The Epidemiology Of Diabetes Mellitus Biology Essay

Diabetess mellitus is a metabolic disease in which saccharide use is reduced whilst that of lipid and protein is enhanced1. It is caused by an absolute or comparative lack of insulin and is characterized, in more terrible instances, by chronic hyperglycemia, glycosuria, H2O and electrolyte loss, diabetic acidosis, and coma1,2. There are two categorizations of diabetes mellitus which are viz. primary and secondary classes13. The primary category is divided into diabetes type 1 and diabetes type 22,13. Diabetes type 1 is an autoimmune upset characterised by insulin deficiency1,2. In diabetes type 2 the cells are unable to react to normal degrees of insulin because of reduced insulin receptors and comparative insulin deficiency2.3. The secondary category of diabetes mellitus includes adulthood oncoming type diabetes of the immature ( MODY ) , pancreatic disease, endocrinal disease and gestational diabetes. MODY is characterised by oncoming prior to 25 old ages of age due to damage of ? cell map because of mutants of the assorted cistrons which includes hepatic atomic factor -4? , pancreatic glucokinase and homeodomain written text factor insulin booster factor ( IPF-1 ) 13.

1.1.1 Epidemiology of diabetes mellitus

Diabetess mellitus affects 6 % of the universe ‘s population14. WHO estimates that more than 180 million people worldwide have diabetes mellitus and this figure will most likely dual by 203014,15. In 2005 an estimated 1.1 million people died from diabetes and 80 % of these deceases occurred in low and in-between income states such as Zimbabwe, half of these people being under the age of 70 and 55 % being women16. Before the 1990s, diabetes was considered a rare medical status in Africa16. Almost all the studies published between 1959 and 1985 showed a prevalence of diabetes below 1.4 % , except those from South Africa, where higher prevalence was reported15,16.

The prevalence of diabetes in Africa was about 3 million in 1994 ; but the part has experienced a two-to treble addition by the twelvemonth 201017. Among the population of Indian beginning in South Africa and Tanzania, the prevalence is between 12 and 13 % 18. The prevalence in inkinesss follows a Westernization gradient, with that of rural Africa by and large below 1 % and that of urban Africa between 1 and 6 % . In general the prevalence of type 2 diabetes is low in both rural and urban communities of West Africa except in urban Ghana, where a high rate of 6.3 % was late reported19. Moderate rates have been reported from South Africa: 4.8 % in a semi-urban community in the Orange Free State, 6.0 % in an urban community of the Orange Free State, 5.5 % in Durban and 8 % in Cape Town17. The incidence of type 1 diabetes scopes from 1, 9 to 7, 0/100 000/year in Africa14,15. The prevalence of type 2 diabetes is 0, 3 -1, 17 in Africa14,15. Type 2 diabetes histories 90 % of diabetics worldwide14. Type 1 diabetes affects 3 in 1 000 children14,15.

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The prevalence of diabetes mellitus in Zimbabwe from 1991-97 increased from 150 to 550 per 100 000 people. Harmonizing to the Zimbabwe National Health profiles ( 1996-98 ) the figure of new instances recorded in the ages 15years and supra rose from 2734 instances in1996 to 5114 in 1998 which is an addition of 87 % of recorded instances. In Zimbabwe diabetes mellitus is among the top five chronic conditions seen in the OPD Clinics. The 2005 study noted that the prevalence among the grownup population is 10 % with a big figure unaware of their increased glucose degrees.

1.1.2 Pathogenesis of diabetes mellitus

Type 1 diabetes mellitus is an auto-immune upset whereby tolerance is broken down ensuing in devastation of insulin bring forthing ? cells20. Risk factors of developing type 1 diabetes mellitus include disease of the pancreas that inhibits insulin production, exposure to overawe ‘s milk proteins, environmental factors, genetic sciences and household history20,21.

The chief cistron associated with the development of type 1 diabetes is major histocompatibility composite ( MHC ) . The MHC part is associated with the cistrons for immune system acknowledgment known as HLA-DQ, HLA-DR and HLA-DP22. The pancreas is a cloistered organ so its antigens are non presented to the T-lymphocytes and B-lymphocytes during their development23. T and B-lymphocytes are reactive against self-antigens of the pancreas mounting an immune response and destructing the pancreatic cells20,23. Damage to the membrane sequestering the pancreas exposes the pancreatic antigens on islet cells ensuing in devastation of the ? cells by the production of the undermentioned antibodies islet cell cytoplasmatic antibodies that react with antigens located in the cytol of the pancreatic islet cell, islet cell antibody that targets islet antigens on ? cells, anti-glutamic acid decarboxylase which destroys glutamic acerb decarboxylase expressed on pancreatic cells hence destructing ? cells ensuing in insulin deficiency20.

Environmental factors such as viruses besides lead to the devastation of ? cells. Infection of the ? cells with a virus such as the coxasckievirus, adenovirus, CMV ( CMV ) causes devastation of ? cells due to molecular apery of the viral protein to the ? cell so when the organic structure mount an immune response against the viral proteins it besides destroys the ? cells taking to type 1 diabetes22. The septic ? cell releases cytokines which activates anti-viral cytotoxic lymph cells, cytokines and groups produced by macrophages augment the cytotoxic response to ? cells22. Other environmental factors such as vaccinums, toxins and diet for illustration if cow ‘s milk is given to a babe its leads to ? cell devastation because cow ‘s milk have the same sequence with ? cell so an immune response to the cow ‘s milk besides destroys the ? cells doing type 1 diabetes25. Strain of pes and oral cavity virus harm the ? cells straight ensuing in type 1 diabetes25.

Inflammatory response to pancreatitis particularly the reactive O species ( ROS ) amendss the ? cells because ? cells weakly express the enzyme that reduces the superoxide24. Continued release of cytokines at the inflammatory site taking to overexpression of HLA-1 on ? cells potentiating their devastation by production of antibodies, antibody dependent cell cytotoxicity ( ADCC ) and cytotoxic cytokines ( IL-7, IL-1 ) 24.

Under normal fortunes plasma glucose concentration is maintained within a narrow scope and is tightly regulated with a dynamic interaction between tissue sensitiveness to insulin and insulin secretion28. In type 2 diabetes this mechanism is bedraggled due to defects in impaired insulin secernment and action due to resistance. Risk factors of developing type 2 diabetes mellitus include fleshiness, sedentary life manner, household history, above 45 old ages of age, insulin opposition, history of gestational diabetes, increased triglycerides degrees and hypertension26.

The aetiology of type 2 diabetes includes familial defects in insulin action due to mutant of the insulin cistron and receptor, disease of the pancreas e.g. iron-storage disease, pancreatic carcinoma and chronic necrotizing pancreatitis which decrease the ? cell size and drugs that impair insulin action e.g. cyclosporin A.

The pathogenesis of type 2 diabetes mellitus is insulin opposition and insulin insufficiency26. Insulin opposition involves normal degrees of insulin being produced but the receptors are insensitive26. The receptors are insensitive due to mutants in the receptor cistron therefore it codes for a faulty receptor which is non sensitive to insulin26,28. The receptor can be normal but the insulin produced is unnatural or there is uncomplete transition of the proinsulin molecule due to mutant in the proinsulin to insulin cleavage sites, the insulin will hold a faulty biological function26, 28. The insulin can be normal but are go arounding adversaries such as anti-insulin receptor antibody which destroys the insulin receptors26,28. Insulin and its receptors can be normal but go arounding anti-insulin antibodies trap the insulin in plasma compartment and changes the clip class of insulin therefore cause insulin resistance29. The presence of non-hormonal adversary such as free fatty acids ( FFA ) in elevated sums AIDSs to insulin opposition because when oxidised they are associated with decrease in peripheral glucose use and insulin resistance29. Low serum hydrogen carbonate degrees and high anionic spread is associated with insulin opposition because metabolic acidosis decreases the binding of insulin to its receptors30.

In comparative insulin lack the size of the ? cell is reduced so that the sum of insulin produced is reduced31. The cell size can be reduced after enduring from chronic get worsing pancreatitis so the pancreatic tissue is replaced with hempen tissue31. Aging is characterised by progressive changes in insulin secernment and action because they take multiple drugs which interfere with insulin action27. Islet cell amyloidosis is a diabetogenic factor because addition in islet starchlike polypeptide ( IAPP ) fibirilar aggregates inhibits insulin secernment and reduces ? cell size28.

1.1.3 Complications of diabetes mellitus

Acute complications of diabetes mellitus due to terrible hyperglycemia are polyuria, polydipsia, polyphagia, weight loss and increased susceptibleness to infections1,2. Chronic complications include development of neuropathy, retinopathy, and nephropathy and generalised degenerative alterations in big and little blood vessels1,2.

1.1.4 Alanine aminotransferase

Liver map trials ( LFTs ) are used to test for liver disease, monitor the patterned advance of known disease, and supervise the effects of potentially hepatotoxic drugs10. Elevations of transaminases greater than eight times the upper bound of normal reflect acute viral hepatitis, ischaemic hepatitis, or drug- or toxin-induced liver injury10. ALT is an enzyme involved in cellular N metamorphosis, aminic acid metamorphosis and liver gluconeogenesis4.ALT is found chiefly in the cytol of hepatocytes and in cardiac cells, harm to hepatocytes due to infection or fat accretion leads to leakage of ALT in serum and harm to hepatocytes due to ischemia taking to myocardial misdemeanor elevates serum ALT4,10. ALT serves as a marker of hepatocyte and cardiac cells hurt 4,10.

1.1.5 Pathophysiology of diabetes mellitus

Insulin facilitates intake of glucose in cells, animal starch synthesis and inhibits gluconeogenesis7. Diabetic mellitus patients have insulin impairment and loss of insulin leads to cut down entry of glucose into cells8. There is a lessening in intracellular glucose which stimulates gluconeogenesis7,8. Proteins are catabolised to amino acids and the amino acids are used in the coevals of glucose. ALT is the major enzyme involved in amino acid transamination taking to its addition in circulation8. Loss of insulin besides leads to lipolysis of the stored lipoids to triglycerides and free fatty acids ( FFA ) 8. Adipose tissue is unable to re-use glycerin formed as a consequence of hydrolysis of triglycerides ; alternatively it requires freshly synthesized glycerin phosphate2. Glucose is the beginning of the substrate for the formation of glycerin phosphate, which is needed for the re-esterification of FFA in the formation of triglycerides1. Lack of the go arounding insulin leads to failure of entry, of glucose into adipose tissue hence deficit of glycerin phosphate and the sum of FFA is increased1. The extra FFA are toxic to the hepatocytes taking to hepatic hurt hence escape of ALT in circulation9,10.

In ill controlled diabetes mellitus there is an insulin independent influx of glucose in hepatocytes31,34. The chronic hyperglycaemic province inactivates glycogen phosphorlylase hence inhibiting glycogenolysis and activates glycogen synthase ensuing in inordinate animal starch accretion in the hepatocytes taking to glycogenic hepatopathy31,32. Glycogenic hepatopathy causes liver hurt and there is a pronounced lift of ALT in serum33,34,35.

Non-alcoholic fatso liver disease ( NAFLD ) is a chronic liver status characterised by insulin opposition and hepatic fat accretion in the absence of intoxicant maltreatment, viral hepatitis and autoimmune hepatitis35. Peoples with diabetes mellitus have a higher hazard of developing NAFLD and liver related deaths35. NAFLD is the common cause liver trial abnormalcies and it accounts for 70 % of all instances of symptomless elevated ALT in US adults35. The prevalence of NAFLD in diabetes mellitus is 70 % and is associated with fatty liver and inveterate elevated ALT35, 36. NAFLD is a marker of CVD hazard and mortality in diabetic patients 35. Diabetess with NAFLD have a 7.2 crease increased hazard of mortality from cirrhosis and CVD compared with those without diabetes35. The comparative hazard of a liver related decease is straight related to the badness of DM with those necessitating insulin holding a 6.8 crease increased hazard, those necessitating hypoglycemic medicine holding 4.9 increased hazard 36. High blood pressure is the taking cause NAFLD and 50-62 patients with diabetes have high blood pressure doing them prone to NAFLD.

Hyperinsulinemia and hyperglycemia in type 2 diabetes promotes lipogenesis by up modulating steroid alcohol regulative component adhering protien1c ( SREBP1c ) and carbohydrate regulative component adhering protein ( ChREP ) activity5. The up-regulation of SREBP-1c and subsequent simulation of de novo lipogenesis in the liver leads to increased intracellular handiness of triglycerides, advancing fatty liver5. Excess FFA are straight toxic to hepatocytes and the putative mechanisms include cell membrane break at high concentration, mitochondrial disfunction, toxin formation, and activation and suppression of cardinal stairss in the ordinance of metabolism5. Increase in mitochondrial oxidative emphasis due to increased intracellular FFA produces free groups which induces redness and cellular necrosis35. Cellular mortification elevates ALT due to the rupturing of the hepatocytes let go ofing the ALT36. Insulin immune province is besides characterized by an addition in pro-inflammatory cytokines such as tumour mortification factor-? ( TNF-? ) , which may besides lend to hepatocellular injury37.

NAFLD is associated with the presence of vascular disease which is the most common cause of decease in DM. Cross-sectional surveies of population s with DM have demonstrated that NAFLD is associated with increased carotid intima media thickness, carotid athermanous plaques, cardiovascular disease and myocardial misdemeanor. Diabetes mellitus affects ?6 % of the US population but is present in every bit many as 30 % of patients hospitalized with acute coronary syndromes. It has been recognized for some clip that diabetics experience a greater mortality during the acute stage of myocardial infarction. Before the coming of coronary attention as we know it today, mortality among diabetic patients in MI was reported to be every bit high as 40 % .

Diabetes entirely or in combination with a assortment of hazard factors ( high blood pressure, hypercholesteremia ) can impair endothelial map. Increased oxidative emphasis brought approximately by hyperglycemia may be an of import nexus between diabetes and vascular events. Advanced glycosylated terminal merchandises may slake azotic oxide through the coevals of O free groups, taking to impaired endothelial vasodilatation. Angiotensin II augments oxidative emphasis by increasing the vascular production of superoxide groups, which in bend interfere with the bioavailability of azotic oxide. By increasing free extremist production, angiotensin II increases leukocyte adhesion to the endothelium, thrombocyte collection, and cytokine look, ensuing in macrophage infiltration at the site of atherosclerotic plaques, taking to increased plaque exposure. The plaque becomes unstable, ruptures and organize a thrombus which occludes the arteria barricading the flow of blood taking to ischemia and the cardiac cells die let go ofing ALT in circulation.

Greater 40 % of diabetic patients studied had antecedently had angina, ischaemic preconditioning might hold mitigated the extent of left ventricular disfunction. Myocardial infarction in diabetic patients normally is more extended and more terrible than in non- diabetic patients. The long-run endurance rate after acute myocardial infarction among diabetic patients is besides lower than that among non-diabetic patients. In fact, the 5-year endurance rates for diabetic patients after the first major coronary event have been found to be 38 % and merely 25 % for those with subsequent events, compared with the corresponding figures in non-diabetic patients of 75 % and 50 % , severally.

Persons with diabetes mellitus have a higher incidence of liver map trial abnormalcies as compared with non-diabetics10. Mild chronic lifts of alanine aminotransferase frequently reflect underlying insulin opposition or no insulin production10,11. Alanine aminotransferase is elevated three times the upper bounds of normal7.In a survey done in Jordan the prevalence of elevated serum ALT in diabetic patients is 9.4 % , males had a higher prevalence of 10.6 % and females had a prevalence of 8.2 % 11. The normal mention scope of serum ALT in males is ?45U/L and in females is ?34U/L11. The prevalence is higher in males and hapless metabolic control12. The prevalence of ALT is decreased in aged people due to diminish in the release of musculus proteins for gluconeogenesis and decreased hepatic function12.

1.1.6 Diagnosis and direction of diabetes mellitus

Different trials can be used to name and supervise blood glucose degrees in diabetes mellitus. For diagnosing the OGTT, fasting and random blood glucose trials are ideal and harmonizing to the WHO guidelines, if the plasma glucose is & A ; lt ; 5.5 mmol/L so diabetes is improbable. A fasting plasma glucose of 7.0 mmol/L or more, or a random glucose of 11.1 mmol/L or more makes diabetes more likely.

In the direction and control of diabetes, blood glucose determined at the clip of the clinic attending can merely give limited information and may non stand for the overall intimacy of control at other times therefore it has restrictions in supervising glucose control. The HbA1c trial provides a better index of diabetic control than plasma glucose since it is non greatly affected by short-run fluctuations in plasma glucose. Other trials such as blood carbamide ( BUN ) , blood insulin, blood fructosamine, macroalbumin, glycosylated hemoglobin ( HbA1c ) , blood gases, C-peptide and electrolytes are used in the monitoring of diabetes.

1.2 Statement of the job

Diabetic patients have elevated serum ALT degrees due to damage of insulin7.Diabetic patients have liver disease due to extra FFA which are toxic to the hepatocytes and hence leads to hepatic hurt taking to the release of ALT in the serum3.Fats besides accumulates in hepatocytes doing NAFLD which inveterate elevates ALT. The unnatural lipid profile promotes atherogenesis taking to atherosclerosis which doing soundless ischaemic myocardial infarction. The infarcted myocardial cells release ALT in circulation. The mortality of NAFLD is 70 % in diabetics and of soundless ischaemic myocardial infarction is greater than 40 % . Unfortunately clinicians are incognizant of these conditions in diabetic patients. The proposed research is to find the serum ALT degrees in diabetic patients, to gauge the prevalence of elevated ALT in diabetic mellitus patients and the prevalence of people who are at hazard of liver related deceases and CVD.

1.3 Hypothesis

Null hypothesis – The prevalence of elevated serum ALT degrees in diabetes mellitus patients at Parirenyatwa Group of Hospitals is less than 9.4 % 11

Alternate hypothesis – The prevalence of elevated serum ALT degrees in diabetes mellitus patients at Parirenyatwa Group of Hospitals is greater than 9.4 % 11

1.4 Aims

This survey aims to:

Measure the serum degrees of ALT in diabetes mellitus patients go toing Parirenyatwa Group of Hospitals Diabetic Clinic.

Estimate the prevalence of elevated ALT in diabetes mellitus patients go toing Parirenyatwa Group of Hospitals Diabetic Clinic.

Chapter Two: Materials AND METHODS

2.1 Materials

Mindray BS120 chemical science analyse

Serum pots

Plain tubings

Pasteur pipettes

Latex baseball mitts

Micro pipettes

Mighty shapers

Distilled H2O

ALT reagent


Lab coat

2.2 Study design

• A transverse sectional analytical survey will be done on blood samples of diabetes mellitus patients go toing Parirenyatwa Group of Hospitals Diabetic Clinic.

2.3 Sample size finding

S = Z2pq/E2

Where Z = Test statistic

E = Standard Error

P = Population Proportion with desired characteristic

S = 1,962 ten 0,094 ten 0, 86 ( q = 1 -p )


S = 124, 2

S =124

A lower limit of 124 samples will be used in this survey.

2.4 Study population and scene

The survey population will dwell of diabetic patients aged between 18 and 65 old ages go toing Parirenyatwa Group of Hospitals Diabetic Clinic.

2.5 Sampling technique

2.5.1 Sampling process

Consecutive Convenience sampling will be used for choice of diabetic patients at Parirenyatwa Diabetic Clinic who would hold come for everyday check-up or monitoring. Participants who will run into the eligibility standards will be enrolled into the survey.

2.5.2 Inclusion standards

Diabetic patients of an age scope between 18 and 65 old ages go toing Parirenyatwa Group of Hospitals Diabetic Clinic between 1st of November 2012 and 30th of April 2013.

2.5.3Exclusion standards

• Non-diabetic patients

• Diabetic patients below 18 old ages and above 65 old ages of age

2.6 Ethical considerations

Permission will be sought from the Parirenyatwa Group of Hospitals Clinical Director, Head of Department of the Chemistry Laboratory, the Advisers at the Diabetic Clinic, Matrons and Sister-in-charge working at PGH Diabetic Clinic to roll up demographic informations and utilize residuary modus operandi samples handed over for analysis in the research lab. Ethical clearance will be sought from the Joint Research Ethics Committee of the Parirenyatwa Group of Hospitals and University of Zimbabwe College of Health Sciences. Confidentiality will be maintained and no names will be used for designation to guarantee privateness. Subjects on any sort of intervention or appraisal of patients will non be altered in any manner because of the undertaking. Consequences will non be accessible to any unauthorized individuals. Safe disposal of residuary samples and natural informations will be done after the undertaking has been successfully rated.

2.7 Laboratory methods

2.7.1 Collection of samples

Left over diabetic patient samples handed in for everyday checks to the research lab in field tubings will be used.

2.7.2 Principle of ALT assay

?-oxoglutarate + L-alanine ALT L-glutamate + pyruvate

Pyruvate + NADH + H+ LDH L-lactate + NAD-

Alanine transaminase catalyzes the reversible transamination of L-alanine and ? – oxoglutarate to pyruvate and L- glutamate. The pyruvate is so reduced to breastfeed in the presence of lactate dehydrogenase ( LDH ) with the coincident oxidization of decreased ?-nicotinamide A dinucleotide ( NADH ) to ?-nicotinamide A dinucleotide ( NAD ) .This alteration in optical density is straight relative to the activity of ALT in the sample.

2.7.3 Processing

Samples will be centrifuged at 3 000 revolutions per minute ( revolutions per minute ) . The serum will be aliquoted into plastic made serum pots utilizing a micropipette and so stored in a icebox at a temperature maintained between 2 – 8oC and so processed in batches. Prior to processing of the samples they are brought to room temperature and the analyzer will be calibrated. After standardization the control samples will be analysed. The samples will be loaded in the sectors of the machine ( Mindray BS 120 ) and assayed for ALT.