الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Vitamin D is not only a fat-soluble vitamin, but also considered as a prohormone
within the entire body. Although the classic function of vitamin D was long thought to
increase the intestinal absorption of calcium for proper bone health, its role in health
maintenance is beginning to expand with the finding of VDRs in many cells throughout
the body, including cardiomyocytes, vascular smooth muscle, and endothelium.
Vitamin D levels are inadequate in about 50% of the world population. Vitamin D
deficiency is thus prevalent across all geographic areas, age groups, and seasons and is
increasing in incidence. Risk factors for vitamin D deficiency include decreased exposure
to sunlight, decreased cutaneous synthesis related to age, low dietary intake, obesity and
high degree of skin pigmentation.
Cardiovascular diseases are currently the leading cause of death for both men and
women. Emerging evidence suggests that optimal serum 25(OH)D levels could also
improve cardiovascular outcomes, such as reducing hypertension, improving lipid
management, and reducing incidence of myocardial infarction and cardiovascular
mortality.
The general aim of the study is to evaluate the relationship between vitamin D status
and cardiovascular diseases. The specific objectives are to determine the different factors
that may be associated with deficiency of serum 25(OH) D specially dietary intake and sun
light exposure among cases and controls, moreover investigating the association between
serum level of 25(OH) D and cardiovascular diseases in addition to correlating the findings
with other cardiovascular risk factors with special emphasis on anthropometric
measurements among the studied subjects, CRP, fasting blood glucose and lipid profile.
A case control study approach was used to conduct the study. Newly diagnosed
adult male and female patients aged over 40 years suffering from cardiovascular diseases
specially hypertension and ischemic heart diseases attending cardiology clinics in
Alexandria Main University Hospital, Private Hospitals and Nutrition Clinic of High
Institute of Public Health were included in our study. The samples were collected till the
sample size (150 cases, 150 controls) was reached. The following exclusion criteria were
strictly applied for all those who accepted to participate in the study where subjects were
not suffering from co-morbid other endocrinal disorders (e.g hyperthyroidism,
hypothyroidism, hyperparathyroidism, hypoparathyroidism, cushing disease, crohn’s
disease, Addison’s disease, growth hormone disorders, etc), hematological, renal, hepatic
or neurological disorders, autoimmune diseases, malignancies and subjects were not taking
vitamin D supplements.
A pre-designed structured coded questionnaire was used to collect the needed data
from the studied groups. The questionnaire consisted of the following parts; Sociodemographic
characteristics: including age, sex, marital status, educational level,
occupation and residency, medical condition: including type of the cardiovascular disease
(such as hypertension, coronary artery disease, myocardial infarction), type of medication
taken (such as diuretic, calcium channel blockers, beta blockers, ACE inhibitors, digoxin,
anti-arrhythmic drugs), history of diabetes (including the duration and type of medication
taken), history of dyslipidemia (including duration and type of medication taken) and any
Summary
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other associated medical conditions, pattern of exposure to the sun light: including
duration of the sun exposure, percentage of this time spent under shade, percentage of this
time spent wearing hat/veil and/or long sleeves and wearing sun screens. Dietary intake
data: to estimate the pattern of consumption of different food types with special emphasis
on dietary sources of vitamin D including dairy products, eggs, fish, rich in vitamin D
including tuna, salmon, macrel and herring, fat sources used in cooking, meat especially
those with high vitamin D content such as liver and kidney, fortified breakfast cereals.
Physical examination of the studied groups was done including color of the skin
being dark, medium or fair, measurement of blood pressure in mm/Hg and
anthropometric measurements according to Jellife et al. criteria and including weight in
kg, height in cm, BMI, waist & hip circumferences and waist/hip ratio. Serum samples
were collected and analyzed to check fasting plasma glucose, lipid profile, CRP and
serum level of 25(OH)D.
The results of the study could be summarized as follows:
The age of the studied subjects ranged from 40 to above 60 years with mean age of
54.6± 4.08 years. Regarding the sex, females were of higher percentage in both the
cases and the controls. The majority of both the cases (96.7%) and the controls
(100%) were married. Concerning the education of the studied subjects, almost
quarter of the cases (24%) have completed their primary education, while in the
control group those who completed their university education contributed to 24.7%,
also most of the cases (20.7%) had professional jobs while as among the control
group, those with no work were of the highest percentage (22%). Regarding the
residency, 55.3% of the cases and 45.3% of the control group were from rural areas
while about 44.7% of the cases and 54.7% of the control group were from urban
areas.
On comparing the two studied groups regarding these sociodemographic data, there
was no statistical significant difference between them.
Among the cases, 45.3% were newly diagnosed as hypertensives with mean systolic
BP of 164.6±11.23 and mean diastolic BP of 109.6±9.28, 27.3% their diagnosis was
acute myocardial infarction, 24% were having coronary artery disease, and 3.3 % had
other cardiovascular diseases, ACE inhibitors contributed the highest percentage of
the drugs taken (12%) ,about one third (32%) had history of hyperlipidemia with
mean duration of 2.36±3.99 years among which 54.2% were treated by statins.
Almost half of the cases (48.7%) had history of diabetes which is a cardiovascular
risk factor with mean duration of 6.98±4.33 years, 41.1% of them were on oral
hypoglycemic drugs.
The majority of the cases as well as the controls had dark skin with the percentages
of 40.7% and 38% respectively and this was consistant with the fact that people with
light skin are less likely to develop vitamin D deficiency.
The height of the studied subjects ranged from less than 155cm to more than 165cm,
while the body weight of the studied subjects ranged from less than 60 kg to more
than 90 kg where subjects weighing from 80 to less than 90 kg contributed the
majority of the cases (40%), as well as among controls (32.7%).
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The body mass index mean value among the cases was 25.2±3.65 kg/m2 which was
less than that among the controls (26.8±4.01kg/m2), the waist hip ratio mean values
among the cases and controls respectively in males were 0.758±0.119 and
0.754±0.131, however among females were 0.801±0.243 and 0.772±0.209. and on
comparing both groups there was no statistical significant difference regarding their
anthropometric measurements.
In general, the pattern of sun exposure among the cases was significantly lower than
that among the controls.
Concerning the lipid profile; among the cases, the total cholesterol 28.7% of which
had elevated levels (above 200mg/dl), while the triglycerides 32% have high levels
(above 150mg/dl) and regarding the calculated LDL-C level 28% of the cases had
increased levels (above 130mg/dl). On comparing both groups, it was found that the
cases were significantly having disturbed lipid profile as compared to their matched
control group.
The cases had statistically significant higher levels of fasting plasma glucose,
however there was no significant statistical difference between the two groups as
regards their CRP levels.
Among the cases, 25(OH) vit.D ranged from 8.11 to 22.6 ng/ml with mean level of
15.11±5.11 ng/ml where the majority of the cases had abnormal low levels of
25(OH) vit.D (48% being deficient [below 10 ng/ml] and 45.3% being insufficient
[10-20 ng/ml])
In the control group, 25(OH) vit.D ranged from 8.6 to 25.5 ng/ml with mean level of
22.3±6.13 ng/ml where the majority of the control group had normal levels of
25(OH) vit.D (58.7%), 18.7 % were deficient [below 10 ng/ml] and 22.7% were
insufficient [10-20 ng/ml].
On comparing both groups, the cases had statistically significant lower levels of
serum 25(OH) vit D.
There was statistically significant negative correlation between vitamin D level and
blood pressure among cases and controls, incidence of CAD and MI among cases,
exposure to sunlight among the studied subjects, anthropometric measurements
among both groups and lipid profile among cases and controls, however there was
statistically significant positive correlation between vitamin D level and HDL levels
and consumption of some vitamin D rich food (milk, yogurt and fatty fish) among
them.
Thus the most important conclusions from our study are:
Vitamin D is postulated to improve cardiovascular health through multiple pathways
with emerging evidence suggesting that optimal serum 25(OH)D levels could also
improve cardiovascular outcomes, such as reducing hypertension, improving lipid
management, and reducing incidence of myocardial infarction and cardiovascular
mortality.
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Exposure to sunlight (being the most important source for vitamin D) sufficiently
reduces vitamin D deficiency as a result of the negative significant correlation that
was present between serum 25(OH)D and the pattern of sun light exposure.
Serum 25(OH)D shows inverse relation with measures of obesity specially BMI,
waist circumference and waist/hip ratio.
Subjects with serum 25(OH)D levels < 20 ng/mL are at an increased risk for
development of myocardial infarction and CAD compared with those with sufficient
serum 25(OH)D levels (>30 ng/mL). This might be attributed to the effect of vitamin D
on vascular smooth muscle proliferation , inflammation and calcification of blood
vessels.
Thus the most important recommendations can be summarized as follows:
Due to the significant burden of vitamin D deficiency and its consequent health
adverse effects, wide screen program for early detection of vitamin D deficiency
among the population specially those of high risk is needed
Regular outdoor activities (while paying attention to the risk of skin cancer due to
unprotected or prolonged sun exposure) should be considered as well as optimizing
vitamin D intake, in particular during winter.
Though lacking sufficient evidence for the benefits of vitamin D supplementation in
reducing risk of cardiovascular disease mortality, the literature does give reassurance
that long-term supplementation with ordinary doses of vitamin D does not seem to be
associated with an adverse effect.