Disc degeneration of the lumbar spine in relation to overweight.
OBJECTIVE
To study the association between overweight and lumbar disc degeneration.


METHODS
Population-based 4-y follow-up magnetic resonance imaging (MRI) study.


METHODS
The subjects were 129 working middle-aged men selected to the baseline magnetic resonance imaging (MRI) study from a cohort of 1832 men representing three occupations: machine drivers, construction carpenters, and office workers. The selection was based on the paticipants' age (40-45 y) and place of residence. MR images of the lumbar spines were obtained at baseline and at 4-y follow-up.


METHODS
Signal intensity of the nucleus pulposus of the discs L2/L3-L4/L5 was visually assessed by two readers using the adjacent cerebrospinal fluid as an intensity reference. The weight (at age 25 and 40-45 y) and height of the subjects, history of car driving, smoking, and back injuries were assessed by questionnaire.


RESULTS
Multiple regression analyses allowing for occupation, history of car driving, smoking, and back injuries showed that persistent overweight (body mass index (BMI) > or =25 kg/m(2) at both ages) associated strongly with an increased risk of the number of lumbar discs with decreased signal intensity of nucleus pulposus at follow-up, adjusted odds ratio (OR) being 4.3 (95% confidence intervals (95% CIs) 1.3-14.3). Overweight at young age (risk ratio (RR) 3.8; 95% CI 1.4-10.4) was a stronger predictor of an increase in the number of degenerated discs during follow-up than overweight in middle age (RR 1.3; 95% CI 0.7-2.7).


CONCLUSIONS
The study provides evidence that the BMI above 25 kg/m(2) increases the risk of lumbar disc degeneration. Overweight at young age seems to be particularly detrimental.
Liuke
M
M
Department of Epidemiology and Biostatistics, Finnish Institute of Occupational Health, Topeliuksenkatu 41a A, Helsinki, Finland.
Solovieva
S
S
Lamminen
A
A
Luoma
K
K
Leino-Arjas
P
P
Luukkonen
R
R
Riihimäki
H
H
D000328:Adult; D000367:Age Factors; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000473:pathology*; D017116:Low Back Pain / Q000473:pathology; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000150:complications / Q000473:pathology*; D009784:Occupational Diseases / Q000150:complications / Q000473:pathology*; D009790:Occupations; D013122:Spinal Diseases / Q000150:complications / Q000473:pathology*