The objective was to examine the influences of body anthropometrics, axial disc area, and lifting strength on disc degeneration and to compare these with the effects of lifetime physical demands and age.
Although recent studies have shown that heredity is a dominant factor in disc degeneration, the common notion that occupational physical loading is the major risk factor persists. However, substantial variations in disc degeneration, particularly at the lowest lumbar levels, remain unexplained by heredity or occupational physical demands.
Univariate methods and stepwise multiple regression modeling were used to estimate associations of body height, weight, fat content, axial disc area, isokinetic lifting performance, and lifetime routine physical activities at work and leisure with disc height narrowing and disc signal (in T2 images) based on lumbar MRIs. These data were available from a population sample of 600 men, 35 to 70 years of age.
Lower disc signal, representing disc desiccation, was associated with higher age, lower body mass and lifting strength, and larger axial disc area. Of the variance in disc signal, age explained 8.0% (P