Albanian j. agric. sci. 2014;(Special edition)
Agricultural University of Tirana
(Open Access)
RESEARCH ARTICLE
HDL-cholesterol and Coronary Heart Disease in a sample of Elbasan district. KUÇI MIMOZA1*, REXHA TEFTA2 1
Clinical and Biochemical Laboratory, Hospital Center of Elbasan, Elbasan, Albania
2
Department of Biology,Faculty of Natyral Science, University of Tirana, Tirana, Albania
*Corresponding author email:
[email protected];
Abstract The risk of developing coronary heart diseases and atherosclerosis increases as the total cholesterol level increases and HDL cholesterol level decreases. Atherosclerosis can affect the arteries that supply blood to the heart (coronary artery disease), those that supply blood to the brain (cerebrovascular disease). The role of high levels of total cholesterol and LDL cholesterol and the protective role of HDL cholesterol in coronary artery diseases and atherosclerosis, links between them and family history with coronary artery diseases or dislipidemia, diabetes, obesity is analyzed in this study. A sample population consisting of 300 persons from Elbasan district, selected at random, was taken into examination. They were examined about blood analyses for the level of: triglycerides, total cholesterol, HDL-cholesterol and the level of LDL-cholesterol. The analysis of contingent tables and the determination of Hi squares is used to see the association between variables. A low level of HDL cholesterol and a high level of LDL-cholesterol increase the risk of cardiovascular disease. The persons suffering from the diabetes, or who had a family history with dislipidemia are more likely to be affected by the coronary heart diseases. Women are characterized by higher values of HDL-cholesterol (45.4mg/dl ± 8.2) than men (40.5mg/dl ± 8.7), therefore are more protected from coronary heart diseases. Between level of HDLcholesterol and gender has a high association (χ2 square = 30,567 df = 1). Increased triglyceride level is associated with reduced levels of HDL-cholesterol χ2 = 4.963 (df = 1) and increased levels of total cholesterol χ2 = 6.053 (df = 1). Key words: HDL cholesterol, coronary heart disease, total cholesterol, atherosclerosis.
1. Introduction The body needs cholesterol to function normally. However, our body makes all the cholesterol it needs. Over a period of years, extra cholesterol and fat circulating in the blood build up in the walls of the arteries that supply blood to the heart. This buildup, called plaque, makes the arteries narrower and narrower. As a result, less blood gets to the heart. Blood carries oxygen to the heart. If not enough oxygen-rich blood can reach our heart, we may suffer chest pain. If the blood supply to a portion of the heart is completely cut off, the result is a heart attack. Cholesterol travels in the blood in packages called lipoproteins. LDL [2, 5] carries most of the cholesterol in the blood. Cholesterol packaged in LDL is often called "bad" cholesterol, because too much LDL in the blood can lead to cholesterol buildup and blockage in the arteries. Another type of cholesterol is HDL, known as "good" cholesterol. That's because HDL helps remove cholesterol from the body, preventing it from building up in the arteries. When levels of total cholesterol, triglycerides and LDLcholesterol become too high the risk of coronary heart 281
diseases is significantly increased. In different studies low level of HDL-cholesterol [1, 12] was a strong predictor of CHD (coronary heart diseases) and atherosclerosis. Having family history [4, 8] of dislipidemia or CHD seems to increase the risk. In many studies is stated that smoking [6], consumption of alcohol, having diabetes [13] and obesity [9,10] increase the value of LDL-cholesterol and decrease the value of HDL-ch increasing the risk for atherosclerosis and CHD. The objective of this study is to see the association between total cholesterol, LDL cholesterol and the risk for coronary heart diseases, the happening of CHD if there are present two or more risk factors and to see how protective are the higher values of HDL-cholesterol in coronary heart diseases and atherosclerosis. 2. Materials and Methods Serum was used to measure the concentration of lipids levels present in blood circulation in 178 female and 122 male in the range age 25-65 years from Elbasan district that had fasted for 9 hours or more.
Kuçi & Rexha
The sample was selected in different group-ages and was examined the level of HDL cholesterol, LDL cholesterol, total cholesterol and triglicerydes. Patients that were under medication therapy about dislipidemia or hypertension were excluded from the study. We used a standardized questionnaire to take information for the sample about: age, weight, height, diabetes, family history for dislipidemi or coronary heart diseases and obesity. BMI was calculated as weight in kilograms divided by the square of height in meters. Females were examined to see their characteristics in reproductive and menopausal age about HDL-ch and total cholesterol level. First was determined the value of total cholesterol and triglycerides with colorimetric, enzymatic, endpoint method. For HDL-cholesterol first, was used the precipitation method with acid fosfotungistic and Mg2+ ion and then the determination of HDLcholesterol value with enzymatic, colorimetric, endpoint method. For LDL-cholesterol was used the formula: LDL- ch=T.cholesterolT- (Trig/5 + HDLch). NCEP (National Cholesterol Education Program) has decided these values as risk for coronary heart diseases: Total Cholesterol: < 200 mg/dl normal, risk for CHD >240 mg/dl; Triglicerides: < 150 mg/dl normal, risk for CHD > 200 mg/dl; HDL > 60 mg/dl low risk, HDL < 40 mg/dl high risk, LDL < 160 mg/dl normal, risk for CHD > 160mg/dl. We estimated the mean value and the standard deviation for all values. The χ2 squares of Pearson and p-value were done to see significance between variables. The analyses were performed using the SPSS 12. 3. Results and discussion In our study 59 % were females and 41 % were males. 16 % had a family history with coronary heart disease, 7.1% were diabetics, 15, 3 % had the smoking habit. BMI was calculated as weight in kilograms divided by the square of height in meters and resulted that 36.5 % were normal, 48 % overweight, 14 % obese and 1.5 % were super obese. Table 1 shows the mean levels of lipid profile for males and females in different group age. The results observed in this study are consistent with different studies [4,8] about correlation between coronary heart diseases atherosclerosis [3] and levels of total cholesterol [6], LDL cholesterol and HDL cholesterol. A significant increase of LDL-cholesterol in both genders was present with increasing age (table 2). To
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see the association between two variables LDL ch and total cholesterol we found the value of chi square χ 2= 110.86 p= 0.000 df= 1 (table 3) which is higher than the critical value x2=3.84 (for p=0.05 probability level) which shows the area of acceptance or rejection for H0 hypothesis, (H0 - means that between two variables has no correlation). In our case H0 is not accepted. Thus the risk for atherosclerotic diseases is elevated because it is known [5] that high levels of LDL cholesterol mean high risk for CHD. Increased triglyceride level is associated with reduced levels of HDL-cholesterol and increased levels of total cholesterol. The values of χ2 square are respectively: 4.963 and 6.053 (df = 1). HDL/LDL-cholesterol quotient is reduced and the risk for CHD and atherosclerotic diseases is elevated. In our study females (45.4mg/dl ± 8.2) are characterized from higher HDL-cholesterol levels than males (40.5mg/dl ± 8.7) (figure 1). We have studied females in different group age, to see the level of lipid profile and especially the HDL cholesterol. In different studies [2] result that females in reproductive and premenopausal age, are in a lower risk about coronary heart diseases because the HDL cholesterol the level is higher and is known the protective role of “good” cholesterol. The level of Estrogen is higher at females in reproductive age [11]. Thus females are more protected than males. Between level of HDL-cholesterol and gender has a high association (χ2 = 30,456 df = 1). A lot of evidence [1, 12] suggest that higher HDL ch levels are associated with a lower risk of heart disease and conversely that low HDL ch levels are associated with an increased risk. The prevalence of high triglycerides combined with a low HDL ch in our study was increased in groups who were diabetics [13] (344.3±132.5 mg/dl) (table 4), obese (217 ± 112 mg/dl) [9] or who suffered from family history with coronary heart diseases or dislipidemia (259 ± 133 mg/dl), (41 ± 6.4mg/dl) [4,8]. To see the association between obesity and total cholesterol levels, we found the value of chi square χ 2 =3.21 with p=0.05 that did not exceed the critical value for p= 0.05 probability level (χ 2=3.84). This shows us that in our study in difference with other studies [10] there’s no correlation between cholesterol levels and obesity. In our study resulted that the most part of the sample was overweight and only 14% were obese, and we think for that reason in our study there is no correlation between obesity and total cholesterol.
HDL-cholesterol and Coronary Heart Disease in a sample of Elbasan district. Table 1. The lipid profile values for males and females in different group-age Group age Males 25-45 ys Females Males 46-55 ys Females Males 56-70 ys Females
Triglycerides mg/dl 201.3
T.Cholesterol mg/dl 193.5
HDL ch mg/dl 44.3
LDL ch mg/dl 110.2
161.1 272.3
195.6 228.7
49.4 39.5
114.3 134.2
213.8
221.5
45.6
133.1
225.7
219.8
40.3
134.7
195.6
218
44.2
134.8
Table 2. LDL ch. & total cholesterol Crosstabulation LDL-ch
Normal
High
Too high
Total
T Cholesterol Normal High Too high Total
92 70 8 170
2 64 18 84
0 6 40 46
94 140 66 300
Table 3. Chi square test of LDL ch. vs T. cholesterol Value
df
Asymp. Sig. (2-sided)
Pearson Chi-Square Likelihood Ratio
161.079 156.644
4 4
.000 .000
Linear-by-Linear Association N of Valid Cases
110.861 300
1
.000
48 46 44 42 40 38 36 34 Females
Males
Figure 1. HDL-cholesterol and gender Table 4. The mean values and SD of diabetic and no diabetic group Lipid profile mg/dl Triglycerides
Diabetic group 344.3±132.5
N/diabetic group 211.2±105.4
Normal values < 150
Total cholesterol
229.6±42.7
207.5±40.3
< 200
HDL-ch
41.1±4.3
43.9±9.5
> 60
LDL-ch
119.1±30.3
120±41.2
< 160
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4. Conclusions
Kuçi & Rexha 3. Chisolm GM, Steinberg D: The oxidative
In our study 16 % had a family history with coronary heart diseases, 7.1% had diabetes disease. Both these groups [8, 13] were characterized from higher levels of total cholesterol and LDL ch and lower levels of HDL ch than the others. In our study as in other studies [4] resulted that higher levels of LDL cholesterol are associated with high levels of total cholesterol χ 2= 110.86 and a higher risk for coronary heart diseases. Females are more protected than males [11] because of their high HDL cholesterol level (45.4mg/dl ± 8.2), especially in reproductive age that is in higher levels. We found as in other studies [7] that there is a high association between HDL ch and gender (χ2 = 30,456 df = 1). The level of HDL cholesterol is lower in diabetic group [13], family history group [4]. It is better suggesting that for people with heart disease lower LDL cholesterol is better because there is a direct relationship between lower LDL cholesterol and reduced risk for heart attack. An HDL cholesterol level of less than 40 mg/dl is a major risk factor for heart disease. The higher your LDL level and the more other risk factors you have, the greater your chances of developing heart disease or having a heart attack. Among males or females with low HDL-cholesterol and high total cholesterol, diabetes, family history with CHD, sedentariness and obesity were much more prevalent than among those at low risk with high HDL cholesterol and low total cholesterol and triglycerides.
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