DEVELOPMENTAL TRAJECTORIES OF BODY MASS INDEX THROUGHOUT ADULTHOOD: EVIDENCE FROM THE NATIONAL POPULATION HEALTH SURVEY
Bibliographic record
Abstract
Background There is little research that uses group-based trajectory modeling to capture adult body mass index (BMI) trajectories for the Canadian population. Objectives The aims of this study are 1) to identify and determine the number and features of mutually exclusive body mass trajectory groups throughout adulthood; 2) to examine the association between covariates and each BMI trajectory group; 3) to assess whether health consequences vary within different trajectory groups. Methods This study will apply group-based trajectory modeling to map adult body mass trajectories with an age axis spanning 18 to 64 years, based on the longitudinal data from Statistics Canada's National Population Health Survey 1994 (n=17276). Group-based trajectory modeling is a powerful semi-parametric statistical approach that captures information about inter-individual differences within a large population. Risk factors (time-instable covariates) including gender and age cohort, and time-varying covariates such as diet, daily activities, education level, income, lifestyle (sleep, smoking, and alcohol), stress, and mental health are identified and evaluated for group membership. To confirm that distinct trajectory groups are linked to different health consequences, Rao-Scott chi-square test and analysis of variance will be applied to handle categorical and continuous health outcome variables. The health outcomes include hypertension, diabetes, heart disease, stroke, asthma, arthritis, and back problems. Lastly, this study will compare group-based trajectory modeling to a standard statistical methodology (multilevel modeling) when modeling longitudinal data, and discuss possible benefits.
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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 | 0.006 | 0.026 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.009 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".