The pancreatic beta cells show pathological damage in the form of insulinitis with pancreatic mononuclear cell infiltration, which is a characteristic feature at the onset of the disorder. Cytokines may play a role in the early destruction of the pancreas.

T1DM is prone to ketoacidosis.

Around ninety percent of T1DM cases begin in childhood, mostly between the ages of 10 and 14. While this observation led to the use of the term "juvenile diabetes" for the disorder, it is no longer used as T1DM can occur at any age, although juvenile onset is the typical pattern.

Islet cell autoantibodies are frequently present around the time of onset. If T1DM is induced by a virus, the autoantibodies are transient. Occasionally, the antibodies may persist long term, especially if they are associated with other autoimmune disorders. Approximately 50% of T1DM cases are related to problems with the major histocompatibility complex on chromosome 6. This is correlated with an increased frequency of certain human leukocyte antigen (HLA) alleles. The HLA types DR3 and DR4 are most commonly associated with diabetes.

Body mass index (BMI) is a measure of adiposity. It is calculated using the equation 38.1. The BMI of healthy lean individuals ranges from 20 to 25. A BMI higher than 25 indicates overweight, while a BMI higher than 30 indicates obesity. Being overweight or obese is a risk factor for various pathologies, including insulin resistance, dyslipidemia, diabetes, cardiovascular disease, and hypertension.

White adipose tissue (WAT) is divided into subcutaneous and intraabdominal depots. Intraabdominal WAT primarily refers to omental and mesenteric fat and is the smaller of the two depots. These depots have different blood supplies and drainage pathways. Intraabdominal fat is drained into the hepatic portal system, resulting in most of the FFAs being cleared by the liver. Subcutaneous fat, on the other hand, is the primary site for providing FFAs to muscles during exercise or fasting. The regulation of intraabdominal and subcutaneous adipose tissue also differs. Abdominal fat has a higher turnover rate and is highly innervated by autonomic neurons. Additionally, these two depots exhibit differences in hormone production and enzyme activity.

Men tend to accumulate fat in the intraabdominal depot, resulting in android (apple-shaped) adiposity. Women, on the other hand, tend to accumulate fat in the subcutaneous depot, particularly in the thighs and buttocks, leading to gynecoid (pear-shaped) adiposity. Excess abdominal fat poses a greater risk factor for the mentioned pathologies. Therefore, another indicator of body composition is the waist-hip ratio, which is calculated by dividing the waist circumference (measured around the narrowest point between the ribs and hips when viewed from the front after exhaling) by the hip circumference (measured at the point where the buttocks are largest when viewed from the side). A waist-hip ratio greater than 0.95 in men or 0.85 in women is associated with a significantly higher risk for developing diabetes and cardiovascular disease.

In recent years, several hormones and neuropeptides have been implicated in the regulation of appetite, satiety, and energy expenditure in humans, both chronically and acutely. One simplified model involves two peptide hormones, leptin.
Thereispathologicaldamagetothepancreaticbetacells.Insulinitiswithpancreaticmononuclearcellinfiltrationisacharacteristicfeatureattheonsetofthedisorder.Cytokinesmaybeinvolvedintheearlydestructionofthepancreas.
3.
PeoplewithT1DMarepronetoketoacidosis.
4.
Ninetypercentofcasesbegininchildhood,mostlybetween10and14yearsofage.Thiscommonobservationledtoapplicationofthetermjuvenile diabetes tothedisorder.ThistermisnolongerusedbecauseT1DMcanariseatanytimeoflife,althoughjuvenileonsetisthetypicalpattern.
5.
Isletcellautoantibodiesarefrequentlypresentaroundthetimeofonset.IfT1DMisinducedbyavirus,theautoantibodiesaretransient.Occasionallyantibodieswillpersistlongterm,particularlyiftheyareassociatedwithotherautoimmunedisorders.About50%ofT1DMisrelatedtoproblemswiththemajorhistocompatibilitycomplexonchromosome6.Itiscorrelatedwithanincreasedfrequencyofcertainhumanleukocyteantigen(HLA)alleles.TheHLAtypesDR3andDR4aremostcommonlyassociatedwithdiabetes.
who received poor nutrition and into a life that meant chronic undernourishment.
A measure of adiposity is the body mass index (BMI). The BMI of an individual is calculated as:
Equation 38.1
The BMI of healthy lean individuals ranges from 20 to 25. A BMI greater than 25 indicates that the individual is overweight, whereas a BMI higher than 30 indicates obesity. The condition of being overweight or obese is a risk factor for multiple pathologies, including insulin resistance, dyslipidemia, diabetes, cardiovascular disease, and hypertension.
WAT tissue is divided into subcutaneous and intraabdominal (visceral) depots. Intraabdominal WAT refers primarily to omental and mesenteric fat and is the smaller of the two depots. These depots receive different blood supplies that are drained in a fundamentally different way in that venous return from intraabdominal fat leads into the hepatic portal system. Thus intraabdominally derived FFAs are mostly cleared by the liver, whereas subcutaneous fat is the primary site for providing FFAs to muscle during exercise or fasting. Regulation of intraabdominal and subcutaneous adipose tissue also differs. Abdominal fat is highly innervated by autonomic neurons and has a greater turnover rate. Furthermore, these two depots display differences in hormone production and enzyme activity.
Men tend to gain fat in the intraabdominal depot (android [apple-shaped] adiposity), whereas women tend to gain fat in the subcutaneous depot, particularly in the thighs and buttocks (gynecoid [pear-shaped] adiposity). Clearly an excess of abdominal fat poses a greater risk factor for the pathologies mentioned earlier. Thus another indicator of body composition is circumference of the waist (measured in inches around the narrowest point between the ribs and hips when viewed from the front after exhaling) divided by the circumference of the hips (measured at the point where the buttocks are largest when viewed from the side). This waist-hip ratio may be a better indicator of body fat than BMI, especially as it relates to risk for development of diseases. A waist-hip ratio of greater than 0.95 in men or 0.85 in women is linked to a significantly higher risk for development of diabetes and cardiovascular disease.
In recent years, numerous hormones and neuropeptides have been implicated in both chronic and acute regulation of appetite, satiety, and energy expenditure in humans. One
CHAPTER 39 Hormonal Regulation of Energy Metabolism simplified model involves two peptide hormones, leptin