Physical activity, multimorbidity, and life expectancy: a UK Biobank longitudinal study.
Level 3 - non-randomized controlled study
Prospective longitudinal cohort study
PubMed 31186007 · doi:10.1186/s12916-019-1339-0
What was done
Researchers analyzed prospective cohort data from 491,939 UK Biobank participants (96,622 with multimorbidity, defined as 2 or more of 36 chronic conditions) over a median follow-up of 7.0 years (IQR 6.3-7.6). Leisure-time physical activity (LTPA) and total physical activity (TPA) were self-reported and categorized into low (<600 MET-min/week), moderate (600 to <3000 MET-min/week), and high (≥3000 MET-min/week). A subset had wrist-worn accelerometer data categorized by daily brisk walking time (low: 4 min/day, moderate: 10 min/day, high: 22 min/day). Survival models estimated adjusted hazard ratios (HRs) for all-cause mortality and predicted differences in life expectancy at age 45.
What was found
Among participants with multimorbidity, moderate and high LTPA were associated with adjusted mortality HRs of 0.75 (95% CI 0.70-0.80) and 0.65 (95% CI 0.56-0.75), respectively, compared to low LTPA. With objective accelerometer PA, corresponding HRs were 0.49 (95% CI 0.29-0.80) and 0.29 (95% CI 0.13-0.61). At age 45, moderate and high LTPA were associated with 3.12 (95% CI 2.53-3.71) and 3.55 (95% CI 2.34-4.77) additional life years in participants with multimorbidity, compared to 1.95 (95% CI 1.59-2.31) and 1.85 (95% CI 1.19-2.50) in those without multimorbidity. Objective PA was associated with 3.60 (95% CI -0.60 to 7.79) and 5.32 (95% CI -0.47 to 11.11) life years gained for moderate and high levels in individuals with multimorbidity.
Why it matters
These findings show that regular physical activity is associated with substantial survival and life-expectancy gains in individuals managing multiple chronic conditions, supporting targeted physical activity promotion in multimorbid populations.
Limits
The observational design cannot establish causality or eliminate residual confounding and reverse causation (severe illness reducing activity levels). Primary activity assessments relied on self-report questionnaires, and the accelerometer sub-study had wide confidence intervals crossing zero for life expectancy estimates in the multimorbidity group. The UK Biobank is also subject to healthy volunteer selection bias.
Cited by
- supports Population data show that meeting guidelines of 150 minutes of moderate-to-vigorous physical activity and two days of muscle-strengthening exercises per week is associated with an average of approximately four extra years of life.