BIOSTATISTICS AND EPIDEMIOLOGY PRE-FINAL

“Epidemiology” comes from three words, what are these three words?

epi, demo, and logy

In the word epidemiology, what does “epi” means?

on, upon, befall

In the word epidemiology, what does “demo” means?

people, population, man

Epidemiology is the study of what?

The study of that which befalls man.

What is generally seen as a scientific method to investigate disease?

Epidemiology

An investigative method used to detect the cause or source of diseases, disorders, syndromes, conditions, or perils that cause pain, injury, illness, disability, or death in human populations or groups.

Epidemiology

The study of nature, cause, control, and determinants if the frequency and distribution of disease, disability, and death in human populations.

Epidemiology/Scope of Epidemiology

It involves characterizing the distribution of health status, diseases, or other health problems in terms of age, sex, race, geography, religion, education, occupation, behaviors, time, place, person, etc.

Epidemiology/Scope of Epidemiology

Why is characterization done in epidemiology?

To explain the distribution of a disease or health related problems in terms of the causal factors.

Serves as the foundation and logic of interventions made in the interest of public health and preventive medicine.

Epidemiology/ Scope of Epidemiology

It is considered a cornerstone methodology of public health research, and is highly regarded in evidence-based medicine for identifying risk factors for disease and determining optimal treatment approaches to clinical practice.

Epidemiology/Scope of Epidemiology

In the work of communicable and non-communicable diseases, the work of epidemiologist’s ranges from outbreak investigation to study design, data collection, and analysis including the development of statistical models to test hypotheses and the documentation of results for submission to peer-reviewed journals.

Scope of Epidemiology

Epidemiologists may draw on a number of other scientific disciplines such as biology which is?

Understands disease processes.

Social science is also part of the other scientific disciplines that epidemiologists may draw on to?

In order to better understand proximate and distal risk factors. Also, it includes sociology and philosophy.

What are the three purposes of Epidemiology?

1. Explain the etiology (cause) of a single disease or group of diseases using information management.

2. Determine if data are consistent with proposed hypothesis.

3. Provide basis for developing control measures and prevention procedures for groups and at-risk populations.

A substance produced by or a semisynthetic substance derived from a microorganism and stable in dilute solution to inhibit or kill another microorganism.

Antibiotics

A pattern of response by a living organism to some form of invasion by a foreign substance or injury which causes an alteration of the organisms normal functioning.

Disease

The ongoing, usual level of, or constant presence of a disease in a given population.

Endemic

Outbreak or occurrence of one specific disease from a single source, in a group population, community, or geographical area, in excess of the usual level of expectancy.

Epidemic

The factors contributing to the source of or causation or a disease.

Etiology

A disease that is highly prevalent in a population and is commonly acquired early in life in most of the children of the population.

Holoendemic

Persistent level of activity beyond or above the expected prevalence.

Hyperendemic

The extent that people, within a population who do not have the disease, develop the disease during a specific time period.

Incidence

Are those which the pathogen or agent has the capability to enter, survive, and multiply in the host.

Ineffective Diseases

The ability to get into a susceptible host and cause a disease within the host.

Invasiveness

Epidemic that is widespread across a country, continent, or large populace, possible worldwide.

Pandemic

Organisms or substances such as bacteria, viruses, or parasites that are capable of producing diseases.

Pathogens

The development, production, or process of generating a disease.

Pathogenesis

Disease causing or producing.

Pathogenic

Describes the potential ability and strength of a pathogenic substance to cause disease

Pathogenicity

How many cases of a disease exist in a group of people at that moment.  It relies on two factors: number of people with the disease in the past and duration of the disease.

Point Prevalence

Point of prevalence relies on two factors, what are these two factors?

Number of people with the disease in the past and duration of the disease.

The number of people within a population who have a certain disease at a given point in time.

Prevalence

A poisonous substance that is a specific product of the metabolic activities of a living organism and is usually very unstable.

Toxins

The extent of pathogenicity or strength of different organisms.

Virulence

What are the uses of epidemiology?

The following are the reasons for being of this method:

1.     Look at risks of individuals as they affect populations

2.     Determine the causes and sources of diseases

3.     Assessment, evaluation and research

4.     Study the history of the disease.

5.     Completing the clinical picture

6.     Identification of syndromes

7.     Community diagnosis

What is a model that helps epidemiologists explain the multifaceted phenomena or disease transmission?

Epidemiology Triangle

It is a model for explaining the organism causing the disease and the conditions that allow it to reproduce and spread.

Epidemiology Triangle

The occurrence of more cases of disease, injury, or other health condition that expected in a given area or among a specific group of persons during a specific period.

CDC’s definition of outbreak or epidemic

What are the three corners of the Epidemiology Triangle?

The triangle is made up of three corners: agent (what), host (who), and environments (where). 

This is usually pathogen (virus, bacterium, parasite or other microbes. This also includes chemical or physical causes of disease or injury.

Agent

This is the organism who is exposed to and harbor a disease. Sometimes, it may not show any signs or illness and could be unaware that they have the disease.

Host

What are the factors of the host?

Age, gender, hygiene practices and genetic composition can influence a host’s susceptibility to an infectious agent.

Who are more susceptible to becoming a host?

Children and elderly people who have compromised immune systems are more susceptible to becoming a host.

This refers to any extrinsic factors that can influence exposure and susceptibility. 

Environment

Environmental factors may include?

Physical aspects like climate change, biological aspects like animals transmitting agents and socioeconomic factors like crowding or lack of sanitation. 

It is the is the favorable surroundings and conditions external to the host that cause or allow the disease to be transmitted. 

Environment

Is the introduction of a contamination into the environment.

Pollution

Is the introduction of particulates, biological materials, or other harmful materials into the atmosphere. 

Air Pollution

This contamination of the atmosphere can cause disease, death to humans, and damage to other living organisms. 

Air Pollution

According to 2014 WHO report, in 2012 air pollution caused around ___ million dead people worldwide.

7

What can easily contaminate our atmosphere? This process creates by-products, such as smoke and invisible irritants, which can easily contaminate our atmosphere.

Toxic contaminants or Volatile Organic Compound (VOC) and Burning of Coal

The sources of air pollution can be divided into two, what are these two?

Natural and Man-made

Natural sources of air pollution include?

Pollen grains, volcanic eruption, forest fires, dust storms, spores, bacteria and other microorganisms. 

Man-made sources of air pollution include?

Industrial units, thermal power plants, automobile exhausts, fossil fuel burning, mining, nuclear explosions.

Are substances dwelling temporarily or permanently in the air.  These substances alter the environment by interfering with the health and comfort of living organisms, and even the food chain. These substances can be solid, liquid or gas. 

Air Pollutants

Air pollutants can be grouped into two categories:

Primary and Secondary

Are emitted directly from identifiable sources.

Primary Air Pollutants

What are primary air pollutants?

Particulate matter (PM), sulfur dioxide, nitrogen oxides, volatile organic compounds (VOCs), carbon monoxide, and lead.

What are secondary air pollutants?

Atmospheric sulfuric acid

Are produced in the atmosphere when certain chemical reactions take place among primary pollutants.  Some primary air pollutants react with one another or with other chemicals present in the atmosphere to form this type.

Secondary Air Pollutant

A noxious mixture of gases and particles produced when strong sunlight triggers the reaction in the atmosphere. A major component of these is ozone.

Smog/Photochemical Smog

Effects of Air Pollution

1.     SMOG / PHOTOCHEMICAL SMOG

2.     Air pollution is a major threat to our health because it can cause illnesses such as lung diseases, asthma, bronchitis, and emphysema.

3.     Air pollution has serious effect to our environment.  Contaminant particles, which are released into the air through factories, power plants and cars, combine with water particles in the atmosphere and fall to Earth in a form of acid rain.  When acid rain falls into bodies of water that contain living organisms, definitely the organisms will be contaminated until it will perish.

4.     Air pollution corrodes metals.  Ozone and PAN causes cracking of rubber and various electrical insulations.

Is an international agreement created under the United Nations Framework Convention on Climate Change in Kyoto Japan in 1997.  It aims to reduce the collective greenhouse gas emissions of developed country at least 5% below 1990 levels.

Kyoto Protocol

What only happens when substances or conditions is present to such a degree that the water cannot be used for a specific purpose?

Water Pollution

It can also be defined as the presence of excessive amounts of hazardous pollutants in water in such a way that it is no longer suitable for drinking, bathing, cooking or other uses.

Water Pollution

What are sources of water pollution?

The sources of water pollution, generally are induced by humans.

1. The growth of human population, industrial, and agricultural practice are the major causes of water pollution.

2. Agricultural, domestic, and industrial wastes are the major pollutants of agnatic habitats.

3. Sewage is the biggest pollutant of fresh water.

4. Discharge of hot water from cooling engines in the industries.

5. Excess fertilizers, herbicides and pesticides when washed out by rain into the bodies of water.

6. Oil spill in large bodies of water kills aquatic flora and fauna along with the sources of food for humans such as sea weeds, mollusks, marine birds, crustaceans, fishes and many other.

 

What are effects of water pollution?

The following are the consequences of contaminating the water system of our community:

1. Immediate decrease in the amount of the dissolved oxygen in water.  This happens because organic matter stimulates decomposers especially bacteria which break down suspended solids in the sewage.

2. Biological Oxygen Demand (BOD) also decreases when the decomposers will use the dissolved oxygen (DO) in water.

3. The polluted body of water release obnoxious smell and contain little or no flora and fauna.

4. The increase in temperature of water decreases the metabolic rate of organisms.

5. Runoff contaminants causes serious danger to aquatic life. Example, excess phosphorus cause eutrophication.

6. Polluted water is a potent agent of disease especially if ground water is contaminated.

7. It causes 14,000 deaths per day, mostly because of contaminated drinking water by untreated sewage.

This may be any chemicals or contaminants that harm the living organisms. 

Soil Pollution

What are three types of soil pollution?

Agricultural pollution, industrial waste, and urban activities.

This includes: agricultural processes, fertilizers, pesticides and other substances or chemicals being used for agricultural purposes.

Agricultural Pollution

This constitute about 90% of soil pollution.  It includes improper disposal of waste, toxic fumes from regulated landfills.

Industrial Waste

This includes human activities, improper drainage and increase runoff, improper disposal of trash, increase waste deposition, and decomposition of too much bacteria.

Urban Activities

What are sources of soil pollution?

1.     Industrial effluents like harmful gases and chemicals;

2.     Use of chemicals in agriculture like pesticides, fertilizers, and insecticides;

3.     Improper or ineffective soil management system;

4.     Unfavorable irrigation practices;

5.     Improper management and maintenance of septic system;

6.     Sanitary waste leakage;

7.     Toxin fumes from industries mixed with acid rain;

8.     Improper waste disposal

What are effects of soil pollution?

The following maybe the effect of soil pollution.

1.     Soil contamination or soil pollution may lead to health issues due to direct or indirect contact with contamination.

2.     Soil pollutants cause huge disturbances in the ecological balance and health of organisms.

3.     Crops cannot grow and flourish.

4.     Ultimately, soil becomes unhealthy for planting, and so will become useless.

What are the measures of the control soil pollution?

There are a number of ways to control the pollution rate of soil.  Here are some:

1.     Ban the use of plastic bags below 20 microns thick;

2.     Recycling of plastic wastes;

3.     Ban on deforestation;

4.     Encouraging plantation programs

5.     Chemical fertilizers and pesticides should be replaced with organic fertilizers and pesticides.

Is one of the two world’s worst toxic pollution problems in 2008 and up until now. 

Indoor Pollution

What refers to air quality within and around the buildings and structures, especially as it relates to the health and comfort of occupants in the buildings?

Indoor Pollution

What are the primary cause of indoor pollution?

The primary cause of indoor pollution are gases or particles released into the air. Inadequate ventilation and high temperature and humidity can increase concentration of indoor pollutants.

What are sources of indoor pollution?

1.     Fuel-burning combustion appliances

2.     Tobacco products

3.     Building materials and furnishing

4.     Household cleaning and maintenance, personal care, or hobbies.

5.     Central heating and cooling systems and humidification devices

6.     Outdoor sources: radon, pesticides, outdoor air pollution.

What are effects of Indoor Pollution?

These are some known effects of indoor pollution:

1.     Irritation of the eyes, nose, and throat; headaches, dizziness, and fatigue.

2.     Symptoms of diseases like asthma may surface, then aggravate and worsen.

3.     It has similar effects to those who experience colds or other viral diseases.

4.     Respiratory diseases, heart diseases and cancer may result from prolong exposure to indoor pollution.

What is one measure that can control indoor pollution?

The most effective way to improve indoor air quality is to eliminate individual sources of pollution or to reduce their emissions.  Asbestos, can be sealed or enclosed; others like gas stoves, can be adjusted to decrease the amount of emissions.

Is any substance, radionuclide, or radiation that promotes carcinogenesis – the formation of cancer.

Carcinogen

They have the ability to damage the genome, or to disrupt the cellular metabolic processes. 

Carcinogen

This chemical or substance is produced by fungus Aspergillus flavus growing on stored grains, nuts, and peanut butter.  This is a very potent (strong) carcinogen and a naturally occurring microbial carcinogen. 

Aflatoxin B₁

These two viruses are known to cause cancer to humans.

Hepatitis B and human papilloma viruses

What are two organisms that can cause cancer to humans?

Helicobacter pylori and helminths (e.g. Opisthorchis viverrini and Clonorchis sinensis

They are also considered carcinogenic.

Dioxins and dioxin like compounds (products of burning backyard garbages), benzene, ketone and asbestos have all been classified as carcinogenic.

Once the carcinogens enter our body, the body will attempt to eliminate it through a process called? Makes the carcinogen more water-soluble so it can be removed from the body. However, it some cases, the same reaction also converts a less toxic carcinogen into a more toxic one.

Biotransformation

Why is DNA nucleophilic?

soluble carbon electrophiles are carcinogenic, because DNA attacks them.

It has been defined as any departure, subjective or objective, from a state of physiological or psychological well-being. It encompasses disease, injury, and disability.

Morbidity

Measures of morbidity frequency characterize the number of persons in a population who become?

ill (incidence) or are ill at a given time (prevalence)

It refers to the occurrence of new cases of disease or injury in a population over a specified period of time.

Incidence

What are two types of incidence?

Incidence proportion and incidence rate

Is the proportion of an initially disease-free population that develops disease, becomes injured, or dies during a specified (usually limited) period of time.

Incidence proportion

Is a measure of the risk of disease or the probability of developing the disease during the specified period.

Incidence Proportion