25(OH)D	25-hydroxyvitamin D
BMI	body mass index
CHD	coronary heart disease
CI	confidence interval
EMIS	Egton Medical Information Systems
GP	general practitioner
HR	hazard ratio
ICD-10	International Statistical Classification of Diseases
IQR	interquartile range
LBP	low back pain
N.A.	not applicable
NHS	National Health Service
OTC	over-the-counter
RCS	restricted cubic splines
Ref	reference
RIQAS	Randox International Quality Assessment Scheme
SAS	Statistical Analysis System
UK	United Kingdom
VIF	variation inflation factor