Weight Loss and Triglyceride Level - Essay Example

Investigating the Relationship between Changes in Weight Loss and Triglyceride Level Introduction: In economically affluent countries and in some developing countries, obesity is a health problem. The connection between obesity and premature death from hypertension and coronary heart disease is well established. The basic cause of obesity is over-nutrition. A diet containing more energy than needed may lead to prolonged postprandial hyperlipidaemia and to deposition of triglycerides in adipose tissues resulting in obesity. From a practical point of view, all hypotheses regarding the genesis of obesity can be put down to over-nutrition, meaning a hyper-energy food intake. If at all a relationship exists, this could make a sound basis for preventive and therapeutic recommendations (Anderson, J.W. and Hoie, L.H., 2005). Elevation of serum cholesterol is one of the factors that carry an increased risk for the development of coronary heart disease. Today, there is a vast body of evidence demonstrating a triangular causal relationship between habitual diet, blood cholesterol-lipoprotein levels, and coronary heart disease. In a very large proportion of individuals with a raised cholesterol level, the blood concentration of the triglycerides is also markedly increased. It has been claimed that correlation between triglycerides and coronary heart disease is as good as that between serum cholesterol and coronary heart disease. Research work has suggested that triglyceride levels may act as significant independent risk factors for coronary heart disease. Both cholesterol and triglycerides are associated with specific proteins in the plasma to form lipoproteins (Van Gaal, L.C., Mertens, I.L., and Ballaux, D., 2005). Thus the significance of the risk factor has not been determined, and this case study aims at finding this relationship in a small sample size of 35 obese patients with the hypothesis that restricting the consumption of fatty acids and exercise in order to reduce the body weight of these patients will reduce the triglyceride levels and would reduce the risks of coronary heart disease in these patients in a predictable manner such that a generalization can be made as to how much weight needs to be reduced to achieve a goal serum triglyceride level, and this can be calculated with the formula in a given population that matches with the patients included in this study. Characteristics of the Patients: The patients were obese. By definition, obesity is abnormal growth of the adipose tissue due to an enlargement of the fat cell size or increase in the fact cell number or a combination of both. Obesity is often expressed in terms of body mass index. The composition of the diet and the amount of energy driven from it are relevant to the aetiology of obesity. Consequently, a diet containing more energy than needed may lead to prolonged post-prandial hyperlipidaemia and to deposition of triglycerides in adipose tissue resulting in obesity. This group of patients is obese as per the previous definition. In these patients, the obesity is presumed to be due to high energy intake in the diet as opposed to the energy expenditure in the form of work or exercise (Nordmann, A.J. et al., 2006). The most important determinant of triglyceride level is the activity of the enzyme lipoprotein lipase in the endothelial lining of the capillaries of a variety of tissues including heart. If dietary fat intake is high, then the capacity of this enzyme to remove triglycerides particularly from the very low density lipoproteins and converting them to lipoproteins of the higher density would be affected. The result would be deposition of triglycerides in the media of the small arteries leading to atherosclerosis and luminal compromise leading to decreased blood flow at the time of the need. Thus the only way to reduce this risk of coronary heart disease is to reduce body weight by means of reduced consumption of fatty acids and exercise. Concomitantly, drug therapy with statins would also reduce the triglyceride load in the blood to reduce this risk (Sato, F. at al., 2007). As expected a combined regimen of diet, exercise, and medical therapy would reduce the weight and reduce the triglyceride levels. This could reduce the overall risk of coronary heart disease. In this case, these 35 obese patients were treated with weight reduction diet and exercise regimens, and their baseline weights and triglyceride levels were recorded. After 8 weeks of therapy, the weights and triglyceride levels were re-recorded. This case study analyzes the data, presents them in graphical formal, interprets and examines them to prove the hypothesis that weight loss has indeed effect on triglyceride level of an individual, so that if the triglyceride levels are reduced as a result of weight loss, the risks of coronary heart disease is also reduced (Truesdale, K.P., Stevens, J., and Cai, J., 2005). Apparent Relationship between Change in Triglyceride Level and Change in Weight: The data recorded from these individuals are showing there is a reduction in body weight after 8 weeks of low-fat diet, exercise regimens, and drug therapy. The change of weight is evident in individuals whose baseline weight is below 80 kg, although the weight reduction happened in almost all individuals. Graphs 1 Showing Change in Weight after 8 weeks of Diet, Exercise, and Drug Therapy. The next question is whether in the same period, there has been a concomitant reduction of serum triglyceride levels of these individuals. Graphical representation of the collected data demonstrates, there is indeed reduction of triglyceride levels as a result of this 8-week regimen. These data show in most of the cases, this regimen has been effective in reducing the serum triglyceride levels. However, in some cases, the triglyceride levels have remained unchanged, and there are some cases, the levels have increased. From the graphs, it can be comfortably stated that overall, apart from the sporadic interindividual variation, this weight reduction regimen has been successful in reducing the serum triglyceride levels. Graphs Showing Changes in Triglyceride Levels following 8 weeks of diet, exercise, and drug therapy as compared to baseline. The next question appears to be very partinent. How much reduction is respensible for how much triglyceride level reduction To be able to do that one must explore the relationship between basal body weight and basal triglycerides. Then these findings may be compared to 8-week body weight to 8-week triglycerides. On the same scale, if the scatter diagrams of these sets of data are compared, we can see that there is indeed a reduction of the triglyderide levels in this set of population. Apart from the interindividual variability the values tend to scatter over a specific area, and the comparison suggests for a given value of weight reduction the ranges of values for triglycerides are lower in the following fashion and grade. Graphs Showing Reduction of Triglyceride Levels following an 8-week weight reduction therapy: Comparison of Linear Triglycerides After comparison of linear triglycerides, these show that the trigycerides have reduced on an average in the range of 80 to 180 mg/dl. The comparative values before institution of weight reduction therapy were in the range of 120 to 240 mg/dl. To be able to find a simple formula as to how much of weight reduction will lead to how much triglyderide decrease, one needs to find the linear relationship between these changes. In order to find out whether there is a significant association or not between these variables. Graphically represented, the tabulated data shows the following relation Graph Showing Relation between Change in weight and Change in Triglyceride Levels. This relationship may be obtained from the following formula to assess whether there is any significant association or not between these variables. This is known as coefficient of correlation and is represented by the symbol "r." X is change is weight. Y is change is triglyceride level. If x is the mean of sets of values of X and y is the mean of sets of values of Y, then r = (X-x) (Y-y)/[(X-x)2 ][(Y-y)2] can be used to determine the significance of the correlation. If r is near +1, this indicates a strong positive association between these two arrays of values. Calculation shows this value to be near +1, hence there is a positive correlation. The calculation of a predictable range of values for triglycerides for a person who loses 5 kg over a 8-week period will be as follows. Every 3.93 kg weight loss would account for 8.29 mg/dL of triglyceride reduction(calculating the mean of the data). Calculating from these data, in a linear relationship, 1 kg weight loss would account for 8.29/3.93 mg/dL of triglyceride dip (please see appendix). Therefore, for a 5 kg weight loss, the predicted triglyceride level change would be 8.29 x 5/3.93= 10.55 mg/dL. From this graph and table of data, it is evident that none of the individuals have achieved a 10-kg weight change, as a result, it is difficult to calculate or extrapolate the data from this linear relationship as to predict the actual change in triglyceride level. Thus utilization of the linear graphs would be incorrect to predict the correlation. Appendix Change in weight in kg Change inTriglyceride level mg/dL 1.6 -41 1.8 55 5.2 30 4.1 0 0.4 17 2.7 -61 2.4 27 2.6 1 2.4 -67 7.2 80 3.7 -70 8.4 41 1.5 -37 8 0 0 7 7.1 -50 2.8 74 8.2 21 2.3 56 5 18 5.9 4 6.2 15 3.6 69 1.6 -6 3.2 32 2.6 57 1.6 59 5.8 68 2.8 -89 1.2 8 -1.5 -349 7.8 169 2.5 51 9.6 43 7.4 58 Mean 3.934286 8.285714 Sum 141.6343 298.2857 References Anderson, J.W. and Hoie, L.H., (2005). Weight Loss and Lipid Changes with Low-Energy Diets: Comparator Study of Milk-Based versus Soy-Based Liquid Meal Replacement Interventions. J. Am. Coll. Nutr., Jun 2005; 24: 210 - 216. Nordmann, A.J. et al., (2006). Effects of Low-Carbohydrate vs Low-Fat Diets on Weight Loss and Cardiovascular Risk Factors: A Meta-analysis of Randomized Controlled Trials. Arch Intern Med; 166: 285 - 293. Sato, F. at al., (2007) Effects of Diet-Induced Moderate Weight Reduction on Intrahepatic and Intramyocellular Triglycerides and Glucose Metabolism in Obese Subjects. J. Clin. Endocrinol. Metab; 92: 3326 - 3329. Truesdale, K.P., Stevens, J., and Cai, J., (2005). The Effect of Weight History on Glucose and Lipids: The Atherosclerosis Risk in Communities Study. Am. J. Epidemiol.; 161: 1133 - 1143. Van Gaal, L.C., Mertens, I.L., and Ballaux, D., (2005). What is the relationship between risk factor reduction and degree of weight loss Eur. Heart J. Suppl., Nov 2005; 7: L21 - L26. Read More