Physical activity is associated with lower mortality in adults with obesity: a systematic review with meta-analysis

Background Obesity is a complex chronic disease associated with several adverse health outcomes that increase mortality risk.

Physical activity (PA) is recommended for the prevention and treatment of obesity and is related to a decreased risk of cardiovascular disease, cancer and all-cause mortality.

This systematic review and meta-analysis estimates the effect of PA levels on mortality (cardiovascular, cancer and all-cause mortality) in adults with obesity.

Methods A systematic search was conducted in MEDLINE, Embase, Web of Science and SPORTDiscus from inception to June 2024.

Prospective cohort studies that explored the association between PA and mortality in adults with obesity (according to their body mass index, ≥ 30 kg/m^2) aged ≥ 18 years were included.

Our main outcomes were all-cause mortality, and cardiovascular, and cancer mortality reported in primary studies by hazard ratios or relative risk, which were pooled for the meta-analysis when at least two studies reported the effect estimate for the same outcome.

The PRISMA recommendations and the MOOSE guidelines were followed.

The reported mortality risk estimates comparing insufficiently active versus active (moderate to very active) adults with obesity were pooled using the DerSimonian and Laird random-effects model.

Results A total of 9 prospective cohort studies involving 199,425 adults with obesity (age range: 35–85 years) were included, of which 59,873 were insufficiently active and 84,328 were active.

Active individuals had a 21% lower risk of all-cause mortality (HR: 0.79, 95%CI: 0.74 to 0.84; I^2 = 38.2%), and a 24% lower risk of cardiovascular mortality (HR: 0.76, 95%CI: 0.66 to 0.87; I^2 = 0.0%) than insufficiently active individuals.

The HR for cancer mortality was 0.91 (95%CI: 0.80 to 1.02; I2 = 0.0%), and although this was mostly consistent with a benefit, it was based on only two studies.

Conclusion Our data support that moderate to high levels of PA are associated with a 21% lower risk of all-cause and 24% cardiovascular disease mortality in adults with obesity.

Although data from the only two published studies seem to indicate a protective effect of PA on cancer risk, the estimates are not statistically significant.

Systematic review registration PROSPERO CRD42022309346.