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Commercial smartphone apps that promote self-monitoring of weight loss are widely available. The development of disease-specific apps has begun, but there is no app for specific health guidance (SHG) to prevent metabolic syndrome, type 2 diabetes, and cardiovascular diseases in middle-aged adults in Japan.
This study aimed to determine the efficacy of an SHG mobile health app in facilitating weight loss in Japanese adults with obesity and hypertension.
In a 12-week, statistician-blinded, randomized parallel controlled trial, 78 overweight and obese men aged 40-69 years were assigned in a 1:1 ratio to either the usual support plus KENPO-app group (intervention group) or the active control group. KENPO-app (release April 10, 2019; OMRON Healthcare Co., Ltd.) was developed by the study team and focus groups and uses behavior change techniques (ie, self-monitoring and goal-setting theory). This app was developed for SHG based on the four specific health checkups and guidance system in Japan: (1) focusing primarily on achieving the target (weight loss of ≥2 kg); (2) assessing healthy eating, exercise habits, smoking habits, relaxation, and self-weighing; (3) providing information on the results of specific health checkups; and (4) starting an intervention period of 6 months with the interim assessment at 3 months. The initial assessment explored the following: personality traits (4 types), health checkup data concerns (10 items), symptom concerns (10 items), and the aim of the intervention (weight loss, improving fitness, symptoms, laboratory data). Chatbot-supported health information on health and health behavior was selected from 392 quizzes based on app data and was provided to participants. The KENPO-app had chatbot-supported feedback and information provision combined with a self-monitoring tool (weight, steps, and blood pressure). Data on active exercise, healthy eating, and healthy lifestyle habits were obtained using a web-based self-administered questionnaire at baseline and 12 weeks.
The trial’s retention rate was 95% (74/78). The adherence to daily self-weighing, wearing the pedometer, and blood pressure monitoring in the KENPO-app group was significantly higher than those in the active control group. Compared with the active control group, the median body weight and BMI of the intervention group significantly decreased at 3 months (–0.4, IQR –2.0 to 0.6 kg vs –1.1, IQR –2.7 to –0.5 kg;
The SHG-specific KENPO-app was feasible and induced modest but significant weight loss in adults with obesity.
University Hospital Medical Information Network Center UMIN000046263; https://tinyurl.com/bderys3b
In 2008, all health insurers in Japan were mandated to provide specific health guidance (SHG) to prevent metabolic syndrome, type 2 diabetes, and cardiovascular diseases in middle-aged adults in Japan [
This study was a 12-week, statistician-blinded, parallel-group, randomized controlled trial (RCT) of adults with obesity and hypertension. The data were obtained between October 2021 and May 2022.
The study protocol was approved by the institutional review board of Kyoto Medical Center (NO.21-057), and the protocol of the study was registered at the University Hospital Medical Information Network Center (UMIN000046263).
Participants were recruited from the screening panel of the Omron monitor recruitment site for product development and research in Japan. Therefore, participants may have relatively higher computer/internet literacy. We held an online information session for this trial. Inclusion criteria were as follows: age 40-64 years, BMI≥25 kg/m2, systolic blood pressure (SBP) ≥130 mm Hg or diastolic blood pressure (DBP) ≥85 mm Hg, smartphone users capable of installing apps, and individuals capable of communicating online. Exclusion criteria were as follows: receiving SHG at present, taking antihypertensive medicine, contraindication for healthy eating and active exercise by a doctor, pregnant or breastfeeding women, and inappropriate cases (ie, severe psychiatric disorders) as determined by a research doctor.
The independent statistician randomly allocated participants into one of two intervention arms according to sex-, age-, SBP-, and BMI-stratified block randomization (seed=1221 and block size=2). We adopted a single-blind approach; thus, the effectiveness was assessed by blinded researchers who were unaware of the randomization results.
Participants in both groups received a Bluetooth weighing scale (HBF-227T, OMRON Healthcare Co, Ltd), pedometer (HJA-405T, OMRON Healthcare Co, Ltd), and upper arm blood pressure (BP) monitor (HCR-7501T, OMRON Healthcare Co, Ltd).
The participants in the active control group received the usual support. The usual support was based on intensive SHG, and the participants in both groups received initial online face-to-face counseling by a health care professional (ie, a registered dietician) who had completed the established Ministry of Health, Labor and Welfare (MHLW) training course. Participants were briefed about their health condition and lifestyle through a review of their SHG results. They were instructed to set achievable personalized behavioral goals. After the initial counseling, a health care professional provided email support three times at 2, 6, and 12 weeks. Implementation points according to the MHLW in the active control group were comparable to the required points of ≥180 in the SHG. Daily recording of body weight and steps were recommended. Measurements of BP in the morning and evening were also recommended.
KENPO-app (release April 10, 2019; OMRON Healthcare Co, Ltd) was developed using behavior change techniques (ie, self-monitoring and goal-setting theory) by the study team and focus groups. This app was developed for SHG based on the four specific health checkups and guidance system in Japan: (1) focusing on achieving the primary target (weight loss of ≥2 kg); (2) assessing healthy eating, exercise habits, smoking habits, relaxation, and self-weighing; (3) providing information on the results of specific health checkups; and (4) starting an intervention period of 6 months with the interim assessment at 3 months. The initial assessment explored the following: personality traits (4 types), concerns about health checkup data (10 items), concerns about symptoms (10 items), and the aim of the intervention (weight loss, improving fitness, symptoms, laboratory data;
Screenshot and initial assessment of KENPO-app system. (A) KENPO-app at APP Store; (B) KENPO-app at Google Play; (C) initial assessment items.
Outline of KENPO-app system.
Initial assessment (laboratory data, symptoms, and clinical goals)
Personality trait
Setting weight loss goal
Targeting behavioral agenda (exercise, dietary, lifestyle habits, daily steps)
Pedometer, weight, and blood pressure, and behavioral agenda
SHG based on app data and personality trait
Pedometer, weight, and blood pressure, and behavioral agenda
Chatbot-supported feedback of app data and sign of weight regain
Chatbot-supported quiz on health and health behavior
Final assessment (laboratory data, symptoms, objective)
Behavioral agenda (exercise, dietary, and lifestyle habits)
The outcome included changes in body weight and BMI. Weight measurements were uploaded to the cloud where the data were obtained, and the 7-day average weight was calculated. Other outcomes included changes in SBP, DBP, and adherence to the device. The frequency of weight, BP, and step uploads was recorded as a measure of adherence. Data on active exercise habits (10 items), healthy eating habits (10 items), and healthy lifestyle habits (10 items) were obtained using a web-based self-administered questionnaire at baseline and 12 weeks. Quality assurance was performed through standard operating procedures and benchmarking. Adherence to the apps was defined based on the sending rate of body weight measurements, and an attrition diagram was made.
Data are expressed as the mean (SD), median (IQR), range, or number. Blinded data were analyzed using the R software version 4.0.0. (R Foundation for Statistical Computing) on an intention-to-treat basis by the statistician. Statistical analysis of quantitative data was performed using the Shapiro-Wilk test, Mann-Whitney
After 80 participants were screened, we enrolled 78 participants and excluded 2. Of the 78 participants, the mean age was 52.0 (SD 6.5) years, and 55% (n=43) were male. Those who had full- and part-time jobs accounted for 65% (n=51) and 19% (n=15) of the sample, respectively. Participants were assigned to either the KENPO-app group (intervention group; n=39) or the active control group (n=39). There were no differences in age (mean 52.5, SD 6.6 years vs mean 51.4, SD 6.4 years;
CONSORT flow diagram of KENPO-app study.
Attrition diagram on self-weighing and mean changes in body weight during the study period.
The percentage of participants who reported ≥8000 steps per day, slow eating speed, vegetable intake before rice, selecting a healthy menu, and relaxation in the intervention group increased after the 12-week study period, while the percentage of eating breakfast and reducing snacks in the active control group increased (
Healthy lifestyle and symptoms during the study period according to the group.
Item | Intervention group (n=39), n (%) | Control group (n=39), n (%) | ||||||||||||
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Pre | Post | Pre | Post | ||||||||||
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Use of stairs instead of the escalators | 5 (14) | 8 (22) | .45 | 9 (24) | 14 (38) | .13 | |||||||
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Walking ≥8000 steps | 6 (16) | 13 (35) | .046 | 9 (24) | 8 (22) | >.99 | |||||||
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At least 30 min of brisk daily walks | 4 (11) | 9 (24) | .18 | 6 (16) | 6 (16) | >.99 | |||||||
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Do gymnastics/stretching everyday | 3 (8) | 6 (16) | .37 | 2 (5) | 8 (22) | .08 | |||||||
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Do not stay home and do nothing on holiday | 3 (8) | 7 (19) | .22 | 7 (19) | 12 (32) | .18 | |||||||
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Stand up and exercise once an hour | 8 (22) | 13 (35) | .18 | 9 (24) | 9 (24) | >.99 | |||||||
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Do housework (cooking, cleaning, etc) | 15 (41) | 18 (49) | .37 | 24 (65) | 25 (68) | >.99 | |||||||
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Resistance training ≥3 times per week | 1 (3) | 2 (5) | >.99 | 1 (3) | 2 (5) | >.99 | |||||||
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Use the gym or pool at least once per week | 1 (3) | 1 (3) | >.99 | 0 (0) | 1 (3) | >.99 | |||||||
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Play sports at least once a week | 0 (0) | 4 (11) | .13 | 3 (8) | 4 (11) | >.99 | |||||||
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Eat moderately | 1 (3) | 7 (19) | .08 | 6 (16) | 10 (27) | .22 | |||||||
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Eat breakfast | 22 (60) | 22 (60) | >.99 | 25 (68) | 31 (84) | .04 | |||||||
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Eat vegetable first | 12 (32) | 23 (62) | .01 | 22 (60) | 26 (70) | .22 | |||||||
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Eat slowly and well | 1 (3) | 9 (24) | .01 | 13 (35) | 16 (43) | .37 | |||||||
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Eat with nutritional balance in mind | 4 (11) | 9 (24) | .13 | 12 (32) | 15 (41) | .45 | |||||||
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Do not overeat carbohydrates | 1 (3) | 5 (14) | .13 | 9 (24) | 14 (38) | .13 | |||||||
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Eat fried food up to 3 times per week | 1 (3) | 6 (16) | .07 | 12 (32) | 16 (43) | .29 | |||||||
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Reduce salt | 1 (3) | 6 (16) | .07 | 11 (30) | 12 (32) | >.99 | |||||||
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Reduce sweet buns and delicatessen bread | 7 (19) | 9 (24) | .72 | 11 (30) | 14 (38) | .37 | |||||||
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Reduce eating in dinner | 1 (3) | 4 (11) | .25 | 8 (22) | 13 (35) | .13 | |||||||
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Reduce sugar-sweetened beverages | 8 (22) | 14 (38) | .15 | 20 (54) | 23 (62) | .45 | |||||||
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Reduce sweets | 4 (11) | 5 (14) | >.99 | 5 (14) | 15 (41) | .02 | |||||||
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Check food labels | 7 (19) | 12 (32) | .13 | 11 (30) | 14 (38) | .45 | |||||||
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Choose healthy menu | 0 (0) | 8 (19) | .02 | 9 (24) | 9 (24) | >.99 | |||||||
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Do not eat anything 2 h before bedtime | 9 (24) | 15 (41) | .08 | 13 (35) | 14 (38) | >.99 | |||||||
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Go to bed early | 8 (22) | 12 (32) | .39 | 10 (27) | 10 (27) | >.99 | |||||||
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Try to have alcohol-free days | 26 (70) | 30 (81) | .29 | 27 (73) | 29 (78) | .62 | |||||||
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Reduce alcohol drinks | 27 (73) | 28 (76) | >.99 | 24 (65) | 25 (68) | >.99 | |||||||
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Stop smoking | 33 (89) | 32 (87) | >.99 | 33 (89) | 33 (89) | >.99 | |||||||
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Relaxation | 6 (16) | 16 (43) | .02 | 15 (41) | 13 (35) | .79 | |||||||
|
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Headache | 10 (27) | 3 (8) | .07 | 8 (22) | 7 (19) | >.99 | |||||||
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Shoulder stiffness | 23 (62) | 12 (32) | .006 | 21 (57) | 13 (35) | .04 | |||||||
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Heartburn | 6 (16) | 1 (3) | .07 | 7 (19) | 1 (3) | .04 | |||||||
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Lumbago | 17 (46) | 9 (24) | .10 | 17 (46) | 15 (41) | .75 | |||||||
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Knee pain | 13 (35) | 8 (22) | .12 | 6 (16) | 5 (14) | >.99 | |||||||
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Constipation | 7 (19) | 0 (0) | .02 | 8 (22) | 8 (22) | >.99 | |||||||
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Chillness | 9 (24) | 2 (5) | .02 | 13 (35) | 4 (11) | .02 | |||||||
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Fatigue | 11 (30) | 8 (22) | .37 | 14 (38) | 10 (27) | .29 | |||||||
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Difficulty in waking up | 3 (8) | 3 (8) | >.99 | 9 (24) | 7 (19) | .68 | |||||||
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Leg cramps | 6 (16) | 2 (5) | .13 | 6 (16) | 5 (14) | >.99 |
This is the first study to confirm the effectiveness of the SHG-specific KENPO-app in obese adults with hypertension. The mHealth KENPO-app is feasible and can produce modest but significant weight loss. Compared with standard care, the mHealth app produced modest weight loss (–1.0 kg to –2.4 kg of body weight) in obese adults with diabetes [
Self-monitoring of weight was a significant predictor of weight loss [
The current consensus states that obtaining less than 5000 steps per day is sedentary behavior, whereas obtaining >8000 steps indicates an active exercise habit [
Moreover, slow eating speed, vegetable intake before rice, selection of a healthy menu, and relaxation in the intervention group increased after the intervention. Fast eating speed is positively associated with obesity [
Personality traits are an important factor in health behaviors. Interestingly, personality traits were associated with the degree of weight change in this study. Specific aspects of personality (ie, agreeableness) are relevant to weight loss maintenance [
The strengths of this study include the SHG-specific mHealth app, objective measurement of data, and a high retention rate. Although mHealth apps for weight management are popular and widely available, many apps lack professional content expertise. Encouraging app development based on evidence-based online approaches would ensure content quality, allowing health care professionals to recommend their use [
In conclusion, the SHG-specific KENPO-app was feasible and induced significant weight loss in Japanese adults with obesity and hypertension.
CONSORT-eHEALTH checklist (V 1.6.1).
blood pressure
diastolic blood pressure
information and communications technology
mobile health
Ministry of Health, Labor and Welfare
randomized controlled trial
systolic blood pressure
specific health guidance
This study was partly supported by the Japan Society for the Promotion of Science KAKENHI (grant 22K11253) and the Japan Agency for Medical Research and Development DOUKI-APP Study (grant 21ek0210124). This study was funded by OMRON Healthcare Co, Ltd.
None declared.