Tag

Observational evidence

Filters
Domain
Factor
Tag (1)
Evidence strength
Study type
Publication year
Journal
Clear
32 results

Systematic review and meta-analysis of helmet use and helmet laws to reduce mortality in adult motorcycle riders

Strong for helmet protection; insufficient for riding itself
Motorcycle ridingConfounding riskMeta-analysisObservational evidence
Systematic review & meta-analysis
Helmet use mortality OR ~0.48 in recent meta-analysis; other cohorts ~0.65
Causal status: Strong for helmet intervention; riding-vs-nonriding mortality effect not cleanly estimated
Reliability / bias notes: Confounding by riding behaviour, speed, alcohol, road exposure; helmet evidence often crash-conditioned
Ratnasekera et al. · 2025 · PMID 40462278
Read the study →

Life expectancy at birth, by country

Limited — ecological/country-level statistic, not an individual mortality study
Planned country of residenceEcological / population-level dataObservational evidence
Ecological / population-level data
National life expectancy at birth varies by roughly a decade across upper-middle vs high-income countries (WHO 2023 estimates); healthcare access and quality are the primary drivers of that gap
Causal status: Ecological/population-level association only — no study directly measures individual mortality risk for people who relocate for retirement
Reliability / bias notes: Expatriates and financially-resourced retirees often access better care than local population averages suggest, so this factor is treated as a small, precautionary adjustment rather than a well-evidenced individual risk factor
WHO Global Health Observatory. · 2023
Read the study →

Low skeletal muscle mass index and all-cause mortality risk in adults: A systematic review and meta-analysis of prospective cohort studies

Strong
Muscle massMeta-analysisObservational evidenceSystematic review
Systematic review & meta-analysis
Low skeletal muscle mass index associated with 57% higher all-cause mortality risk (pooled RR 1.57, 95% CI 1.25–1.96) across 16 prospective studies, 81,358 participants
Causal status: Associational; prospective cohort evidence, biologically plausible via frailty/functional decline pathway
Reliability / bias notes: Heterogeneous SMI definitions across studies; risk magnitude varies substantially by BMI subgroup
Wang et al · PLoS One · 2023 · PMID 37285331
Read the study →

Prior cancer diagnosis and mortality profile in US adults

Strong
Cancer historyObservational evidenceSelf-report bias
Observational study
Prior cancer diagnosis associated with 29% higher multivariate-adjusted all-cause mortality (HR 1.29, 95% CI 1.22–1.35)
Causal status: Associational; prospective cohort with national death-registry linkage
Reliability / bias notes: Self-reported prior diagnosis; heterogeneous cancer types and time-since-diagnosis pooled together
Wang et al · Am J Med Sci · 2023 · PMID 36279936
Read the study →

Systematic review and meta-analysis of 90 cohort studies of social isolation, loneliness and mortality

Strong for association
Social connectionConfounding riskMeta-analysisObservational evidence
Systematic review & meta-analysis
90-cohort meta-analysis: isolation pooled effect ~1.32; loneliness ~1.14 for all-cause mortality
Causal status: Association; intervention evidence for mortality less direct
Reliability / bias notes: Definitions differ; loneliness ≠ isolation; socioeconomic/health confounding
Wang et al · Nat Hum Behav · 2023 · PMID 37337095
Read the study →

Association of low-density lipoprotein cholesterol levels with the risk of mortality and cardiovascular events: A meta-analysis of cohort studies with 1,232,694 participants

Moderate
LDL cholesterolLarge cohort (100k+)Meta-analysisObservational evidence
Meta-analysis
LDL-C ≥160 mg/dL associated with higher all-cause mortality (RR 1.34, 95% CI 1.00–1.80) and CVD death (RR 1.79, 95% CI 1.26–2.54) vs LDL-C 70–129 mg/dL, in a meta-analysis of 1,232,694 adults
Causal status: Causal support strong for CVD via Mendelian randomization and RCTs; all-cause mortality signal weaker/borderline
Reliability / bias notes: All-cause mortality CI crosses 1.0; relationship appears non-linear/U-shaped, complicated by reverse causation in low-LDL groups (illness-driven cholesterol decline)
Peng et al · Medicine · 2022 · PMID 36482567
Read the study →

Resistance Training and Mortality Risk: A Systematic Review and Meta-Analysis

Strong
Resistance TrainingMeta-analysisObservational evidenceSelf-report bias
Systematic review & meta-analysis
Any resistance training vs none associated with 15% lower all-cause mortality (RR 0.85, 95% CI 0.77–0.93); dose-response peaked at ~60 min/week (27% reduction)
Causal status: Observational; supported by RCT evidence on intermediate outcomes
Reliability / bias notes: Only 10 cohort studies pooled; self-reported exposure; nonlinear dose-response not fully resolved
Shailendra et al · Am J Prev Med · 2022 · PMID 35599175
Read the study →

UK Biobank cardiometabolic multimorbidity and all-cause mortality study

Strong prognostic evidence; generic single HR heterogeneous
Cardiovascular diseaseObservational evidence
Cohort study
Mortality varies substantially by MI/CHD, stroke, HF, PAD and multimorbidity; no single generic CVD HR recommended
Causal status: Prognostic/causal disease burden; exact estimate varies by disease
Reliability / bias notes: Disease heterogeneity, treatment, severity, time since event
2022 · PMID 35757322
Read the study →

Contribution of type 2 diabetes to all-cause mortality in White Europeans and South Asians: UK Biobank

Strong
History of DiabetesObservational evidence
Cohort study
UK Biobank: T2D HR 1.59 in White Europeans and 2.83 in South Asians vs no T2D, after broad lifestyle/sociodemographic adjustment
Causal status: Strong disease causality; cited HR observational
Reliability / bias notes: Duration, treatment, HbA1c and complications strongly modify risk
Hussain et al. · 2020 · PMID 31908795
Read the study →