| Abstract|| |
Objective: The objective of this study was to compare the pattern of lipid profile among subjects with or without anemia. Methods: All proven cases of anemia (hemoglobin <13 g% in men and <12 g% in women), irrespective of the causes, were included as cases. The controls were age- and sex-matched population without anemia. Patients with underlying diseases/medication that could affect either lipid profile or anemia were excluded from the study. The data collected include demographics and laboratory investigations such as complete hemogram, random blood sugar, serum creatinine, liver function tests, serum ferritin, serum iron, and fasting lipid profile. Results: A total of 200 participants were included in the study, which includes 100 cases and 100 controls. The mean cholesterol in patients with anemia is 122.47 ± 29.32 mg/dl, whereas in controls is 160.43 ± 38.91 mg/dl. The mean serum triglyceride level in patients with anemia was 89.41 ± 33.1532 mg/dl and in control group was 111.45 ± 40.6632 mg/dl. Mean high-density lipoprotein levels were 36.13 ± 12.8132 mg/dl in anemic patients and 45 ± 13.032 mg/dl in control group, whereas low-density lipoprotein (LDL) cholesterol level was 70.12 ± 21.64 mg/dl in the anemic group and 100.45 ± 30.8032 mg/dl in control group. Very LDL levels were higher in control group (21.96 ± 8.132 mg/dl) compared to the anemic group (18.34 ± 7.6432 mg/dl). The differences between two groups with regard to all lipoprotein levels were statistically significant; all the values being lower in anemic patients. Conclusion: Lipoproteins levels were significantly lower in anemic patients compared to nonanemic patients, and the reduction was proportionate to the severity of anemia. Type of anemia did not have any effect on lipid profile.
Keywords: Anemia, cholesterol, lipid profile, triglycerides
|How to cite this article:|
Chowta NK, Reddy SB, Chowta MN, Shet A, Achappa B, Madi DR. Lipid profile in anemia: Is there any correlation?. Ann Trop Med Public Health 2017;10:837-40
|How to cite this URL:|
Chowta NK, Reddy SB, Chowta MN, Shet A, Achappa B, Madi DR. Lipid profile in anemia: Is there any correlation?. Ann Trop Med Public Health [serial online] 2017 [cited 2020 Jun 3];10:837-40. Available from: http://www.atmph.org/text.asp?2017/10/4/837/215846
| Introduction|| |
The burden of coronary artery disease (CAD) in India is increasing and addressing the risk factors of the same is the need of the hour to reduce its prevalence. Dyslipidemia being one of the important risk factors for CAD, effective preventive measures, including lifestyle modification should be adopted to achieve recommended lipid goals. Another equally important public health concern is the prevalence of anemia. Dyslipidemia may be more prevalent in an affluent society, whereas anemia obviously more common in people with low socioeconomic status. Anemia could be associated with low levels of all the subfractions of lipoproteins. Decreased levels of lipoproteins in anemia could be due to factors such as plasma dilution, increased cholesterol requirement as a result of erythroid hyperplasia, increased cholesterol uptake by the reticuloendothelial system. Anemia thus may have a protective effect on lipid profile thereby reducing the risk of CAD. Epidemiological studies also have shown a higher prevalence of CAD in upper socioeconomic class, wherein patients are likely to be dyslipidemic than in lower socioeconomic strata where people are more likely to have nutritional anemia.
Several studies have examined the relationship between anemia and lipid profile. However, the results were contradictory among these studies, especially with regard to the triglyceride and very low-density lipoprotein (VLDL) levels. Verma et al. and Antappanavar et al. showed that triglycerides and VLDL levels are elevated in the iron deficiency anemia compared to nonanemic patients, whereas lower levels of low-density lipoprotein (LDL) cholesterol were found in anemic patients. Sandeep et al. observed lower levels of total cholesterol, high-density lipoprotein (HDL), LDL, VLDL, and triglyceride levels in anemic patients compared to healthy controls. These contradictory findings prompted us to carry out this study to compare the pattern of lipid profile among patients with or without anemia.
| Methods|| |
This cross-sectional case–control study was done in patients attending a tertiary care hospital attached to a medical college in South India. The study has been approved by the Institutional Ethics Committee and the participants were enrolled into the study after obtaining their written informed consent. All proven cases of anemia, irrespective of the causes, were included as cases. Anemia was defined as hemoglobin <13 g% in men and <12 g% in women. Patients with diabetes mellitus, CAD, cerebrovascular disease, nephrotic syndrome, retroviral disease, obesity (BMI 25 kg/m 2), and those who were receiving glucocorticoids, diuretics, beta blockers, and statins were excluded from the study. The controls were age- and sex-matched population without anemia.
The following investigations were done in all participants: complete hemogram, random blood sugar, serum creatinine, liver function tests, thyroid-stimulating hormone, serum ferritin, serum iron, and fasting lipid profile. Total cholesterol, HDL, and triglycerides were estimated by the enzymatic colorimetric method. VLDL was calculated using the formula VLDL-TG/5. LDL cholesterol was calculated using the Friedewald's equation. LDL = total cholesterol−([TG/5 + HDL]) mg/dl.
For categorical variables, frequencies/percentages were calculated and continuous variables were expressed as mean ± standard deviation. Comparisons among groups were performed using ANOVA/student t-test. All tests were performed using a two-tailed test at a significance level of 0.05. SPSS for Windows version 20 (SPSS, Inc., Chicago, IL, USA) was employed for all statistical analyses.
| Results|| |
A total of 200 participants were included in the study, which includes 100 cases and 100 controls. Among the cases, 53 were females and 47 were males. In the control group, 56 were females and 44 were males. There was no difference in the age-wise distribution of patients between two groups. Of 100 cases, 33 had hemoglobin <7 g%, 44 had hemoglobin between 7 and 10 g, and 23 had hemoglobin more than 10 g%. Based on the red cell indices, 53 had microcytic hypochromic anemia, 32 had normochromic anemia, 10 had dimorphic anemia, 3 had normocytic hypochromic anemia, 1 each had macrocytic anemia and pancytopenia.
[Table 1] shows the comparison of lipid profile among patients and controls. The mean cholesterol in patients with anemia is 122.47 ± 29.32 mg/dl, whereas in controls is 160.43 ± 38.91 mg/dl. The mean serum triglyceride level in patients with anemia was 89.41 ± 33.15 mg/dl and in control group 111.45 ± 40.66 mg/dl. Mean HDL levels were 36.13 ± 12.81 mg/dl in anemic patients and 45 ± 13.0 mg/dl in control group, whereas LDL cholesterol level was 70.12 ± 21.64 in the anemic group and 100.45 ± 30.80 mg/dl in control group. VLDL levels were higher in control group (21.96 ± 8.1 mg/dl) compared to the anemic group (18.34 ± 7.64 mg/dl). The differences between two groups with regard to all lipoprotein levels were statistically significant; all the values being lower in anemic patients. Comparison of lipid values of patients with hemoglobin more than 10 g% with the control group also showed statistical significance, the values being higher in control group.
The comparison of lipid values among patients with different grades of anemia showed statistical significance for LDL and total cholesterol, the values being positively correlating with levels of hemoglobin. Even patients with mild anemia (Hb >10 g%) also had lower values of lipoproteins compared to the nonanemic counterparts [Table 2].
There were no significant differences in the various lipoproteins with different types of anemia [Table 3].
| Discussion|| |
Both iron and cholesterol are important metabolites in the human body, and excess or deficiency of either of them could affect seriously. There is no consistent evidence with respect to changes in plasma cholesterol on the basis of iron and anemic status of an individual.
We observed significant differences in the levels of lipoproteins among patients with anemia and their nonanemic counterparts, being lower in the anemic group. Choi et al. also demonstrated that though there were no significant differences in serum lipid concentrations between subjects with moderate iron deficiency anemia and healthy controls, serum total cholesterol, and triglyceride level were significantly lower in severely anemic subjects (Hb <8.0 g/dL) compared to normal controls. They also showed that the reduced serum lipid levels return to normal following iron supplementation. In the severely anemic subjects, blood hemoglobin concentration was positively correlated with serum total cholesterol and triglyceride concentrations. Studies by Ece et al. and Sandeep et al. also showed similar results.
The decrease in total cholesterol was not due to a specific lowering of any of the lipoprotein families. Proportionate reduction in all major lipoproteins contributed for the decrease in the total cholesterol in anemic patients. However, in contrast to our findings, several studies reported higher levels of all lipoproteins in iron deficiency anemia. A study by Yang et al. showed higher levels of triglyceride and lower HDL-cholesterol levels in the iron-deficiency anemia women. Verma et al. and Antappanavar et al. reported significant elevation of triglycerides and VLDL cholesterol levels in patients with iron deficiency anemia as compared to controls, whereas LDL cholesterol levels were significantly lower in patients as compared to controls.
As the severity of anemia increased, there was a proportionate decrease in the lipoprotein values, suggesting that the association of anemia with hypocholesterolemia. Choi et al. also showed that total cholesterol concentration in the blood is positively correlated with the hemoglobin levels in patients with iron deficiency anemia.
Several factors such as plasma dilution, increased erythropoiesis leading to increased cholesterol demand, activation of macrophage system with the release of cytokines as well as increased uptake of cholesterol by the reticuloendothelial system may lead to hypocholesterolemia with anemia. The liver is the main site for interaction between lipid and iron metabolism as it is an important site for both these metabolic pathways. Iron plays a role in hepatic lipogenesis. Iron being the important component of some enzymes and transporters involved in lipid metabolism, may exert a direct effect on hepatic lipid metabolism. The effects of iron deficiency on transcriptional/posttranscriptional mechanisms may lead to interference with lipid metabolism. Iron may also have effects on the kinetics/activity of enzymes that depend on iron as a cofactor. Iron in its ferrous form can generate free radicals, leading to oxidative stress and lipid peroxidation. Graham et al. study in mice with increased hepatic iron store showed upregulation of several enzymes, including the rate-limiting enzyme of cholesterol biosynthesis, HMG-CoA reductase. This fact suggests that hepatic iron loading increases liver cholesterol synthesis. Ece et al. proposed that the iron deficiency itself has no direct effect on the lipid and lipoprotein profile. It is likely that an iron-deficient diet could also be deficient in energy and protein. A hypocaloric diet could cause hypolipidemia.
Microcytic hypochromic anemia was the most common anemia seen in our patients. It is well known that the nutritional deficiency, especially the iron deficiency, is the most common cause of anemia irrespective of age, gender, and socioeconomic status. There was no significant difference found when lipid values were separately compared for various types of anemia such as iron deficiency, megaloblastic, and hemolytic anemias. Therefore, type of anemia did not have any effect on lipid profile, suggesting that anemia per se rather than the type of anemia is responsible for lowered levels of lipoproteins in anemia.
The limitations of our study include cross-sectional design, wherein the correlation of anemia with complications of dyslipidemia was not evaluated. Long-term follow-up studies are required to know whether the hypocholesterolemia caused by anemia has a beneficial effect on atherosclerosis and its complications. The effect of treatment of anemia on lipid profile also needs to be evaluated.
| Conclusion|| |
Lipoprotein levels were significantly lower in anemic patients compared to nonanemic patients, and the reduction was proportionate to the severity of anemia. Type of anemia did not have any effect on lipid profile.
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Conflicts of interest
There are no conflicts of interest.
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Mukta N Chowta
Department of Pharmacology, Kasturba Medical College, Manipal University, Light House Hill Road, Mangalore - 575 001, Karnataka
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2], [Table 3]