Sex differences in the association of physical function and cognitive function with life satisfaction in older age: The Rancho Bernardo Study

Objectives: This study examines the cross-sectional associations of cognitive and physical function with life satisfaction in middle-class, community-dwelling adults aged 60 and older. Study design: Participants were 632 women and 410 men who had cognitive function tests (CFT) and physical function tasks (PFT) assessed at a clinic visit between 1988 and 1992, and who responded in 1992 to a mailed survey that included life satisfaction measures. Cognitive impairment was defined as <= 24 on MMSE, >= 132 on Trails B, <= 12 on Category Fluency, <= 13 on Buschke long-term recall, and <= 7 on Heaton immediate recall. Physical impairment was defined as participants' self-reported difficulty (yes/no) in performing 10 physical functions. Multiple linear regression examined associations between life satisfaction and impairment on >= 1 CFT or difficulty with >= 1 PFT. Main outcome measures: The Satisfaction with Life Scale (SWLS; range:0-26) and Life Satisfaction Index-Z (LSI-Z; range:5-35). Results: Participants' average age was 73.4 years (range = 60-94). Categorically defined cognitive impairment was present in 40% of men and 47% of women. Additionally, 30% of men and 43% of women reported difficulty performing any PFT. Adjusting for age and impairment on >= 1 CFT, difficulty performing >= 1 PFT was associated with lower LSI-Z and SWLS scores in men (beta = -1.73, -1.26, respectively, p < 0.05) and women (beta = -1.79, -1.93, respectively, p < 0.01). However, impairment on >= 1 CFT was not associated with LSI-Z or SWLS score after adjusting for age and difficulty with >= 1 PFT. Conclusions: Limited cognitive function was more common than limited physical function; however, limited physical function was more predictive of lower life satisfaction. Interventions to increase or maintain mobility among older adults may improve overall life satisfaction. (C) 2016 Elsevier Ireland Ltd. All rights reserved.