Study design and sample
A cross-sectional survey was carried out in September and October 2014 in five refugee camps near Tindouf, Algeria. The total population in all five camps was estimated to be approximately 165,000. In the present study, the eligible population were all adults, both males and females, above 18 years of age living in one of the five refugee camps: Smara, El Aiune, Ausserd, Dakla and Boujdor. Individuals that were sick, bedridden or due to some reason unable to answer questions were excluded from the study.
The sample size was chosen based on an estimated prevalence of an inadequate PA level (i.e., not meeting the WHO recommendations of at least 150 min of moderate-intensity PA throughout the week, or at least 75 min of vigorous-intensity PA throughout the week, or an equivalent combination of moderate- and vigorous-intensity activity (MVPA) ) of 50% and an absolute precision of 5% for the 80% confidence interval  Assuming incomplete sampling from 10% of the participants, we calculated a final desired sample size of 180 men and 180 women, as determined with Open Source Epidemiologic Statistics for Public Health (OpenEpi). Due to the unequal number of inhabitants in the five camps, a probability proportional to size (PPS) method was used to select participants from each camp . We assumed a 50/50 gender balance in all the camps. This resulted in an estimated sample of 51, 51, 38, 23 and 17 persons of each gender from Smara, El Aiune, Ausserd, Dakla and Boujdor, respectively . During the study period, 52 participants withdrew mainly due to work obligations or personal or family illness, and two participants were excluded. Forty-nine additional participants were randomly recruited, so that the final sample consisted of 355 participants: 175 men and 180 women. Three hundred three participants reported some form of PA and are thus included in the PA analysis.
A three-staged cluster sampling was performed. The first stage was to select camps (PPS) and the second stage was to select households. They were randomly selected by tossing a pen in order to decide the direction in which the research team was to drive upon leaving the dispensaries. The team drove toward the boarder of the camp and each seventh household was selected. The third stage was to randomly select one man and one woman from each household. If more than one man or woman in the household was eligible and wished to participate, numbers were assigned to each person. A fieldworker then pointed to a piece of paper with numbers in random order and the person who matched the selected number was included. In households where men were not present, the woman was included and a man in the neighboring household was asked to participate.
The international physical activity questionnaire short form (IPAQ-SF)  was used to assess PA. Local field workers fluent in English, Spanish or Hassania (the local language) interviewed the participants in their own homes. All field workers were trained in interview technique over a 7 days period, including 2 days for conducting a pilot study. The researchers oversaw all interviews. After the interview the researcher checked the answers and asked both the interviewer and the participant some control questions to make sure that the interviewer had asked the questions in the right manner and that the participant had understood the questions. The IPAQ focuses on the amount of PA performed over the past 7-day period. The IPAQ includes questions about the time spent engaging in vigorous PA, moderate PA and walking in 10-min bouts or longer. Within these domains, participants are asked to consider all types of physical activities, including activities performed during leisure time, domestic and gardening activities, work-related activities and transport-related activities. Relevant examples of activity performed at the different intensities were mentioned in the items. The data obtained from the IPAQ were used to estimate the total amount of PA completed in a 7-day period by weighting the reported min per week in each domain by a metabolic equivalent (MET) energy expenditure estimate. The weighted MET minutes per week were then calculated by multiplying the duration (minutes), frequency (days) and MET intensity and then summing the three domains, namely, vigorous (8 METs), moderate (4 METs) and walking (3.3 METs), to produce a weighted estimate of total PA per week (min∙week–1) . The participants were categorised into three PA levels according to the IPAQ scoring criteria: Low (category 1): meets neither moderate nor high criterion. Moderate (category 2): meets any of the following three criteria: (a) three or more days of vigorous-intensity activity of at least 20 min∙day–1, (b) five or more days of moderate-intensity activity and/or walking of at least 30 min∙day–1, and (c) five or more days of any combination of walking, moderate-intensity, or vigorous-intensity activities achieving a minimum of at least 600 MET∙min∙week–1. High (category 3): meets any one of the following two criteria: (a) vigorous-intensity activity on at least three days and accumulating at least 1500 MET∙min∙week–1 and (b) seven or more days of any combination of walking, moderate intensity, or vigorous-intensity activities accumulating at least 3000 MET∙min∙week–1. Those categorised as having moderate or high activity were classified as being sufficiently active according to the WHO PA guidelines . Data cleaning and processing were carried out in accordance with the guidelines published by the IPAQ Research Committee, and the methods used to score the IPAQ are described in the IPAQ scoring protocol . Additional questions (supplementary material online), including views of one’s own PA level on a 5-point scale (0=far too low, 1=slightly too low, 2=satisfying, 3=slightly too high and 4=far too high), views regarding engaging in PA on a 3-point scale (e.g. 0=silly, 1=neutral, 2=wisely), what activities they usually engaged in, what they liked to do, and organised physical activities they would like to be arranged in the camps, were included in the questionnaire.
Weight was measured with the participants in light clothing using digital Tara scales produced for UNICEF (SECA 890; SECA, Hamburg, Germany). Participants’ height, without shoes, was measured to the nearest 0.1 cm using an ultrasonic metre from Soehnle Professional (Backnang, Germany) or a UNICEF portable stadiometer if the participant had a similar or taller height than the field worker performing the measurements. Waist circumference was measured by trained personnel midway between the hipbone and lowest rib using an ergonomic measuring tape from SECA (SECA 201; SECA). A waist circumference ≥ 80 cm and ≥ 94 cm, for women and men respectively, was considered high . BMI was calculated as body weight divided by squared body height (kg.m-2).
All statistical analyses were performed using SPSS (Statistical Package for the Social Sciences for Windows, version 26, IBM, Inc., Chicago, IL, USA). Continuous variables are presented as medians and interquartile ranges (IQRs) since they were not normally distributed, and categorical variable are presented as percentages. Differences between groups were assessed by the Mann-Whitney U test for continuous variables and Pearson’s chi-squared test for categorical variables. Associations between sociodemographic (gender (man/woman), age (18-59/60-90), education (up to 6th grade/7 to 9th grade/10 to 12th grade/higher education), marital status (married/not married), work status (paid work/not paid work) and anthropometric factors (BMI (underweight/normal weight/overweight/obese)) and low PA level (category 1 in IPAQ) were assessed with multivariable logistic regression, with low PA level as the dependent variable. All significance tests were two-sided.
Ethics approval for the survey was given by the Regional Committees for Medical and Health Research Ethics in Norway (ref. 2014/1155) and by the Saharawi Ministry of Public Health.
Informed consent was obtained from all participants both orally and in writing. It was emphasised that refusal to participate or withdrawal from the survey would not have any negative consequences for the participants. The study was conducted according to the guidelines provided in the Declaration of Helsinki.