There are multiple definitions:

1. acid-fast bacillus(English)

   • acid fastness is a physical property that gives a bacterium the ability to resist decolorization by acids during staining procedures
   • AFB, API, ATT, DOTS, HCC, HIV, IUATLD, MDR, NNRTI, PAS, SCC, TB, WHO
   • Bacteriology
   • https://www.ncb…ooks/NBK537121/
   • http://pubmed.n…h.gov/16800350/

2. age at first birth(English)

   • as risk factor for breast cancer
   • BMI, HRT, MLO, PD
   • Gynecology, Risk factor, Mammary gland
   • https://doi.org…3058-017-0894-6
   • http://karmastudy.org/

3. atrial fibrillation burden(English)

   • the percentage of time a person spends in atrial fibrillation (AFib) during a defined monitoring period (e.g., spending 3 hours in AFib during a 24-hour window yields a 12.5% burden). It measures the quantitative severity of the condition rather than just its presence
   • AF, AT, ECG, EHRA, LA, PAF, PWD
   • Cardiology, Electrophysiology, Scoring systems/scales
   • https://doi.org…europace/euw376
   • https://doi.org…rheartj/ehae373