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Effect of Ramadan fasting on diabetes mellitus: a population-based study in Qatar

Bener, Abdulbaria,b; Yousafzai, Mohammad T.c

The Journal Of The Egyptian Public Health Association: August 2014 - Volume 89 - Issue 2 - p 47–52
doi: 10.1097/01.EPX.0000451852.92252.9b
Original articles
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Background Over one billion Muslims fast worldwide during the month of Ramadan. Fasting during Ramadan is a radical change in lifestyle for the period of a lunar month, and it might affect the biochemical parameters among diabetic patients.

Aim This study aimed to investigate the effect of Ramadan fasting on the blood levels of glucose, glycated hemoglobin (HbA1c), and lipid profile among diabetic patients observing fast during the Ramadan.

Patients and methods An observational study recruiting 1301 Muslim diabetic patients above 18 years age was conducted in diabetic outpatient clinic of Hamad General Hospital, Hamad Medical Corporation, and Primary Health Care Center, Qatar, from July 2012 to September 2013. Data on sociodemographic characteristics (age, sex, nationality, marital status, education level, and occupation) and lifestyle habits (smoking and physical activity), blood pressures, and anthropometric measurements were obtained by a face-to-face interview and measurement using a structured questionnaire. Blood samples were collected for testing glucose, glycosylated hemoglobin (HbA1C), lipid profile, urea, and creatinine (by the licensed research assistants).

Results Slightly less than half of the participants were overweight (BMI: 25–29.9). Significantly higher proportion of female participants were obese as compared with male participants (P<0.001). Among both male participants and female participants, the average level of blood glucose, HbA1c, total cholesterol, low-density and high-density lipoprotein cholesterol, triglycerides, albumin, bilirubin, uric acid, and systolic and diastolic blood pressures were significantly lower during the Ramadan as compared with before Ramadan (P<0.001 each).

Conclusion Results revealed that fasting during Ramadan is significantly associated with decrease in blood lipid profile, blood pressures, glucose, and HbA1C level among diabetic patients. Muslim diabetic patients after the consultation of their primary physician can fast during the month of Ramadan and it might be beneficial for their health.

aDepartment of Medical Statistics and Epidemiology, Hamad Medical Corporation, Doha

bDepartment of Public Health, Weill Cornell Medical College, Ar-Rayyan, Qatar

cDepartment of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan

Correspondence to Abdulbari Bener, Department of Medical Statistics and Epidemiology, Hamad Medical Corporation, PO Box 3050, Doha, Qatar Tel: +974 4439 3765/+974 4439 3766; fax: +974 439 3769; e-mails: abener@hmc.org.qa, abb2007@qatar-med.cornell.edu

Received March 6, 2014

Accepted June 14, 2014

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Introduction

One of the five fundamental rituals of Islam, the religion professed by over one billion people, is fasting during the month of Ramadan. Muslims neither eat nor drink anything from dawn until sunset 1,2. The time of observance differs each year because it is a lunar calendar. Fasting period varies with the geographical site and the season. In summer months and northern latitudes, the fast can last up to 18 h or more. Muslims observing the fast must not only abstain from eating and drinking, but also from taking oral medications, smoking as well as intravenous fluids and nutrients 1–7.

The prevalence of diabetes mellitus (DM) in several countries with large Muslim populations appears to be similar to the rates observed in western countries and is increasing by 10% per year as a result of urbanization and socioeconomic development 2. Indeed, fasting is one of the five pillars of Islam. However, when fasting may significantly affect the health of the faster or when an individual is sick, Islam exempts that person from fasting. However, a significant number of patients persists in fasting against the advice of their doctors and the permission of religious authorities 2.

DM 1,5 and cardiovascular diseases 3,8–10 are approaching epidemic proportions worldwide and is associated with substantial public and personal burden 2. DM is one of the major causes of mortality and morbidity in most developed and developing countries 7–9. Fasting during Ramadan is essentially a radical change in lifestyle for the period of 1 lunar month that may affect diabetic and cardiac patients 2–4,10,11.

During the Ramadan fast, Muslims eat two meals, one before dawn and the other shortly after sunset. This change of meal schedule is accompanied with changes in sleep habit (shortening of time to sleep) and lifestyle habits 11–14. The drug schedule during the day time is changed because of fasting, which may have an effect on DM patients. Fasting is not obligatory for children or menstruating women; sick and traveling people are excused from fasting 1,2.

In Arabian Gulf countries during the month of Ramadan, Muslim people usually go for very high calorie food; they neither diet nor exercise, and they sleep and work for less hours 4,11–14. Despite the large number of Muslims worldwide, there is lack of data on DM in Ramadan. The objective of this study was to investigate the effect of Ramadan fasting on the blood levels of glucose, glycated hemoglobin (HbA1c), and lipid profile among diabetic patients observing fast during Ramadan in Qatar.

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Patients and methods

Study patients and setting

This is an observational study that was conducted among Arab Muslim diabetic patients above 18 years of age, registered in diabetic clinics of Hamad General Hospital, Hamad Medical Corporation (HMC), and Primary Health Care centers in Qatar during the period from July 2012 to September 2013. Of the total 1645 eligible participants, 1301 (79.15%) agreed and gave their consent to take part in this study. IRB ethical approval was obtained from HMC before commencing data collection.

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Data collection methods

Questionnaire

Qualified nurses who can speak and write both English and Arabic were recruited to administer the questionnaires and perform anthropometric measurements. A standardized questionnaire-based face-to-face interview was conducted by the nurses to fill the questionnaires. The questionnaire was composed of: (a) sociodemographic data such as age, sex, nationality, marital status, education level, occupation, height, weight, and parental consanguinity; (b) Anthropometric data such as height and weight; (c) lifestyle habits such as physical activity and smoking status; (d) Blood pressure measurements; and (e) Laboratory investigations during and before Ramadan, such as blood glucose, glycated hemoglobin (HbA1c), low-density and high-density lipoprotein (HDL and LDL) cholesterol, cholesterol levels, triglyceride, urea, creatinine, bilirubin, albumin, etc. Data related to anthropometry and laboratory were filled based on actual measurements and laboratory investigations as described below during Ramadan. Laboratory investigations before the Ramadan were obtained from the respective medical records.

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Anthropometric measurements

Height was measured in centimeters using a height scale (SECA, Germany) while the patient was standing bare feet and with normal straight posture. Weight was measured in kilograms using a weight scale (SECA). BMI was calculated as the ratio of weight (kg) to the square of height (m). A person was considered obese if the BMI value was at least 30 kg/m2 and overweight if BMI was greater than 25 kg/m2 and less than 30 kg/m211,15,16.

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Blood pressure measurements

Hypertension was defined according to the WHO, which is systolic blood pressure at least 130 mmHg or diastolic blood pressure at least 85 mm Hg or using antihypertensive medication. Two readings of systolic blood pressure and diastolic blood pressure were taken from the participant’s left arm while seated and his/her arm at heart level, using a standard zero mercury sphygmomanometer after at least 10–15 min of rest. Thereafter, the average of the two readings was obtained 16–18.

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Lifestyle habits

Smoking habit was classified in terms of currently being past or current smoker or nonsmoker. Patients were classified as physically active, if they reported participating in walking or cycling for more than 30 min/day.

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Laboratory measurements

A blood sample of 10 ml was collected through venipuncture from each participant after fasting for 10 h into vacutainer tubes containing EDTA. The samples were kept at room temperature and transported within 2 h to a central certified laboratory at Hamad General Hospital, HMC Doha Qatar. Plasma glucose, total cholesterol, triglyceride, HDL-cholesterol, and LDL-cholesterol were measured by an autoanalyzer (Hitachi 747 autoanalyzer, Japan). Glycosylated hemoglobin (HbA1c) was analyzed using a high-performance liquid chromatography method. Other biochemical values such as creatinine, potassium, bilirubin, and uric acid were collected from their latest medical records 16.

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Definitions

Diabetes mellitus

The presence of DM was determined by the documentation in the patient’s previous or current medical record of a documented diagnosis of DM that had been treated with medications or insulin 19–21.

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Ramadan

Time periods corresponding to the month of Ramadan in the Gregorian calendar have been established, as the lunar calendar is 11–12 days shorter than the solar year 1,2. More than 95% of Qatari and other Arabs Muslim adults fast without fail during the month of Ramadan. Data were collected at the beginning of the month.

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Statistical analysis

Data were entered and analyzed using SPSS version 21 (IBM Corp., Armonk, New York, USA). Student’s paired t-test was used to determine difference between baseline and 1 month before, regarding biochemistry parameters, and this was confirmed by the Wilcoxon signed ranked test, which is a nonparametric test that compares two paired groups. The χ2 and the Fisher exact tests were performed to test for differences in proportions of categorical variables between two or more groups. The level of P less than 0.05 was considered as the cutoff value for significance.

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Results

Table 1 shows comparison of sociodemographic and lifestyle characteristics of the participants in Qatar (N=1301). Of 1301 participants, 675(51.9%) were men. The mean±SD age of the participants was 45.9±15.3 years. Female participants were significantly older than male participants (46.8±16.1 vs. 44.7±14.5; P=0.031, respectively). Overall, about two-third of the participants were Qatari nationals, with significantly higher proportion among female participants as compared with male participants (females: 79.6% Qatari and 20.4% non-Qatari, whereas males: 49.6% Qatari and 50.4% non-Qatari; P<0.001). In addition, about three quarters of the participants were married with significant difference across sex (P<0.001). Slightly less than half of the participants were overweight (BMI: 25–29.9 kg/m2), whereas the proportion of normal weight and obese participants was equal. Significantly higher proportion of female participants were obese as compared with male participants (P<0.001) (Table 1).

Table 1

Table 1

Table 2 shows the comparison of mean biochemical characteristics and blood pressures among the participants before and during Ramadan. On average, blood glucose, HbA1c level, total cholesterol, triglycerides, HDL-C, LDL-C, bilirubin, albumin, uric acid, and systolic and diastolic blood pressures were significantly lower during the holy month of Ramadan as compared with before Ramadan (P<0.001 for each).

Table 2

Table 2

Table 3 shows the comparison of biochemical characteristics and blood pressures among male and female participants before and during the holy month of Ramadan fasting. Among both male and female participants, the mean±SD blood glucose levels were significantly different before and during the fasting of holy month of Ramadan (8.44±2.09 vs. 7.62±2.10; P<0.001 and 9.08±2.33 vs. 8.27±2.19; P<0.001, respectively). In addition, mean ±SD HbA1c levels were significantly lower among both male and female participants during Ramadan as compared with before Ramadan (8.15±2.02 vs. 8.66±2.04; P<0.001 and 8.37±2.04 vs. 8.88±2.11; P<0.001, respectively). Both LDL and HDL cholesterol levels were significantly reduced among both men and women during Ramadan fasting as compared with before Ramadan (P<0.001). In addition, total cholesterol and triglycerides were also significantly reduced among both men and women during Ramadan fasting (men: 4.87±1.02 vs. 5.64±0.79; P<0.001 and 1.42±0.63 vs. 1.67±0.81; P<0.001, women: 4.94±1.12 vs. 5.67±0.83; P<0.001 and 1.39±0.61 vs. 1.63±0.80; P<0.001, respectively).

Table 3

Table 3

Figure 1 shows comparison of average HbA1c level before and during the holy month of Ramadan fasting across different age groups. There was a significant decrease in HbA1c level during Ramadan as compared with before Ramadan in each age group among both men and women.

Figure 1

Figure 1

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Discussion

The present study included representative Muslim diabetic population in the State of Qatar where more than 95% of the Muslims fast regularly during the holy month of Ramadan. The current study found positive impact of Ramadan fasting on blood glucose level, HbA1C, and lipid profile. It revealed significant reduction in blood sugar (P<0.001). This was confirmed by HbA1C that showed significant improvement (P<0.001), which is consistent with the previous reports 1,4–7,13,14. Moreover, the study did not find any negative effects of Ramadan fasting during the holy month of Ramadan on the status of DM concerning lipid profile – LDL, HDL, cholesterol, and triglyceride. This is consistent with that reported in other studies 1,4–7,14,19–24.

In fact, although blood sugar levels in diabetes can be achieved through manipulation of diet, exercise, and medication 1,14, a change in any one of these three things can skew blood sugar levels and create complications associated with hyperglycemia or hypoglycemia. Fasting during the month of Ramadan is a religious activity that devout Muslims practice whether they are diabetic or not. As such fasting involves abstinence from food and water for 12 h or more during the day from dawn to dusk, it is evident that advice regarding exercise and medication will have to be modified appropriately during this period 1–4. There is ample evidence that it is safe for well-controlled diabetics to fast during the month of Ramadan 1,2,19,20.

Sahin et al.6 examined 122 patients in Istanbul with type 2 diabetes before and after Ramadan; 88 of 122 patients fasted during Ramadan. The frequencies of both severe hyperglycemia and hypoglycemia were higher in the fasting group, but the difference was not significant. Weight, BMI, waist circumference, blood pressure, fasting blood glucose (143.38±52.04 vs. 139.31±43.47 mg/dl), postprandial glucose (213.40±98.56 vs. 215.66+109.31 mg/dl), fructosamine (314.18±75.40 vs. 314.49±68.36 µmol/l), HbA1c (6.33±0.98 vs. 6.22±0.92%), and fasting insulin (12.61±8.94 vs. 10.51±6.26 µU/ml) were unchanged in patients who fasted during Ramadan. Microalbuminuria significantly decreased during Ramadan (132.85±197.11 vs. 45.03±73.11 mg/dl). They concluded that fasting during Ramadan did not worsen the glycemic control of patients with type 2 diabetes.

More recent studies did not find any negative effects of extended fasting on glucose regulation of patients with diabetes who are using certain medications. No serious adverse event was observed, and they have failed to demonstrate benefits of increasing the number of meals in patients with diabetes 5,13,14. This is confirmative with the current reported study.

Meanwhile, Ramadan fasting for pregnant women with diabetes remains controversial and underreported. A retrospective study carried out by Ismail et al.13 in a tertiary hospital in Malaysia over a period of 3 years including pregnant diabetic women, who were on short-acting, intermediate-acting, or a combination of them, and opted to carry out Ramadan fasting, investigated the glycemic control in pregnant diabetic women on insulin who fasted during Ramadan. Glycemic control was assessed before, in the middle of, and after Ramadan fasting. There was no difference between glycemic control of type 2 DM and gestational DM women before fasting. In the middle of Ramadan, serum fructosamine decreased in both groups. However, only serum HbA1c was reduced in gestational DM after Ramadan. They concluded that the pregnant diabetic women on insulin were able to fast during Ramadan and that their glycemic control was improved during fasting period.

Carbohydrate and lipid metabolism is influenced by fasting, resulting in changes in blood chemistry. There is no caloric intake during fasting, and the continual use of glucose in the body for various vital functions 23 leads to lowering of blood glucose level. The depletion of glycogen stores after prolonged fasting further decreases its level. Our study participants demonstrated lower levels of blood glucose during the month of Ramadan, which were consistent with the observations reported by earlier workers 6,13,23–25. The variation in lipid levels observed by different workers may be attributed to the difference in dietary habits and duration of fasting in different seasons and countries. It is also obvious from the present study that the benefits of Ramadan dietary habits in terms of reduction in cholesterol, TGs, and LDL levels and rise in HDL levels are transient and may be helpful only if the diet pattern is framed according to the routine followed in Ramadan on regular basis 23.

Ensuring good control of plasma glucose during the fasting month of Ramadan is a challenge for both physicians and patients 1. Along with these changes in medication, it is important that doctors educate their patients about how their plasma glucose depends on the relationship between food intake and glucose-lowering medication. Patients should also be told of the need to monitor their plasma glucose on a regular basis throughout the fasting month 14.

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Conclusion

This study revealed that fasting during Ramadan is significantly associated with decrease in blood lipid profile, blood pressures, glucose, and HbA1C level among diabetic men and women. Muslim diabetic patients after the consultation of their physicians can fast during the month of Ramadan, and it might be beneficial for their health.

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Acknowledgements

This work was generously supported and funded by the Qatar Foundation Grant No. UREP 13-136-3-025. The authors thank the Hamad Medical Corporation for their support and ethical approval (HMC RP # Research proposal #13234/13).

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Conflicts of interest

There are no conflicts of interest.

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Keywords:

blood glucose; diabetes mellitus; epidemiology; HbA1C; Ramadan fasting

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