Genetic and environmental contributions to back pain in old age: a study of 2,108 danish twins aged 70 and older.

Study Design, Self-reported 1-month prevelence of back pain in older twins assessed at intake in a populetion-based longitudine: survey. Objectives. To determine the relative contribution of genetic and environmental factors to back pain in old age. of Background Data. To date, genetic contri-butions to back pain in old age have not been assessed, to the authors best knowledge. Methods. Interview data given at entry into a nationwide cohort-sequential population-based survey of Danish twins aged 70 years and older in 1995, 1997, 1999, and 2001 form the basis of this analysis. Analysis of twin similarity was estimated using probandwise concordance rates, odds ratios, and tetrachoric corretations for back pain. Heritability (proportion of the population variance attributable to genetic variation) was estimated by bivariate probit etimation and adjusted for known significant environment factors Odds ratios far known environmental effects were estimated after controlling for age, sex, and genetic effects. Results. Modest and nonsignificant differences be tween monozvgotic and dizygotic twin pairs were found for probaridwise concordance rates, odds ratios, and tetrachoric corretations for both men and women, in the bivariate probit estimation, a current or previous diagnosis of osteoporosis, degenerative joint disease, or lumbar disc prolapse was found to significantly affect the risk of back pain. Additive genetic effects explained approximately one fourth of the liability to report back pain in men and none of the occurrence in women. Individual environmental effects were found to explain roughly 75% of the occurrence or back pain in men and 100% women. Conclusions. Additive genetic effects are modest contributors to back pain in older men but not in women. A current or previous medical diagnosis of osteoporosis, degenerative joint disease, or lumbar disc prolapse isstrongly associated with back pain, also when genetic factors are controlled for, Becense of intrerent methodologic issues, this satimate of the genetic influence on back pain in old age is probably conservative.