Physiological Aging

Aging is a highly complex phenomenon that can be examined at the genetic, cellular, organ-system, and psychosocial levels (Aldwin & Gilmer 2004). Although there are some conflicting evidence on which systems decline, for the most part, persons aging with SCI exhibit decreases in health status and physical functioning over time, which could serve as markers of premature aging.

In this section, 1 systematic review on physiological aging after SCI is reviewed.

 

Table 2: Systematic Review on Physiological Aging

Author Year; Country

Date included in the review

Total Sample Size
Level of Evidence

Type of study
Score

Methods

Databases

Outcome
 

 

 

Reviewed published articles from 1980 to December 2009

 

N=74

(16 with longitudinal design)

 

Level of Evidence:

Downs & Black

Modified Sackett scale

 

Type of study:

Longitudinal

 

AMSTAR: 5

Methods: Literature search for English articles with non-intervention studies exploring aging of the body systems after spinal cord injury (compared to at least age-matched able bodied controls).

No intervention.

Outcome measures include effects of aging with SCI on cardiovascular, respiratory, endocrine, immune, genitourinary, gastrointestinal, nervous, skin subcutaneous tissues, and musculoskeletal systems.

 

Databases: MEDLINE/PubMed, CINAHL, EMBASE and PsycINFO.

1.     Premature aging in SCI was supported by level 2 evidence for the musculoskeletal system, level 5 evidence for the cardiovascular and endocrine systems and limited level 5evidence for the immune system.

2.     Premature aging in SCI was supported by levels 4 and 5 evidence for the respiratory system.

3.     Evidence on the genitourinary system, gastrointestinal system, and for skin and subcutaneous tissues provide levels 4 and 5 evidence that premature aging may not be occurring in these systems.

 

 

Discussion

In this systematic review (Hitzig et al. 2011), the hypothesis that SCI represents a model for premature aging is supported by level 5 evidence for the cardiovascular and endocrine systems, level 2, 4 and 5 evidence for the musculoskeletal system, and limited level 5 evidence for the immune system. Only a few level 4 and 5 studies for the respiratory system were found. Evidence on the genitourinary system, gastrointestinal system, and for skin and subcutaneous tissues provide level 4 and 5 evidence that premature aging may not be occurring in these systems.

  • SCI may represent a partial model for premature aging.

    There is stronger evidence that the endocrine and musculoskeletal systems are prematurely aging.

    There is limited evidence that the respiratory, skin and subcutaneous tissues, genitourinary, and gastrointestinal systems are prematurely aging.

    There is weak and limited evidence that the immune and nervous system are prematurely aging.

The following sections review each body system individually, including the cardiovascular and endocrine systems (see Table 3), immune system (see Table 4), musculoskeletal system (see Table 5), respiratory system (see Table 6), nervous system (see Table 7), skin and subcutaneous tissues (see Table 8), and the genitourinary and gastrointestinal systems (see Table 9).