Abstract
Objectives
Evidence on the effectiveness of cooking activities as a well-being promotion intervention for older adults with subjective cognitive decline (SCD) and their caregivers is scarce. In view of this, a randomized controlled trial was conducted to examine whether a dyadic cooking-based intervention can improve the subjective health and well-being of older adults with SCD and their caregivers, as well as the cooking competence of the former group.
Design
Randomized controlled trial.
Setting
Community.
Participants
Sixty pairs of community-dwelling older adults aged 60 years or above with SCD (mean age = 78.4 years) and their caregivers (mean age = 65.3 years) were randomly assigned to the intervention group (N = 30 pairs) and the wait-list control group (N = 30 pairs).
Intervention
The intervention was an innovative 5-week (two hours per week) dyadic cooking-based intervention employing procedural learning methods specifically adapted for older adults with SCD.
Measurements
The outcome measures included 1) a well-being index composed by four indicators: life satisfaction, feeling of happiness, sense of purpose and meaning in life, and perceived health, and 2) cooking competence.
Results
For both older adults with SCD and their caregivers, the increases in the well-being index were significantly greater in the intervention group than in the control group (β = 0.508, 95% CI [0.036, 0.980]). For older adults with SCD, the increases in the cooking competence score were significantly greater in the intervention group than in the control group (β = 1.629, 95% CI [0.165, 3.071]).
Conclusion
The dyadic cooking-based intervention resulted in improvements in the cooking competence and well-being of older adults with SCD, as well as the well-being of caregivers.
Key words: Caregivers, cooking, cooking competence, dyadic intervention, older adults, procedural learning, subjective cognitive decline, well-being
Introduction
With an ageing population, cognitive decline is becoming an increasingly important issue. The number of individuals who have concerns and seek medical advice about cognitive decline is also growing. These concerns can be associated with different levels of cognitive and functional impairments, among which dementia is the most severe one. At the other end of the continuum, some individuals experience worsening confusion or memory loss, which can be collectively defined as subjective cognitive decline (SCD), but with their cognitive performance otherwise showing no evidence of impairment (1, 2). In other words, SCD is the mildest form of cognitive decline and is clinically distinct from the more severe forms of cognitive decline, such as mild cognitive impairment (MCI) and advanced dementia. Although SCD seems to be a benign problem, it has been recognized as a risk factor for incident MCI and dementia due to Alzheimer disease (AD) (3, 4).
Besides the cognitive aspect, SCD can also influence one's health and psychological well-being. For many older adults, SCD can impact not only their cognitive abilities, but also their daily skills such as meal preparation and cleaning, which can in turn undermine their perceived health and sense of psychological well-being. A previous study showed that in an older population without dementia, cognitive decline was negatively associated with various aspects of well-being (e.g., purpose in life, self-acceptance, and autonomy) (5). A systematic review also revealed that SCD is associated with mild symptoms of depression or anxiety (6). Possible underlying reasons are that older adults with SCD may get frustrated as they lose their cognitive and daily skills (6, 7), or when forced to give up some of their day-to-day household activities and chores. One particular example in this regard is that older adults with SCD may be prohibited to cook, as some cooking procedures (e.g., chopping ingredients) may carry a risk of causing injuries. In addition, SCD does not only affect the older adults' well-being, but also increases the amount of time spent and level of stress experienced by the caregivers, especially when behavioural changes begin to take place in an unexpected and inconsistent manner, thereby undermining their health and psychological well-being.
Given the detrimental effects of SCD, services or interventions for older adults with SCD and their caregivers (including those who take care of the daily living of the older adults, as well as companions in the broader sense) aiming to help them adjust to the changes and to promote health and psychological well-being for both parties are crucial. For older adults with SCD, cognitive training is the most widely available form of interventions, which has been demonstrated to be able to improve cognitive functions in some specific domains (e.g., memory, attention, and executive function), decrease the feeling of loneliness (8), reduce anxiety and stress (9), and improve psychological well-being in general (10). For caregivers, however, most interventions have been designed for dementia caregiving aiming to improve caregivers' ability to cope with the more severe symptoms of dementia (e.g., behaviour problems), and to help them learn about the available resources that may be of assistance in delaying the progress of dementia, although caregiving for persons with SCD could be quite different from those for persons with dementia. In contrast, less consideration has been paid to the caregivers of those with SCD or other earlier stages of dementia. It may be due to the perception that the health conditions of older adults with SCD are relatively stable and not as severe, thereby being less problematic from the perspective of caregivers. On the other hand, most of the aforementioned interventions did not simultaneously consider the perspectives of older adults with SCD and their caregivers, in spite of their intertwining nature. With reference to the social contextual model (11), it is important to include both care receivers and caregivers in a psychosocial intervention to minimize the potential risks resulting from miscommunication or misunderstanding between the dyad. For example, the stress faced by caregivers has been shown to interfere with the rehabilitation of stroke survivors (12). Therefore, given the dyadic nature of caregiving, more adequate interventions can be designed to better promote the mutual understanding between older adults with SCD and their caregivers, and ultimately their well-being.
Regarding dyadic interventions, numerous approaches including support groups and counselling have been applied in various contexts (13). While these traditional methods hold considerable promise, some novel approaches such as mindfulness exercise (14) and art-based interventions (e.g., choral singing and visual arts interventions) (15) have also demonstrated positive effects on the psychological well-being of the dyads. Other dyadic interventions (e.g., home environmental skill-building programme and home-based exercise) focusing on engaging both care receivers and caregivers in daily activities were also proven to be effective (16, 17, 18). However, the psychosocial benefits of dyadic cooking interventions for SCD have been less studied, although cooking is an essential part of daily living and previous studies have shown that cooking could mitigate psychological distress (19). Some studies also reported that cooking helped reduce passivity and agitations in people who had varying degrees of dementia (20), and that cooking activities conducted together with partners (e.g., spouse) could strengthen their bonds and relationships (21).
To summarize, providing dyadic interventions in the form of cooking activities may contribute to better adaptations and improved well-being for both older adults with SCD and their caregivers. In view of this, the present study designed a dyadic cooking programme, named “Chef Anchor”, and examined its effects on the subjective health and well-being of older adults with SCD and their caregivers, as well as the cooking competence of the former group.
Methods
Study design and participants
The study is a randomized controlled trial (RCT) built on a 5-week cooking intervention for older adults with SCD and their caregivers, which was conducted between June 2021 and January 2022. A total of 60 pairs of participants were identified based on a screening of SCD, which was operationalized as self-reported confusion or memory loss, and were recruited from a community centre for older adults in Wan Chai, Hong Kong. To be eligible to participate, older adults had to be aged 60 years or above, with SCD but no history of MCI or dementia, not terminally ill, able to stand and use kitchen utensils safely, and had a caregiver who could also participate in the study. Two questions were used to assess SCD, including “do you feel that your thinking or memory is getting worse over the past 12 months?” and “if yes, are you worried about it?” Those who answered “yes” in both questions were classified as having SCD. However, no diagnostic assessments for MCI and dementia were carried out, as such detailed, technical and lengthy assessments were neither feasible to be conducted in the community setting, nor what the participants were initially looking for when joining the programme. Caregivers had to be aged 18 years or above and without SCD. The 60 pairs of participants were interviewed and randomly assigned to either the intervention group or the wait-list control group, using a computerized block randomization procedure with a block size of four. Participants were blinded to the group allocation. Treatment outcomes were re-assessed after the 5-week period, and were compared across the two groups.
Intervention
The intervention was a group-based nutrition education and cooking class programme aiming to promote cooking safety, confidence and skills, introduce the concept of nutrition considerations in cooking, improve communication and relationships, create social network and provide relevant community resources, and eventually enhance the health and psychological well-being of older adults with SCD and their caregivers. At the beginning of the programme, an orientation session was conducted, in which an occupational therapist introduced some cognitive training techniques based on the procedural learning paradigm, and social workers shared some tips for relieving caregiver stress. The programme was then followed by five weekly 2-hour cooking classes ran by a trained cooking instructor. Each cooking class comprised nutrition education, recipe cooking, and a meal sharing session, where the dyads shared their dishes with other participants. They were also given a cookbook consisting of the recipes of five Chinesestyle dishes that are familiar to the local older population in general (Supplementary Table 1). This cookbook employed procedural learning methods specifically designed for older adults, particularly those with SCD, which contains step-by-step instructions elaborated in much greater detail, as well as a complete list of ingredients.
Each weekly session lasted for two hours and took place in a kitchen with 16 cooking stations, including those for the 15 pairs of participants and the remaining one for the cooking instructor. All participants firstly grouped together and listened to the cooking instructor regarding the preparation of ingredients, cooking procedures, safety issues, and nutritional information of the dish. After watching a live demonstration, each pair of participants returned to their respective cooking station to cook the dish. This process was accompanied by a volunteer, who provided encouragement and assistance when necessary. The cooking instructor and all these volunteers had received a training session on the skills of communicating with SCD subjects before the programme began. As regards the wait-list control group, during the 5-week period, they could participate in ordinary centre activities as usual, after which they also received the cooking class programme. At the end of the programme, an additional sharing session was conducted, in which participants expressed their opinions about the intervention programme.
Outcome measures
Subjective health and well-being
The primary outcome was the change in subjective health and well-being between baseline and five weeks after the intervention, as assessed using four items covering a range of elements associated with the evaluative, hedonic, and eudemonic aspects of well-being, as well as perceived health. More specifically, the first three items were 1) “how satisfied are you with your life?”, 2) “how happy were you in the past month?”, and 3) “do you feel that your life's meaning is clear to you?”, which were administered on 11-point Likert scales ranging from 0 (not satisfied at all/not happy at all/no clear sense of purpose and meaning in life) to 10 (very much satisfied/very happy/a clear sense of purpose and meaning in life). The fourth question asked the participants to rate their perceived health, using “how would you rate your overall health at the present time?”, on a 5-point Likert scale with 1 indicating “poor” and 5 indicating “excellent”. The scores of these four items were then assembled into a unidimensional well-being index, using a standard principal component analysis procedure, the details of which will be deferred until the “Statistical analysis” section.
Cooking competence
The secondary outcome was the change in cooking competence between baseline and five weeks after the intervention, as measured with five items including 1) “I forgot to turn off the gas after cooking”, 2) “I forgot to apply/repeatedly applied seasoning”, 3) “my judgment in cooking was affected by memory loss”, 4) “my confidence in cooking was affected by memory loss”, and 5) “I could not plan out and cook a meal on my own”. For each item, older adults with SCD were asked to indicate whether the described situation had frequently, occasionally, or never happened in the previous week. In view of the SCD of the older adults, their caregivers could provide assistance in answering these questions if necessary.
Demographics and covariates
Participants also completed questions about their gender, age, and education level. Cognitive function was also assessed for older adults with SCD, using the Hong Kong Montreal Cognitive Assessment (HK-MoCA), with a cut-off score of 22 for indicating MCI (i.e., those with a score of < 22 are more prone to having MCI) (22). It should be emphasized that the HK-MoCA was not used to screen for SCD; instead, it was used to assess the cognitive function of those who had already been identified as having SCD.
Statistical analysis
To examine whether the cooking intervention was effective in improving the subjective health and well-being of participants, a linear mixed-effect regression was employed. For this particular analysis, data of older adults with SCD and their caregivers were pooled together to explicitly capture the dependence structure of the data (i.e., subjective health and well-being should be correlated within each dyad), thereby enhancing the precision of estimation by utilizing as much information as possible. To begin, a composite well-being index was formed using principal component analysis. More specifically, the data of all participants at both time points were pooled together to estimate the correlation matrix of the four items. This correlation matrix was then used to compute the “optimal” weights for combining the four items into a single index (cf. a simple sum or average). By construction, the resulting score generated by principal component analysis always has an overall mean of 0. Thus, this analysis cannot be performed separately for the baseline and follow-up data, since otherwise the pre-post comparison will become meaningless. In addition, the correlation matrix (cf. covariance matrix) was used, because the scales (i.e., variability) of the four items were rather different. This composite well-being index was then treated as the dependent variable in the regression model, while the main independent variable was the interaction effect between intervention grouping and time. In essence, this variable captured how the pre-post change in the composite index differed across the intervention and control group, that is, the intervention effect. To take into account the homogeneity within each dyad and the longitudinal nature of the data, two random effect terms (i.e., “pair” and “subject”) were added respectively. In addition, several covariates were included in the model. In particular, an “identity” variable (older adults with SCD vs. caregivers) was included to allow the values of the composite index to differ across these two types of participants. As an exploratory attempt, the interaction between this “identity” variable and the intervention grouping and time was also examined to see whether the intervention effect differed across these two types of participants. However, since this was not the primary focus of the present study, this interaction would be dropped from the model if deemed statistically insignificant. On the other hand, the analysis on cooking competence was only performed on older adults with SCD, thus no data pooling was required. The linear mixed-effect regression model was similar, but without the “pair” random effect and the “identity” variable. All statistical analyses were performed using the lmer package (version 1.1–32) in R. A p-value of less than .05 was considered statistically significant.
Results
Baseline characteristics of the participants
Participant flow is shown in Supplementary Figure 1. Data from all participants initially enrolled in the programme were included in the analysis, and their characteristics are shown in Table 1. Of the 60 participants with SCD, 55.0% were women, and the mean age was 78.4 years. The two treatment groups were well matched at baseline, except that the intervention group had a slightly higher level of education (p < .05). Of the 60 caregivers, 80.0% were women, and the mean age was 65.3 years. There were no differences between the treatment groups in all the variables being considered. Notably, however, the mean HK-MoCA score was only 18.4, which was considerably lower than the threshold as mentioned above (i.e., 22). In fact, 33 (55%) out of the 60 participants with SCD had a HK-MoCA score of < 22, indicating the possibility that some of these participants might not only have SCD, but in fact MCI or even dementia. As stated previously, although the cooking programme was specifically designed for and targeted towards those with SCD, the present study did not conduct any formal assessments to differentiate those with SCD from those with MCI or dementia. In view of this, the main analyses (i.e., the linear mixed-effect regressions on composite well-being index and cooking competence) were repeatedly performed on two subgroups (as split by the HK-MoCA score) to examine whether the effects of the programme depended on the objective cognitive status of the older adults.
Table 1.
Baseline characteristics of older adults with SCD and caregivers by treatment groups
| Older adults with SCD | Caregivers | |||||||
|---|---|---|---|---|---|---|---|---|
| Total (N = 60) | Intervention (N = 30) | Control (N = 30) | Total (N = 60) | Intervention (N = 30) | Control (N = 30) | |||
| Variable | Mean (SD)/N (%) | p | Mean (SD)/N (%) | p | ||||
| Gender | .436 | .104 | ||||||
| Men | 27 (45.0) | 12 (40.0) | 15 (50.0) | 12 (20.0) | 9 (30.0) | 3 (10.0) | ||
| Women | 33 (55.0) | 18 (60.0) | 15 (50.0) | 48 (80.0) | 21 (70.0) | 27 (90.0) | ||
| Age, years | 78.4 (8.8) | 77.1 (9.3) | 79.8 (8.2) | .245 | 65.3 (11.8) | 62.5 (10.9) | 68.1 (12.2) | .065 |
| Education | .022 | † | ||||||
| Functionally illiterate | 3 (5.0) | 1 (3.3) | 2 (6.7) | 0 (0.0) | 0 (0.0) | 0 (0.0) | ||
| Marginally illiterate | 6 (10.0) | 5 (16.7) | 1 (3.3) | 1 (1.7) | 1 (3.3) | 0 (0.0) | ||
| No education | 4 (6.7) | 0 (0.0) | 4 (13.3) | 0 (0.0) | 0 (0.0) | 0 (0.0) | ||
| Primary | 22 (36.7) | 7 (23.3) | 15 (50.0) | 13 (21.7) | 1 (3.3) | 12 (40.0) | ||
| Secondary | 18 (30.0) | 12 (40.0) | 6 (20.0) | 30 (50.0) | 20 (66.7) | 10 (33.3) | ||
| Tertiary | 7 (11.7) | 5 (16.7) | 2 (6.7) | 16 (26.7) | 8 (26.7) | 8 (26.7) | ||
| Subjective well-being | 0.3 (1.7) | 0.2 (1.6) | 0.4 (1.8) | .637 | −0.3 (1.5) | −0.5 (1.5) | −0.2 (1.4) | .232 |
| Cooking competence | 12.5 (2.4) | 11.6 (2.6) | 13.3 (1.9) | .006 | / | / | / | / |
| HK-MoCA | 18.4 (7.6) | 17.1 (7.8) | 19.7 (7.3) | .192 | / | / | / | / |
Note. p-values were obtained from two-sample t-test or χ2 test of independence. Boldface is used to indicate p < .05. †: p-value was not calculated due to an excess of zero counts.
Effects of the cooking programme on subjective health and well-being
With regard to the primary outcome, the cooking intervention provided benefits on subjective health and well-being to both older adults with SCD and their caregivers. Indeed, a preliminary analysis showed that the intervention group had improvements in the composite well-being index after five weeks of intervention (0.344 points), whereas no such improvement was found in the control group (−0.164 points) (data not shown). After employing the linear mixed-effect regression model and controlling for other covariates including gender, age, and education level, it was found that the intervention effect did not significantly differed across older adults with SCD and their caregivers (β = 0.176, 95% CI [−0.451, 0.803]) (data not shown), which was thus omitted in the final analysis and results. The intervention effect on the composite index was found to be significantly positive (β = 0.508, 95% CI [0.036, 0.980]) (Table 2a). That is, the pre-post difference of the intervention group was estimated to be 0.508 points higher than that of the control group, and such difference was applicable to older adults with SCD and their caregivers to an equal extent. However, subgroup analysis showed that such intervention effect remained significant only among those pairs whose older adult had a HK-MoCA score of < 22 (β = 0.761, 95% CI [0.129, 1.394]) (Table 2b), whereas no such improvement was found in the other subgroup (Table 2c).
Table 2a.
Linear mixed-effect regression on the composite well-being index (N = 120)
| Fixed effect | β | s.e. | 95% CI |
|---|---|---|---|
| Time | -0.164 | 0.170 | (−0.498, 0.170) |
| Group | |||
| Control | Ref. category | ||
| Intervention | −0.501 | 0.344 | (−1.166, 0.163) |
| Time x Intervention group (i.e., intervention effect) | 0.508 | 0.241 | (0.036, 0.980) |
| Gender | |||
| Men | Ref. category | ||
| Women | −0.355 | 0.266 | (−0.865, 0.159) |
| Age, years | −0.002 | 0.014 | (−0.029, 0.025) |
| Identity | |||
| Caregiver | Ref. category | ||
| Older adult with SCD | 0.502 | 0.286 | (−0.050, 1.050) |
| Education | |||
| Illiterate/No education | Ref. category | ||
| Primary/Secondary | −0.231 | 0.462 | (−1.129, 0.676) |
| Tertiary | −0.264 | 0.489 | (−1.227, 0.702) |
| Random effect | σ2 | 95% CI | |
| Pair | 0.678 | (0.143, 1.311) | |
| Subject | 0.987 | (0.495, 1.544) | |
| Residual | 0.872 | (0.672, 1.116) | |
Note. The pair and subject random effects were assumed to be independent.
Table 2b.
Linear mixed-effect regression on the composite well-being index for those pairs whose older adult had a HK-MoCA score of < 22 (N = 66)
| Fixed effect | β | s.e. | 95% CI |
|---|---|---|---|
| Time | −0.192 | 0.238 | (−0.659, 0.275) |
| Group | |||
| Control | Ref. category | ||
| Intervention | −0.591 | 0.457 | (−1.455, 0.277) |
| Time x Intervention group (i.e., intervention effect) | 0.761 | 0.323 | (0.129, 1.394) |
| Gender | |||
| Men | Ref. category | ||
| Women | −0.713 | 0.428 | (−1.545, 0.093) |
| Age, years | −0.004 | 0.018 | (−0.040, 0.031) |
| Identity | |||
| Caregiver | Ref. category | ||
| Older adult with SCD | 0.858 | 0.543 | (−0.195, 1.880) |
| Education | |||
| Illiterate/No education | Ref. category | ||
| Primary/Secondary | −0.283 | 0.626 | (−1.462, 0.896) |
| Tertiary | −0.119 | 0.667 | (−1.381, 1.151) |
| Random effect | σ2 | 95% CI | |
| Pair | 0.133 | (0.000, 1.008) | |
| Subject | 1.749 | (0.796, 2.545) | |
| Residual | 0.853 | (0.599, 1.187) | |
Note. The pair and subject random effects were assumed to be independent.
Table 2c.
Linear mixed-effect regression on the composite well-being index for those pairs whose older adult had a HK-MoCA score of ≥ 22 (N = 54)
| Fixed effect | β | s.e. | 95% CI |
|---|---|---|---|
| Time | −0.136 | 0.243 | (−0.611, 0.340) |
| Group | |||
| Control | Ref. category | ||
| Intervention | −0.446 | 0.545 | (−1.499, 0.594) |
| Time x Intervention group (i.e., intervention effect) | 0.142 | 0.364 | (−0.571, 0.855) |
| Gender | |||
| Men | Ref. category | ||
| Women | −0.212 | 0.270 | (−0.715, 0.304) |
| Age, years | 0.000 | 0.020 | (−0.037, 0.038) |
| Identity | |||
| Caregiver | Ref. category | ||
| Older adult with SCD | 0.182 | 0.235 | (−0.253, 0.620) |
| Education | |||
| Illiterate/No education | Ref. category | ||
| Primary/Secondary | −0.014 | 0.711 | (−1.340, 1.332) |
| Tertiary | −0.043 | 0.763 | (−1.468, 1.389) |
| Random effect | σ2 | 95% CI | |
| Pair | 1.366 | (0.644, 2.469) | |
| Subject | 0.118 | (0.000, 0.442) | |
| Residual | 0.884 | (0.597, 1.213) | |
Note. The pair and subject random effects were assumed to be independent.
Effects of the cooking programme on cooking competence
With regard to the secondary outcome, the cooking intervention improved the cooking competence of older adults with SCD. The intervention group showed a mean increase of 1.113 points in the cooking competence score, whereas no such increase was found in the control group (−0.467 points) (data not shown). After employing the linear mixed-effect regression model and controlling for other covariates including gender, age, and education level, the intervention effect on cooking competence was found to be significantly positive (β = 1.629, 95% CI [0.165, 3.071]) (Table 3a). That is, the pre-post difference of the intervention group was estimated to be 1.629 points higher than that of the control group. However, subgroup analysis showed that such intervention effect remained significant only among those pairs whose older adult had a HK-MoCA score of ≥ 22 (β = 2.600, 95% CI [0.451, 4.749]) (Table 3c), whereas no such improvement was found in the other subgroup (Table 3b).
Table 3a.
Linear mixed-effect regression on cooking competence (N = 60)
| Fixed effect | β | s.e. | 95% CI |
|---|---|---|---|
| Time | −0.477 | 0.521 | (−1.488, 0.555) |
| Group | |||
| Control | Ref. category | ||
| Intervention | −1.576 | 0.657 | (−2.820, −0.325) |
| Time x Intervention group (i.e., intervention effect) | 1.629 | 0.741 | (0.165, 3.071) |
| Gender | |||
| Men | Ref. category | ||
| Women | −0.508 | 0.549 | (−1.545, 0.528) |
| Age, years | −0.018 | 0.034 | (−0.083, 0.046) |
| Education | |||
| Illiterate/No education | Ref. category | ||
| Primary/Secondary | 0.576 | 0.789 | (−0.915, 2.066) |
| Tertiary | −0.100 | 0.829 | (−1.665, 1.466) |
| Random effect | σ2 | 95% CI | |
| Subject | 1.792 | (0.364, 3.211) | |
| Residual | 4.068 | (2.791, 5.812) | |
Table 3c.
Linear mixed-effect regression on general cooking competence for those who had a HK-MoCA score of ≥ 22 (N = 27)
| Fixed effect | β | s.e. | 95% CI |
|---|---|---|---|
| Time | −0.933 | 0.778 | (−2.366, 0.499) |
| Group | |||
| Control | Ref. category | ||
| Intervention | −2.371 | 0.858 | (−3.950, −0.791) |
| Time x Intervention group (i.e., intervention effect) | 2.600 | 1.167 | (0.451, 4.749) |
| Gender | |||
| Men | Ref. category | ||
| Women | 0.289 | 0.601 | (−0.818, 1.396) |
| Age, years | 0.037 | 0.047 | (−0.050, 0.125) |
| Education | |||
| Illiterate/No education | Ref. category | ||
| Primary/Secondary | 0.913 | 1.679 | (−2.179, 4.004) |
| Tertiary | 0.984 | 1.723 | (−2.189, 4.157) |
| Random effect | σ2 | 95% CI | |
| Subject | 0.000 | (0.000, 1.208) | |
| Residual | 4.537 | (2.710, 5.780) | |
Table 3b.
Linear mixed-effect regression on cooking competence for those who had a HK-MoCA score of < 22 (N = 33)
| Fixed effect | β | s.e. | 95% CI |
|---|---|---|---|
| Time | 0.000 | 0.690 | (−1.355, 1.355) |
| Group | |||
| Control | Ref. category | ||
| Intervention | −0.467 | 1.024 | (−2.338, 1.418) |
| Time x Intervention group (i.e., intervention effect) | 0.861 | 0.944 | (−1.024, 2.684) |
| Gender | |||
| Men | Ref. category | ||
| Women | −1.509 | 0.926 | (−3.197, 0.176) |
| Age, years | −0.058 | 0.059 | (−0.165, 0.049) |
| Education | |||
| Illiterate/No education | Ref. category | ||
| Primary/Secondary | 0.548 | 1.091 | (−1.439, 2.535) |
| Tertiary | −1.359 | 1.184 | (−3.515, 0.799) |
| Random effect | σ2 | 95% CI | |
| Subject | 3.453 | (0.547, 5.693) | |
| Residual | 3.570 | (2.124, 5.803) | |
Discussion
The “Chef Anchor” cooking programme improved the subjective health and well-being of the dyads (i.e., the older adults and their caregivers), as well as the cooking competence in older adults with SCD. Retention rate was excellent as all participants enrolled in the programme completed the full intervention. Based on qualitative comments made by participants, they were highly satisfied with the cooking classes, and found the cookbook (recipes) helpful and easy to use. In what follows, the intervention effects will be interpreted and discussed separately for older adults with SCD and their caregivers. This is because while some of the analyses were performed by pooling the data together, the underlying mechanisms for explaining the intervention effects may be different for these two groups of participants.
Opportunities to engage in healthy and meaningful behaviours in daily life may be a possible way to help promote well-being of older adults with SCD. “Chef Anchor”, a 5-week cooking programme, is the first-ever cooking intervention precisely designed for older adults with SCD to offer such opportunities. Findings of this RCT demonstrated significant improvement in older adults' cooking competence in the intervention group. Such positive effect may be explained by the design of the programme, which employed procedural learning methods in which the recipes had been deconstructed into smaller procedures to guide older adults with SCD to complete the cooking tasks more easily and safely. Furthermore, the programme was guided by experiential learning theory, which provided an opportunity for older adults with SCD to gain hands-on experiences in preparing dishes that are typically considered to be available only in restaurants, thereby boosting their self-efficacy and confidence in undertaking the cooking tasks. Results regarding the improvement in cooking competence for the intervention group are consistent with a previous study evaluating the effectiveness of a cooking programme to increase older adults' cooking confidence and their healthy cooking skills (23). However, this particular study, as well as the majority of other previous cooking interventions (24), were mostly confined to populations without cognitive decline. Therefore, the present study constitutes one of the first pieces of evidence on the positive effects of dyadic cooking interventions on community-dwelling older adults with SCD and their caregivers.
More importantly, the present findings also showed significant improvement in older adults' subjective health and well-being in the intervention group. One possible explanation is that the dyadic design of the programme can facilitate communication, enhance emotional support, and improve the sense of relatedness between older adults with SCD and caregivers, which could be associated with positive health and well-being. Furthermore, the interventions were delivered to participants in a large group setting, which may bring beneficial effects by increasing their social interactions. Indeed, there is evidence suggesting that older people may benefit from dining together. For example, in a study conducted in a nursing home environment, home-like meal times improved the nutritional status of the residents (25). A scoping review also revealed that a shared mealtime approach can enhance social interaction, decrease loneliness, and promote positive well-being (26).
While the overall intervention effects were significant, results from the subgroup analyses demonstrated that the effect on cooking competence remained only among older adults who had a better objective cognitive status. Such finding is not completely unexpected, given that this subgroup might have more cognitive reserve and capacity to learn and retain information, thereby having a higher chance to preserve the ability to perform cooking tasks in the future. Indeed, cooking is a complex process that requires attentional, task-switching, and working memory resources. Thus, even though the procedural learning methods employed by the cooking class were very effective in ensuring that all participants could follow the steps and cook the dishes easily, older adults with worse objective cognitive status might find it more difficult to retain the cooking skills in the long run. In contrast, the intervention effect on subjective health and well-being remained only among older adults who had a worse objective cognitive status. This result could be partly explained by the fact that those with worse objective cognitive status had lower levels of subjective health and well-being at baseline (data not shown) and therefore had more room for improvement. Another possible explanation could be that those with better cognitive status tended to be more consciousness of and fixate more on their cooking skills and performance, but less on other internal and psychological aspects, leading to the lack of improvement in the subjective health and well-being measures.
On the other hand, regarding the overall improvement in subjective health and well-being among caregivers, the intervention effect might be due to the improvement in caregiving knowledge. Indeed, caregivers are often left on their own to obtain information and support that are necessary for delivering care to older adults with SCD. Therefore, the intervention might provide a good opportunity for caregivers to address their own concerns, receive support, and possibly reframe the meaning of caregiving in a positive manner, which in turn could enhance their well-being. Subgroup analysis revealed that subjective health and well-being was only improved among those caregivers whose partner had a worse objective cognitive status. Such positive effect may be partly attributed to the improvement in well-being among the older adults in that subgroup. In other words, caregivers' subjective well-being may be, to a great extent, dependent on the care recipients' subjective well-being. Although this claim was not backed up by rigorous statistical analysis, it did coincide with the qualitative observations, in which many caregivers said that they were happy because they saw the smile on their partner's face. In addition, this explanation is also supported by the social contextual model, which emphasizes the interacting and reciprocal influences between partners, such as care recipients and caregivers in the current context (27).
Strengths and limitations
The study was completed smoothly in accordance with the protocol. It was a pragmatic RCT that included participants meeting a widely accepted definition of SCD and had the minimal exclusion criteria. The employment of procedural learning methods, cooking classes that were led by a culinary professional, and the dyadic design that recognizes the importance of linked lives in an ageing context were possibly the important elements that made the intervention effective. Regarding the limitations, however, the sample size was relatively small, and all participants were recruited from a single community centre. Therefore, a multicentre trial with a larger sample size may be conducted to validate and generalize the findings of the present study. Future studies may also consider developing other modes of delivery (e.g., home-based cooking programme) that will enable a larger number of older adults with SCD and caregivers to benefit from the intervention, and at a lower cost. Furthermore, although those who had history of MCI or dementia have been excluded, the simple SCD assessment employed in the present study could not rule the possibility that some might in fact have MCI or dementia upon taking a closer examination. Finally, the cooking programme actually consisted of various components, including the cognitive training at orientation, nutritional education, procedural cooking, and shared mealtime, each of which might have generated some effects on the outcome measures. However, the present analysis could not disentangle such effects or identify the component that contributed the most to the beneficial outcomes.
Conclusions
This study is the first to demonstrate the benefits of cooking interventions for SCD. The findings suggest that the dyadic cooking intervention can improve the cooking competence of older adults with SCD, particularly those with better objective cognitive status, as well as the subjective health and well-being of both sides of the dyad, particularly among those pairs whose older adult had a worse objective cognitive status. Further research to integrate dyadic interventions into community-based programmes for both older adults with SCD and their caregivers is warranted.
Acknowledgments
We would like to express our gratitude to the Social Welfare Department (Partnership Fund for the Disadvantaged) for funding the study. We would also like to thank our project partners, including, in alphabetical order, Judy Chan and Lillian Lai from The Hong Kong and China Gas Company Limited (Towngas), and Ester Wong, Jojo Ng, Kit-Ying Law, Sammi Chun, Suki Chan, Tommy Wong, Twiggy Wong, and Wilson Lo from the Hong Kong Sheng Kung Hui Welfare Council Limited. Finally, we would like to thank the participants for their valuable support and participation.
Conflict of Interest:
None declared.
Ethical standards:
Ethical approval was obtained from the Survey and Behavioural Research Ethics Committee of The Chinese University of Hong Kong. All participants provided their informed consent before participation.
Electronic Supplementary Material
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