A team of researchers based in Japan found that the trunk angle of inclination - the angle between the true vertical and a straight line from the first thoracic vertebra to the first sacral vertebra- is linked to becoming dependent on help for activities of daily living (ADL) such as bathing, feeding, toilet, maintaining continence, dressing, and transferring in or out of a bed or chair.
The authors said that the spinal posture changes with age, but evidence shows that a good spinal posture is important to help the aged to maintain independent lives.
The team's data were sourced from 804 participants aged 65 years or older.
The subjects' spinal posture was measured with a spinal mouse, which is a computer-assisted noninvasive device for measuring spinal shape.
The device is guided along the midline of the spine, starting at the spinous process and finishing at the top of the anal crease.
Of the four spinal measurements taken by the mouse, only trunk angle of inclination was associated with future dependence in ADL - defined by the researchers as either admission to a nursing home or need of home assistance after a 4.5 year follow-up period.
In the study times, 15.7 percent subjects became dependent in ADL, 7.6 percent died, and 0.7 percent shifted. The group was 58 percent female.
The subjects in the highest quartiles, who had the greatest angle of spinal inclination, were 3.47 times more likely to become dependent in ADL than those in the lowest quartiles, even after adjusting covariates like age, sex, back pain, and stiffness.
The study has been published in Journals of Gerontology Series A: Biological Sciences and Medical Sciences.