Normal body appearance can mask gross malnutrition, particularly mineral and vitamin deficiency, problems of measurement in the elderly. Obesity is associated with joint degeneration and systemic disease but with reduced incidence of fractures. Undernutrition is associated with skin breakdown, poor wound healing and fractures. Body composition changes due to disease include dysphagia, myxoedema, anaemia, chronic cardiac and renal disease. Skeletal changes include osteoporosis and Paget's disease.
Body composition can change due to treatment, control of dietary energy intake and tube-feeding.