The Physical Activity and Minority Health Study was a randomized controlled trial whose main goal was to increase the level of PA in a group of Pakistani immigrant men. The study protocol was approved by the Regional Committee for Medical Research Ethics (ref. no. S-07300b) and the Norwegian Social Science Data Services (ref. no. 17212/2/KS), and all study participants gave written informed consent.
Formative Research: Physical Activity Influences
To better understand why many Pakistani immigrants are physically inactive and how to positively influence their PA behavior, we conducted two focus groups with representatives from the male Pakistani immigrant group (n = 10 in each group, age ranged from 25 to 60 years). Each focus group meeting lasted approximately 2 h. The aims of these group meetings were to explore self-efficacy, expectations, expectancies, preferences and barriers to PA among the Pakistani immigrant men. These discussions indicated that the men had very few physically active friends or family members, had little knowledge about non vigorous PA, the link between PA and health and staying regularly physically active, and identified many barriers to PA (e.g., managing time) and did not know if they were able to overcome them, and they did not see many benefits of being regularly physically active. Using these results and numerous studies showing successful changes to the PA behavior by the use of social cognitive theory (SCT) constructs , we decided to target three primary SCT concepts to promote PA change: self-efficacy (i.e., confidence to perform PA), outcome expectancies (i.e., expected benefits and costs of performing PA) and the social environment (i.e., social support for PA from family and friends, physically active role models). The secondary SCT components included the physical environment (opportunities to perform PA) and behavioral capability (knowledge and skill).
Men living in Oslo, Norway, with a Pakistani background (either born in Pakistan or parents born in Pakistan) in the 25–60 year age group who were not physically active were eligible for the study (the definition of “not physically active” was exercising no more than twice a week at a moderate or high intensity for 30 min or more at a time or active commuting (e.g., cycling or walking to work on most days of the week)). Participants were recruited during the autumn of 2008. We gave a brief oral presentation about the project at six mosques and at various Muslim festivals in Oslo. One hundred and eighty-two men volunteered to participate in the study, 32 failed to meet the inclusion and exclusion criteria, giving 150 participants. Figure 1 presents the flow of participants through the trial.
In close collaboration with representatives from the target group, we developed an intervention to target the key SCT constructs via the following components: structured group exercise sessions twice a week led by an exercise physiologist, two group lectures, one individual counseling session, written material and a phone call. Table 1 provides an overview of how these components were conceptualized with reference to SCT. The intervention program lasted 5 months. The control group members received their baseline results approximately 2 weeks after the testing, and were offered organized exercise, one group lecture and written material following completion of the intervention period.
Each participant was examined for PA habits, cardiorespiratory fitness and MetS risk factors both before and after the five-month intervention. After an overnight fast, venous blood samples were drawn from an antecubital vein. Blood samples were centrifuged for 10 min at 2,500g. An oral glucose tolerance test was performed, in which 75 g of glucose in 200 ml of water was ingested and plasma glucose and insulin concentrations were measured before (fasting) and 2 h after (postprandial) ingestion of the glucose drink. A Modular P Machine (Roche, Japan) was used to measure the concentrations of HDLc (immunoturbidimetric assay), low density lipoprotein cholesterol (LDLc) (direct enzymatic method), triglycerides (TG) (enzymatic assay), glucose (photometric assay) and insulin (immunoassay). Waist circumference was measured in the standing position and after a light expiration horizontally to the chest, midway between the lower rib margin and the iliac crest. Weight was measured without shoes in light clothing using a SECA electronic scale (SECA model 767, Germany) to the nearest 0.5 kg. Height was measured without shoes with a transportable stadiometer (Harpenden; Holtain, Crymych, UK) to the nearest 0.5 cm. Body mass index (BMI) was calculated as weight divided by height squared (kg m−²). Blood pressure was measured automatically using an Omega non-invasive blood pressure monitor (In vivo Research, Inc., Orlando, FL., USA) in the morning after the participant had rested for 10 min in a quiet room. Three consecutive blood pressure measurements were performed with 1 min rest between each measurement. Blood pressure was recorded as the average value of the three recordings.
The Metabolic Syndrome
The MetS was defined according to the criteria set by the International Diabetes Federation . According to this definition, men must have central obesity, defined as waist circumference with ethnicity specific values (≥90 cm for south Asians) plus any two of the following four factors: serum TG concentration ≥1.7 mmol l−1, HDLc concentration ≤1.03 mmol l−1, systolic blood pressure (SBP) ≥130 mmHg or diastolic blood pressure (DBP) ≥85 mmHg or fasting plasma glucose concentration ≥5.6 mmol l−1.
By this definition, a person can have a maximum of five MetS components. If a MetS component was present, it was given the value 1 and 0 if not present. For example, a value of 3 would indicate three MetS-factors.
Assessment of PA and Cardiorespiratory Fitness
Habitual PA was assessed with an Actigraph accelerometer (model 7164; ActiGraph, Fort Walton Beach, FL, USA). The participants were instructed to wear the accelerometer on the right hip during all waking hours for 7 days except while swimming and bathing. The epoch length was set to 1 min. When analyzing the accelerometer data, epoch periods with a value of 0 for 60 min (with allowance for two exceptions above 0) or longer were interpreted as “accelerometer not worn” and removed from the analyses [23, 24]. PA data were included if the participant had accumulated a minimum of 8 h of activity data per day for at least 2 days, regardless of the type of day (weekday or weekend). Accelerometer data were processed and analyzed using the SAS-based (version 9) (SAS Institute Inc. Cary, NC, USA) program CSA-Analyzer (http://csa.svenssonsport.dk). One hundred and forty-two participants had valid recordings at the baseline test (95%). Four lost their monitor and four had less than two valid days of recordings. At the post-test, 126 participants (84%) had valid recordings (intervention group n = 76, control group n = 50), 17 were lost to the post-test, five had less than 2 days of recordings, and two did not return their accelerometer.
Cardiorespiratory fitness was assessed by measuring oxygen consumption, which was defined as the highest measured oxygen consumption (VO2peak in ml kg−1 min−1). Oxygen consumption was measured during a maximum exercise test on a treadmill using a modified Balke protocol . Gas exchange was sampled continuously into a mixing chamber every 30 s by having the participant breathe into a Hans Rudolph two-way breathing valve (2700 series, Hans Rudolph Inc., Kansas City, MO, USA) connected to a Jaeger Oxycon Pro gas analyser (Erich Jaeger GmbH, Hoechberg, Germany), which measured the oxygen and carbon dioxide content. The analyzer was volume- and gas calibrated before each test. The test result was approved when scoring ≥16 on the Borg 6–20-point rating of perceived exertion scale and when the respiratory quotient was >1.1. For safety reasons, we tested only those younger than 40 years (n = 99).
The mean and standard deviation (SD) were used to describe baseline data. Independent samples t tests were used to test differences between groups at baseline. The response to the intervention was measured as the difference between the corresponding final and baseline values for all variables (post-baseline; per protocol analysis without imputations). Repeated measures ANCOVA was used to test differences between the mean changes in the two groups, all analyses were adjusted for age. Effect size (ES) was calculated as: (changes in the control group ÷ changes in the intervention group)/SD in the control group. We analyzed all data using the Statistical Package for the Social Sciences (version 15, IBM, Inc., Chicago, IL, USA). There was a discrepancy between the inclusion criteria and the baseline PA levels. This is due to the use of different methods to assess PA; self-report was used for screening and an accelerometer was used in the testing. By any method, they would be characterized as having a low PA level .