| Summary: | 博士 === 國立成功大學 === 公共衛生研究所 === 104 === INTRODUCTION: Depression is a leading disease burden worldwide and associated with several health conditions. It is closely associated with quality of life in community-dwelling older adults. However, how depressive symptoms affect each facets of quality of life in community-dwelling older adults is still unclear. Furthermore, the relationship among physical function, depressive symptoms and the respective domains of quality of life also requires further investigation. Moreover, the robust evidence regarding the effects of exercise on depressive symptoms is lacking. Although there are several exercise models recommended for adults’ physical health, there are still lacking age-friendly exercise models in considering physical and psychological benefits for older adults.
METHODS: This series of studies were divided into four parts. For study 1-1 and 1-2, a total of 490 ambulatory community-dwelling older adults aged 65 years or above were interviewed using the brief version of the World Health Organisation Quality of Life instrument (WHOQOL-BREF), the Modified Barthel Index (MBI), the 15-item Geriatric Depression Scale (GDS-15), and the Mini-Mental State Examination (MMSE). Depressive symptoms were divided into no depressive symptoms (NDS), which means GDS-15=0; lower level of depressive symptoms (LLDS), 1≦GDS-15≦5; and higher level of depressive symptoms, 5〈GDS-15≦15. In study 1-1, sequential models for multiple linear regressions were analysed to determine if the MBI, GDS-15 and MMSE scores predict the WHOQOL-BREF scores. The potential mediation effects of depression (as determined by the GDS-15) on the relationship between MBI and WHOQOL-BREF were also analysed. In study 1-2, we applied multiple linear regression analyses were conducted to assess associations between the WHOQOL-BREF and its covariates for different levels of depressive symptoms.
Study 2-1 and 2-2 used the Taiwan Longitudinal Survey on Ageing (TLSA) undertaken by the Health Promotion Administration, Ministry of Health and Welfare, Taiwan. Four waves of survey in 1996, 1999, 2003 and 2007 were included in the analysis. The 2673 participants who were 65 years or older in 1996 were selected, with the total number of 8397 observations. Depressive symptoms were measured with the Center for Epidemiologic Studies Depression Scale (CES-D). Depressive symptoms were divided into no depressive symptoms (NDS), which means CES-D=0; lower level of depressive symptoms (LLDS), 0〈CES-D≦9; and higher level of depressive symptoms, 10≦CES-D≦30.The degree of exercise was estimated with the frequency (0, ≦2, 3-5, ≧6 times per week), duration (〈15 min, 15-30 min, 〉30 min), and moderate intensity of exercise, which required at least a little sweating and panting after exercise. The four exercise models were classified as EM1 as the exercise of at least moderate intensity was performed ≧3 times/week, ≧15 min/time; EM2, ≧3 times/week, 〉30 min/time; EM3, ≧6 times/week, ≧15 min/time; EM4, ≧6 times/week, 〉30 min/time. Physical activity function, emotional social support, and socio-demographic variants including included gender, age, marital status, education, economic satisfaction and employment were controlled during the analysis. Study 2-1 applied the generalized linear mixed models (GLMM) via PROC GLIMMIX to estimate how respective exercise models in the present and previous survey affect the current depressive symptoms. Study 2-2 further analyzed the effects of transitional patterns of respective exercise models on depressive symptoms with GLMM models.
RESULTS: In study 1.1, the GDS-15 score was predictive of the scores of the four domains and all 26 facets of the WHOQOL-BREF. The significant predictive effects of the MBI score on 15 of the 26 facets of the WHOQOL-BREF were reduced to three after the adjustment for the GDS-15 score. Depression (as assessed by the GDS-15) is a mediator of the relationship between MBI and the physical, psychological and environmental domains of the WHOQOL-BREF. In Study 1.2, the GDS-15 and MBI scores significantly affected the WHOQOL-BREF physical and psychological domain scores in the LLDS group. Gender influenced the WHOQOL-BREF scores in the NDS group, and increased age demonstrated protective effects on the three domains in the HLDS group. Moreover, the association between the WHOQOL-BREF and its covariates varied for different levels of depressive symptoms.
In Study 2-1, the LLDS and HLDS prevalence was 24.2% and 23.4% respectively. 38.6% of the population met the criteria of EM1; 32.1%, EM2 ; 34.5%, EM3; and 28.0%, EM4. The present practice of EM4 had a significant odds ratio of 0.80 (0.66-0.95) for HLDS. The previous level of depressive symptoms, physical activity function, emotional social support, self-assessed health and economic satisfaction were all positively predictive to HLDS. However, none of the practices of exercise models in the previous survey can predict the present HLDS. Study 2-2 showed that all the persistent patterns of exercise transitions reveal a significantly protective effect for HLDS, though the effects may be decreased over time because of the significant effects of interaction between time and transitional patterns of exercise. After stratified by time and age, the analysis showed that the persistent pattern of both EM3 and EM4 in the transitional period of 1996-1999 (OR (95% C.I.)=0.66 (0.45-0.98) and 0.58 (0.36-0.93) for EM3 and EM4 respectively) and the increasing pattern in the transitional period of 1999-2003 showed significantly protective effects for HLDS (OR (95% C.I.)=0.52 (0.35-0.79) and 0.49 (0.31-0.76) for EM3 and EM4 respectively). Furthermore, the increasing patterns of both EM3 and EM4 had protective effects for HLDS, though the effects were statistically significant in the age of 65-74 (OR (95% C.I.)=0.66 (0.45-0.97) and 0.63 (0.42-0.95) for EM3 and EM4 respectively), but not in the age of 75-84.
CONCLUSION: Depressive symptoms may affect each facets of WHOQOL-BREF and may mediate the relationship between physical function and quality of life in apparently healthy community-dwelling older adults. Furthermore, the lower level depressive symptoms may modify the manifestations of determining factors for quality of life, which indicated that quality of life may be more sensitive to the changes of depressive symptoms or physical function in the lower level of depressive symptoms.
An age-friendly exercise model, which is also known as the low-volume exercise, i.e. moderate exercise lasting more than 15 minutes each time and as frequent as five or more times a week, has shown the benefits for all-cause mortality and cancer rate. Our study showed that persistent low-volume exercise may be also protective for depressive symptoms. We recommend taking depressive symptoms into consideration when measuring QOL and promoting low-volume exercise for the physical and psychological health of community-dwelling older adults.
|
|---|
