The Upper Limit of Normal Rate of Lung Function Decline in Healthy Adults in the Framingham Heart Study
Bibliographic record
Abstract
Background Lung function declines over the course of adulthood; however, a consensus on the normal range of decline in an individual's lung function is lacking. Research Question What is the normal range and the upper limit of normal (ULN) decline in lung function in adults without prior tobacco use, occupational dust exposure, or a known diagnosis or symptoms of cardiopulmonary disease? Study Design and Methods A retrospective analysis of healthy individuals who have never smoked (N = 1,305) from the Framingham Heart Study with repeated lung function meeting standards for acceptability and reproducibility was conducted. Longitudinal change was derived using a linear mixed effects model and estimated to a 6-year interval. The ULN decline was defined as the 95th percentile. Results The mean follow-up between spirometry examinations was 5.5 years, whereas the mean follow-up between diffusing capacity for carbon monoxide studies was 5.9 years. Decline in FEV 1 , FVC, and D accelerated with age, whereas decline in FEV 1 /FVC decelerated with age. Decline varied with sex, age, and height. Over a 6-year period, the ULN decline in FEV 1 ranged from 383 to 667 mL, and the ULN decline in Dlco ranged from 3.6 to 9.5 mL/min/mm Hg. Overall, male individuals had faster absolute rates of decline than female individuals, whereas relative (%) rates of decline were similar between sexes. Interpretation Lung function decline is nonlinear and accelerates with age. In this cohort, the ULN decline over 6 years often exceeded current guidelines for interpreting significant longitudinal change in lung function.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.009 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".