Effect of ramadan fasting on glycemic control and other essential variables in diabetic patients.

Background: Fasting during the holy month of Ramadan is a religious obligation for all Muslims who represent 1.8 billion of the world population (24%). This study explores the effect of Ramadan fasting on the blood glucose, glycated hemoglobin (HbA1c), lipid profile, sleeping quality, and essential lifestyle parameters and also explores the safety of fasting for a whole month among diabetic patients. Aim: The aim of the present study was to assess the impact of Ramadan fasting on the blood glucose, HbA1c, lipid profile, sleeping quality, and lifestyle parameters among patients with type 2 diabetes mellitus (T2DM) in Turkey. Subjects and
Methods: A total of 1780 diabetic patients were approached, and 1246 (70%) participated in this cross-sectional study carried out during the period from May 27, 2017, to June 24, 2017. Data analysis comprised sociodemographic features, lifestyle habits, blood pressure measurements, serum lipid profiles, serum calcium, Vitamin D 25-hydroxy, uric acid, and HbA1c at before 4 weeks and after 12 weeks from Ramadan.
Results: Out of 1246 patients, 593 (47.6%) were male and 653 (52.4%) were female. The mean ± standard deviation age of the patients was 50.39 ± 15.3 years. Males were significantly older than females (51.53 ± 12.56 vs. 49.26 ± 14.4; P = 0.003, respectively). Significant differences were found in Vitamin D, blood glucose, HbA1c level, creatinine, bilirubin, albumin, total cholesterol, triglycerides, high-density lipoprotein-cholesterol (female), low-density lipoprotein-cholesterol (male), uric acid, and systolic and diastolic blood pressure after and before the holy month of Ramadan (P < 0.05 for each). HbA1c (P < 0.001), physical activity (P < 0.001), hours of sleeping (P < 0.001), systolic blood pressure (BP) (mmHg) (P = 0.007), BMI (P = 0.016), diastolic BP (mmHg) (P = 0.018), family history (P = 0.021), and smoking (P = 0.045) were identified as significantly associated with Ramadan fasting as contributing factors.
Conclusion: In one of the largest studies of its kind, we show that Ramadan fasting has positive effects on T2DM patients as it reduces their blood pressure, blood glucose, HbA1C, and BMI. Furthermore, there are improvements in the duration of sleep and physical activity, the role of Ramadan fasting in diabetes therapy has been confirmed.

INTRODUCTION

Ramadan fasting is one of the five main pillars of Islam that is practiced by over one and a half billion people.[123] Fasting during Ramadan is a mandatory duty for all healthy sane Muslims, and they should endure without food, drink, oral medications, smoking, and other sensual pleasures from break of dawn to sunset.[1234567]

Numerous studies have mentioned the biochemical alterations while fasting among both in nondiabetic patients and diabetic patients.[1234567] The population-based Epidemiology of Diabetes and Ramadan 1422/2001 study performed among 12,243 people in 13 Islamic countries and reported that approximately 43% of Muslims with type 1 diabetes and 79% of Muslims with type 2 diabetes fast during Ramadan.[2] Furthermore, more than 50 million Muslims who have diabetes fast during Ramadan.[2]

Diabetes mellitus[15] and cardiovascular diseases[38910] are reaching epidemic proportions worldwide and lead to important public and personal burden.[2] Furthermore, diabetes mellitus is a primary reason of mortality and morbidity in many developed and developing countries.[789] Ramadan fasting change lifestyle of Muslims for one lunar month that may have an impact on diabetic and cardiac patients[2341011] because during the Ramadan Muslims eat meals before dawn and after sunset. The alteration in meal schedule has an effect on sleep habit, lifestyle properties, and diabetes complications.[111213141516] The aim of the present study was to assess the impact of Ramadan fasting on the blood glucose, glycated hemoglobin (HbA1c), lipid profile, sleeping quality, and lifestyle parameters among patients with type 2 diabetes mellitus (T2DM) in Turkey.

SUBJECTS AND METHODS

This cross-sectional study was conducted among Turkish adult patients with T2DM in the Medipol Hospitals. Institutional Review Board ethical clearance for this study was given by the International School of Medicine, Istanbul Medipol University. The study comprised patients with T2DM who treated at the Medipol International Hospital at the time of the study. The diagnosis of DM was assigned by the documentation in the patient's previous or current medical records.[151617]

The study design was a nonrandomized interventional controlled from May 27, 2017 to June 24, 2017 in two periods as follows: first period (4 weeks before Ramadan) and the second period (4 weeks after Ramadan). The exclusion criteria of the current study were serious comorbidities such as renal diseases, alertness problems, newly diagnosed T2DM (18 months), hospitalization a short time ago, unawareness of hypoglycemia, and partially or completely nonfasting during the month of Ramadan.

The sample size calculation was based on previous studies that determined the prevalence of T2DM and MetSyn in Turkey[1618] to be between 16.2%, with the 99% confidence level and with 2.5% error of estimation, the minimum sample size for the current study was 1780. Patients were recruited by the systematic 1-in-2 sampling procedure. Although 1780 patients were approached, 1246 (70%) patients agreed to participate in this study. One hundred patients were used to determine content validity, face validity, and reliability of the questionnaire. The questionnaire has a high level of validity and a high degree of repeatability (κ = 0.86).

Data collection methods: Questionnaire

This research comprised sociodemographic and lifestyle characteristics such as age, gender, marital status, level of education, occupation, Body Mass Index (BMI), physical activity, the frequency of fast food consumption, and smoking habits, clinical data including systolic and diastolic blood pressures (DBP). Laboratory investigations were performed to examine blood glucose, HbA1c, high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), cholesterol, triglyceride, urea, creatinine, bilirubin, albumin, calcium, Vitamin D 25-hydroxy (25-OH), and uric acid before and after Ramadan. BMI was calculated as the ratio of weight (kilogram) to the square of height (meters). The patient was classified as obese if the value of BMI was ≥30 kg/m2, overweight if BMI was >25 kg/m2, and normal if BMI <20 kg/m2.[1216] In line with the World Health Organization guidelines, hypertension was evaluated as systolic blood pressure ≥130 mmHg or DBP ≥85 mmHg or using anti-hypertensive medication.[121619] Smoking habits were classified as being past, current smoker or nonsmoker. Patients were categorized as physically active if they walked or cycled for more than 30 min a day.

Laboratory measurements

After 10 h of fasting, blood sample (10 ml) were collected from the patients. Subsequently, different blood parameters were determined in a central certified laboratory at the Medipol Hospital. Plasma glucose, total cholesterol, triglyceride, HDL-C, and LDL-C were measured using an auto-analyzer (ROCHE COBAS 6000). A high-performance liquid chromatography method was used to evaluate HbA1c concentration.[1218]

Statistical analysis

Student's paired t-test was performed to specify the differences between biochemistry parameters 4 weeks before and 12 weeks after while the Wilcoxon signed-rank test was used for the nonparametric dataset. Chi-square and Fisher's exact tests were used to determine for differences in proportions of categorical variables between two or more groups. A multivariable linear regression model with step-wise elimination was performed to evaluate the association between dependent and independent variables and to predict potential factors for diabetes. Statistical significance was accepted at the P < 0.05 level.

RESULTS

Table 1 presents sociodemographic and lifestyle characteristics of the participants (n = 1246). Out of 1246 patients, 593 (47.6%) were male and 653 (52.4%) were female. The mean ± standard deviation (SD) age of the participants was 50.39 ± 15.3 years. Males were significantly older than females (51.53 ± 12.56 vs. 49.26 ± 13.4; P = 0.003, respectively). There were significant differences between females and males in the level of education, occupation, smoking status, physical, and sporting activity.

Table 1

Comparison of sociodemographic characteristics of the participants in Istanbul, Turkey (n=1246)

	Total, n (%)	Male (n=593), n (%)	Female (n=653), n (%)	P
Age in years (mean±SD)	50.39±15.3	51.53±12.56	49.26±13.40	0.003
Age (years)
<40	274 (22.0)	94 (15.9)	180 (27.6)	<0.001
40-49	317 (25.4)	159 (26.8)	158 (24.2)
50-59	344 (27.6)	199 (33.6)	145 (22.2)
60 and above	311 (25.0)	141 (23.8)	170 (26.0)
Marital status
Single	184 (14.8)	89 (15.0)	95 (14.5)	0.734
Married	9580 (76.9)	451 (76.1)	507 (77.6)
Divorced/widow	104 (8.3)	53 (8.9)	51 (7.8)
BMI (kg/m2)
<25	326 (26.2)	131 (22.1)	195 (29.9)	0.006
25-29.9	574 (46.1)	293 (49.4)	281 (43.0)
30 and above	346 (27.8)	169 (28.5)	177 (27.1)
Level of education
Elementary	282 (22.6)	145 (24.6)	137 (21.0)	<0.001
Intermediate	307 (25.4)	168 (28.3)	149 (22.8)
Secondary	334 (26.8)	164 (27.7)	170 (26.01)
University	313 (25.1)	116 (19.6)	197 (20.2)
Occupational status
Housewife	176 (14.1)	0 (0.0)	176 (27.0)	<0.001
Sedentary	325 (26.2)	155 (26.1)	170 (26.0)
Manual	348 (27.8)	181 (30.5)	114 (17.5)
Businessman	180 (14.4)	106 (17.9)	74 (11.3)
Arm/police/security	76 (6.1)	77 (13.0)	50 (7.7)
Clark	143 (11.4)	74 (12.5)	69 (10.6)
Household income (TL)*
<2,500	330 (26.5)	139 (234)	191 (29.2)	0.033
2,500-4,499	381 (30.6)	197 (332)	184 (28.2)
4,500-6,999	320 (25.7)	162 (27.3)	158 (24.2)
>7,000	215 (17.3)	95 (16.0)	120 (18.4)
Eating frequency (times)
2	999 (80.6)	467 (79.3)	532 (81.8)	0.280
3	240 (19.4)	122 (20.7)	118 (18.2)
Smoking status
Never	1027 (82.4)	464 (78.2)	563 (86.2)	<0.001
Current	147 (11.8)	88 (14.8)	59 (9.0)
Past smoker	72 (5.8)	41 (6.0)	31 (4.7)
Physical activity				0.003
Yes	312 (25.2)	126 (21.2)	186 (28.5)
No	934 (75.0)	467 (78.8.2)	467 (71.5)
Sport activity
Yes	330 (26.5)	176 (29.7)	154 (23.6)	0.015
No	916 (73.5)	417 (70.3)	499 (76.4)

*1 $ US Dollars = 4,000 TL. SD=Standard deviation, BMI=Body mass index

Table 2 presents the mean of biochemical characteristics and blood pressures among males and females before 4 weeks and after 12 weeks of Ramadan. The significant differences were found in serum Vitamin D 25-OH, blood glucose, HbA1c level, creatinine, bilirubin, albumin, total cholesterol, triglycerides, HDL-C (female), LDL-C (male), uric acid, systolic and DBP before and after Ramadan (P < 0.05 for each). Furthermore, there were significant differences in the number of sleeping hours between during and after Ramadan (5.61 ± 0.58 vs. 6.93 ± 0.72; P < 0.001, respectively).

Table 2

The comparison of biochemical characteristics and blood pressures among males and females before and after Ramadan (n=1246)

Blood investigations	Mean±SD		Change (after-before) (95% CI)	P
	After Ramadan	Before Ramadan
Vitamin D 25-OH
Male	20.70±10.74	19.11±10.50	1.59 (1.59-1.40)	<0.001
Female	21.20±10.82	19.64±10.56	1.56 (1.43-1.68)	<0.001
Blood glucose (mmol/L)
Male	7.18±1.17	9.14±2.10	−1.95 (−2.098-−1.81)	<0.001
Female	7.39±1.09	9.82±2.03	−2.43 (−2.56-−2.94)	<0.001
HbA1c
Male	7.54±1.13	8.77±1.20	−1.23 (−1.34-−1.12)	<0.001
Female	7.40±1.09	9.21±1.13	−1.81 (−1.93-−1.69)	<0.001
Calcium (mmol/L)
Male	4.03±1.70	3.05±1.97	0.97 (0.17-1.78)	0.018
Female	3.72±1.91	3.02±2.58	0.70 (0.22-1.17)	0.004
Urea (mmol/L)
Male	5.39±2.17	5.61±3.14	−0.22 (−0.49-0.37)	0.092
Female	4.94±1.59	5.11±2.09	−0.17 (−0.35-−0.02)	0.076
Creatinine (mmol/L)
Male	72.09±32.88	70.35±29.19	1.73 (0.11-3.36)	0.036
Female	67.27±34.45	64.55±27.75	2.72 (1.14-4.29)	0.010
Bilirubin (mmol/L)
Male	7.72±3.63	8.64±3.01	−0.92 (−1.45-−0.39)	<0.001
Female	7.50±3.63	8.56±2.04	−1.05 (−1.55-−0.55)	<0.001
Albumin (mmol/L)
Male	38.13±4.46	40.47±4.79	−3.44 (−3.85-−3.03)	<0.001
Female	36.82±3.93	40.47±3.93	−3.66 (−4.10-−3.19)	<0.001
Cholesterol (mmol/L)
Male	3.22±1.21	4.75±1.07	−1.52 (−1.62-−1.42)	<0.001
Female	3.27±1.23	4.81±0.98	−1.54 (−1.64-−1.44)	<0.001
Triglycerides (mmol/L)
Male	1.52±0.46	1.63±0.75	−0.11 (−0.17-−0.33)	<0.001
Female	1.51±0.42	1.64±0.71	−0.12 (−0.27-−0.20)	<0.001
HDL-C (mmol/L)
Male	1.06±0.21	1.08±0.28	−0.02 (−0.04-−0.03)	0.068
Female	1.07±0.20	1.09±0.27	−0.02 (−0.04-−0.01)	0.021
LDL-C (mmol/L)
Male	2.00±0.89	1.82±0.97	0.19 (−0.24-−0.06)	0.001
Female	2.07±0.84	1.94±0.80	0.13 (−0.21-−0.08)	0.077
Uric acid (mmol/L)
Male	283.9±89.3	269.1±72.7	14.10 (6.61-21.6)	<0.001
Female	286.5±88.9	272.2±65.5	14.4 (7.30-21.5)	<0.001
SBP (mmHg)
Male	128.5±14.4	135.4±14.6	−6.5 (−7.45-−5.54)	0.010
Female	128.9±14.2	136.1±15.1	−7.3 (−8.16-−6.44)	<0.001
DBP (mmHg)
Male	76.7±9.9	78.3±8.7	−2.4 (−3.5-−1.35)	0.018
Female	78.1±8.5	78.8±8.5	−0.75 (−1.67-−1.69)	0.004
BMI
Male	26.54±4.15	28.00±4.32	−1.46 (−1.52-−1.39)	<0.001
Female	25.93±4.00	27.42±4.20	−1.49 (−1.55-−1.40)	<0.001

Two-sided P values based on pair t-test. SD=Standard deviation, BMI=Body mass index, 25-OH=25-hydroxy, HDL-C=High-density lipoprotein-cholesterol, LDL-C=Low-density lipoprotein- cholesterol, SBP=Systolic blood pressure, DBP=Diastolic blood pressure, HbA1c=Glycated hemoglobin, CI=Confidence interval

Table 3 shows the comparison of average biochemical characteristics and blood pressures among the participants before 4 weeks and after 12 weeks of Ramadan. There were significant differences Vitamin D 25-OH, blood glucose, HbA1c level, calcium, creatinine, albumin, total cholesterol, HDL-C, LDL-C, uric acid, systolic and DBP, hours of sleep, and BMI before and after Ramadan (P < 0.001 for each).

Table 3

The comparison of biochemical characteristics and blood pressures among patients before and after Ramadan (n=1246)

Blood investigations	Mean±SD		Change (after-before) (95% CI)	P*
	After Ramadan	Before Ramadan
Vitamin D 25-OH	20.97±10.78	19.39±10.53	−2.57 (−1.48-−1.66)	<0.001
Blood glucose (mmol/L)	7.29±1.13	9.50±2.09	−2.20 (−2.30-−2.0)	<0.001
HbA1c (%)	7.95±1.15	9.01±1.17	−1.46 (−1.53-−1.39)	<0.001
Calcium (mmol/L)	4.03±1.70	3.05±1.97	0.97 (0.17-1.78)	<0.001
Urea (mmol/L)	5.16±1.17	5.35±2.66	−0.04 (−0.11-0.02)	0.015
Creatinine (mmol/L)	69.59±17.78	67.34±14.63	2.24 (1.11-3.38)	<0.001
Bilirubin (mmol/L)	8.09±3.24	8.87±3.11	−0.77 (−1.27-−0.27)	0.002
Albumin (mmol/L)	34.46±9.12	41.01±8.59	−3.54 (−3.85-−3.24)	<0.001
Cholesterol (mmol/L)	3.25±1.21	4.78±1.02	−1.53 (−1.60-−1.46)	<0.001
Triglycerides (mmol/L)	1.52±0.44	1.63±0.73	−0.11 (−0.15-−0.76)	0.003
HDL-C (mmol/L)	1.06±0.20	1.09±0.27	−0.02 (−0.03-−0.006)	<0.001
LDL-C (mmol/L)	2.04±0.86	1.88±0.31	0.16 (0.75-−0.233)	<0.001
Uric acid (mmol/L)	285.0±89.1	271.0±68.9	14.28 (9.15-19.42)	<0.001
BP
SBP (mmHg)	128.5±14.4	135.4±14.29	−6.92 (−7.55-−6.28)	<0.001
DBP (mmHg)	76.7±9.9	78.3±8.70	−1.55 (−2.25-−0.84)	<0.001
Hours of sleep	6.93±0.72	5.61±0.58**	1.32 (1.35-1.28)	<0.001
BMI (male and female)	26.22±4.08	27.70±4.31	−1.48 (−1.52-−1.42)	<0.001
BMI males (kg/m2)	26.54±4.15	28.00±4.32	−1.46 (−1.52-−1.39)	<0.001
BMI females (kg/m2)	25.93±4.00	27.42±4.20	−1.49 (−1.55-−1.40)	<0.001

*Two sided P values based on pair t-test, **Number of sleeping hours during Ramadan timing. BP=Blood pressure, SD=Standard deviation, BMI=Body mass index, 25-OH=25-hydroxy, HDL-C=High-density lipoprotein-cholesterol, LDL-C=Low density lipoprotein-cholesterol, SBP=Systolic blood pressure, DBP=Diastolic blood pressure, HbA1c=Glycated hemoglobin, CI=Confidence interval

Table 4 shows the results of multiple linear regression analysis to indicate predictors and impact of Ramadan fasting on several biochemical and lifestyle parameters in diabetic patients. As can be seen from this table, HbA1c (P < 0.001), physical activity (P < 0.001), hours of sleeping (P < 0.001), systolic BP (mmHg) (P = 0.007), obesity (P = 0.016), diastolic BP (mmHg) (P = 0.018), family history (P = 0.021), and smoking (P = 0.045) were significantly associated with Ramadan fasting as contributing factors.

Table 4

Multivariable linear regression analysis to show predictors and effect of Ramadan fasting on different biochemical and anthropometric parameters in diabetic patients

Independent variables	Unstandardized coefficient (B)	SE	Standardized coefficient (β)	t	P
HbA1c level	−3.530	0.984	−0.231	−3.587	<0.001
Less physical activity	−4.939	1.267	−0.330	−3.898	<0.001
Less hours of sleeping	−2.856	0.787	−0.229	−3.628	<0.001
SBP (mmHg)	−2.320	0.858	−0.176	−2.703	0.007
BMI (kg/m2)	−3.761	1.545	−0.215	−2.434	0.016
DBP (mmHg)	−2.121	0.890	−0.155	−2.383	0.018
Family history	−2.094	0.897	−0.145	−2.334	0.021
Smoking (yes)	−2.657	1.321	−0.129	−2.011	0.045

SE=Standard error, SBP=Systolic blood pressure, DBP=Diastolic blood pressure, HbA1c=Glycated hemoglobin, BMI=Body mass index

DISCUSSION

In Turkey, a large proportion of patients with diabetes mellitus fast regularly during Ramadan. Ramadan fasting is a challenge for diabetic patients because of the acute changes in their dietary and lifestyle patterns. Therefore, it is difficult to suggest a treatment for this group of people. The number of studies on Ramadan fasting T2DM patients from Turkey is limited and has been restricted to using few patients, with the largest study using 122 patients.[5] In this context, the current study is much larger as it recruited 1246 T2DM patients. The present study, with a much larger number of patients, revealed the favorable impact of Ramadan fasting on the important parameters of diabetes including blood glucose, HbA1c levels, and lipid profile. The results are consistent with previous studies reported in the literature.[1456712131415192021222324] In patients with T2DM, diet, exercise, and antidiabetic medications can help stabilize blood glucose level. However, any alteration can fluctuate the blood glucose level and lead to hyperglycemia or hypoglycemia.[11416] A previous small study (n = 122) investigated Turkish patients with T2DM before and after Ramadan. It did not find any negative effects of fasting on this group of patients.[5] This is in agreement with our much larger study (1246 T2DM patients). Therefore, the current evidence suggests that Ramadan fasting is unlikely to be risky for well-controlled patients.[12162021222324] According to previous studies, Ramadan fasting had no negative impacts on glucose regulation of patients with T2DM who use antidiabetic medications.[5671213142021222324] This is in good agreement with our study. The findings from our study revealed that fasting leads to a statistically significant reduction in blood glucose levels that were consistent with other studies.[5613] It has been previously reported that weight loss is important for improving the health status of T2DM patients.[25] For example, weight loss has been found to be a stronger predictor of HbA1c goal attainment in T2DM compared to medication adherence.[26] The finding of this study revealed that after the month of Ramadan fasting there is a significant decrease in body weight which could beneficial for T2DM patients and Ramadan fasting could play a role in diabetes therapy. There is now consensus that physical activity can be beneficial for diabetes as it can improve various risk factors associated with diabetes including blood glucose level.[27] The study reveals that compared to before Ramadan, there is a statistically significant increase in physical activity after Ramadan. The precise reason for this change is not clear, but the reduction in body weight and the improvement in blood parameters may have some contributory roles. In addition to improvements in blood parameters, Ramadan fasting led to a statistically significant increase in the duration of sleep compared to before Ramadan. This is important since there is insufficient sleep duration is associated with a poor glycemic control in T2DM.[28]

In a comprehensive study,[29] several suggestions have been recommended for patients with diabetes mellitus.[29] The suggestions were blood glucose monitoring, consultation with their physicians, not skipping predawn meal, not doing tiring exercises, and regulation of medication dose. Monitoring plasma glucose during Ramadan fasting is a difficult issue for doctors and patients.[2] The plasma glucose levels are determined by food intake, physical activity, and medications. Patients with T2DM should be recommended to monitor blood glucose regularly throughout the fasting month.[12]

CONCLUSION

The current study represents the largest study (n = 1246) with Turkish T2DM patients to explore the impact of Ramadan fasting on different biochemical and lifestyle parameters. We found significant differences between Ramadan fasting and decrease in blood lipid profile, blood pressure, blood glucose, HbA1c levels, BMI, and sleeping problems among patients with T2DM. The study suggests that Muslim diabetic patients can fast during Ramadan after consultation with their physicians. Indeed, Ramadan fasting can be considered as a strategy for managing and improving the health of diabetic patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.