AGING WITH SCI: Aging, SCI, and Research
Diana Weinel, MS, RN, ONC
Edited by Susan S. Thomason, MN, RN, APRN-BC
Introduction
The life expectancy of individuals with spinal cord injury (SCI) has increased greatly since the 1960s. Today, that life expectancy is close to 80% of that of individuals without SCI. It is not uncommon to see people with SCI in their 60s and 70s. Even a 20-yearold individual, 1-year post -injury and ventilator-dependent, can expect to live into his or her 40s. It is estimated that 40% of the individuals with SCI are over the age of 45 years (Cristian, 2004). A quarter of these individuals have lived with SCI for over 20 years. Aging with SCI is a reality.
Aging
Aging is a natural process for all individuals. It begins shortly after development ends, which is usually about age 20. A person develops physically until they reach their peak level of functioning. There is a “reserve,” or “excess,” capacity in which the body has more capacity than it actually needs to meet its basic needs. As aging occurs, there is a gradual decline in function at various levels: cellular, organ, performance, and psychosocial. With an average rate of decline of 1% per year, it would take the average person 50 to 60 years to reach a vulnerable level of 40% of his or her optimum capacity. Of course, such things as genetics, environment, general health status, and lifestyle influence the rate of decline. The presence of SCI also affects the rate of decline, increasing it to an estimated 1.5% per year (Kemp, Adkins, & Thompson, 2004). Therefore, persons with SCI experience the characteristics related to aging at an earlier age than the average population.
Aging and Spinal Cord Injury
Researchers have not determined the exact cause of this increase in the rate of aging for individuals with SCI. One possibility attributes aging to the “wear and tear” effect. For example, constant long-term use of the upper extremities for transfers and mobility may accelerate musculoskeletal aging. Another plausible explanation is that repetitive, minor damage to organ systems may increase organ aging. A third theory is that SCI alters some of the body’s endocrine functioning, causing acceleration of the overall aging process (Kemp et al., 2004). The effects of SCI on aging are further complicated by variables such as age at injury onset, duration of injury, level of injury, and extent of neurological deficit. A person with complete tetraplegia will most likely age differently than a person with incomplete tetraplegia. Likewise, a person injured before age 20 would age differently than a person injured later in life.
Research Investigations
The challenge of research on aging is to describe the effects of age and to identify those variables that most influence aging. Early research study designs for SCI and aging were most commonly descriptive or cross-sectional studies. Investigators examined such areas as mortality, morbidity, and patterns of secondary conditions for individuals with SCI. Frequently, study participants were grouped as having either paraplegia or tetraplegia, without accounting for complete and incomplete SCI. As the life expectancy of individuals with SCI increased, researchers developed longitudinal studies.
Longitudinal aging research studies, such as the Framingham study, focus on studying a large group of people over a long period of time (Polit & Beck, 2003). This type of research allows the researchers to study the changes people encounter as they age. Often these studies span 20 years or more.
Cross-sectional studies compare independent groups of different ages at the same time. For example, a sample of 50-year-old individuals may be compared to a sample of 70year-old individuals. This type of research design is complicated by environmental factors and scientific advances experienced during the lifetime of the participants. Some research studies add a longitudinal component to the cross-sectional design. The independent groups of different ages are compared several times at specified intervals, such as every 10 years. Information from research studies on the physical aspects of aging, and relationships between disease and aging, is increasing our understanding of aging in general. When SCI is added to the research equation, the additional variables related to SCI create a more complex challenge for researchers. Despite this, research designed to specifically study aging and SCI is gaining momentum as the population of older individuals with SCI increases.
To reach a significant number of individuals with SCI requires access to a large database. Long-established SCI centers, or centers that serve a large population of individuals with SCI, have large databases amenable to conducting SCI aging research. Rancho Los Amigos National Rehabilitation Center, Craig Hospital, Shepherd Center, and the Veterans Affairs hospitals are examples of such centers. Large samples of individuals with SCI are needed to examine the additional SCI variables of age at injury onset, duration of injury, level of injury, and extent of neurological deficit. The Model SCI System project, sponsored by the National Institute on Disability and Rehabilitation Research, maintains a national database of individuals with SCI. Organizations such as United Spinal Association, Paralyzed Veterans of America, and Canadian Paraplegia Association have access to large numbers of individuals with SCI. In addition, multi-center studies can provide large samples to survey. Researchers are actively using a myriad of resources to study aging and SCI.
Researchers are disseminating the results of several longitudinal studies. These studies use data from some of the sources previously mentioned. The influence of aging with SCI on physical changes, functional abilities, health status, well-being, life satisfaction, and quality-of- life are some of the areas in which researchers are providing exciting and vital information. Implications for SCI clinical practice will depend on the analysis and interpretation of their research. Future columns will address these areas in more detail.
Summary
What was once uncharted territory for the individual with SCI is being vigorously explored. Health promotion, proactive interventions, and services to limit the effects of age-related changes will be essential to successful aging with SCI. Research studies on aging with SCI can make a significant impact on evidence-based SCI practice. Health care providers will need that knowledge to successfully guide the individual with SCI into the arena of aging.
References
Cristian, A. (2004). Living with spinal cord injury. New York: Demos Medical Publishing.
Kemp, B., Adkins, R., & Thompson, L. (2004). Aging with a spinal cord injury: What recent research shows. Topics in Spinal Cord Injury Rehabilitation, 10(2), 175-197.
Polit, D., & Beck, C. (2003). Nursing research: Principles & methods, (7th ed.). Philadelphia: Lippincott.
Diana Weinel, MS, RN, ON, is SCI patient education coordinator at the James A. Haley VA Hospital in Tampa, Florida
Susan S. Thomason, MN, RN, APRN-BC, is coordinator, OPD Center for SCI Services at the James Haley VA Medical Center in Tampa Florida.
The editor of Aging with SCI welcomes your input. Please contact Susan S. Thomason at susan.thomason@med.va.gov with comments, questions and suggestions.