A Community-Wide Intervention Trial for Preventing and Reducing Frailty Among Older Adults Living in Metropolitan Areas: Design and Baseline Survey for a Study Integrating Participatory Action Research With a Cluster Trial

Background Preventing and reducing frailty is an important challenge for Japan in the next decade, especially in metropolitan areas. We launched a community-wide intervention trial (the Ota Genki Senior Project) in 2016 to develop effective community-based strategies for frailty prevention in metropolitan areas. This report describes the study design and baseline survey. Methods This study is a community-wide intervention trial that integrates participatory action research into a cluster non-randomized controlled trial for adults aged 65 years or older living in Ota City, Tokyo. We allocated 3 of 18 districts to an intervention group and the other 15 to a control group. Using a mailed self-administered questionnaire, we conducted a baseline survey of 15,500 residents (8,000 and 7,500 in the intervention and control groups, respectively) from July through August 2016. In addition to socioeconomic status and lifestyle variables, we assessed frailty status (primary outcome) and physical, nutritional, and psychosocial variables (secondary outcomes). Based on the baseline findings, an intervention to improve outcomes will be implemented as participatory action research. Follow-up surveys will be conducted in the same manner as the baseline survey. Results A total of 11,925 questionnaires were returned (76.9% response rate; 6,105 [76.3%] and 5,820 [77.6%] in the intervention and control groups, respectively), and 11,701 were included in the analysis (mean age, 74.3 [standard deviation, 5.5] years; 48.5% were men). Conclusions This study is expected to contribute to development of a prototype of a community-wide frailty prevention strategy, especially in metropolitan areas in Japan. Trial registration: UMIN Clinical Trials Registry (UMIN000026515).

2 150 minutes/week or more of walking were evaluated. 20,26 We asked about performing exercise more than once a week by multiple answers. Recreational walking and walking for transport were both considered engagement in walking. We asked about the number of days per week and the mean number of minutes walked per day, which are part of the International Physical Activity Questionnaire Short-Form 27, 28 and calculated the weekly total minutes of walking time.
Physical function was assessed by using the Motor Fitness Scale. 29,30 The responses to each item in this 14-item index of physical tasks are "yes" (able to perform), for 1 point, and "no" (unable to perform), for 0 points. The total score ranges from 0 to 14. Lower scores indicate lower physical function, and a total score of ≤11 for men or ≤9 for women is defined as low physical function. 30 Mobility limitation was defined as self-reported difficulty in walking one-quarter of a mile (0.4 km) or climbing 10 steps without resting. 31 The response options were "no difficulty," "some difficulty," or "inability" to perform. Those who reported at least some difficulty performing these activities were considered to have limited mobility. 32

Dietary variety
We assessed the frequency of food intake and dietary variety by using a 3 self-administered questionnaire. 33, 34 Over a period of 1 week, participants were asked about their frequency of consumption for each of the 10 main food groups in the Japanese diet (meat, fish/shellfish, eggs, milk, soybean products, green/yellow vegetables, potatoes, fruit, seaweed, and fats/oils). There were four responses for frequency of food intake for each food group: almost daily (3 points), 3 or 4 days a week (2 points), 1 or 2 days a week (1 point), and hardly ever (0 points). Food Frequency Score (FFS) 34 was calculated as the sum of scores for each of the 10 food groups (range 0−30), and Dietary Variety Score (DVS) as the sum of the number of times each participant answered "almost daily" for each food group (range 0−10). 33 DVS was treated as both a continuous and dichotomous (score of ≥4) variable.

Social activity and psychosocial function
Self-rated health, depressive mood, well-being, frequency of outing, social isolation, and cognitive and structural social capital were evaluated by analyzing responses to a commonly used self-administered questionnaire. Self-rated health was assessed with the question, "How would you rate your current overall health?" The response options were "excellent," "good," "fair," and "poor." The 5-item Geriatric Depression Scale   35,36 and World Health Organization-Five (WHO-5) Well-Being Index 37, 38 were 4 used to assess depressive mood and well-being, respectively. We asked about frequencies of outing and contact with family/relatives and friends, apart from cohabiting family members. Contact with others (apart from cohabiting family members) less than once a week was defined as social isolation. 39 Cognitive social capital included trust in neighbors. The response options were "agree," "tend to agree," "tend to disagree," and "disagree." Structural social capital included frequency of social participation. Participation in any of the following activities or groups more than once a month was defined as the presence of social participation: volunteering, civic action, and nonprofit organizations; sports groups; hobby and learning groups; senior citizen clubs; neighborhood associations; and others.

Additional measures
We obtained information on age, sex, family composition (not alone or alone), marital status (married, widowed, divorced, or never married), education (junior high school graduate, high school graduate, junior college/vocational college graduate, college/graduate school graduate, or other/unknown), equivalent income (<1.0, 1.0-2.49, 2.5-3.99, ≥4.0 million yen), alcohol drinking and smoking status (current, former, or never), body mass index (self-rated height and weight), history of physician-diagnosed 5 diseases (hypertension, hyperlipidemia, cardiovascular disease, cerebrovascular disease, diabetes mellitus, and/or others), musculoskeletal pain (shoulder, low back, and/or knee), sleep duration, quality of sleep (excellent, good, fair, or poor), number of meals (n/day), eating status (eat with others or eat alone), 46 neighbor relationships (visiting each other, standing and chatting, no more than an exchange of greetings, or none), employment status (yes or no), information and communication technology use (any, smartphone, mobile phone, computer, internet, or none), Pet ownership (current, former, or never), subjective happiness (happy, rather happy, rather unhappy, or unhappy), and Tokyo Metropolitan Institute of Gerontology Index of Competence. 47 eTable 1. Baseline characteristics of participants (measures not included in