Epidemiology Flashcards
what is Epidemiology?
Epidemiology is the study of the distribution and determinants of health-related states or events (including disease), and the application of this study to the control of diseases and other health problems.
what is the purpose of Epidemiology?
The purpose of epidemiology is to search for the causes of disease, or how it is spread, and to identify a system for surveillance of its occurrence.
how to measure Epidemiology?
Various methods can be used to carry out
epidemiological investigations:
- Surveillance and descriptive studies can be used to study distribution;
- Analytical studies are used to study determinants.
what are the fundamental assumptions of Epidemiology?
- Human disease is NOT random
- Human disease has causal and preventative factors that can be identified through scientific investigation of different populations or subgroups of individuals within a population (Hennekens, 1987)
Physical activity Epidemiology?
• …focuses on physical activity within populations
and investigates how physical activity levels impact on health and disease, and consequently decrease mortality and morbidity
• …typically incorporates both the assessment of
physical activity, as well as, intervention efforts
focusing on increasing physical activity
Hippocrates – “Father of Medicine” why is he important?
First Epidemiologist
• Based his medical practice on observations and study of the human body.
• Kept records of associations between
disease and climate, living conditions
and habits such as diet and exercise
what is does-response?
Relationship in which a change in the amount, intensity or duration of exposure is associated with a change in risk of a specified outcome
what is the does in physical activity?
- Mode
- Frequency
- Intensity
- Duration
- Total Volume
what are the risks of inactivity?
676,000 deaths each year
were down to inactivity vs.
337,000 from carrying too
much weight
Eliminating inactivity in Europe would cut mortality rates by nearly 7.5%, or 676,000 deaths, but eliminating obesity would cut rates by just 3.6%.
Medical complications of INactivity?
Depression Stroke Coronary heart disease Diabetes Dyslipidaemia Hypertension Cancer Osteoporosis Overweight
what were the number of obese adults in 1995?
200 million
obese adults
what were the number of obese adults in 2000?
how many u5s are obese?
> 300 million
obese adults
18 million u5s
overweight
what were the number of obese adults in 2016?
how many u5s are obese?
650 million
obese adults
41 million u5s
overweight
what is the prevalence of obesity in the UK?
England 26.2% (prevalence of obesity) 61.4% (Prevalence of Obesity
or overweight)
Scotland 29.0% (prevalence of obesity) 65.0% (Prevalence of Obesity
or overweight)
Wales 23.0% (prevalence of obesity) 59.0% (Prevalence of Obesity or overweight)
What is the prevalence of obesity for children in the UK?
England 9.6% (prevalence of obesity) 22.6% (Prevalence of Obesity or overweight)
Scotland 10.0% (prevalence of obesity) 22.0% (Prevalence of Obesity or overweight)
Wales 11.7% (prevalence of obesity) 26.2% (Prevalence of Obesity or overweight)
how many people on average in 2020 will be obese?
8-10 men
7-10 women
why is obesity increasing?
Is it because we have drastically reduced our physical activity (decreasing energy expenditure), tried to compensate by ‘dieting’ (decreasing energy intake) – and can’t get that low…?
what happens in the body during inactivity?
- When dietary intake exceeds energy expenditure for a prolonged period of time
- Chronic positive energy balance
- Energy converts to triglycerides
- Stored in adipose tissue depots and expand in size EXCESSIVE FAT STORAGE
obesity can also lead to what?
Musculoskeletal Disease
• Osteoarthritis: Inflammation of one or more joints.
Alzheimer Disease • Alzheimer Disease: type of brain disorder that causes problems with memory, thinking and behaviour
what is feast and famine?
In time of famine-genes for fat accumulation promoted survival
in times of feast-they promote chronic disease.
Our Genes expect what?
Physical activity:
Failure to maintain gene expression at the expected level
Genes requiring physical activity are also disease-susceptibility genes
inhibition of health proteins activation of disease proteins
Gene-environment interaction
Environmental disease: g + E
Common disease: G + E
Genetic disease: G + e
how does Genetic Predisposition lead to obesity?
Energy intake increases+ Energy expenditure= Energy storage facilitating fat+ Adipogenesis= overweight=obesity
its also affected by external; factors such as food intake, no exercise, viruses, alcohol, home , prenatal factors, lactation, nutrition, physical environment, economic factors
Evidence of environmental influences
- Pima Indians from Sierra Madre/ Maycomb of Mexico are isolated leading a traditional lifestyle
- Whereas in Arizona, western influences have caused a high fat diet and sedimentary lifestyle
- Resulting in an obesity epidemic over the previous 50 years
Evidence of genetic influences in humans?
- Familial clustering:
- Obesity in families
- Twin studies:
- Greater concordance in MZ twins
- Family studies:
- Variety of statistical models consistent with this
Amish lifestyle and obesity linked with it?
• Farming/subsistence
community
• No motorised transport
– only animals
• High calorie, high fat
diet
• ~3% Obesity
Physical Activity Exposures and Outcomes
Exposure: volume frequency intensity duration mode
Risk factors: Blood pressure Cholesterol Insulin resistance metabolic syndrome Arterial stiffness bone density
Morbidity: CHD Stroke Cancer mental health Osteoporosis Diabetes Obesity
Mortality:
death
what is the Additive effects of physical activity?
“With the possible exception of diet, we know of no single intervention with greater promise than physical exercise to reduce the risk of virtually ALL chronic disease simultaneously…”
