Research into the connection between vitamin D-insuffiency, sarcopenia and the frailty-syndrome based on a sample of the Berlin Aging Study II (BASE-II)
Author(s) Spira, Dominik
Place of birth: Grünstadt
1. Referee Prof. Dr. med. E. Steinhagen-Thiessen
Further Referee(s) Priv.-Doz. Dr. med. R. Lenzen-Großimlinghaus
Prof. Dr. med. M. Pirlich
Summary In this thesis the connection between vitamin D-insufficiency, sarcopenia and frailty-syndrome has been examined. Vitamin D-insufficiency is common in germany regardless of age but has an even higher prevalence in the elderly. Sarcopenia describes the age-associated and functional relevant loss of muscle mass -following some definitions also muscle strength- whereas the frailty-syndrome is a multidimensional syndrome leading to negative outcomes such as heightened mortality. The hypothesis was that vitamin D-insufficiency favors the incidence of sarcopenia as well as frailty and that sarcopenia is a key factor in the development of the frailty-syndrome. Vice versa it could be imagined that frailty with limited mobility could lead to vitamin d-insuffiency due to reduced time spent outside and limited sun exposure.
360 community-dwelling participants of BASE-II aged 61 to 84 took part in the examinations. Serum level of vitamin d was determined via direct chemoluminescence immunoassay and muscle mass for diagnosing sarcopenia was measured using a DEXA-scan. Frailty was assessed with the frailty-index after Fried et al. and the five frailty criteria weight loss, exhaustion, physical activity, gait speed and weakness were determined via anamnesis, questionnaires, geriatric assessment and grip strength measurement.
The expected high prevalence of vitamin d-insufficiency was confirmed in the BASE-II-sample (69,7%). The prevalence of sarcopenia (19,5% women, 15,5% men) lies in the middle compared to other studies whereas the prevalence of frailty (1,1%) was considerably lower compared to other studies presumably due to a lower mean age.
The further analyses showed no correlation between vitamin d-level, sarcopenia and frailty. The variance of values of the skeletal muscle mass-index used for measuring sarcopenia could only very little be explained by age and physical activity as possible factors of influence. Furthermore the influence of skeletal muscle mass and age on frailty showed to be less than ten percent. These findings diminish the hope that a single factor like vitamin d will serve as a predictor for sarcopenia and frailty-syndrome which may offer options for prevention and treatment. Beyond that sarcopenia may not be the key factor in the pathogenesis of frailty as commonly considered. It can be assumed that sarcopenia and notably frailty are highly multifactorial conditioned and therefore the identification and emphasis of separate pathophysiological relevant factors may be a difficult task.
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