Study: Muscle Weakness and Low Vitamin D Status Increase Risk of ADL Disability

January 28, 2019

The inability to perform activities of daily living (ADLs) such as bathing, toileting, and dressing negatively impacts quality of life and often leads to admission to a nursing home or other post-acute/long-term care (PALTC) setting. A study in the January issue of JAMDA identified some important risk factors for ADL disability in middle-aged and older adults.

In “Combined Effect of Dynapenia (Muscle Weakness) and Low Vitamin D Status on Incident Disability,” the authors studied 4,630 community-dwelling adults aged 50 years and older (average age 66 years) without ADL disability at baseline. After two years, the study showed that older adults with dynapenia only and those with lower serum levels of 25-hydroxyvitamin D had higher incidence of ADL disability risk compared with non-dynapenic adults and those with normal 25-hydroxyvitamin D levels.

While a major strength of this study is its large sample size, the authors did note that ADL disability was based on a self-reported measure. Nonetheless, the instruments in the study are common in international disability investigations and standardized protocols were used to ensure data quality.

The authors concluded, “Our findings, along with other recent evidence showing the importance of vitamin D and muscle strength on multiple health outcomes, draw attention to the combined effect of these conditions on incident disability among older adults.”

This study was conducted by researchers at the State University of Campinas in Brazil, the Department of Epidemiology and Public Health at the University College London in the United Kingdom, and the Departments of Gerontology and Physical Therapy at the Federal University of Sao Carlos in Brazil.

Click here for more information on the findings above and more details about the study. To contact the researchers or JAMDA editor for an interview, please email



JAMDA is the official journal of AMDA – The Society for Post-Acute and Long-Term Care Medicine. JAMDA publishes peer-reviewed articles including original studies, reviews, clinical experience articles, case reports, and more, on all topics more important to post-acute and long-term care medicine. Visit for more information.

About the Society for Post-Acute and Long-Term Care Medicine
AMDA – The Society for Post-Acute and Long-Term Care Medicine is the only medical specialty society representing the community of over 50,000 medical directors, physicians, nurse practitioners, physician assistants, and other practitioners working in the various post-acute and long-term care (PA/LTC) settings. Dedicated to defining and improving quality, we advance our mission through timely professional development, evidence-based clinical guidance, and tireless advocacy on behalf of members, patients, families, and staff. Visit for more information.