Week 3- Diabetes Flashcards
what is diabetes mellitus
A metabolic disease that involves abnormally elevated blood glucose levels
diabetes mellitus as one of the leading causes of mortality
Reduces lifespan by 5-15 years and the all-cause mortality rate is twice as high as for those without diabetes
what % in US and Canada have diabetes
10-15%
subtypes of diabetes mellitus
type 1 and type 2
maturity-onset diabetes of the young, gestational diabetes, secondary causes due to endocrinopathies/steroid use, etc.
type 1 diabetes- which cells are effected?
Due to the destruction of pancreatic islet beta cells – typically secondary to an autoimmune reaction
age most common to get T1D
4-6 or 10-14 yrs
causes of T1D
One-third of the disease susceptibility is due to genetic factors, with two-thirds attributed to environmental factors
genetic factors for T1D? what’s most common?
HLA
The HLA locus (HLA-DR3, -DR4, -DQ) confers about 40% of the genetic risk to developing Type 1 diabetes, while the 5’ polymorphic region of the insulin gene adds 10%
- Most patients will have circulating antibodies to islet cells, glutamic acid decarboxylase 65, insulin, tyrosine phosphatase IA2, and zinc transporter 8
environmental factors for T1D
less prevalent near the equator
migration?
breastfeeding is protective
hygiene hypothesis- public health and immune system dysregulation and develop autoimmune
what % and who doesnt have the typical pancreatic beta cell autoimmunity in T1D
Approximately 5% of patients have no evidence of pancreatic beta cell autoimmunity = the subgroup of “idiopathic type 1 diabetes” (also known as “type 1B”)
Most of these individuals are of Asian or African descent
symptoms of T1D
Excessive urination (polyuria) and thirst (polydipsia)
Blurred vision
Weight loss
Parasthesias
Altered level of consciousness
is screening recommended for T1D?
no
T2D eitology/ causes
Due to the non-autoimmune loss of pancreatic B cell function or development – leading to impaired insulin sensitivity (“insulin resistance”)
T1D vs T2D cause
T1D: Due to the destruction of pancreatic islet beta cells – typically secondary to an autoimmune reaction
T2D: Due to the non-autoimmune loss of pancreatic B cell function or development – leading to impaired insulin sensitivity (“insulin resistance”)
onset of T2D
adults, but rising in kids
what % is T2D
More than 90% of patients with diabetes in the U.S. have Type 2 diabetes
who has higher prevalence of T2D (race and other risk factors)
Prevalence is 2-6x higher in persons of Black (12.9%), South Asian (14.4%), Arab/west Asian (9.4%), Native American (34.8%), Pima Indian, or Hispanic American (4.5%) backgrounds (Sapra 2023)
Other risk factors include: obesity, first-degree relative with Type 2 diabetes, cardiovascular disease, hypertension, HDL cholesterol <35mg/dL (0.91mmol/L) and/or triglycerides >250mg/dL (2.8mmol/L), acanthosis nigricans, polycystic ovary syndrome, gestational diabetes or delivery of baby >9lb
genetic factors in T2D
Epidemiologic studies looking at monozygotic twins >40 years of age have shown that when Type 2 diabetes develops in one twin, in 70% of cases the second twin will also develop Type 2 diabetes within a year
- Genome studies have identified 143 risk variants and regulator mechanisms for Type 2 diabetes, including loci that code for proteins involved in beta cell function/development (TCF7L2), insulin secretion (e.g., CDKAL1, SLC30A8), fat mass and obesity risk (FTO, MC4R), and insulin resistance (PPARG)
T2D envrioenmtnal factors
visceral obesity –> insulin resistance (subcutaneous fat is less correlated)
metabolic obesity= visceral fat without overt obesity
adipocytes and immune system in T2D
Adipocytes secrete abnormal levels of adipokines (e.g., adiponectin and resistin) that can impair insulin signaling
- The release of TNF-alpha and IL-6 by macrophages and other immune cells activated in adipose tissue can also impair insulin signaling
T2D diagnosis - when do you see symptoms?
Many patients have an insidious onset of hyperglycemia and are initially asymptomatic. Diabetes is recognized only after glycosuria or hyperglycemia is discovered on routine lab testing.
At the time of diagnosis, patients may already have some level of neuropathic or cardiovascular complications
T2D - whos effected?
lower income, not finished university, permanatley unable to work
skin conditions of T2D
Chronic skin conditions:
* Vulvovaginal candidiasis in females
* Balanoposthitis in males
* Acanthosis nigricans
* Eruptive xanthomas
* Lipemia retinalis
other T2D symtpoms
weight, pregnancy complication
Weight gain
* Overweight or obese
* Centripetal fat distribution
* Waist circumference >40 inches for men, >35 inches for women
Obstetrical complications
* Consider Type 2 diabetes in women who have delivered babies over 9 lb (4.1 kg) or have had polyhydramnios, preeclampsia, or unexplained fetal losses
is screening recommended for T2D?
yes
screening test for T2d? what factors if patient has will you decide to test in?
Screen asymptomatic adults with a body mass index ≥25 kg/m2, and one or more additional risk factors (American Diabetes Association, ADA) from previous lab results:
* A1C > 5.7%
* Impaired glucose tolerance
* Impaired fasting glucose
clinical features of diabetes SLIDE 30 chart
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ie.
polyuria and thirst in both T1D and T2D but moreso in T1D
nocturnal eneuresis is common in T1d but not in T2D
metabolic syndrome
insulin resistance –> higher risk of diabetes and CVD
gestational diabetes- what %
8% in 2020
prevalence increases with higher BMI
screening time for gestational diabetes? what is the test?
24-48 weeks gestation with non fasting 50g glucose challenge test
If blood glucose >140 mg/dL (7.8 mmol/L), then perform a 3- hour fasting 100g glucose challenge test to confirm (Diagnostic)
* Positive if there is at least one abnormal value (≥180, 155, 140 mg/dL for 1-, 2-, and 3-hour fasting glucose levels, respectively)
what is the value of blood glucose to DIAGNOSE gestational diabetes
> 140mg/dl blood glucose
then 3 hours test
2 step test for gestational diabetes
One-step testing: a single fasting 75g oral glucose tolerance test
Two-step testing: a non-fasting 50g oral glucose tolerance test, followed by a 3-hour fasting 100g glucose tolerance test if the result passed the threshold of 130-140 mg/dL
Diagnosis of gestational diabetes is more common in one-step screening (16.5%) than two-step screening (8.5%) – but no statistically significant differences in perinatal or maternal complications
what is better; 2 step or 1 step test for gestational diabetes
the two-step testing produces equivalent benefits and fewer harms than the one-step testing approach
risks of gestational diabetes
To reduce maternal and fetal complications: preeclampsia, caesarean delivery, congenital malformations, macrosomia, childhood or adolescent obesity, nerve palsy, bone fracture, jaundice, and infant death
gestational hypertension, development of T2D later in life, being overweight in childhood, birth defects, shoulder dystocia
who to screen for gestational diabetes?
Screen women in their first trimester if risk factors are present, such as obesity, advanced maternal age or >35 years of age, history of gestational diabetes, family history of diabetes, belonging to a high-risk ethnic group
Screen asymptomatic patients at or after 24 weeks’ gestation
manage gestational diabetes after birth
test 6-12 weeks postpartum
the types of diabetes that kids can get?
Type 1 diabetes
Type 2 diabetes
Maturity-onset diabetes of the young (MODY)
how many kids have diabetes
20% in 12-18 yrs old have pre diabetes
200,000 kids in US have diabetes
risk factors in kids with T2D
obesity, excess adipose tissue (especially when centrally distributed), and family history
Socioeconomic position, area of residence, and environmental factors may also play a role (e.g., quality of and access to health care, toxic stress, structural racism)
races for kids that are likely to get T2D
Prevalence is highest in American Indian/Alaska Native, Black, Hispanic/Latino, and Hawaiian/Pacific Islander youth
complications of T2D in kids
ketoacidosis, hyperglycemic hyperosmolar state
macrovascular (atherosclerosis)
microvascular (retinopathy, nephropathy, neuropathy)
renal disease, retinopathy, peripheral neuropathy,
hypertesnion, dyslipidemia, NAFLD
screening for T2D in kids
evidence insufficient….
screen if overweight or have history of Type 2 diabetes in a first- or second-degree relative, belonging to a high-risk ethnic group, acanthosis nigricans, hypertension, hyperlipidemia, or polycystic ovarian syndrome (ADA)
maturity onset diabetes of the young (MODY- what is it?
A non-insulin-dependent form of diabetes, typically diagnosed at ≤25 years of age
1-5% of all patients with diabetes have the MODY type
Often misdiagnosed as Type 1 or 2 diabetes
who to suspect MODY in?
non obese if diagnosed with diabetes under 30 yrs old
strong family history of diabetes
Preserved pancreatic beta cell function 3-5 years post- diagnosis (detectable serum C-peptide levels with a serum glucose level >144 mg/dL and no laboratory evidence of pancreatic beta cell autoimmunity)
what is the most common reason for MODY? what genes?
autosomal dominant disease (50% of offspring affected)
14 subtypes (MODY1 to MODY14), with MODY1 to MODY3 accounting for 95% of cases
The subtypes are distinguished by their gene mutations:
* MODY1 (HNF4A): rare
* MODY2 (GCK): less rare
* MODY3 (HNF1A): most common, 30-50% of cases
* Remaining subtypes are very rare
what is the most common gene mutation for MODY?
MODY3 (HNF1A): most common, 30-50% of cases
what does MODY 1 and MODY3 have similar to type 1 and 2 diabetes
MODY1 and MODY3 have progressive hyperglycemia and vascular complication rates similar to patients with Type 1 and Type 2 diabetes
how dangerous is MODY 2?
MODY2 has mild stable fasting hyperglycemia with low risk of diabetes-related complications. These patients generally do not require treatment, except in pregnancy.
screening for MODY
genetic testing and refer to endocrinologist
prevalence of diabetes in older people
> 65 yrs have 20% diabetes
16% are unaware that they have diabetes based on glycosylated hemoglobin, fasting plasma glucose, or oral glucose tolerance testing
most common type of diabetes in older
T2D
older adults: diabetes increases risk of…
mortality and cardiovascular and microvascular complications, as well as other geriatric conditions (e.g., cognitive impairment, frailty, unintentional weight loss, polypharmacy, and functional impairment)
screening for diabetes in older adults recommendation?
no current recommendations
-screening for quality of life and life expectancy
secondary causes of diabetes
Secondary causes include: exocrine pancreas diseases, endocrinopathies, drug- or chemical-induced insulin resistance, and other genetic diseases
Any disorder that damages the pancreas can result in diabetes (e.g., liver cirrhosis, hemochromatosis, hemosiderosis)
slide 56 secondary causes of diabetes chart
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4 diagnostic tests for diabetes
Fasting plasma glucose levels (FPG)
Oral glucose tolerance test (OGTT)
Glycated hemoglobin (HbA1c)
Additional tests (urine, self-monitoring, continuous glucose monitoring, autoantibody)
fasting plasma glucose in diabetes
100-125 mg/dl = prediabetes
>126 (8 hours after fasting)= diagnostic