Introduction
Methods
Study population
Measures
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Well-being (the outcome variable) was measured with the 15-item version of the Social Production Function Instrument for the Level of Well-being [SPF-IL(s)] [29]. This instrument is based on the SPF theory and contains both physical and social well-being. For physical well-being, two basic needs are specified: comfort and stimulation. Social well-being is achieved through the fulfillment of three basic social needs: affection, behavioral confirmation, and status. Answers could be given on a four-point scale, ranging from never (1) to always (4). A higher score indicates greater well-being. An overall sumscore was used, with higher scores indicating higher levels of well-being.
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Self-management was measured with the 30-item Self-Management Abilities Scale (SMAS), which consists of six five-item subscales [24]. The subscales taking initiative, investing, self-efficacy, variety, and multifunctionality are related to the physical and social dimensions of well-being, while the ability to have a positive frame of mind is considered to be a more general cognitive frame [24]. Examples of self-management abilities are investing in resources for long-term benefits, efficaciously managing resources, and taking initiatives (i.e., being instrumental or self-motivating in enhancing health and well-being). Average self-management ability scores ranged from 1 to 5, with higher scores indicating higher self-management abilities.
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Social functioning was measured using the social component of the Short Form 20 Health Survey (SF-20). This social functioning scale focuses on whether the respondent’s health has limited social activities. The scale was transformed to range from 0 to 100, with higher scores indicating higher levels of social functioning.
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Cognitive functioning was assessed with the Mini Mental State Examination (MMSE), which measures cognitive functioning via interviews in which patients are asked questions about orientation in time and space, short- and middle-term memory, comprehension, and other cognitive dimensions. Scores ranged from 0 to 30, with higher scores indicating higher levels of cognitive functioning. Any score ≥25 points (of 30) represents effective cognitive functioning (intact). Below this, scores can indicate severe (≤9 points), moderate (10–20 points), or mild (21–24 points) cognitive functioning losses [30, 31].
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Physical functioning was assessed using the Katz Index of independence in activities of daily living [32, 33], which ranks an individual’s ability to perform six functions: bathe, dress, use the toilet, transfer, remain continent, and feed oneself. Scores of yes (1) or no (2) indicate (in)dependence in each function, with 6 = full physical function, 4 = moderate, and ≤2 = severe physical function impairment.
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Education ranged from 1 (no school or some primary education; <6 years) to 7 (university degree; >18 years).
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Age, gender, and marital status were also assessed.
Analysis
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Condition 1: The theoretically specified independent variables (social, cognitive, and physical functioning) must emerge as significant predictors of the outcome variable (well-being) in correlation analyses.
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Condition 2: The theoretically specified independent variables must emerge as significant predictors of the mediator variable (self-management abilities) in correlation analyses.
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Condition 3: The mediator variable must be significantly associated with the outcome variable after controlling for the independent variables.
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Condition 4: The relationship between the significant independent variables and the outcome variable (well-being) must be significantly reduced when the effects of the mediator variable (self-management abilities) are included in the model.
Results
[Mean ± SD (range)] or % |
n
| |
---|---|---|
Background characteristics
| ||
Age | 75.8 ± 6.8 (65–94) | 291 |
Gender (female) | 45.8% | 295 |
Marital status (married/living together) | 56.6% | 295 |
Education | 4.1 ± 1.6 (1–7) | 295 |
Functioning domains
| ||
Social functioning (SF-20) | 68.6 ± 31.7 (0–100) | 293 |
Cognitive functioning (MMSE) | 28.1 ± 2.0 (19–30) | 293 |
Physical functioning (Katz) | 5.6 ± 0.8 (1–6) | 293 |
Self-management abilities (SMAS) | 2.7 ± 0.8 (0.2–4.8) | 282 |
Well-being (SPF-IL) | 2.8 ± 0.4 (1.3–3.8) | 288 |
1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | |
---|---|---|---|---|---|---|---|---|
1. Age | ||||||||
2. Gender (female) | 0.13* | |||||||
3. Marital status (married) | −0.20*** | −0.34*** | ||||||
4. Education (1–7) | 0.03 | 0.09 | 0.03 | |||||
5. Social functioning (SF-20) | −0.12* | −0.07 | 0.06 | −0.04 | ||||
6. Cognitive functioning (MMSE) | −0.20*** | 0.02 | 0.15** | 0.12* | 0.09 | |||
7. Physical functioning (Katz) | −0.25 | −0.22*** | 0.22*** | −0.02 | 0.34*** | 0.14** | ||
8. Self-management abilities (SMAS) | −0.13* | 0.15** | 0.07 | 0.05 | 0.32*** | 0.23*** | 0.31*** | |
9. Well-being (SPF-IL) | −0.01 | 0.03 | 0.06 | 0.02 | 0.44*** | 0.22*** | 0.31*** | 0.65*** |
Self-management abilities scale (SMAS) | |
---|---|
Background characteristics
| |
Age | −0.02 |
Gender (female) | 0.24*** |
Marital status (married/living together) | 0.04 |
Education (1–7) | 0.01 |
Domains of functioning
| |
Social functioning (SF-20) | 0.22*** |
Cognitive functioning (MMSE) | 0.17** |
Physical functioning (Katz) | 0.25*** |
Adjusted R² for equation | 21.0% |
F-value | 11.512 |
Adjusted R
²
|
F-value |
β (step 1) |
β (step 2) | |
---|---|---|---|---|
Background characteristics (step 1)
| 23% | 12.89*** | ||
Age | 0.11 | 0.12 | ||
Gender (female) | 0.10 | −0.04 | ||
Marital status (married) | 0.02 | 0.00 | ||
Education (1–7) | −0.03 | −0.03 | ||
Domains of functioning
| ||||
Social functioning (SF-20) | 0.34*** | 0.22*** | ||
Cognitive functioning (MMSE) | 0.17*** | 0.08 | ||
Physical functioning (Katz) | 0.22*** | 0.09 | ||
Mediator (step 2)
| 48% | 32.77*** | ||
Self-management abilities (SMAS) | 0.562*** |