Study design
The study is a three-arm one-center randomized controlled trial (Figure 1). Two methods of health promotion are studied in middle-aged men with elevated cardiovascular risk. After screening and randomization, one study group receives a 1½-hour health promotion intervention by a public health nurse. The other intervention group receives, in addition to public health nurse intervention, a guided group exercise intervention of 12 weeks. The third group is randomized to serve as a control and men in this group may participate in the intervention after one year, should they wish to.
Ethics approval
The study received ethics approval from the Coordinating Ethics Committee at Helsinki University Hospital on 8 June 2009 (ref: 4/13/03/00/09). All participants receive both oral and written participant information and are asked to give written informed consent.
Recruitment and time schedule
We recruite men aged 35 to 45 years with at least two cardiovascular risk factors. They are recruited to the project in three ways: 1) by invitation letter to the 40-year-old age cohort, 2) by identifying high-risk group of men within health services (targeted opportunistic screening), and 3) by informing about the project in the media and on the Internet.
The study protocol was accepted in 2009 and recruitment of study subjects and randomization started in 2010.
Inclusion criteria
-
BMI 27–34 kg/m2
-
Waist circumference > 94 cm
-
Fasting glucose >6.1 mmol/l
-
Total plasma cholesterol >4.0 mmol/l
-
LDL-cholesterol > 3.0 mmol/l
-
Triglycerides >2.0 mmol/l
-
Systolic blood pressure > 140 mmHg
-
Diastolic blood pressure > 90 mmHg
-
Currently either :
Exclusion criteria
-
BMI over 34 (or any other physical barrier preventing participation in the exercise intervention)
-
Active exerciser (exercising at least 30 minutes 3 times a week or more)
-
Having an immediate health problem requiring treatment or a severe risk factor; for example, recently diagnosed or uncontrolled type I diabetes, or a symptomatic coronary artery disease.
Study interventions
In addition to study interventions, all groups receive, if necessary, standard treatment at Kirkkonummi Health Center, a municipal public primary care unit. If a participant shows any need of medical treatment, or his medications required medical attention, he is referred to a primary care physician.
Health promotion intervention by nurse
Public health nurses use standard practices in their health promotion intervention. Before onset of the trial they receive education from the Finnish Heart Association. The nurses use the type 2 diabetes disease risk assessment form (Finnish Diabetes Association), and cardiovascular risk assessment (the Finnish Heart Association). The intervention includes assessment of individual risks, dietary habits, physical activity and a motivational talk about the habits. The intervention lasts up to 90 minutes and does not include follow-up.
If the men have elevated blood sugar, total plasma cholesterol over 7.0 mmol/l, uncontrolled hypertension or another reason for medical assessment, the nurse referres the patient to a physician for consideration of medication.
Exercise intervention
In addition to the health promotion intervention, the other group is invited to a group exercise intervention. The size of the teaching groups is from 10 to 20 people. The exercise intervention is guided by a physical education counselor and consists of basic physical training. The exercise sessions each last 60 minutes. During the 12 weekly meetings several safe and moderately strenuous exercise activities are carried out, such as Nordic walking, fitness circle, volleyball, swimming, circuit training, gym, boxing, zumba, etc.
The exercise intervention aims at creating a comfortable atmosphere that encourages safe and regular physical training. Another aim is form groups of men that might continue exercising together.
Control group
The participants of the control group receive both the health examination and the exercise intervention after the 12-month follow-up, if they so wish.
Outcome measures
The outcomes are measured after 3, 6 and 12 months of the randomization. The blood tests are taken at months 0, 3 and 12. Other outcomes are measured by Internet surveys and, if the participant does not respond, by telephone surveys.
Primary outcome measures will be 1) metabolic syndrome defined by International Diabetes Federation/American Heart Association [11], thus fulfilling three or more of the following criteria:
-
systolic blood pressure ≥ 130 or diastolic blood pressure ≥ 85 or specific medication;
-
triglyserides ≥1.7 mmol/L or specific medication;
-
HDL cholesterol < 1.0 mmol/L or specific medication
-
fasting plasma glucose ≥ 5.6 mmol/L or specific medication;
-
waist circumference >94 cm
-
2)
and self-reported physical activity measured by how many times per week a participant performs vigorous exercise activity. Table 1 shows also the secondary outcome measures.
Randomization
Once the men have consented to participate in the study and the baseline measurements are carried out, they are randomly allocated to one of the three study groups. A randomization list based on random numbers is made and transferred to sequentially numbered sealed envelopes.
Sample size
Sample sizes were calculated by statistical power analysis. We hypothesised that the percentage of men continuing the increased exercise level after one year would be 30% in the control group and 50% in the exercise group. To detect this difference with α = .05 and β = .80, 91 men in each group are needed.
Statistical analysis
A primary intention-to-treat analysis will be carried out. The main analyses involve standard two-sample comparisons (parametric or non-parametric depending on the distribution of the data) looking at effect sizes at 3 and 12 months.
Qualitative analysis
In addition to quantitative methods, focus group discussions are conducted in order to study the experiences of the men in the intervention, the acceptability of the intervention and the barriers and facilitators for lifestyle change in men. The focus group discussions are held after the execution of the intervention. Using a qualitative approach we also study what the men’s experiences of the group exercise intervention are and whether they continue these activities after the trial. Also, the men’s preferred methods for joining projects aiming at lifestyle changes and other societal aspects are examined.