Associations between low muscle mass, blood-borne nutritional status and mental health in older patients

BACKGROUND: Although low muscle mass is an important predictor of increased physical morbidity in older patients, information on its impact on mental health and well-being is lacking. The first aim of this report is to look for associations if any between low muscle mass and mental health of older people in clinical practice. The second aim is to study underlying mechanisms including nutritional status. METHODS: In this prospective longitudinal study we randomly selected and studied 432 hospitalized older patients’ baseline demographic data, clinical characteristics and nutritional status on admission, at 6 weeks and at 6 months. Low muscle mass was diagnosed using anthropometric measures based on the European Working Group criteria. Mental health outcome measures including cognitive state, depression symptoms and quality of life were also measured. RESULTS: Out of 432 patients assessed 44 (10%) were diagnosed with low muscle mass. Patients diagnosed with low muscle mass at admission and over a 6-month follow up period had significantly poor cognitive function, quality of life and increased depression symptoms compared with those with normal muscle mass. After adjustment for poor prognostic indicators, age, disability, severity of acute illness and low muscle mass were associated with poor cognitive function and quality of life and higher depression symptoms in older patients over a 6 months period (p < 0.05). Although patients with low muscle mass had lower micronutrient concentrations compared to those patients with normal muscle mass, only serum albumin showed significant correlations with quality of life at admission and depression symptoms at 6 weeks. CONCLUSION: Low muscle mass is associated with poor blood-borne poor nutritional status and mental health in hospitalized older patients, however, this is partly explained by underlying co morbidity.