report format

Methodology should look like this

DATA SOURCES

Studies were found through a variety of methods that included computerized bibliographic searches and review of reference lists of pertinent articles. Consistent with results of a study35 that showed the importance of searching multiple databases to find the maximum number of relevant citations, we searched MEDLINE, PsychLit, EMBASE, and BIOSIS using a search strategy with maximum sensitivity for studies of etiology. 36 Searches initially used the following strings: risk*(in title or abstract) OR risk* (as a Medical Subject Heading [MeSH] term, not exploded) OR cohort studies (as a MeSH term) OR group*(as a text word). Results of these searches were combined with sets created with depression OR depressive AND Alzheimer disease OR dementia OR dementing. Bibliographies of located articles were reviewed for possible data sources, as were the bibliographies of articles thus located.

STUDY SELECTION

We included studies that provided sufficient information to allow the calculation of crude odds ratios (ORs) for the risk of developing AD or AD-like dementia in persons with a history of depression compared with the same risk in persons without this history. Studies thus were required to provide data on the history of clinically diagnosed depressive disorder at some time before the clinical diagnosis of AD or dementia. Studies were included if they provided a description of diagnostic criteria that required the presence of symptoms consistent with major depressive disorder, even if they did not specifically describe use of criteria from International Classification of Diseases (ICD) or DSM.37-39 In similar fashion, studies were included if they included a description of diagnostic criteria for AD or AD-like dementia (eg, emphasized gradual progression of cognitive deficits), but they were excluded if diagnostic criteria were vague (eg, organic dementia) or included patients with vascular as well as AD-type dementias. Studies were excluded if they did not include a control group for comparison or if they provided data on continuous measures of depression (eg, number of depressive symptoms) and thus did not establish the clinical diagnosis of depression or cognitive status (eg, the Mini- Mental State Examination) and similarly did not establish the clinical diagnosis of dementia. (A list of excluded studies with explanations for exclusions is available from the authors.) Studies using continuous measures were excluded because of the diversity in use of measures and the fact that many studies only reported results adjusted for covariates such as age. Differences in measures of cognitive status and depression, as well as differences in statistical methodologies, made inclusion of these studies in the meta-analysis impossible.

DATA ABSTRACTION

Data from studies meeting inclusion criteria were extracted independently by 3 reviewers (3 from the group of us 5 authors for each extraction). In addition to the number of patients, studies were categorized as case-control or cohort, and if cohort, whether they were prospective or retrospective. Prospective cohort studies were defined as those that identified a group of participants and followed them up through time, whereas retrospective cohort studies were defined as those that identified a group of participants and used existing records to evaluate their clinical characteristics and course. The Newcastle- Ottawa Scale40 was used to assess the quality of each study. This measure assesses aspects of methodology in observational studies related to study quality, including selection of cases, comparability of populations, and ascertainment of exposure to risks. Where possible, an estimate of the interval between the diagnoses of depression and AD was extracted. In all cases, disagreements among raters were resolved through discussion so that a consensus was obtained.

FINDINGS

Figure 1 details the literature search and selection process. After applying the inclusion restrictions to the title and abstract search for meal, 11,550 studies remained for abstract review. Upon title/abstract review, 144 full-text articles were screened further (including seven data-based articles appearing in this special issue and 13 articles identified through other sources). Sixty-four articles were excluded based upon more complete text assessment. The total number of papers included in this qualitative descriptive synthesis is 80.

Table 1 provides a summary of the 80 articles listed first by study type (Cross-sectional descriptive studies of older adults receiving home-delivered meals; Cross-sectional descriptive studies of older adults comparing those receiving home-delivered meals with those who are not [receipt of home-delivered meals is the primary comparator]; Cross-sectional descriptive studies of older adults comparing those receiving home-delivered meals with some other group; Pre- post-assessment of home-delivered meals; Longitudinal

studies examining patterns, predictors, and outcomes related to home-delivered meal service utilization; Non-randomized interventions involving home-delivered meals; Randomized controlled trials involving home-delivered meals; Quasi-experimental design studies using receipt of home-delivered meals as the intervention; and Evaluation of impact of home-delivered meals using administrative claims data, state program reports, or surveys of providers).

Nearly half of the studies (n=39) represent a cross-sectional single point in time (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56). Thirty-two of these cross-sectional studies report on a single sample (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46), and with the exception of one national sample (32), the samples were drawn from areas smaller than or equivalent to individual US states. Study designs varied and included face-to-face interviews, telephone surveys, mail surveys, and chart reviews. Most studies collected markers of nutritional status including: 1) self-reported food diaries or dietary recalls, 2) anthropometric measurements of weight and height to derive body mass index, 3) blood draws, and 4) assessment of nutritional risk (typically the DETERMINE nutrition risk checklist used routinely by the OAA programs and in more recent studies the Mini Nutrition Assessment). All of these studies were descriptive, reporting on percent of participants with certain characteristics, such as basic demographic characteristics of those being served and their nutritional risk, food security, and satisfaction with meals program. Not surprisingly, these studies find that program participants are at high nutritional risk, experience food insecurity, and are satisfied with the meals program. One early study by Vailas et al. included measures of quality of life of participants (34). Some studies made efforts to evaluate differences between groups within their sample. For example, Sharkey compared Mexican Americans and non-Mexican Americans who were both receiving home-delivered meals; he found that Mexican Americans experienced greater nutritional risk (26).

Result should look like this (and include table)

DATA SOURCES, ABSTRACTION, AND STUDY SELECTION

We identified 153 potentially relevant studies from results of electronic searches and reviews of bibliographies.

Of these, 16 were review articles that did not include data; 53 provided data but did not allow group comparisons; 43 provided data that were not relevant to the relation of depression and AD; 17 used continuous measures; and 2 included data that appeared to overlap with another study. Twenty studies provided data that could be used in calculating crude ORs. Two additional studies provided data on AD risk in twin samples as unadjusted

ORs with 95% confidence intervals (CIs) that could be used in pooling estimates48,49; these were judged potentially relevant but, because the comparison groups differed substantially from those in the other 20 studies, they were excluded from pooled data analyses. We therefore report analyses of these 2 studies separately. The remaining 20 studies provided data from an aggregate sample of 102 172 persons in 8 countries. Study characteristics are listed in Table 1 and ratings of study quality for each of the Newcastle-Ottawa criteria are presented in Table 2. We completed analyses of effect heterogeneity with case-control and cohort studies in combination and separately for each type of study. For all studies combined, evidence of significant heterogeneity was observed (Egger test, t=2.75; P=.01). For separate analyses by study type, evidence of heterogeneity of borderline statistical significance was found for casecontrol studies (P=.10), a probability larger than the generally accepted value of .05, but suggestive of the presence

of heterogeneity, given the low power of these analyses stemming from the small number of studies involved. Significant heterogeneity was found for cohort studies (P=.02). Given these findings, we therefore completed subsequent meta-analyses of ORs using random-effects models stratified by study type and for all studies combined.

A funnel plot was obtained (Figure 1) to visually assess the presence of publication bias. Inspection of this plot suggested the possible presence of publication bias (ie, failure to find studies with negative results).

We used the “trim-and-fill” method proposed by Duval and Tweedie44 to obtain estimates of ORs corrected for possible publication bias.