Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Low Positive Affect Predicts the Development of Disability over 30-Months: The MOST Study.

Keysor1,  Julie J., Fredman4,  Lisa, Zhang2,  Bin, White3,  Daniel K., Torner8,  James C., Lewis6,  Cora E., Tolstykh7,  Irina

Boston Univ Sargent College, Boston, MA
Boston Univ Schl of Medicine, Boston, MA
Boston Univ School of Med, Boston, MA
Boston University
Boston University School of Medicine, Boston, MA
University of Alabama-Birmingham, Birmingham, AL
University of California and San Francisco, San Francisco, CA
University of Iowa, Iowa City, IA

Low positive affect above and beyond high depressive symptoms is linked to incident frailty among older adults. The impact positive affect has on functional outcomes is not known. Cross sectional studies have the potential flaw that good functional outcomes may make people happy, making cause and effect impossible to disentangle. We propose a longitudinal study to examine whether low positive affect predicted incident disability among adults at risk of developing disabilities.

Methods:

Baseline and 30-month longitudinal data from the Multicenter Osteoarthritis (MOST) Study, a prospective cohort study of progressive and incident symptomatic knee osteoarthritis, were used for these analyses. A three-category variable representing "high positive affect", "low positive affect" and "high depressive symptoms (depressed)" was computed from the Center of Epidemiological Study-Depression Scale (CES-D). Respondents who scored less than 16 on the CES-D and who scored "most of the time" on 4 positive affect questions of the CES-D were categorized as high positive affect; whereas, those reporting anything less than most of the time on the 4 items were classified as low positive affect. Respondents whose overall CES-D score was 16 or greater were classified as depressed. Disability was ascertained using the of the Late Life Disability Instrument-Instrumental Limitation subscale (LLDI-IL). The LLDI-IL was dichotomized into no/mild disability (no disability) and moderate/severe disability (disability) based on previously established cutpoints. Age, sex, education, race, body mass index (BMI), knee pain (max score of right or left knee visual analog scale), and gait speed (m/sec) were taken from baseline data and were used as covariates. Among persons with no disability at baseline, we examined the associations between baseline positive affect and depression and the development of disability at 30-follow-up using logistic regression.

Results:

2054 subjects had no disability at baseline. The mean age of the sample was 63 years. 58% were female and 89% were white. 1381 (67%) had high positive affect; 531 (26%) had low positive affect; 141 (7%) were depressed at baseline. 260 (13%) developed disability at 30-months. Subjects who reported low positive affect and those who were depressed were more likely to report disability at 30-months compared to persons with high positive affect after adjusting for covariates. As expected, high depressive symptoms was also associated with incident disability. (Table 1)

Discussion:

Compared with high positive, low positive affect increased people's risk of developing disability over a 30-month time period, even above and beyond the risk associated with depressive symptoms. Further research is needed to elicit the role positive psychological factors play in disablement.

Table 1. Unadjusted and adjusted odds ratio of low positive affect and "depressed" status compared to high positive affect.

 Event/Subjects (%)Crude OR (95% CI)Adjusted OR (95% CI)
High Positive Affect140/1381 (10%)1.01.0
Low Positive Affect79/531 (15%)1.5 (1.2–2.1)1.5 (1.1–2.1)
Depressed (High Depressive Symptoms)41/141 (29%)3.6 (2.4–5.4)2.7 (1.7, 4.1)

To cite this abstract, please use the following information:
Keysor, Julie J., Fredman, Lisa, Zhang, Bin, White, Daniel K., Torner, James C., Lewis, Cora E., et al; Low Positive Affect Predicts the Development of Disability over 30-Months: The MOST Study. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :683
DOI: 10.1002/art.28451

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