflicts of interest and funding
Bill & Melinda Gates Foundation; author declarations in full text
2. Research question
Exposure, relative risk and attributable burden for 88 risk factors
3. Study design and population
- Study design
- Risk assessment – Comparative risk assessment, Global Burden of Disease Study 2021
- Population
204 countries and 811 subnational locations
- Country
Global (incl. Egypt and Europe)
- Period
1990-2021
- Sample size
54,561 data sources; 631 risk-outcome pairs
- Inclusion and exclusion criteria
Risk-outcome pairs with evidence of association
4. Methods and endpoints
- Exposure / intervention
88 risk factors
- Comparator
Theoretical minimum risk exposure level
- Endpoints
DALYs, deaths
- Statistical methods
Population attributable fractions, mediation adjustment, burden-of-proof risk functions
5. Actual results
- Results
Leading Level 3 risks for global DALYs in 2021: particulate matter 8.0% (6.7-9.4), high systolic blood pressure 7.8% (6.4-9.2), smoking 5.7% (4.7-6.8), low birthweight/short gestation 5.6%, high fasting plasma glucose 5.4%. Full text: dietary risks were the fifth-leading Level 2 risk factor (after child and maternal malnutrition, air pollution, high SBP, tobacco); no single Level 3 dietary risk was among the leading contributors; exposure (SEV) was high for diet low in milk (64.9) and diet low in fruits (40.9).
- Absolute risks
Attributable fractions as reported
- Authors' conclusion
Large progress for maternal/child and WaSH risks; rising burden from high BMI and high fasting glucose; need to address air pollution and high SBP.
6. Strengths
- Most comprehensive global analysis
- Burden-of-proof sensitivity methods
7. Weaknesses
- Model-based; depends on RR assumptions
- Diet assessed with error
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Modelling assumptions; GBD rankings change between rounds.
9. Assessment of the statistical interpretation
Ranking depends on grouping level; diet-attributable burden partly overlaps with SBP, BMI and FPG via mediation.
10. Relevance to the specific claim
Most recent detailed ranking: diet is a leading but not the first risk cluster; air pollution, blood pressure and tobacco rank higher.
11. Independent contrary findings
Diet contributes to high SBP, BMI and glucose, so its total role is larger than its separate ranking.
12. Transferability to Germany and Europe
High (includes Europe and Egypt).
13. Overall methodological judgement
Weakens 'food is the first cause'; supports 'food is a leading cause'.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Rankings in GBD 2023 by Level 2 cluster.
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