Apathy is distinct from depression or fatigue and is associated with poor physical health in an older community cohort.

Objectives: To estimate point prevalence of apathy in older adults, examine its overlap with depression and fatigue, and explore its associations with multimorbidity and objective markers of health.

Design: Sydney Memory and Ageing Study, an Australian population-based cohort.

Setting: Community dwellings between 2005-2007.

Participants: 1,030 older adults, without dementia, aged 70-90.

Measurements: Apathy was classified using strict (=3) and standard (≥2) cutoff scores on the self-report Geriatric Depression Scale (GDS)-3A, and a validated cutoff score (>0) on the informant-report Neuropsychiatric Inventory. Depression was assessed with strict and standard cutoffs on the GDS-12D, and fatigue with the Assessment of Quality of Life-6D. Multimorbidity (≥2 chronic conditions; computed with and without cardiovascular conditions), physical performance (walking speed, sit-to-stand, lateral stability, grip strength), adiposity (BMI, waist circumference), blood pressure, cholesterol and glucose were assessed.

Results: Prevalence of apathy on the self-reported measure was 15.8 % (strict cutoff) or 48.9 % (standard). Informant-reported apathy was lower (2.9 %). Prevalence of self-reported depression was 5.9 % (strict cutoff) or 15.8 % (standard), and fatigue 9.8 %. Apathy overlapped very little with depression or fatigue (κ = .18, 95 % CI .14-.21). Apathy was associated with multimorbidity (even when excluding cardiovascular conditions), adiposity, fasting blood glucose level and physical performance, but not blood pressure or cholesterol.

Conclusions: Apathy is more common than depression or fatigue in dementia-free older adults. It does not typically co-occur with these symptoms, but is accompanied by poorer physical health, including multimorbidity and metabolic dysregulation. Apathy may be relevant for public health and an important consideration in clinical care.