266 MINIMALLY-EFFECTIVE PHYSICAL ACTIVITY DOSE FOR DEPRESSION AMONG OLDER ADULTS: PRELIMINARY FINDINGS FROM THE IRISH LONGITUDINAL STUDY ON AGEING

Background

Among older adults, depression is associated with increased risk of lower physical, social, and cognitive function. Physical Activity (PA) has been associated with lower odds of depression; however, the minimally sufficient dose for protection is unknown. Herein, we quantified the association between different PA doses and depressive symptoms and status among older adults across 10 years (waves 1-5) as part of The Irish Longitudinal Study on Ageing.

Methods

PA was measured at each wave using the short-form International Physical Activity Questionnaire (IPAQ-SF). Five dose categories (0, 1-<600, 600-<1,200, 1,200-<2,400 and ≥2,400 MET.min.week-1) were examined. At all waves, depressive symptoms were assessed using the Center for Epidemiological Studies Depression Scale short form (CES-D) and a score of ≥16 was used to define depression. From Waves 2-5, the Composite International Diagnostic Interview quantified diagnosis of a Major Depressive Episode during the past 12 months, or depression status. Poisson regression quantified associations between PA dose and depressive symptoms and status across time, adjusted for age, health/lifestyle variables and antidepressant medication.

Results

Among 4,017 participants, depression status changed from 8.2% at wave 1 to 12.2% at wave 5. The minimal PA dose associated with lower depressive symptoms was 1-<600 MET.min.week-1 (coefficient = –0.06; 95%CI: –0.10, –0.02; p≤0.003). A dose of 600-<1,200 MET.min.week-1 was significantly associated with lower odds of depression status (OR = 0.66; 95%CI: 0.50, 0.87; p≤0.004). Other positive predictors associated with lower odds of depression included greater age, higher education status, and sufficient vitamin D status.

Conclusion

Present findings suggest that even low physical activity doses appear protective against depressive symptoms among older adults. Moderate PA dose, consistent with WHO recommendations, was protective against major depression over a 10-year period among older adults. However, individuals with chronic conditions may have different PA dose requirements, which should be further investigated.

305 PHYSICAL ACTIVITY & DEPRESSION AMONG OLDER ADULTS WITH DIABETES: PRELIMINARY EVIDENCE FROM 10 YEARS OF THE IRISH LONGITUDINAL STUDY ON AGEING (TILDA)

Background

Older adults living with diabetes are at increased risk of physical and mental health issues, including depression. Among older adults living with diabetes, the salutary benefits of Physical Activity (PA), including increased insulin sensitivity and improved glycaemic control, are well established; however, less is known about the relationship between PA and depression. Thus, we quantified associations between different PA doses and depressive symptoms and status among older adults living with diabetes across 10 years (waves 1-5) as part of The Irish Longitudinal Study on Ageing.

Methods

Older adults (n=268) living with diabetes were identified through self-report and/or medication use. PA was measured with the short-form International Physical Activity Questionnaire. Five dose categories (0, 1-<600, 600-<1,200, 1,200-<2,400 and ≥2,400 MET.minutes per week) were examined. At all waves, depressive symptoms were assessed using the Center for Epidemiological Studies Depression Scale short form; a score of ≥16 classified depression. From Waves 2-5, the Composite International Diagnostic Interview quantified diagnosis of a Major Depressive Episode during the past 12 months, or depression status. Poisson regression models quantified the associations between PA dose and depressive symptoms and status across time, adjusted for age, health/lifestyle variables, and antidepressant medication.

Results

The minimal PA dose associated with lower depressive symptoms was 1-<600 MET.mins (coefficient = –0.20; 95%CI: –0.35, –0.05; p≤0.009). A dose of 600-<1200 MET.min was significantly associated with lower odds of depression status (OR = 0.66; 95%CI: 0.50, 0.87; p≤0.004). Additionally, being male, having sufficient vitamin D intake and lower age were associated with lower odds of depressive symptoms.

Conclusion

Present findings suggest that even low PA doses protect against depressive symptoms among older adults living with diabetes. This further supports the importance of promoting PA for mental health among this high-risk population group.

249 MINIMALLY-EFFECTIVE PHYSICAL ACTIVITY DOSE FOR GENERALIZED ANXIETY DISORDER AMONG OLDER ADULTS: PRELIMINARY FINDINGS FROM THE IRISH LONGITUDINAL STUDY ON AGEING

Background

Among older adults, Generalized Anxiety Disorder (GAD), a debilitating condition characterized by persistent excessive worry, is associated with poorer quality of life and estimated cost to the individual of €1,864 annually. Meeting recommended Physical Activity (PA) levels has been associated with lower odds of GAD; however, the minimally-sufficient dose associated with benefits is currently unknown. Herein, we quantified the association between different PA doses and worry symptoms and GAD status among older adults across 10 years (waves 1-5) as part of The Irish Longitudinal Study on Ageing.

Methods

PA was measured at each wave using the short-form International Physical Activity Questionnaire. Five dose categories were examined (0, 1-<600, 600-<1,200, 1,200-<2,400, and ≥2,400 MET.min.week-1). At all waves, worry symptoms were assessed using the abbreviated Penn State Worry Questionnaire continuous score; a score of ≥23 classified GAD status. Additionally, for Waves 2-5, the CIDI GAD quantified diagnosis of GAD during the past 12 months. Poisson regression with Stata quantified associations between PA dose and GAD and worry symptoms, adjusted for age, health/lifestyle variables and antipsychotics/anxiolytic medication.

Results

Among 2,200 participants, compared to lowest PA dose, only the highest PA dose (i.e., ≥2,400 MET.min.week-1) was significantly associated with 35% lower odds of GAD (OR=0.65; 95%CI: 0.51, 0.82; p≤0.001). For continuous worry symptoms, meeting the recommendation of at least 600 MET.min.week-1 was significantly, inversely associated with worry symptoms (coefficient= –0.02; 95%CI: –0.033, –0.005; p≤0.009). Female sex, less education, taking anxiolytics, and current smoking were also associated with greater odds of GAD and greater worry severity.

Conclusion

High physical activity dose was associated with lower odds of GAD over 10 years among older adults. Present findings suggest that older adults, particularly females and smokers, may need to exceed recommended physical activity levels to protect against GAD.

Decreases in resting plasma beta-endorphin and depression scores after endurance training

That endurance training changes resting plasma beta-endorphin (BE) at the same time that there are improvements in non-clinical depression was tested in medically healthy middle-aged men (40-60 years). Subjects were self-selected based on compliance into treatment (T, n = 10) and placebo (P, n = 6) groups. T attended an eight month fitness program. P had less than 50% attendance in the program. Treadmill tests at the pre and post program were used to estimate the Physical Fitness Score (PFS). The Minnesota Multiphasic Personality Inventory (MMPI) was used to measure depression. All psychological scores were within non-pathological, normal limits. BE was measured with the subjects fasting and resting in the early morning. BE, detected by radioimmunoassay, decreased (p less than .005) from pre 48.53 +/- 3.32 (SE) to post 31.73 +/- 4.43 pg/ml in T. The MMPI depression score also decreased in T (p less than .05) from pre 58.90 +/- 2.81 (SE) to post 53.20 +/- 1.48 T-score units. In contrast, the PFS increased in T (p less than .005) from pre 254.57 +/- 18.62 (SE) to post 304.94 +/- 15.95 PFS units. No pre to post program changes were detected in P. In conclusion, endurance training of eight months duration appeared to decrease the resting plasma BE concentrations and the MMPI depression scores of the middle-aged men in the present study.

Beta-endorphin and components of emotionality discriminate between physically active and sedentary men

Differences between physically active and sedentary men were tested by profile comparison. The study identifies the relative importance of circulating beta-endorphin (BE), atherosclerotic disease risk (ADR) index, and selected components of emotionality in discriminating between physically active and sedentary men. The subjects were psychologically normal and medically healthy middle-aged men. Jogging activity was the subject classification criterion. The data were collected on selected physiological (treadmill), biochemical (blood collected from resting subjects), and psychological (Eysenck and MMPI) variables. The physical fitness score (PFS) was used as an index of fitness. Physically active men with a high PFS (n = 21), when compared to the sedentary men with a low PFS (n = 15), exhibited lower basal plasma BE, lower ADR, lower anxiety index (AI), and lower MMPI depression score (D). Canonical correlation analysis showed that PFS and BE in one set were correlated with D and neuroticism (NS) in another set of variables. Discriminant function analysis showed that the AI was the most powerful discriminator between the physically active and sedentary men, followed by BE and NS. Interestingly, BE and NS exhibited the same magnitude of discrimination power. The ADR exhibited less discrimination power, relative to AI, BE, and NS. In conclusion, the physically active men, compared to the sedentary men in this study, exhibited lower basal plasma BE, which appeared to be associated with less atherosclerotic disease risk, less neuroticism, less anxiety, and less depression.

Beta-endorphin and components of depression as powerful discriminators between joggers and sedentary middle-aged men

This study identifies the relative importance of resting plasma beta-endorphin, used as a marker of perceived stress, and components of non-clinical depression that discriminate between physically active joggers and sedentary men. The profiles of joggers (n = 10) and sedentary (n = 10) middle-aged men (40-60 yr) were compared. The jogger group had been running about 20 miles per week for at least 3 yr.

RESULTS

as expected, the joggers exhibited greater physical fitness, but lower circulating beta-endorphin (measured with the subjects at rest). The joggers also exhibited greater emotional stability (Eysenck scores), and lower depression (MMPI Scale 2 scores). In addition, the joggers had lower scores on MMPI subscales of depression: subjective depression, physical malfunctioning, mental dullness, and brooding. Multivariate discriminant function analyses showed that subjective depression, beta-endorphin, and physical malfunctioning were powerful discriminators between the jogger and sedentary groups.

IN CONCLUSION

(1) subjective depression appeared to be the MMPI component of depression that most powerfully discriminated between joggers and sedentary middle-aged men in this study. (2) Lower beta-endorphin may be an adaptation to exercise training and was related to greater emotional stability and lower depression, especially lower subjective depression. (3) The lower beta-endorphin in the jogger group may be related to lower perceived stress in the joggers, relative to the sedentary group.