Cardiorespiratory fitness, muscular strength and risk of type 2 diabetes: a systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational cohort studies
PubMed 31011778 · doi:10.1007/s00125-019-4867-4
What was done
Authors conducted a systematic review and random-effects meta-analysis of cohort studies identified via PubMed and EMBASE through December 12, 2018. They assessed the dose-response relationship of cardiorespiratory fitness (22 studies) and muscular strength (13 studies) with incident type 2 diabetes in adults, focusing on primary estimates adjusted for adiposity or body size. Study quality was evaluated using the Newcastle-Ottawa Scale.
What was found
For cardiorespiratory fitness (40,286 incident cases across 1,601,490 participants; 10 adiposity-controlled estimates), each 1 metabolic equivalent (MET) increment was associated with an 8% lower relative risk of type 2 diabetes (95% CI 6% to 10%) in a linear relationship. For muscular strength (39,233 cases across 1,713,468 participants; 10 adiposity-controlled estimates), each 1 standard deviation increase was associated with a 13% lower relative risk (95% CI 6% to 19%). Population modeling estimated that feasible population-level cardiorespiratory fitness improvements could prevent 4% to 21% of annual new type 2 diabetes cases among adults aged 45–64 years.
Why it matters
This review quantitatively establishes that both cardiorespiratory endurance and muscular strength independently lower type 2 diabetes risk in a linear fashion, showing that even modest population-level fitness gains could meaningfully reduce diabetes incidence.
Limits
The findings derive entirely from observational cohort studies, which are subject to residual confounding, unmeasured lifestyle differences, and possible reverse causation. Assessment methods for fitness and muscular strength varied across original studies, and the estimated population impact relies on hypothetical modeling rather than direct trial interventions.
Cited by
- supports Higher cardiorespiratory fitness is associated with a reduction in all-cause mortality, cardiovascular disease, and type 2 diabetes.