Longitudinal changes in body composition associated with healthy ageing: men, aged 20–96 years
Bibliographic record
Abstract
Obesity and sarcopenia are health problems associated with ageing. The present study modelled the longitudinal changes in body composition of healthy men, aged from 20 to 96 years, and evaluated the fidelity of BMI to identify age-dependent changes in fat mass and fat-free mass. The data from 7265 men with multiple body composition determinations (total observations 38,328) were used to model the age-related changes in body mass, fat mass, fat-free mass, BMI and percentage of body fat. Changes in fat mass and fat-free mass were used to evaluate the fidelity of BMI and to detect body composition changes with ageing. Linear mixed regression models showed that all trajectories of body composition with healthy ageing were quadratic. Fat mass, BMI and percentage of body fat increased from age 20 years and levelled off at approximately 80 years. Fat-free mass increased slightly from age 20 to 47 years and then declined at a non-linear rate with ageing. Levels of aerobic exercise had a positive influence on fat mass and a slight negative effect on fat-free mass. BMI and percentage of body fat were sensitive in detecting the increase in fat mass that occurred with healthy ageing, but failed to identify the loss of fat-free mass that started at age 47 years.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".