Abbreviation	Meaning
AOR	Adjusted Odds Ratio
BPE	Basic Periodontal Examination
CAL	Clinical Attachment Level
CI	Confidence Interval
CPITN	Community Periodontal Index for Treatment Needs
df	Degrees of Freedom
EFA	Exploratory Factor Analysis
EPV	Events Per Variable
ICC	Intraclass Correlation Coefficient
KMO	Kaiser–Meyer–Olkin (measure of sampling adequacy)
K-NN	K-Nearest Neighbour (missing-data imputation)
S-OHI	Simplified Oral Hygiene Index
OR	Odds Ratio
PCA	Principal Component Analysis
RC	Reference Category
SE	Standard Error
SES	Socioeconomic Status
SPSS	Statistical Package for the Social Sciences
WHO	World Health Organisation