Chronobiology International VoI. 11, No. 5, p p 340-342
0 I994 International Society of Chronobiology
Conference Report
Ramadan, Health, and Chronobiology
F. Hakkou, A. Tazi, and L. Iraki
Hassan II Foundation for Scientific and Medical Research on Health and Ramadan, Casablanca, Morocco
DEFINITION OF RAMADAN
Ramadan occurs during the 9th lunar month of the Islamic Hegic calendar lasting 29-30 days. During this holy month, Moslems practice one of the five obligations of Islam-fasting and abstinence from eating and drinking plus hav- ing sexual intercourse between sunrise to sunset. Life habits are significantly altered, especially eating, sleeping, and working. Usually, two to three evening meals are eaten. The first, called “fasting break,” occurs after sunset. The sec- ond, dinner, is taken 3-4 h later. The last meal occurs 1 h-30 min before sunrise.
The quality of these meals differs from the usual; meals are rich in carbohydrates and lipids but poor in water and vegetables. Because meals are consumed at night, they typically affect the sleep of Moslem fasters. Sleep is often shortened by -3 h and broken by the last meal at the end of the night.
Work hours also vary between countries. Some work during the day for 6-7 h (9:OO-17:00), whereas others work 4 h during the day and 5 h during the night.
Nonetheless, work starts later in the day. These changes in lifestyle during Ram- adan suggest changes in the rhythm of normal life, with special concern about sleeping, eating, and the rest-activity pattern. A question is the extent to which Ramadan has an impact on the biological time structure of healthy and sick fasting persons.
THE FIRST INTERNATIONAL CONGRESS ON HEALTH AND RAMADAN To answer this and other questions, the First International Congress on Health and Ramadan (Casablanca, Morocco, January 19-22, 1994) was organized by the Hassan I1 Foundation for Scientific and Medical Research on Ramadan. Forty communications from 25 countries were presented dealing with the impact of Ramadan on biology, physiology, endocrinology, disease, and therapeutics. The findings of investigators were not identical, particularly for studies of the bio- Address correspondence and reprint requests
toDr. F. Hakkou, Hassan I1 Foundation
forSci- entific and Medical Research on Health and Ramadan,
19,rue Tarik Bnou Ziad, Casablanca, Morocco.
340
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W A N , H M T H , AND CHRONOBIOLOGY 341
chemistry and endocrinology of Ramadan fasters, as illustrated in the following sections.
RAMADAN, BIOLOGY, AND ENDOCRINOLOGY
Tunisian investigators reported that Ramadan conditions induce an increase in uricemia, but a decrease in insulinemia, glucose, creatinine, calcium, phosphate, cortisol, and lipids. A Malaysian team observed decrease in sodium, potassium, calcium, phosphate, and creatinine. In contrast, Iranian scientists reported sig- nificant increase in bilirubin, and significant decrease in calcium, phosphate, and albumin plus a decrease in glucose during the first 10 days of Ramadan, followed by a further decrease during the last days. Findings were conflicting for hormonal changes. One study showed no increase in testosterone, follicle-stimulating hor- mone, luteinizing hormone, T3, and T,, whereas another showed a decrease in testosterone at the end of Ramadan. Conversely, a Malaysian study showed a slight decrease in T3. Several studies found such parameters as fructosamine and glycolated hemoglobin not to vary significantly during Ramadan.
Many hypotheses were raised to address the differences in findings between studies. The first concerns altered eating and sleeping behavior, which differs between Moslem countries. The second concerns differences in research methods among investigators, including subject inclusion criteria, which are not identical across studies. For example, some authors included volunteers on the basis of a weight index or diet regimen. Neither the number of measurements nor the num- ber of evaluations during the month of Ramadan were identical.
RAMADAN AND DISEASE
The impact of Ramadan on certain diseases was also addressed. For example, it was reported that daytime fasting by non-insulin-dependent diabetic individ- uals, controlled by diet or sulfonylurea, resulted in no clinically significant al- teration in glucose or fructosamine, insulin, C-peptide, and glycolated hemoglobin. In insulin-dependent diabetic individuals, decrease in platelet re- sponse to coagulant agents during Ramadan daytime fasting may result in de- creased risk of thrombosis and atherosclerosis. Moreover, during Ramadan it was reported that hospital admissions for angina pectoris and hypertension were de- creased, whereas admissions for duodenal ulcers and bronchial asthma were in- creased. Epidemiologic study of gastroduodenal ulcer indicate an increase in cases, even ulcer perforations, during Ramadan.
RAMADAN AND THERAPEUTICS
It was reported that stabilized subjects receiving oral anticoagulant drugs may take their medication during the night, after fasting break, without risk. Similarly, it was shown that for asthmatic subjects a single theophylline dose, taken during the night after fasting break, was better tolerated than a double nocturnal dose.
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342 F. Et4KKOU ET AL.
RAMADAN AND PHYSIOLOGY
Some physiological functions have been evaluated during Ramadan. Ramadan fasting has been shown to have either no effect on pregnancy, in terms of fetal growth, or a negative one on pregnancy outcome, in terms of the number of stillborn and low-weight neonates. Concerning the gastrointestinal tract, gastric secretions have been found to be more acidic, with an increase in pepsin activity.
Arousal, vigilance, and memory are reported to decrease during Ramadan, es- pecially at the beginning.
RAMADAN AND CHRONOBIOLOGY
Researchers failed to take into account chronobiological variation, subject syn- chronization, i.e., the rest-activity cycles of participants. Chronobiological phe- nomena have to be considered in the design (timing and frequency of measurements, inclusion criteria for quality and quantity of sleep, rest-activity cycle, timing and number of meals, etc.) of research protocols. Similarly, dis- parity in results may be explained, in part, by rhythmic changes. Only three presentations took into account chronobiological phenomena. For example, it was reported that conditions during Ramadan modified circadian rhythms in hepatic enzymes (glutamic pyruvic transaminase, glutamic-oxaloacetic transaminase, cre- atinine phosphokinase, lactate dehydrogenase), trace elements (sodium, potas- sium, calcium), and bilirubin. The circadian acrophase was shifted from 7:OO to 15:00, with a nonsignificant decrease in amplitude. Another study reported mod- ification of the cortisol and inhibiting fibrogenesis activator factor rhythm; the peak was shifted from 4:OO to 9:OO.
Analysis of the conference communications suggest the following.
1. Few investigators linked observed changes occurring during Ramadan, ei- ther totally or in part, to biological rhythms or alteration in synchronizer schedule.
2. Inconisistencies in findings between apparently similar studies are certainly due to differences in scientific methods and life habits of subjects specific to the Moslem country.
3. Even though Ramadan has been practiced for 14 centuries, and involves as many as one billion persons, there have been few well-conducted studies on its impact on health and disease.
These remarks motivated the congressists to make some general recommen- 1. Epidemiological studies are needed in each Moslem country to assess coun-
try-specific health problems during Ramadan.
2. A chronobiological approach is recommended for scientific studies during Ramadan, taking into account the synchronizer rest-activity of participants.
3. To stimulate scientific study of Ramadan and health, an award by His Majesty King Hassan I1 (King of Morocco) is recommended to recognize outstanding research contributions.
dations concerning the conduct of research during Ramadan.
Chronobiol Int, Vol. 11, No. 5, 1994
