Mortality associated with body fat, fat-free mass and body mass index among 60-year-old swedish men-a 22-year follow-up. The study of men born in 1913.
Level 3 - non-randomized controlled study
Prospective cohort follow-up study
PubMed 10702748 · doi:10.1038/sj.ijo.0801082
What was done
This prospective cohort study evaluated 787 men aged 60 years from the 1913 birth cohort in Gothenburg, Sweden. Participants were followed over 22 years (1973 to 1995) to assess total mortality in relation to baseline body mass index (BMI), body fat percentage, and fat-free mass.
What was found
Mortality risk increased linearly with body fat percentage, rising from a relative risk (RR) of 1.00 in the lowest fifth to 1.4 (95% CI 1.11–1.99) in the highest fifth. For BMI, mortality was lowest in the middle fifth (RR 1.00), while the lowest fifth had an RR of 1.3 (95% CI 0.94–1.68) and the highest fifth had an RR of 1.5 (95% CI 1.09–1.96). Joint analysis showed that total mortality increased linearly with higher fat mass and lower fat-free mass.
Why it matters
These findings suggest that the classic U-shaped association between BMI and mortality in older adults is driven by two distinct linear risks: the adverse impact of excess adiposity and the protective effect of lean body mass.
Limits
The study included only 60-year-old men from a single birth cohort in Sweden, limiting generalizability to women, other age groups, and broader populations. The abstract does not specify the body composition measurement method, cause-specific deaths, or adjustments for potential confounders such as smoking or preexisting disease.
Cited by
- context Mortality data indicates that being extremely lean is associated with increased mortality risk, whereas maintaining approximately 15% to 20% body fat in males has a protective effect compared to 30% to 40% body fat.