To evaluate the relationship between depression, somatic symptoms, cognitive impairment and disability in an elderly population.

216 subjects (65-84 years) were clinically examined for somatic symptoms, and underwent a mental health examination. Depression was defined by Geriatric Depression Scale scores >11/30; cognitive impairment by Mini-Mental State Examination scores < 24/30; functional status by Instrumental Activities of Daily Living Scale. Associations between depression, cognitive impairment or somatic symptoms and disability were evaluated by logistic regression analyses, estimating Odds Ratios (ORs) and 95% confidence intervals (95%CI) adjusted by sex, age, education.

Disability was common among depressed individuals (OR(95%CI)=3.60(1.63-7.96)) and among cognitively impaired subjects (OR(95%CI)=7.35(3.07-17.60)). An increasing number of somatic complaints increased the probability of functional impairment: compared with presence of 1-2 somatic symptoms, complaint of 3-6 and 7-12 symptoms were related to disability with OR(95%CI)=3.30(1.11-9.80) and OR (95%CI)=4.20 (1.17-15.09) respectively. Distinguishing pain, gastrointestinal, pseudo-neurological and general symptoms, only general somatic symptoms (palpitations, fatigue, sleep disturbances) were associated with disability (OR(95%CI)=1.81(1.25-2.62), independently by medical conditions (OR(95%CI)=1.57(0.98-2.52)). An additive effect toward disability was observed when general somatic complaints and cognitive impairment were co-existing (OR(95%CI)=23.68(5.50-101.86)). Including simultaneously cognitive impairment, somatic complaints and depression in the model, only cognitive impairment was still significantly related (OR(95%CI)=5.87(2.66-12.96)).

Among many possible causes of disability in the elderly, an important role could be attributed to cognitive deficits.