Prevention of Late-Life Depression (I)

“Late-life depression is a common and highly disabling condition and is also associated with higher health care utilization and overall costs. The presence of depression may complicate the course and treatment of comorbid major medical conditions that are also highly prevalent among older adults — including diabetes, hypertension, and heart disease. Furthermore, a considerable body of evidence has demonstrated that, for older persons, residual symptoms and functional impairment due to depression are common — even when appropriate depression therapies are being used. Finally, the worldwide phenomenon of a rapidly expanding older adult population means that unprecedented numbers of seniors — and the providers who care for them — will be facing the challenge of late-life depression. For these reasons, effective prevention of late-life depression will be a critical strategy to lower overall burden and cost from this disorder. […] This textbook will illustrate the imperative for preventing late-life depression, introduce a broad range of approaches and key elements involved in achieving effective prevention, and provide detailed examples of applications of late-life depression prevention strategies”.

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I gave the book two stars on goodreads. There are 11 chapters in the book, written by 22 different contributors/authors, so of course there’s a lot of variation in the quality of the material included; the two star rating was an overall assessment of the quality of the material, and the last two chapters – but in particular chapter 10 – did a really good job convincing me that the the book did not deserve a 3rd star (if you decide to read the book, I advise you to skip chapter 10). In general I think many of the authors are way too focused on statistical significance and much too hesitant to report actual effect sizes, which are much more interesting. Gender is mentioned repeatedly throughout the coverage as an important variable, to the extent that people who do not read the book carefully might think this is one of the most important variables at play; but when you look at actual effect sizes, you get reported ORs of ~1.4 for this variable, compared to e.g. ORs in the ~8-9 for the bereavement variable (see below). You can quibble about population attributable fraction and so on here, but if the effect size is that small it’s unlikely to be all that useful in terms of directing prevention efforts/resource allocation (especially considering that women make out the majority of the total population in these older age groups anyway, as they have higher life expectancy than their male counterparts).

Anyway, below I’ve added some quotes and observations from the first few chapters of the book.

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“Meta-analyses of more than 30 randomized trials conducted in the High Income Countries show that the incidence of new depressive and anxiety disorders can be reduced by 25–50 % over 1–2 years, compared to usual care, through the use of learning-based psychotherapies (such as interpersonal psychotherapy, cognitive behavioral therapy, and problem solving therapy) […] The case for depression prevention is compelling and represents the key rationale for this volume: (1) Major depression is both prevalent and disabling, typically running a relapsing or chronic course. […] (2) Major depression is often comorbid with other chronic conditions like diabetes, amplifying the disability associated with these conditions and worsening family caregiver burden. (3) Depression is associated with worse physical health outcomes, partly mediated through poor treatment adherence, and it is associated with excess mortality after myocardial infarction, stroke, and cancer. It is also the major risk factor for suicide across the life span and particularly in old age. (4) Available treatments are only partially effective in reducing symptom burden, sustaining remission, and averting years lived with disability.”

“[M]any people suffering from depression do not receive any care and approximately a third of those receiving care do not respond to current treatments. The risk of recurrence is high, also in older persons: half of those who have experienced a major depression will experience one or even more recurrences [4]. […] Depression increases the risk at death: among people suffering from depression the risk of dying is 1.65 times higher than among people without a depression [7], with a dose-response relation between severity and duration of depression and the resulting excess mortality [8]. In adults, the average length of a depressive episode is 8 months but among 20 % of people the depression lasts longer than 2 years [9]. […] It has been estimated that in Australia […] 60 % of people with an affective disorder receive treatment, and using guidelines and standards only 34 % receives effective treatment [14]. This translates in preventing 15 % of Years Lived with Disability [15], a measure of disease burden [14] and stresses the need for prevention [16]. Primary health care providers frequently do not recognize depression, in particular among elderly. Older people may present their depressive symptoms differently from younger adults, with more emphasis on physical complaints [17, 18]. Adequate diagnosis of late-life depression can also be hampered by comorbid conditions such as Parkinson and dementia that may have similar symptoms, or by the fact that elderly people as well as care workers may assume that “feeling down” is part of becoming older [17, 18]. […] Many people suffering from depression do not seek professional help or are not identied as depressed [21]. Almost 14 % of elderly people living in community-type living suffer from a severe depression requiring clinical attention [22] and more than 50 % of those have a chronic course [4, 23]. Smit et al. reported an incidence of 6.1 % of chronic or recurrent depression among a sample of 2,200 elderly people (ages 55–85) [21].”

“Prevention differs from intervention and treatment as it is aimed at general population groups who vary in risk level for mental health problems such as late-life depression. The Institute of Medicine (IOM) has introduced a prevention framework, which provides a useful model for comprehending the different objectives of the interventions [29]. The overall goal of prevention programs is reducing risk factors and enhancing protective factors.
The IOM framework distinguishes three types of prevention interventions: (1) universal preventive interventions, (2) selective preventive interventions, and (3) indicated preventive interventions. Universal preventive interventions are targeted at the general audience, regardless of their risk status or the presence of symptoms. Selective preventive interventions serve those sub-populations who have a significantly higher than average risk of a disorder, either imminently or over a lifetime. Indicated preventive interventions target identified individuals with minimal but detectable signs or symptoms suggesting a disorder. This type of prevention consists of early recognition and early intervention of the diseases to prevent deterioration [30]. For each of the three types of interventions, the goal is to reduce the number of new cases. The goal of treatment, on the other hand, is to reduce prevalence or the total number of cases. By reducing incidence you also reduce prevalence [5]. […] prevention research differs from treatment research in various ways. One of the most important differences is the fact that participants in treatment studies already meet the criteria for the illness being studied, such as depression. The intervention is targeted at improvement or remission of the specific condition quicker than if no intervention had taken place. In prevention research, the participants do not meet the specific criteria for the illness being studied and the overall goal of the intervention is to prevent the development of a clinical illness at a lower rate than a comparison group [5].”

“A couple of risk factors [for depression] occur more frequently among the elderly than among young adults. The loss of a loved one or the loss of a social role (e.g., employment), decrease of social support and network, and the increasing change of isolation occur more frequently among the elderly. Many elderly also suffer from physical diseases: 64 % of elderly aged 65–74 has a chronic disease [36] […]. It is important to note that depression often co-occurs with other disorders such as physical illness and other mental health problems (comorbidity). Losing a spouse can have significant mental health effects. Almost half of all widows and widowers during the first year after the loss meet the criteria for depression according to the DSM-IV [37]. Depression after loss of a loved one is normal in times of mourning. However, when depressive symptoms persist during a longer period of time it is possible that a depression is developing. Zisook and Shuchter found that a year after the loss of a spouse 16 % of widows and widowers met the criteria of a depression compared to 4 % of those who did not lose their spouse [38]. […] People with a chronic physical disease are also at a higher risk of developing a depression. An estimated 12–36 % of those with a chronic physical illness also suffer from clinical depression [40]. […] around 25 % of cancer patients suffer from depression [40]. […] Depression is relatively common among elderly residing in hospitals and retirement- and nursing homes. An estimated 6–11 % of residents have a depressive illness and among 30 % have depressive symptoms [41]. […] Loneliness is common among the elderly. Among those of 60 years or older, 43 % reported being lonely in a study conducted by Perissinotto et al. […] Loneliness is often associated with physical and mental complaints; apart from depression it also increases the chance of developing dementia and excess mortality [43].”

“From the public health perspective it is important to know what the potential health benefits would be if the harmful effect of certain risk factors could be removed. What health benefits would arise from this, at which efforts and costs? To measure this the population attributive fraction (PAF) can be used. The PAF is expressed in a percentage and demonstrates the decrease of the percentage of incidences (number of new cases) when the harmful effects of the targeted risk factors are fully taken away. For public health it would be more effective to design an intervention targeted at a risk factor with a high PAF than a low PAF. […] An intervention needs to be effective in order to be implemented; this means that it has to show a statistically significant difference with placebo or other treatment. Secondly, it needs to be effective; it needs to prove its benefits also in real life (“everyday care”) circumstances. Thirdly, it needs to be efficient. The measure to address this is the Number Needed to Be Treated (NNT). The NNT expresses how many people need to be treated to prevent the onset of one new case with the disorder; the lower the number, the more efficient the intervention [45]. To summarize, an indicated preventative intervention would ideally be targeted at a relatively small group of people with a high, absolute chance of developing the disease, and a risk profile that is responsible for a high PAF. Furthermore, there needs to be an intervention that is both effective and efficient. […] a more detailed and specific description of the target group results in a higher absolute risk, a lower NNT, and also a lower PAF. This is helpful in determining the costs and benefits of interventions aiming at more specific or broader subgroups in the population. […] Unfortunately very large samples are required to demonstrate reductions in universal or selected interventions [46]. […] If the incidence rate is higher in the target population, which is usually the case in selective and even more so in indicated prevention, the number of participants needed to prove an effect is much smaller [5]. This shows that, even though universal interventions may be effective, its effect is harder to prove than that of indicated prevention. […] Indicated and selective preventions appear to be the most successful in preventing depression to date; however, more research needs to be conducted in larger samples to determine which prevention method is really most effective.”

“Groffen et al. [6] recently conducted an investigation among a sample of 4,809 participants from the Reykjavik Study (aged 66–93 years). Similar to the findings presented by Vink and colleagues [3], education level was related to depression risk: participants with lower education levels were more likely to report depressed mood in late-life than those with a college education (odds ratio [OR] = 1.87, 95 % confidence interval [CI] = 1.35–2.58). […] Results from a meta-analysis by Lorant and colleagues [8] showed that lower SES individuals had a greater odds of developing depression than those in the highest SES group (OR = 1.24, p= 0.004); however, the studies involved in this review did not focus on older populations. […] Cole and Dendukuri [10] performed a meta-analysis of studies involving middle-aged and older adult community residents, and determined that female gender was a risk factor for depression in this population (Pooled OR = 1.4, 95 % CI = 1.2–1.8), but not old age. Blazer and colleagues [11] found a significant positive association between older age and depressive symptoms in a sample consisting of community-dwelling older adults; however, when potential confounders such as physical disability, cognitive impairment, and gender were included in the analysis, the relationship between chronological age and depressive symptoms was reversed (p< 0.01). A study by Schoevers and colleagues [14] had similar results […] these findings suggest that higher incidence of depression observed among the oldest-old may be explained by other relevant factors. By contrast, the association of female gender with increased risk of late-life depression has been observed to be a highly consistent finding.”

“In an examination of marital bereavement, Turvey et al. [16] analyzed data among 5,449 participants aged≥70 years […] recently bereaved participants had nearly nine times the odds of developing syndromal depression as married participants (OR = 8.8, 95 % CI = 5.1–14.9, p<0.0001), and they also had significantly higher risk of depressive symptoms 2 years after the spousal loss. […] Caregiving burden is well-recognized as a predisposing factor for depression among older adults [18]. Many older persons are coping with physically and emotionally challenging caregiving roles (e.g., caring for a spouse/partner with a serious illness or with cognitive or physical decline). Additionally, many caregivers experience elements of grief, as they mourn the loss of relationship with or the decline of valued attributes of their care recipients. […] Concepts of social isolation have also been examined with regard to late-life depression risk. For example, among 892 participants aged ≥65 years […], Gureje et al. [13] found that women with a poor social network and rural residential status were more likely to develop major depressive disorder […] Harlow and colleagues [21] assessed the association between social network and depressive symptoms in a study involving both married and recently widowed women between the ages of 65 and 75 years; they found that number of friends at baseline had an inverse association with CES-D (Centers for Epidemiologic Studies Depression Scale) score after 1 month (p< 0.05) and 12 months (p= 0.06) of follow-up. In a study that explicitly addressed the concept of loneliness, Jaremka et al. [22] conducted a study relating this factor to late-life depression; importantly, loneliness has been validated as a distinct construct, distinguishable among older adults from depression. Among 229 participants (mean age = 70 years) in a cohort of older adults caring for a spouse with dementia, loneliness (as measured by the NYU scale) significantly predicted incident depression (p<0.001). Finally, social support has been identified as important to late-life depression risk. For example, Cui and colleagues [23] found that low perceived social support significantly predicted worsening depression status over a 2-year period among 392 primary care patients aged 65 years and above.”

“Saunders and colleagues [26] reported […] findings with alcohol drinking behavior as the predictor. Among 701 community-dwelling adults aged 65 years and above, the authors found a significant association between prior heavy alcohol consumption and late-life depression among men: compared to those who were not heavy drinkers, men with a history of heavy drinking had a nearly fourfold higher odds of being diagnosed with depression (OR = 3.7, 95 % CI = 1.3–10.4, p< 0.05). […] Almeida et al. found that obese men were more likely than non-obese (body mass index [BMI] < 30) men to develop depression (HR = 1.31, 95 % CI = 1.05–1.64). Consistent with these results, presence of the metabolic syndrome was also found to increase risk of incident depression (HR = 2.37, 95 % CI = 1.60–3.51). Finally, leisure-time activities are also important to study with regard to late-life depression risk, as these too are readily modifiable behaviors. For example, Magnil et al. [30] examined such activities among a sample of 302 primary care patients aged ≥60 years. The authors observed that those who lacked leisure activities had an increased risk of developing depressive symptoms over the 2-year study period (OR = 12, 95 % CI = 1.1–136, p= 0.041). […] an important future direction in addressing social and behavioral risk factors in late-life depression is to make more progress in trials that aim to alter those risk factors that are actually modifiable.”