A Mobile Application to Increase Physical Activity

In this randomized controlled study, it will be tested if a mobile application can increase physical activity and reduce the risk of later non-communicable disease.

Participants include individuals that previously have been included in a health survey (Healthy aging initiative, NCT03312439), with a low registered physical activity. Low physical is defined according to WHOs definition, i.e. at least 150 minutes of physical activity per week. Individuals will diabetes will be investigated separately.

Individuals will be excluded that cannot walk for exercise, or if they have diseases that severely affects the ability to exercise. We will also seek participants from the general population to be included with only two inclusion criteria; having a smart phone and at least 18 years of age.

Participants the meet the inclusion criteria will be randomized to an application that only registers physical activity (blind-app) or an application where the participants will set appropriate goals for physical activity and get proper feedback from the app when these goals are reached (feedback-app). Both groups will have individualized information about proper physical activity. Randomization will be made using sealed envelopes in permuted blocks of 10. Randomization will be stratified on year of birth and sex.

The primary outcome will be increased physical activity after 6 months. Secondary outcomes include cardiovascular disease, death, dementia, falls and fractures, diabetes, and improved glucose control in those that already have diabetes. Secondary outcomes also include changes in cardiovascular risk factors, such as blood pressure, blood lipids and obesity. Interaction analysis will be performed to investigate if the effects are different in men and women, based on baseline physical activity and based on age.

Based on the results from the previous health survey the individuals have participated in, a power analyses has been conducted. The participants physical activity were registered using accelerometers. The mean steps taken per week was 48000 with a standard deviation of 22000 steps. With assumption that the feedback-app will increase physical activity by at least 15%, 164 individuals would be needed in each group with an alpha level of 0.05 and a power of 80%. For secondary outcome of cardiovascular disease or death, estimates were based on incidence of these outcomes in 3617 individuals that participated in the health survey. During a mean follow up time of 928 days, 221 participants was diagnosed with cardiovascular disease or died during follow up, and 128 were diagnosed with cardiovascular disease. If assuming that the mobil-application will result in 15% lower risk of these two outcomes in those randomized to the feedback-app, 597 and 1371 individuals would be needed in each group, respectively, with the same follow up time. The effects during follow up will be monitored each year of follow up through patient registers. Follow up time is scheduled to a maximum of 2 years. We estimate that we then would need 895 and 2156 individuals in each group due to the shorter follow up time compared to in the example above.