Coronary Heart Disease (CHD) is a highly prevalent disease all over the world. Magnesium (Mg) plays a role in CHD but it is still unclear. C-Reactive Protein (CRP) is an inflammatory marker which may rise in CHD. Aim of study: To assess the impact of dietary Mg intake and its level in relation to CRP among newly diagnosed CHD at middle zone of Gaza Strip. Methodology: Patients (n = 140) with confirmed CHD, 50 ± 10 years, presented in the cardiac care unit at Aqsa Martyr’s Hospital between 1 April 2012 and 30 December 2012, were enrolled in this cross-sectional study after taking consent. ECG, clinical status, and cardiac markers were used to confirm diagnosis by cardiologist. Food frequency questionnaire was used to assess Mg intake and calcium intake in addition to measurement of its level in serum. CRP latex slide was used for measurement of CRP. Results: Mg intake and serum Mg were inversely associated with risk of CHD. Mean of serum Mg among cases (1.80) was lower than controls (2.41) (P = 0.001). Percent of positive CRP was higher in cases (32.9%) than controls (12.9%) (P = 0.005). Mean of serum Mg was (1.96 ± 0.47) for positive CRP which was lower than the mean of serum Mg (2.15 ± 0.44) for negative CRP. Conclusion: Newly diagnosed patients with CHD have a positive CRP, low serum and low Mg intake, and low serum Mg was associated with elevated CRP.
Cardiovascular disease (CVD) is considered as the first leading cause of death in the world [
Mg has a very important role in proper functioning of the human body, especially the cardiovascular system. Mg deficiency in the body is associated with different risk factors for CVDs and atherogenesis such as increas- ing oxidative stress, cytokine synthesis, nitrogen oxides and mediators of inflammation and adhesion molecules on microvascular endothelial cells [
We hypothesized that this association might be explained, in part, by the anti-inflammatory properties of Mg [
To clarify these uncertainties, we examined the association between dietary and plasma Mg and risk of CHD among newly diagnosed CHD patients in the middle zone of the Gaza Strip. In addition to evaluate whether the association between Mg and CHD could be explained fully through traditional cardiovascular pathways, we used specific inclusion criteria.
A case-control study was conducted in Al-Aqsa martyrs’ hospital, Dier Al-Balah. The type of this study design is used widely, often in epidemiology. It is a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute.
The target population was hospitalized patients in cardiac care unit with CHD and patients and their fellows with- out any suspicion of CHD at other departments who are 50 ± 10 years. They were recruited according to the inclu- sion criteria in the study after getting their consent. A Purposeful, non-random sample included 140 participants divided into two groups according to the eligibility criteria. Participants were allocated into: Group A (n = 70) patients with newly diagnosed with CHD; Group B (n = 70) patients without any suspicion of CHD and their fellows.
Subjects who were eligible to participate in the study were those who met the following criteria.
• Patients diagnosed with acute CHD who are 50 ± 10 years.
• Evident ischemic ECG abnormalities.
• Patients without CHD.
• Patients who 50 ± 10 years.
• No any history of health problem related to the heart.
• Normal ECG.
• Those diagnosed with congestive heart failure, gastrointestinal disease, liver or kidney diseases, diabetes mellitus, hyperthyroidism or hyperparathyroidism.
• Patients post recent acute infection, recent trauma or surgical intervention.
• Those who were taking insulin preparations, vitamin-mineral supplements, hormone replacement therapy, or intake of any medication may cause hypomagnesaemia or hypomagnesaemia and also pregnant or lactating women.
CHD occurs when a substance called plaque builds up in coronary arteries that lead to arteriosclerosis which is leading-cause of myocardial ischemia and myocardial infarction [
Data on usual diet was ascertained by using the food frequency questionnaires. For each food item, each partici- pant was asked how often, on average, he/she had consumed a specified portion size over the past month. We made a list of the richest food of Mg available depending on the United States Agriculture Department (USDA) food database [
Serum Mg and Calcium were detected by colorimetric methods in the serum of cases and controls by spectro- photometer machine with a kit from (DiaSys Diagnostic Systems GmbH—Germany) [
Cardiologists were selected the new cases with CHD and confirmed the diagnosis of CHD on the basis of the criteria of the WHO (symptoms plus either diagnostic ECG changes or elevated levels of cardiac enzymes) [
Lifestyle and dietary data were derived from the questionnaire administered. Intake of saturated-fat food was assessed by a short fat questionnaire designed by Australian Journal of Public Health [
Statistical Package for the Social Sciences (SPSS) program version 19 [
We get all of required ethical approvals including dean of postgraduate studies & research affairs, dean of col- lege of pharmacy, Ministry of Health and informed consent of the participants.
Regarding the gender, it was noticed that the percent of male gender (62.1%) was higher than females (37.9%) among all the participants and among cases and controls. However, no statistically significant difference was found between cases and controls regarding the gender of participants (P = 0.222).
The mean ages of study population were 51.69 ± 5.7 years and 49.86 ± 6.8 years for case and controls, re- spectively. The mean age of male participants was 50.36 (±6.5) years and for females was 51.45 (±6.0) years. Participants’ age was divided into three categories one of them is less than 45 years old, from 45 to 55 years and more than 55 years. The majority of participants’ age was from 45 - 55 years (48.6%) as shown in
Education level of participants was categorized into illiterate, basic, secondary, “diploma or bachelor” and “master or PhD”. According to the results obtained in
. Personal and socioeconomic characteristics of participants.
Variables | Cases No (%) | Controls No (%) | Total | P Value |
---|---|---|---|---|
Gender | ||||
Male | 47 (67.1%) | 40 (57.1%) | 87 (62.1%) | 0.222 |
Female | 23 (32.9%) | 30 (42.9%) | 53 (37.9%) | |
Age | ||||
Less than 45 Years | 10 (14.3%) | 22 (31.4%) | 32 (22.9%) | 0.048* |
From 45 - 55 Years | 39 (55.7%) | 29 (41.4%) | 68 (48.6%) | |
More than 55 Years | 21 (30.0%) | 19 (27.1%) | 40 (28.6%) | |
Education Level | ||||
Illiterate | 2 (2.9%) | 1 (1.4%) | 3 (2.1%) | 0.001* |
Basic | 17 (24.3%) | 6 (8.6%) | 23 (16.4%) | |
Secondary | 30 (42.9%) | 20 (28.6%) | 50 (35.7%) | |
Diploma/Bachelor | 19 (27.1%) | 39 (57.7%) | 58 (41.4%) | |
Master or PhD | 2 (2.9%) | 4 (5.7%) | 6 (4.3%) | |
Employment Status | ||||
Employed | 17 (24.3%) | 26 (37.1%) | 43 (30.7%) | 0.167 |
Unemployed | 35 (50.0%) | 25 (35.7%) | 60 (42.9%) | |
Self-Employed | 18 (25.7%) | 19 (27.1%) | 37 (26.4%) | |
Family Income | ||||
<2$/day/capita | 31 (44.3%) | 17 (24.3%) | 48 (34.3%) | 0.01* |
≥2$/day/capita | 39 (55.7%) | 53 (75.7%) | 92 (65.7%) | |
Family Members | ||||
Less than 5 Members | 13 (18.6%) | 23 (32.9%) | 36 (25.7%) | 0.024* |
From 5 - 10 Members | 50 (71.4%) | 46 (65.7%) | 96 (68.6%) | |
More than 10 Members | 7 (10.0%) | 1 (1.4%) | 8 (5.7%) |
*Statistically significant.
. Life style of participants.
Variables | Cases No (%) | Controls No (%) | Total | P Value |
---|---|---|---|---|
Smoking Status | ||||
Smoker | 39 (55.7%) | 22 (31.4%) | 61 (43.6%) | 0.004* |
Non Smoker | 31 (44.3%) | 48 (68.6%) | 79 (56.4%) | |
Passive Smokers | ||||
Exposed to Other’s Smoke | 30 (42.9%) | 13 (18.6%) | 43 (30.7%) | 0.002* |
Non-Exposed to Other’s Smoke | 40 (57.1%) | 57 (81.4%) | 97 (69.3%) | |
Saturated Fat Consumption | ||||
Low to Moderate | 20 (28.6%) | 30 (42.9%) | 50 (35.7%) | 0.045* |
Moderate | 30 (42.9%) | 31 (44.3%) | 61 (43.6%) | |
Moderate to High | 20 (28.6%) | 9 (12.9%) | 29 (20.7%) |
*Statistically significant.
“diploma or bachelor” degree (27.1%) was lower than controls (57.7%) and this difference was found to be sta- tistically significant (P = 0.001,
The employment status was divided into 3 groups included employed, unemployed and self-employed partici- pants. According to the results shown in
Family income data was analyzed in a way to determine income per capita per day. Income per capita was grouped into two categories according to the poverty line endorsed by The World Bank: those with income of less than 2 American dollars ($) per day and those with 2 $ per day or more [
The number of family members was categorized into three groups: less than five, from five to ten and more than ten members as shown in
The percentages of cases living with family of 5 - 10 members (71.4%) and more than 10 members (10.0%) were higher than controls (65.7% and 1.4%, respectively) and this difference was statistically significant (P = 0.024).
As shown in
The percent of participants exposed to other’s smoke (30.7%) was found to be lower than non-exposed per- sons (69.3%). However,
The data collected in
The collected data in
. Family history of participants.
Variables | Cases No (%) | Controls No (%) | Total | P Value | |
---|---|---|---|---|---|
Hypertension | Positive | 51 (72.9%) | 31 (44.3%) | 82 (58.6%) | 0.001* |
Negative | 19 (27.1%) | 39 (55.7%) | 58 (41.4%) | ||
High Blood Cholesterol | Positive | 21 (30.0%) | 7 (10.0%) | 28 (20%) | 0.003* |
Negative | 49 (70.0%) | 63 (90.0%) | 112 (80%) | ||
Heart Diseases | Positive | 34 (48.6%) | 14 (20.0%) | 48 (34.3%) | 0.000* |
Negative | 36 (51.4%) | 56 (80.0%) | 92 (65.7%) | ||
Obesity | Positive | 29 (41.4%) | 18 (25.7%) | 47 (33.6%) | 0.049* |
Negative | 41 (58.6%) | 52 (74.3%) | 93 (66.4%) | ||
Diabetes Mellitus | Positive | 34 (48.6%) | 21 (30.0%) | 55 (39.3%) | 0.024* |
Negative | 36 (51.4%) | 49 (70.0%) | 85 (60.7%) | ||
Cancer | Positive | 4 (5.7%) | 7 (10.0%) | 11 (7.9%) | 0.346 |
Negative | 66 (94.3%) | 63 (90.0%) | 129 (92.1%) | ||
Gastrointestinal Diseases | Positive | 8 (11.4%) | 3 (4.3%) | 11 (7.9%) | 0.116 |
Negative | 62 (88.6%) | 67 (95.7%) | 129 (92.1%) | ||
Allergies or Asthma | Positive | 9 (12.9%) | 4 (5.7%) | 13 (9.3%) | 0.145 |
Negative | 61 (87.1%) | 66 (94.3%) | 127 (90.7%) | ||
Psychological Disorders | Positive | 1 (1.4%) | 4 (5.7%) | 5 (3.6%) | 0.172 |
Negative | 69 (98.6%) | 66 (94.3%) | 135 (96.4%) |
*Statistically significant.
The results shown in
The percent of cases with family history of heart disease (48.6%) was statistically much higher than controls (20%) (P = 0.000) as shown in
A statistically significant difference was found between cases and controls regarding family history of obesity (P = 0.049) as shown in
It’s noticed that the percent of cases with family history of diabetes mellitus (48.6%) is higher than controls (30.0%) and this disparity was found to be statistically significant (P = 0.024,
The results of this study revealed that there is no statistically significance difference between cases and con- trols regarding other diseases such as cancer, gastrointestinal disease, allergies, asthma and psychological dis- orders (P > 0.05,
Independent t-test was used to compare the means of the number of servings of different types of food rich with Mg. In our study, it was found that cases consumed more servings of cabbage, while controls consumed more servings of molokhia, okra, potatoes and tomatoes. However, there was no statistically significant difference between cases and controls regarding the servings of different vegetables consumed by participants (P > 0.05). Also, the results were revealed that there is no significant difference between cases and controls regarding the means of servings of dates, raisins, banana and grapes consumed by participants (P > 0.05). On the other hand, there was a statistically significant difference between the means of servings consumed of melons and apples.
Regarding to grains, nuts, seeds and legumes the results shown that the number of servings of whole meal bread and cooked bulgur were higher in control than cases. However, only the bulgur intake difference was sta- tistically significant (P < 0.05). On the other hand, the number of servings of white bread was higher in cases than controls, however this difference was not statistically significant (P = 0.761). Regarding the intake of nuts and seeds, it was found that controls consumed more servings of watermelon seeds, pumpkin seeds, sesame seeds; sunflower seeds; cashew; pistachio; peanut; chocolate; tahini in comparison to cases and these differences were found to be statistically significant except for pistachio, peanut and tahini (P > 0.05). On the other hand, the intake of almond was slightly higher in cases than controls but without statistical significance (P = 0.543). It was found that cases consumed more servings of legumes (beans and lentils) than controls; however, this dif- ference was not statistically significant (P > 0.05). There was no significant difference between cases and con- trols regarding the consumption of coffee (P = 0.828). The mean of servings of cocoa consumed by controls was higher than cases that reached to be statistically significant (P = 0.002). The mean of servings of whole milk consumed by controls was higher than cases and this difference was statistically significant (P = 0.092).
The participants were divided into three groups according to their serum Mg level: low (<1.8) mg/dL, normal (1.8 - 2.3) mg/dL and high (>2.3) mg/dL. The results obtained in revealed 48.6% of cases have low serum Mg level when compared with 4.3% of controls with statistical significant difference (P = 0.001,
. Clinical cutoff points for serum magnesium among participants.
Variables | Cases No (%) | Controls No (%) | Total | P value | |
---|---|---|---|---|---|
Serum Magnesium | Low (<1.8) mg/dL | 34 (48.6%) | 3 (4.3%) | 37 (26.4%) | 0.001* |
Normal (1.8 - 2.3) mg/dL | 31 (44.3%) | 21 (30.0%) | 52 (37.1%) | ||
High (>2.3) mg/dL | 5 (7.1%) | 46 (65.7%) | 51 (36.4%) | ||
Total | 70 (100%) | 70 (100%) | 140 (100%) |
*Statistically significant (P-value < 0.05).
The mean of serum Mg level among participants
mean of serum Mg was (1.96 ± 0.47) for positive CRP participants which was lower than the mean of serum Mg (2.15 ± 0.44) for negative CRP participants, with statistical significance (P = 0.03).
The data collected showed that 32.9% of cases have positive CRP results when compared with 12.9% of con- trols and this difference was statistically significant (P = 0.005) as shown in
In this retrospective case control study, we found a modest inverse association between dietary Mg intake and serum Mg in relation to risk of CHD that did reach statistical significance. Percent of cases with low Serum Mg was (48.6%) which is higher than controls (4.3%) and the mean of serum Mg of participants among cases was (1.80 mg/dL) lower than controls (2.41 mg/dL) (P = 0.001). The result of present study agrees with the study of (Altura et al., 2007) that concluded Mg deficiency in the body is associated with different risk factors for CVDs and atherogenesis such as increasing oxidative stress, cytokine synthesis, nitrogen oxides and media- tors of inflammation and adhesion molecules on microvascular endothelial cells.
Authors [
Levels of hypomagnesaemia among participants
. Independent t test comparing the means of Mg and CRP.
Variable | Number | Mean | SD | t | P Value | |
---|---|---|---|---|---|---|
CRP | Negative | 108 (77.1%) | 2.15 | 0.44 | 2.10 | 0.03 |
Positive | 32 (22.9%) | 1.96 | 0.47 | 2.02 |
. Clinical cutoff points for C-reactive protein.
Variables | Cases No (%) | Controls No (%) | Total | P Value | |
---|---|---|---|---|---|
C-RP | Positive | 23 (32.9%) | 9 (12.9%) | 32 (22.9%) | 0.005* |
Negative | 47 (67.1%) | 61 (87.1%) | 108 (77.1%) | ||
Total | 70 (100%) | 70 (100%) | 140 (100%) |
The deficiency of Mg may be caused by eating cooked and processed food which is considered as a common dietary habit among people of Gaza Strip, this proved by Swaminathan [
We found a direct strong relationship between CRP and the development of CHD, in which the percent of cases with positive CRP was (32.9%) higher than controls (12.9%). There was statistically significant relationship that may explained by a role of inflammatory process during the development of CHD. The result of present study agrees with the study of [
We found an inverse relationship between Mg and CRP, in which 22.9% of participants have positive CRP while, 77.1% of them have negative CRP; the mean of serum Mg was (1.96 ± 0.47) for positive CRP partici- pants which was lower than the mean of serum Mg (2.15 ± 0.44) for negative CRP participants, without statis- tical significance. The result of present study agrees with the study of Guerrero-Romero & Rodríguez-Morán [
We found a direct strong relationship between Serum Ca and development of CHD, which the percent of cases with low Serum Ca was (7.1%) higher than controls (1.4%) with statistical significance (P = 0.011). The result of present study contradicts with (Lu, et al., 2012) who concluded that the results of their study were inconsistent and the pooled data do not strongly support a significant effect of greater dietary Ca intake on the risk of CAD. On the other hand, many studies revealed association between the effects of hypomagnesmia over Ca in the body that leads to hypocalcaemia. Studies showed that a reduction in extracellular Mg concentration stimulated the secretion of parathyroid hormone (PTH) in the absence of changes in Ca concentration [
In conclusion, we found that decreased Mg intake was possibly associated with a higher risk of CHD among adults. Whereas the causal effect of Mg is not certain. In spite of that there is sufficient reason to encourage a balanced diet rich in Mg sources, such as whole grains, nuts, fruits and vegetables which are protective against the risk of CHD.
We are very much thankful to the deanship of postgraduate studies & research affairs of Al-Azhar University, deanship of college of pharmacy, ministry of health, Al-Aqsa martyrs’ hospital, special thanks to my uncle in law Mr. Tayseer Ahmed, my friend Mr. Mohammed Najem “Lab. technician” and to the team of Intensive Car- diac Care Unit for their cooperation and assistance in data collection. Finally, I would thank all the patients and volunteers who participated in this study. To all of these individuals I owe many thanks for their insights and unlimited support.
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*Corresponding author.