Disk degeneration genetic? CMAJ 1997;156(4):477 © 1997 Canadian Medical Association Two University of Alberta researchers have uncovered evidence suggesting that degenerative disk disorders are more strongly linked to genetic factors than to environment. Dr. Marie Crites Battié, chair of the Department of Physical Therapy, and Dr. Tapio Videman, a senior heritage scholar in the Faculty of Medicine, drew attention to their study results (Spine 1995;20:2601) last fall while applying for funds for follow-up research. Their research so far concludes that environment and other factors associated with disk degeneration, such as smoking, alcohol consumption and physical stresses related to work and leisure activities, are not as significant in lower-back problems as once thought. Between them, the researchers have obtained 7 prestigious Volvo Awards for research on low-back pain. Drawing on data compiled for the Finnish Twin Cohort Study, the investigators reviewed histories of identical twins with lower-back problems whose occupations and lifestyles were markedly different. Even if one twin worked as a labourer and the other was employed in an office setting, both suffered almost identical disk problems, with the same level and type of degeneration. "The similarities were uncanny," Battié says. Only male identical twins were studied because identical female twins with differing histories could not be found. Variation in the condition between twins is due to familial aggregation, a combination of genetic factors and shared activities during childhood. But so far the researchers do not know what proportion of degeneration is due to genetic factors and what proportion to environment. Battié suspects that disk degeneration is a genetic trait triggered by an environmental or physical stimulus. "The study we are hoping to do over the next few years will look at nonidentical twins so we will be able to estimate better how much of the degeneration is influenced by genes and if there is interaction between the genetic and the environmental," she says. -- R. Cairney | CMAJ February 15, 1997 (vol 156, no 4) / JAMC le 15 février 1997 (vol 156, no 4) |