The prevalence of low back pain in the elderly. A systematic review of the literature.

STUDY DESIGN: The prevalence of low back pain in the older population (> = or 65 years) was reviewed in an analysis of the literature from 1966 to the present. OBJECTIVE: To determine the prevalence of low back pain in the geriatric population. SUMMARY OF BACKGROUND DATA: Back pain is one of the most frequently reported conditions affecting the adult population. However, the prevalence of low back pain in the older age population is not accurately known. METHODS: A methodologic search of five computerized bibliographic databases was performed to identify citations on the prevalence of low back pain in the elderly. Data were summarized, and prevalence studies were critically appraised in detail for their quality. RESULTS: There is wide variability in the reported prevalence of back pain. Many factors have been proposed to explain these findings including sample source, study design, definitions of back pain, and use of patient-reported data. Comorbidity among older patients also contributes to the variability in the reporting of prevalence of back pain. CONCLUSION: There is an under-representation of the older population in the back pain literature. The data in the current study suggest that the prevalence of low back pain in this population is not known with certainty and is not comparable with that in the younger population. The authors stress the need for future studies to improve the reporting of age information to make prevalence studies more informative and applicable.

On becoming a parasite: evaluating the role of wall oxidases in parasitic plant development.

BACKGROUND: The temporal and spatial control of the transition from vegetative to parasitic growth is critical to any parasite, but is essential to the sessile parasitic plants. It has been proposed that this transition in Striga spp. is controlled simply by an exuded oxidase that converts host cell-surface phenols into benzoquinones which act as developmental signals that mediate the transition. An understanding of this mechanism may identify the critical molecular events that made possible the evolution of parasitism in plants. RESULTS: PoxA and PoxB are identified as the only apoplastic phenol oxidases in Striga asiatica seedlings, and the genes encoding them have been cloned and sequenced. These peroxidase enzymes are capable of oxidizing the 60 known inducing phenols into a small set of benzoquinones, and it is these quinones that induce parasitic development. Analysis of the reaction requirements and comparisons to host enzymes, however, lead us to argue that PoxA and PoxB are not necessary for host recognition. CONCLUSIONS: A new model is proposed where constitutive production of an activated oxygen species (in the case of Striga, H2O2) mediates host recognition. This strategy would allow a parasite to exploit abundant host enzymes to produce the diffusible recognition signals by converting a standard host defense into a parasitic offense.