Study design and population
This is a community-based cohort study which aimed to explore the effect of Ramadan fasting on physical activity assessed by daily steps count per day in Qatar. A total of 209 participants took part in this study (adults aged 18 and above) registered members of the Step into Health (SIH) program during a period of 5 years (2015-2019). Details and program description have been published elsewhere . Participants were excluded if they refused to participate, had invalid physical activity data or in case of incomplete questionnaire (described below).
This study was conducted in Qatar which has a population of estimated 2.8 million (as of 2019). The pedometry data was collected to represent the Ramadan months for the past 5 years (2015-2019) where Ramadan dates were: June 17 to July 16, June 6 to July 5, May 26 to June 24, May 16 to June 14 and May 5 to June 4, respectively. The usual temperature ranged from 27 degrees Celsius to 41 degrees over the study periods . The usual fasting hours in Qatar lasts around ~14-15 hours each day.
Basic demographic information of the study population was extracted from the program database, including age, gender, and nationality. Body Mass Index (BMI) was calculated based on self-reported body weight and height. According to the WHO classification, normal weight was defined as BMI <25, overweight as BMI 25–<30, and obese as BMI ≥30 . Other information, such as education, marital status, and religion were gathered later through a questionnaire (described below).
In addition to basic demographic information, the questionnaire included a series of questions related to health status such as smoking habits, diagnosis of any chronic disease (i.e. hypertension, diabetes mellitus, heart disease, allergy, kidney disease, etc.). It also included Ramadan-related questions such as the fasting duration throughout the period 2015-2019, exercise habits, preferred time for exercise, in addition to the influence of Ramadan on levels of physical activity and weight (body mass in kg) change. Participants were also asked about their preferred location for physical activity. The questionnaire was developed in English and was then translated into Arabic. The Arabic version of the questionnaire was back-translated into English to ensure the wording used in English corresponded with cultural context in Arabic and standards used within this population. The questionnaire was anonymous. Participants provided their identification details such as email address and national ID, to enable use to link their responses with the physical activity pedometry data in the SIH system. In order to increase response rate, we had announced that 2 participants who completed the survey will be randomly selected to receive a lucky draw prize (137$ coupon- Winners were one man and one woman).
Physical activity measurement
Step count was extracted from the SIH web database for three consecutive months (before, during and after the month of Ramadan for each of the Ramadan periods during the past 5 years (2015-2019). Daily habitual physical activity was assessed through Omron HJ-324U pedometer (Omron Healthcare Co., Ltd., Kyoto, Japan) which was used to record the total step count each day. These pedometers were previously validated, and have an absolute percent error of < 3.0% and a coefficient of variation of < 2.1% [30, 31]. Individuals have been uploading their pedometer recordings through an online platform (www.stepintohealth.qa). Daily step counts <500 and above 50,000 per day were considered invalid , thus, excluded from analyses . Aerobic step counts are computed separately by the pedometer when a person successively walks >60 steps/min for a duration of at least 10 minutes, as per the definition . To be eligible for inclusion, participant must have provided ≥4 days of valid pedometer data during a week (at least 3 weekdays and 1 weekend day) .
Study size: All participants with valid data on pedometer for a given year, before during and after Ramadan were contacted by email. For a five-year period, eligible number of participants with valid pedometer data was 1306 participants Of all the participants who were invited, only 209 provided completed questionnaires and were included in the analysis. Participants were divided into two groups participants who fasted all or most of the days in Ramadan against participants who rarely or did not fast (see questionnaire).
Statistical data analysis:
All data was coded and analyzed using IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp. All data was mostly categorical data and hence presented as counts and percentages. Steps count data was continuous and it was analyzed using linear mixed models to describe time changes in physical activity. Socio-demographic factors and fasting status were considered as fixed factors separately and participant ID was the clustering random variable using unstructured covariance structure for time (before, during and after Ramadan) as repeated measurement. Estimated marginal means ± standard error was presented and post hoc pairwise differences were reported after Bonferroni adjustment. P-value <0.05 was considered cut-off for statistical significance.