Epidemiology of Metabolic Disease: Diabetes and Insulin Resistance Flashcards
What is type 1 diabetes?
Insulin not produced by pancreas - need insulin injections
Autoimmune
Sudden onset in youth
What is type 2 diabetes?
Cell does not recognise insulin signal - in insulin-resistant state
Treat with diet, insulin, drugs
Gradual adult onset
What is gestational diabetes?
Diabetes during pregnancy - resolves after
Increased later life risk of type 2 diabetes
What is glycated haemoglobin?
Glucose attached to haemoglobin in RBCs
What does glycated haemoglobin indicate and why?
Gives 3 month average of glucose circulating - as RBCs have life of 3 months
Which methods can be used to establish a cut off point for diabetes diagnosis?
Glycated haemoglobin
Fasting glucose
Glucose tolerance test - glucose 2 hours after glucose load
Glycaemic level where risk of diabetic retinopathy increases
What is the largest cause of diabetes?
Obesity
What are the relative contributions of genetics and environment to diabetes?
Genetic role
Mainly due to lifestyle
What is the effect of living, working, and commuting closer to a takeaway food outlet?
Increased average BMI
How are men affected by living in more walkable environments?
Decreased diabetes risk
What is the relationship between birthweight and adult type 2 diabetes risk (decreased adult glucose tolerance)?
U-shaped
What is higher maternal fasting glucose associated with?
Increased chance of offspring obesity
Why might higher maternal fasting glucose be associated with an increased chance of offspring obesity?
Genotype - weak evidence
Shared familial lifestyles - weak evidence
Pedersen hypothesis
What is the Pedersen hypothesis?
Gestational diabetes causes early obesity
Maternal high glucose causes foetal hyperinsulinaemia
Foetal insulin acts as growth hormone - via IGF-1 - causes rapid early growth
Interuterine programming of metabolic syndrome affects multiple foetal tissues - changes combine to impair glucose tolerance - insulin resistance
What are the main complications of diabetes?
CV disease - main diabetes-related cause of death Cataracts Nephropathy Neuropathy Foot ulcers Cognitive decline Cancer
What is the evidence that diabetes accelerates ageing?
Diabetes increases frequency of dementia, mild cognitive impairment, poor physical function (increased fractures)
What are the vascular complications of diabetes?
Blood vessel stiffening, leaking, cell death, thrombus formation
How does diabetes lead to vascular complications?
Metabolic disease - causes inflammation, DNA damage, apoptosis, O2 stress
Causes structural damage - impacts microcirculation - causes complications (e.g. retinopathy)
Causes fibrosis of perivascular space, vessel stiffening, fewer arteries - impairs blood delivery to organs
Causes macrovascular complications (e.g. CVD, stroke)
What is the ‘metabolic memory’ of tissues and what is the implication of this?
Tissues retain memory of previous high glucose - damage develops even when glucose returns to normal levels
Must treat diabetes early to avoid CV complications
Which diabetes complications are CVD risk factors?
High triglycerides
High LDL
Low HDL
When do CVD risk factors appear in diabetes?
Cluster with diabetes onset - ~10yrs before diagnosis
For individuals at high risk of diabetes which treatments had the lowest progression rates?
Diet and exercise plan - then metformin - then placebo
What is a problem with a diet and exercise plan for individuals at high risk of diabetes?
Not appropriate for LMICs
What are potential problems with long-term diabetes and CVD prevention interventions?
Lifestyle and metformin improve CVD risk factors - but no evidence for decreased CVD rates
Enthusiasm for diet and exercise plan likely to decline
Must consider generalisability to other countries
Age of intervention - midlife often targeted - but early life also affects diabetes development
What are the 2 main approaches to diabetes prevention?
Individual approach
Population-based approach
Give an example of an individual approach to diabetes prevention
Screen high risk individuals - refer to diet and exercise support
Give an example of a population-based approach to diabetes prevention
Government restrictions on food fat and salt content
What do programmes against smoking suggest is the best preventative approach?
Population-based
What is the effect of drugs to lower blood glucose in diabetics?
Slightly decreased CV events
No effect on death rate
What is the effect of statins and blood pressure lowering drugs in diabetics and what does this suggest?
Decreased CV events
Decreased death rate
Diabetes treatments should target lipids and BP - more than blood glucose levels - to decrease CV risk
