BACKGROUND~Changing unhealthy lifestyle improves health and reduces morbidity. Motivation is a key component in initiation and maintenance of lifestyle changes. Identifying and motivating individuals with unhealthy lifestyle to change behaviour may be achieved through preventive health checks as already implemented in some countries. However, knowledge about the impact of individual components included in preventive health checks is lacking. Consequently, the most effective composition of preventive health checks remains unknown.~In a Danish municipality, the Check your Health Prevention Program (CHPP) was recently initiated, offering preventive health checks to all 30 to 49 year-old citizens. This program provides the unique opportunity to evaluate single components of a preventive health check in a real-life setting. Only a few previous studies have included cardiorespiratory fitness (fitness) testing in a preventive health check. Fitness is associated with multiple health benefits such as improved cardio-metabolic profile and reduced risk of cancer, diabetes, and depression.~The investigators aim to investigate the effect of including fitness testing in preventive health checks on fitness level, motivation for changing physical activity behaviour, physical inactivity prevalence and self-rated health. The investigators hypothesize that fitness testing as part of preventive health checks compared to preventive health checks without fitness testing 1) increases fitness level assessed after one year and the percentage of participants increasing motivation to change physical activity behaviour assessed after two weeks, and 2) reduces physical inactivity prevalence and improves self-rated health scores during the one-year study period.~METHODS~Nested-design~The present trial is embedded in the above mentioned health promotion program, CHPP, which is conducted during the years 2012 to 2017. In the CHPP, all citizens living in the municipality of Randers aged 30-49 years per 1st of January 2012 (n = 26,216) were identified in the Danish Civil Registration System.The identified population was randomized into five equal groups, one for each year of the CHPP. Invitations are dispatched continuously by mail and include information about the CHPP and a prefixed appointment for a health check. Health checks and health behavioural courses will take place at Randers Health Centre and health consultations at the citizen´s general practitioner.~The health check~Besides the addition of fitness testing in the intervention group, the preventive health checks will include assessments of the following: body weight and height, waist circumference, blood pressure, lipid profile (total cholesterol, LDL, HDL, and triglycerides), HbA1c and lung function. Moreover, a baseline questionnaire regarding physical activity level, motivation for changing physical activity behaviour, self-rated health, smoking, and alcohol will be answered in connection with the health check. At the end of the health check, the results are presented in a personalized health profile leaflet, which includes recommendations for follow-up according to the risk-profile. The baseline questionnaire and the subsequent follow-up procedures are identical in the two study groups.~Standardization and education~The health check will be conducted by health professionals who have been trained in all measurement procedures as well as in risk communication to ensure standardization and quality. Execution of the health check is further standardized by a written protocol and adherence to the protocol is checked continuously. Furthermore, a process evaluation will be conducted.~Outcome assessment~Cardiorespiratory fitness will be assessed by submaximal cycle ergometer testing. Motivation for changing physical activity behavior will be assessed using the Transtheoretical Model´s Stages of Change, and secondary outcomes using a modified version of the questions developed by Saltin and Grimby and the Short-Form 12, Health Survey, version 2.~Follow up~All participants will receive a questionnaire regarding motivation for changing physical activity behaviour two weeks after the health check and will be invited for fitness testing after one year.~Randomization and blinding~Randomization is handled by a data-manager with no scientific involvement. The eligible population for this trial was defined by the CHPP randomization. Citizens randomized for the third out of five years of the CHPP will be further randomized by household to either intervention or control in the present trial. The intervention, the outcomes, group assignment, and the future outcome assessments in this trial are unrevealed in the invitation for the CHPP. The health behavioural courses and the health consultations will be carried out un-blinded due to the real-life setting. At the one-year follow-up, the personnel assessing the outcomes will be independent and blinded to group allocation.~Sample size~An estimated sample size of 1,500 participants allows for a categorical analysis of fitness level and is calculated on the basis of the following assumptions: 1:1 randomization, false positive error rate of 0.05, power of 0.8, intracluster correlation coefficient of 0.05 and categorical analysis with a power to detect a difference of 10% in the prevalence of very low fitness between the study groups. The investigators determined this 10% difference to be clinically meaningful based on expert opinions and criteria employed in other research. The intracluster correlation coefficient was included to reflect a possible clustering effect of the general practitioners (n = 46), which is seldom greater than 0.05 in primary care settings. The estimated sample size accounts for a 30% loss to follow-up.~Statistics~Statistical analysis will be performed using STATA 12.0 software. Continuous variables are presented as mean ±standard deviation and categorical variables as absolute numbers and relative (%) frequencies. In the comparative analyses Student´s t-test will be used, when comparing means or changes in means of continuous variables and Chi2-test or Fisher's exact t-test, when comparing proportions for categorical variables. Analyses will be adjusted for baseline physical activity. Stratified analyses will be performed on sex and age groups and analysis of motivation will only be performed on the subgroup comprising precontemplaters, contemplaters, and preparators at baseline. All analyses will follow the intention-to-treat principle. If appropriate, multiple imputation methods will be applied (using data from social and medical national registries coupled with health check data), and sensitivity analyses will be performed. Moreover, the potential effect of clustering by the general practitioners will be investigated. The statistical significance level is set at p < 0.05.~ETHICS AND LEGAL ASPECTS~The trial will comply with The Declaration of Helsinki and each participant will provide written informed consent for data to be used for research purposes in agreement with the Danish Health Law. Approval by The Danish Data Protection Agency is obtained (2013-41-2527).
The purpose of this study is to investigate if including fitness testing in preventive health checks increase cardiorespiratory fitness and motivation to change physical activity behavior compared with preventive health checks without fitness testing.