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Being overweight and obese are major risk factors for noncommunicable diseases such as cardiovascular diseases. The prevalence of overweight and obesity is high throughout the world and these issues are very serious in the Shunyi District in China. As mobile technologies have rapidly developed, mobile apps such as WeChat are well accepted and have the potential to improve health behaviors.
This study aims to evaluate the effectiveness of a mobile app (WeChat) as an intervention on weight loss behavior.
This study was conducted among an occupational population from August 2015 to February 2016 in the Shunyi District of Beijing. Before the intervention, the Shunyi District Government released an official document for weight loss to all 134 government agencies and enterprises in Shunyi District. Participants willing to use our official WeChat account were enrolled in a WeChat group and received 6 months of interventions for weight loss; those who were not willing to use the account were in a control group given routine publicity on weight loss.
In total, 15,310 occupational participants including 3467 participants (22.65%) in the control group and 11,843 participants (77.35%) in the WeChat group were enrolled. Participants in the WeChat group lost more weight (mean 2.09, SD 3.43 kg) than people in the control group (mean 1.78, SD 2.96 kg), and the difference in mean weight loss between the two groups for males was significant based on the stratification of age and educational level. To control for confounding factors and to explore the effects of WeChat on weight loss, the propensity score method with a multinominal logistic regression was utilized. For males, this showed that the WeChat group (with both active and inactive subgroups) had a higher probability of maintaining weight, weight loss from 1 to 2 kg, or weight loss more than 2 kg than the control group. However, the control group had higher probability of weight loss from 0 to 1 kg. Being active in WeChat was likely to be associated with weight loss. The more active participants were in the weight loss program via WeChat, the more weight they lost.
The weight loss intervention campaign based on an official WeChat account focused on an occupation-based population in Shunyi District was effective for males. The more active male participants were in using WeChat, the more weight they lost. There might be no effect or there may even be a negative effect on weight loss for females. Future research should focus on how to improve adherence to the WeChat weight loss interventions, to improve and refine the WeChat content such as developing a variety of materials to attract interest, and to protect personal privacy, especially for females.
Being overweight is defined as having a body mass index (BMI) of 25 kg/m2 or higher; a person with a BMI of 30 kg/m2 or higher is regarded as obese. Worldwide in 2014, more than 1.9 billion adults were overweight and more than 600 million adults were obese. The percentage of obesity in the world’s adult population was 13%. The prevalence of obesity in 2014 was twice that of 1980 [
Obesity is a major risk factor for noncommunicable diseases such as diabetes, cardiovascular diseases, and some cancers [
Various media such as radio, television [
Social media interventions have measurable impacts on health outcomes compared with non-social media–based interventions [
WeChat (the Chinese version is
This study was conducted on an occupation-based population from August 2015 to February 2016 in the Shunyi District of Beijing to explore the effectiveness of the mobile app WeChat on weight loss behavior. Participants who were willing to use our official WeChat account were enrolled in a WeChat group and received 6 months of interventions for weight loss, and those who were not willing to use the account were in the control group. Before the interventions began, the Shunyi District Government released an official weight loss document to all 134 government agencies and enterprises in Shunyi District. At least 60% of the staff of government agencies were required to participate in this activity. The government agencies included the Shunyi Branch of the Beijing Municipal Public Security Bureau, the Shunyi Court, the Shunyi People’s Procuratorate, the Shunyi Branch of the Beijing Administration for Industry and Commerce in the Urban Management Law Enforcement Bureau, the Shunyi State Administration of the Taxation of China, the Beijing Shunyi Local Taxation Bureau, and the Food and Drug Administration of Beijing Shunyi District. At least 30% of the staff of other units were required to participate as well.
Interventions were given to the WeChat group through the WeChat app and routine publicity, such as the slogan “take the stairs and lose weight,” was given to the control group. Participants were asked to report their demographic characteristics such as gender, age, educational level, and telephone number online when they registered with our official WeChat account. Additionally, on average, two weight managers per agency were trained to obtain participants’ data on height, weight, and waist circumference before and after the interventions were initiated for both groups. The demographic characteristics of participants in the control group were collected by weight managers.
Participants were enrolled if they (1) were from one of any of the 134 government agencies and enterprises in Shunyi District, (2) were 18 years of age or older, and (3) wanted to lose weight. Participants willing to lose weight via WeChat were enrolled as members of the WeChat group and those who were willing to lose weight but did not want to use WeChat were in the control group. Pregnant women and those whose health conditions were not suitable for weight loss were excluded from the study.
All participants gave verbal consent to participate in the study and they were entitled to withdraw from the study whenever they wished and for whatever reason. The official weight loss document also addressed all the individuals who enrolled or who dropped out of our study voluntarily. People in the WeChat group would scan a QR code, below which was the phrase “enrolled or dropped out voluntarily” and for people in the control group, before they enrolled, weight managers in each agency told them everything about our study and asked them if they were willing to enroll. From the perspective of each participant’s private information, an agreement was made between the Shunyi Center for Disease Prevention and Control (SYCDC) and a technology company that provided technological support to protect all private information. Only two people from the technology company and two people from the SYCDC knew all the information. Private information such as a telephone number or identification number was deleted when the data were analyzed.
The SYCDC developed an official WeChat account, known as the “Health Education in Shunyi District, Beijing,” with the technological support of a specialized information technology company (
The official WeChat account consisted of the following six components: introduction, weight loss process, weight loss unit rankings, weight loss school, activity area, and awards (
The weight loss process was designed to provide feedback on weight, diet, and exercise during the intervention process to motivate participants to lose weight. The duration of 12 types of activities, including walking, running, cycling, playing, skipping, swimming, sit-ups, push-ups, plank flat support, doing housework, workshops, and climbing stairs, were reported daily (
The weight loss unit rankings component aimed to rank the total score per unit, including the number of participants and the total amount of weight lost, to motivate and encourage participants to compete with one another (
At the end of the program, winners and losers were determined on the basis of their cumulative scores (
The interface of the WeChat interventions (originally in Chinese). (a) The official WeChat account “Health Education in Shunyi District, Beijing,” (b) introduction of the official account, (c) feedback on exercise, (d) feedback on diet, (e) the weight loss unit rankings, (f) the weight loss school, (g) the experts team, (h) the microcommunity, and (i) cumulative scores.
A total of 210 messages were sent (one message every other day, on average) to participants in the intervention group during the period. The messages were read more than 247,000 times and were sent to other WeChat accounts more than 6500 times. In total, 3620 participants communicated with others in “microcommunity discussions” and there were more than 20,000 posts.
Participants in the intervention group could ask weight loss-related questions on our official WeChat account expert consultation page at any time during the 6-month period. Experts were consulted online more than 14,576 times and 28,000 questions were asked, among which 270 representative questions were responded to in detail. In addition, more than 8200 people regularly received feedback on their weight, diet, and exercise data and conducted self-assessments via WeChat. Examples of the content of WeChat messages can be found in
Examples of the content of WeChat messages.
Content examplesa | Reading quantity | Number of forwards and favorites |
Will beer increase your weight? Eight diet mistakes that will make you fatter! | 2871 | 26 |
You do not have to go to the gym, seven other ways to burn fat | 2945 | 44 |
Obesity is not an excuse to keep smoking | 2982 | 24 |
Excessive weight will shorten your life! Eat less and exercise more to lose weight. | 3060 | 60 |
Have you been cheated by the eight fallacies of weight loss? | 3222 | 41 |
Want to have a good body image by spring? Do you know how to exercise now? | 3233 | 24 |
New ways to lose weight. You do not need to diet. | 3411 | 7 |
Five bad habits of running that will hurt your body! | 3853 | 8 |
Do not miss the best season for weight loss! Weight loss is easier in winter! | 4248 | 25 |
Changing these habits will keep you from regaining weight! | 4577 | 28 |
a Original text was in Chinese.
Data was analyzed using SPSS version 18.0. Mean and standard deviation were used to present continuous variables for normal distribution or median and quartile for nonnormal distribution. Frequency and percentages were employed to express categorical variables. The chi-square test for categorical variables was used to compare parameters between the control group and the WeChat group, or
At the beginning, a total of 15,818 participants were enrolled, including 12,296 participants in the WeChat group and 3522 in the control group. Data were collected on a total of 15,523 participants, including 12,002 in the WeChat group and 3521 in the control group at the baseline. After 6 months of interventions, data were collected on a total of 15,310 participants, including 11,843 in the WeChat group and 3467 in the control group at the baseline and after 6 months of interventions (
The data that were collected both at baseline and after 6 months of interventions were used. That is, a total of 15,310 participants were enrolled in this study. The mean age of the control group was 39.0 (SD 9.5) years and that of the WeChat group was 35.1 (SD 8.5) years. Participants in the WeChat group were younger than those in the control group, and the difference was significant. Participants in the WeChat group were largely females (66.53%, 7879/11,843) and largely had university/college degrees or above (91.85%, 10,878/11,843). In the control group, nearly half the participants were female (40.47%, 1403/3467) and more participants had university/college degrees or above. Baseline demographics including age, gender, and educational level between the two groups were not balanced (
WeChat activeness was represented by WeChat cumulative scores, which were related to actual official WeChat account use. Higher scores indicated that an individual was more active in using WeChat to lose weight. Scores less than or equal to 50 were regarded as inactive, and scores of 50 or more were active. A significant number of participants in the WeChat group were inactive (83.18%, 9852/11,843) and only 16.8% (1991/11,843) were active. The differences between the control group and the WeChat group on demographics were all statistically significant (
The weight and waist circumference in the control group decreased by mean 1.78 (SD 2.96) kg and mean 2.39 (SD 3.91) cm, respectively, whereas in the WeChat group, weight and waist circumference decreased by mean 2.09 (SD 3.43) kg and mean 2.74 (SD 4.48) cm. A stratified analysis was performed to show the mean weight loss of the two groups. It also showed that for males, a decrease in weight loss was statistically significant, which indicated the 6-month WeChat interventions were effective for weight loss; however, for females, weight loss changes were not statistically significant (
The flowchart of participation.
Demographic characteristics of the control group and the WeChat group (N=15,310).
Demographics | Control group, n (%) (n=3,467) | WeChat group, n (%) (n=11,843) | χ2a | ||||
Inactive (n=9852) | Active (n=1991) | Total (n=11,843) | |||||
798.0 | <.001 | ||||||
Male | 2064 (59.53) | 3415 (34.66) | 549 (27.57) |
||||
Female | 1403 (40.47) | 6437 (65.34) | 1442 (72.43) | 7879 (66.53) | |||
443.1 | <.001 | ||||||
<40 | 1672 (50.61) | 6,874 (70.32) | 1180 (59.78) | 8054 (68.55) | |||
≥40 | 1632 (49.39) | 2,901 (29.68) | 794 (40.22) | 3695 (31.45) | |||
536.9 | <.001 | ||||||
Low | 772 (22.31) | 779 (7.91) | 186 (9.34) | 965 (8.15) | |||
High | 2689 (77.69) | 9073 (91.09) | 1805 (90.66) | 10,878 (91.85) |
a Chi-square and
b Low education level: high school or below; high education level: university/college or above.
Mean weight loss in the two groups by gender, educational level, and age (N=11,530).
Gender, educational level,a age, and groups | n | Mean (SD) | |||||
3.36 (291) | .001 | ||||||
Control | 104 | 1.18 (4.51) | |||||
189 | 3.22 (5.20) | ||||||
≥ |
3.32 (485) | .001 | |||||
Control | 274 | 1.95 (3.88) | a | ||||
213 | 3.27 (4.91) | ||||||
8.10 (2231) | <.001 | ||||||
Control | 856 | 1.48 (2.79) | a | ||||
2405 | 2.51 (4.14) | ||||||
≥ |
2.25 (1649) | .03 | |||||
Control |
1.7 (2.82) | ||||||
1115 | 2.01 (3.12) | ||||||
1.95 (263) | .05 | ||||||
Control | 46 | 3.37 (5.26) | |||||
219 | 2.08 (3.77) | ||||||
≥ |
1.45 (540) | .15 | |||||
Control | 237 | 2.57 (3.40) | |||||
305 |
|||||||
0.36 (914) | .72 | ||||||
Control | 666 | 1.98 (2.73) | |||||
5241 | 1.94 (3.21) | ||||||
≥ |
0.43 (622) | .66 | |||||
Control | 392 | 1.87 (2.29) | |||||
2062 | 1.82 (2.73) |
a Low education level: high school or below; high education level: university/college or above.
Propensity score methods are increasingly used to control for confounding factors in many medical studies. In our study, demographics including age, gender, and educational level between the two groups were not balanced at the baseline; thus, propensity score methods were used to control for them. With a group variable (the WeChat group and the control group) as the dependent variable and two demographic characteristics (age and educational level) as covariates, a binomial logistic regression analysis was used to estimate the propensity score based on gender.
To estimate WeChat effectiveness on weight loss, multinominal logistic regression used to test the parallel lines of the ordinal logistic regression that did not meet the criteria. The weight loss outcome was categorized as follows: weight gain, weight unchanged, weight loss from 0 to1 kilograms, weight loss from 1 to 2 kilograms, and weight loss more than 2 kilograms. The reference category for the dependent variable was the classification of weight gain. The propensity score was used as a continuous covariate replacing all single covariates with the independent variable, WeChat active group, in the multinominal logistic regression to estimate the adjusted WeChat effectiveness on weight loss.
For males, in the control group, 52.37% (1081/2064) of participants lost 0 to 1 kg, 35.72% (1220/3415) in the inactive group, and 41.17% (226/549) in the active group lost more than 2 kg. For females, 38.92% (546/1403) of participants in the control group and 31.30% (2015/6437) in the inactive group lost 0 to 1 kg and 33.36% (481/1442) in the active group lost more than 2 kg (
The frequency and percentage of weight loss outcomes between two groups based on gender.
Gender and weight | Control, n (%) | Inactivity, n (%) | Activity, n (%) | Total, n (%) | |
Weight gain | 187 (9.06) | 272 (7.96) | 45 (8.20) | 504 (8.36) | |
Weight unchanged | 61 (2.96) | 305 (8.93) |
407 (6.75) | ||
Weight loss (0-1 kg) | 1081 (52.37) | 932 (27.29) | 136 (24.77) | 2149 (35.65) | |
Weight loss (1-2 kg) | 219 (10.61) | 686 (20.09) | 101 (18.04) | 1006 (16.69) | |
Weight loss (≥2 kg) | 516 (25.00) | 1220 (35.72) | 226 (41.17) | 1962 (32.55) | |
Weight gain | 81 (5.77) | 597 (9.27) | 105 (7.28) | 783 (8.44) | |
Weight unchanged | 77 (5.49) | 732 (11.37) | 112 (7.77) | 921 (9.92) | |
Weight loss (0-1 kg) | 546 (38.92) | 2015 (31.30) | 427 (29.61) | 2988 (32.19) | |
Weight loss (1-2 kg) | 259 (18.46) | 1317 (20.46) | 317 (22.00) | 1893 (20.39) | |
Weight loss (≥2 kg) | 440 (31.36) | 1776 (27.59) | 481 (33.36) | 2697 (29.06) |
For males, the results of the multinominal logistic regression showed that when controlling for confounding factors, compared with the classification of weight gain, the WeChat group (with both active and inactive subgroups) had higher probability of maintaining weight, weight loss from 1 to 2 kg, or weight loss of more than 2 kg than the control group. However, the control group had higher probability of weight loss from 0 to 1 kg. For females, the difference between maintaining weight and weight gain was not statistically significant. As for weight loss of more than 1 kg, the WeChat inactive group had lower probability than the control group. As for weight loss from 0 to 1 kg, the WeChat group (with both active and inactive subgroups) had lower probability than the control group (
Results of the multinomial logistic regression based on gender.
Gender and weight lossa | B | SE | Wald | OR (95% CI) | ||||
Intercept | –0.08 | 0.44 | 0.03 | .85 | ||||
Propensity score | –1.68 | 0.67 | 6.20 | .01 | 0.19 (0.05-0.70) | |||
Activity (1) | 1.10 | 0.26 | 17.47 | <.001 | 3.01 (1.80-5.05) | |||
Inactivity (2) | 1.34 | 0.18 | 58.70 | <.001 | 3.84 (2.72-5.41) | |||
Intercept | 1.03 | 0.33 | 9.61 | <.001 | ||||
Propensity score | 1.01 | 0.51 | 4.02 | .045 | 2.75 (1.02-7.41) | |||
Activity (1) | –0.62 | 0.19 | 10.61 | <.001 | 0.54 (0.37-0.78) | |||
Inactivity (2) | –0.50 | 0.11 | 20.68 | <.001 | 0.61 (0.49-0.75) | |||
Intercept | 1.22 | 0.36 | 11.62 | <.001 | ||||
Propensity score | –1.77 | 0.55 | 10.34 | <.001 | 0.17 (0.06-0.50) | |||
Activity (1) | 0.75 | 0.21 | 13.09 | <.001 | 2.12 (1.41-3.18) | |||
Inactivity (2) | 0.90 | 0.13 | 49.17 | <.001 | 2.46 (1.91-3.17) | |||
Intercept | 1.48 | 0.33 | 19.91 | <.001 | ||||
Propensity score | –0.73 | 0.51 | 2.06 | .15 | 0.48 (0.18-1.30) | |||
Activity (1) | 0.61 | 0.19 | 10.93 | <.001 | 1.85 (1.28--2.66) | |||
Inactivity (2) | 0.53 | 0.11 | 21.69 | <.001 | 1.69 (1.36--2.11) | |||
Intercept | –0.56 | 0.58 | 0.94 | .33 | ||||
Propensity score | 0.61 | 0.68 | 0.79 | .37 | 1.83 (0.48-6.97) | |||
Activity (1) | 0.10 | 0.21 | 0.24 | .63 | 1.11 (0.73-1.68) | |||
Inactivity (2) | 0.23 | 0.17 | 1.85 | .17 | 1.26 (0.90-1.77) | |||
Intercept | 1.43 | 0.45 | 10.32 | <.001 | ||||
Propensity score | 0.46 | 0.53 | 0.76 | .38 | 1.59 (0.56-4.49) | |||
Activity (1) | –0.41 | 0.16 | 6.26 | .01 | 0.66 (0.48-0.91) | |||
Inactivity (2) | –0.62 | 0.13 | 21.93 | <.001 | 0.54 (0.42-0.70) | |||
Intercept | 1.40 | 0.46 | 9.30 | <.001 | ||||
Propensity score | –0.31 | 0.55 | 0.32 | .57 | 0.73 (0.25-2.14) | |||
Activity (1) | –0.02 | 0.17 | 0.02 | .89 | 0.98 (0.70-1.37) | |||
Inactivity (2) | –0.34 | 0.14 | 5.96 | .02 | 0.71 (0.54-0.93) | |||
Intercept | 2.37 | 0.43 | 29.91 | <.001 | ||||
Propensity score | –0.86 | 0.52 | 2.78 | .10 | 0.42 (0.15-1.16) | |||
Activity (1) | –0.09 | 0.16 | 0.32 | .57 | 0.91 (0.66-1.26) | |||
Inactivity (2) | –0.54 | 0.13 | 16.25 | <.001 | 0.58 (0.45-0.76) |
a The reference category for the dependent variable was the classification as weight gain.
b WeChat active was a subgroup variable, and the reference group was the control group.
This study proved that the weight loss intervention campaign, which was largely promoted by the Shunyi Government and based on an official WeChat account focused on an occupation-based population in Shunyi District, was very effective for males.
A total of 15,310 participants were enrolled in this study, among which 77.35% were willing to use WeChat for weight loss, which was consistent with a study that a WeChat health education program was evaluated with high levels of satisfaction from participants [
Participants in the WeChat group lost more weight (2.09 kg) on average than people in the control group (1.78 kg), and the difference in mean weight loss between the two groups for males was significant. For males, the results of the propensity score methods with a multinominal logistic regression showed that the WeChat group (with both active and inactive subgroups) had a higher probability of maintaining weight, weight loss from 1 to 2 kg, or weight loss more than 2 kg than the control group. However, the control group had higher probability of weight loss from 0 to 1 kg. Being active in WeChat is likely to be associated with weight loss. The more active participants were in the weight loss program via WeChat, the more weight they would lose.
Our WeChat intervention campaign provided participants with information on weight loss that could improve their knowledge, attitudes, practices, and so on. The results were in accordance with a previous study showing that participants’ knowledge, attitudes, skills, practices, and overall health literacy experienced greater changes via official WeChat accounts [
The difference in mean weight loss between the two groups of females was not significant. WeChat might not affect or may even negatively affect weight loss for females. For females, the results of the propensity score methods with a multinominal logistic regression showed that the difference between maintaining weight and weight gain was not statistically significant. For the classification of weight loss more than 1 kg, the WeChat inactive group had lower probability than the control group. As for weight loss from 0 to 1 kg, the WeChat group (with both active and inactive subgroups) had lower probability than the control group. WeChat might have no effect on maintaining weight and might result in a lower chance of weight loss for females.
The WeChat intervention was effective on weight loss only for male employees. Females were more active using WeChat, but they lost less weight during the study. One reason might be that females were more motivated by the rewards than males and the rewards were given to the top 60 WeChat active participants per month, regardless of whether or not they in fact lost weight. Additionally, the fact that females spent more time on WeChat might negatively affect weight loss. One study showed that the more time a person spent on Facebook, the more negative feelings they had about their bodies due to more frequent body and weight comparisons for females [
In the WeChat group, most of the participants were inactive in this study. It may be that participants showed greater interest in our WeChat intervention program at the beginning, but few people were able to adhere to our weight loss activities. The effectiveness of a weight loss intervention has been associated with intervention adherence [
This study had some limitations. First, this study was a nonrandomized trial and although propensity score methods were used to control for confounding factors, the conclusions were limited. Second, weight loss behavior is a multifactorial phenomenon in that adherence [
This weight loss intervention campaign based on an official WeChat account focused on an occupation-based population in Shunyi District was found to be effective for males. The more active male participants were in using WeChat, the more weight they lost. There might be no effects or even negative effects on weight loss for females. Future research should focus on how to improve adherence to the WeChat weight loss interventions and to protect personal privacy, especially for females.
body mass index
Shunyi Center for Disease Prevention and Control
We appreciate the efforts of Shunyi community health workers. They contributed considerable energy and time during data collection; without them, this meaningful research could not have been completed.
HC was responsible for the study design and data collection. SYW performed the statistical analysis, interpreted the results, and wrote the manuscript. YYZa, ZL, and YYZb were responsible for the manuscript translation. JL, LW, SYW, and CQL helped interpret the results. YDL and XYS were responsible for reviewing the study design, the manuscript, and all study results.
None declared.