Preventive medicine

# Overview
Generally speaking, preventive medicine is the part of medicine engaged with preventing disease rather than curing it. It can be contrasted not only with curative medicine, but also with public health methods (which work at the level of population health rather than individual health).
Professionals involved in the public health aspect of this practice may be involved in entomology, pest control, and public health inspections. Public health inspections can include recreational waters, pools, beaches, food preparation and serving, and industrial hygiene inspections and surveys.
Preventive medicine or preventive care consists of measures taken to prevent diseases, (or injuries) rather than curing them or treating their symptoms. This contrasts in method with curative and palliative medicine, and in scope with public health methods (which work at the level of population health rather than individual health). Occupational medicine operates very often within the preventive medicine.

# Levels
Preventive medicine strategies are typically described as taking place at the primary, secondary, tertiary and quaternary prevention levels. In addition, the term primal prevention has been used to describe all measures taken to ensure fetal well-being and prevent any long-term health consequences from gestational history and/or disease. The rationale for such efforts is the evidence demonstrating the link between fetal well-being, or "primal health," and adult health. Primal prevention strategies typically focus on providing future parents with: education regarding the consequences of epigenetic influences on their child, sufficient leave time for both parents, and financial support if required. This includes parenting in infancy as well.
Simple examples of preventive medicine include hand washing, breastfeeding, and immunizations. Preventive care may include examinations and screening tests tailored to an individual's age, health, and family history. For example, a person with a family history of certain cancers or other diseases would begin screening at an earlier age and/or more frequently than those with no such family history. On the other side of preventive medicine, some nonprofit organizations, such as the Northern California Cancer Center, apply epidemiologic research towards finding ways to prevent diseases.

## Definitions

# Universal, selective, and indicated
Gordon (1987) in the area of disease prevention, and later Kumpfer and Baxley in the area of substance use proposed a three-tiered preventive intervention classification system: universal, selective, and indicated prevention. Amongst others, this typology has gained favour and is used by the U.S. Institute of Medicine, the NIDA and the European Monitoring Centre for Drugs and Drug Addiction.
Outside the scope of this three-tier model is environmental prevention. Environmental prevention approaches are typically managed at the regulatory or community level and focus on ways to deter drug consumption. Prohibition and bans (e.g. on smoking, alcohol advertising) may be viewed as the ultimate environmental restriction. However, in practice, environmental preventions programs embrace various initiatives at the macro and micro level, from government monopolies for alcohol sales through roadside sobriety or drug tests, worker/pupil/student drug testing, increased policing in sensitive settings (near schools, at rock festivals), and legislative guidelines aimed at precipitating punishments (warnings, penalties, fines).

# Professionals
Professionals involved in the public health aspect of this practice may be involved in entomology, pest control, and public health inspections. Public health inspections can include recreational waters, swimming pools, beaches, food preparation and serving, and industrial hygiene inspections and surveys.
In the United States, preventive medicine is a medical specialty, one of the 24 recognized by the American Board of Medical Specialties (ABMS). It encompasses three areas of specialization:
- General preventive medicine and public health
- Aerospace medicine
- Occupational medicine
To become board-certified in one of the preventive medicine areas of specialization, a licensed U.S. physician (M.D. or D.O.) must successfully complete a preventive medicine medical residency program following a one-year internship. Following that, the physician must pass the preventive medicine board examination. The residency program is at least two years in length and includes completion of a  master's degree in public health (MPH) or equivalent. The board exam takes a full day: the morning session concentrates on general preventive medicine questions, while the afternoon session concentrates on the one of the three areas of specialization that the applicant has studied.
In addition, there are two subspecialty areas of certification:
- Medical toxicology (MT)
- Undersea and hyperbaric medicine (UHB), formerly "undersea medicine"
These certifications require sitting for an examination following successful completion of an MT or UHB fellowship and prior board certification in one of the 24 ABMS-recognized specialties.

# Screening for diseases
Preventive health screening has long been advocated as one of the most important health care strategies to facilitate early diagnosis and treatment, improve quality of life, and prevent premature death.
Expanding the delivery of preventive services of proven value would enable millions of Americans to live longer, healthier, and more fulfilling lives.
Annual wellness visits may increase screening.

# Prophylaxis
Prophylaxis (Template:Lang-el to guard or prevent beforehand) is any medical or public health procedure whose purpose is to prevent, rather than treat or cure a disease. In general terms, prophylactic measures are divided between primary prophylaxis (to prevent the development of a disease) and secondary prophylaxis (whereby the disease has already developed and the patient is protected against worsening of this process).

## Examples
Some specific examples of prophylaxis include:
- Many vaccines are prophylactic, vaccines such as polio vaccine, smallpox vaccine, measles vaccine, mumps vaccine and others have greatly reduced many childhood diseases; HPV vaccines prevent certain cancers; influenza vaccine.
- Birth control methods are used to prevent unwanted pregnancy. Condoms, for instance, are sometimes euphemistically referred to as "prophylactics" because of their use to prevent pregnancy as well as the transmission of sexually transmitted infections.
- Daily and moderate physical exercise in various forms can be called prophylactic because it can maintain or improve one's health. Cycling for transport appears to very significantly improve health by reducing risk of heart diseases, various cancers, muscular- and skeletal diseases, and overall mortality.
- Eating plenty of fruits and vegetables each day may be prophylactic. It may reduce the risk of heart disease .
- Fluoride therapy and tooth cleaning, either at home or by a professional, are parts of dental prophylaxis or oral prophylaxis.
- Antibiotics are sometimes used prophylactically: For example, during the 2001 anthrax attacks scare in the United States, patients believed to be exposed were given ciprofloxacin. In similar manner, the use of antibiotic ointments on burns and other wounds is prophylactic. Antibiotics are also given prophylactically just before some medical procedures such as pacemaker insertion.
- Tricyclic antidepressants (TCAs) may, with caution, be an example of a chronic migraine preventive (see amitriptyline and migraines' prevention by medicine).
- Antimalarials such as chloroquine and mefloquine are used both in treatment and as prophylaxis by visitors to countries where malaria is endemic to prevent the development of the parasitic Plasmodium, which cause malaria.
- Mechanical measures (such as graduated compression stockings or intermittent pneumatic compression) and drugs (such as low-molecular-weight heparin, unfractionated heparin, and fondaparinux) may be used in immobilized hospital patients at risk of venous thromboembolism.
- Risk reducing or prophylactic mastectomies may be carried out for carriers of the BRCA mutation gene to minimise the risk of developing breast cancer.
- Early and exclusive breastfeeding provides immunological protection against infectious diseases and well as reduced risk of chronic diseases for both mother and child.
- Polypill for prevention of e.g. cardiovascular disease.
- Potassium iodide is used prophylactically to protect the thyroid gland from absorbing inhaled or ingested radioactive iodine, which may lead to the development of thyroid cancer; radioactive iodine may be released into the environment in the event of an accident at a nuclear power plant, or the detonation of a nuclear explosive (see thyroid protection due to nuclear accidents and emergencies).
- Prophylaxis may be administered as oral medication. Oral prophylaxis includes: PEP, nPEP, or PrEP. PEP stands for post-exposure prophylaxis used in an occupational setting e.g., to prevent the spread of HIV or Hepatitis C from patient to staff following an accidental needlestick. nPEP is non-occupational post-exposure prophylaxis. nPEP may be used in a sexual or injection exposure to HIV, hepatitis, or other infectious agents; for example, during intercourse, if the condom breaks and one partner is HIV-positive, nPEP will help to decrease the probability that the HIV-negative partner becomes infected with HIV. (An nPEP is sometimes known as a PEPse - i.e. post-exposure prophylaxis sexual encounter.)  PrEP is a measure taken daily (before, during, and after) possible exposure; for example, by a person who inconsistently uses condoms during sex with a partner who may have an HIV infection.

# Limitations
Since preventive medicine deals with healthy individuals or populations the costs and potential harms from interventions need even more careful examination than in treatment.  For an intervention to be applied widely it generally needs to be affordable and highly cost effective.
For instance, intrauterine devices (IUD) are highly effective and highly cost effective contraceptives, however where universal health care is not available the initial cost may be a barrier.  IUDs work for several years (3 to 7 or more) and cost less over a year or two's time than most other reversible contraceptive methods.  They are also highly cost effective, saving health insurers and the public significant costs in unwanted pregnancies.  Making contraceptives available with no up front cost is one way to increase usage, improving health and saving money.
Preventive solutions may be less profitable and therefore less attractive to makers and marketers of pharmaceuticals and medical devices.  Birth control pills which are taken every day and may take in a thousand dollars over ten years may generate more profits than an IUD, which despite a huge initial markup only generates a few hundred dollars over the same period.

# Leading cause of preventable death

# As a medical specialty
In the United States, preventive medicine is a medical specialty, one of the 24 recognized by the American Board of Medical Specialties (ABMS). It encompasses three areas of specialization:
- General preventive medicine and public health
- Aerospace medicine
- Occupational medicine
In order to become board-certified in one of the preventive medicine areas of specialization, a licensed U.S. physician (M.D. or D.O.) must successfully complete a preventive medicine medical residency program following a one year internship. Following that, the physician must complete a year of practice in that special area and pass the preventive medicine board examination. The residency program is at least two years in length, and includes completion of a post-graduate masters degree in public health (MPH) or equivalent. The board exam takes an entire day: The morning session concentrates on general preventive medicine questions. The afternoon session concentrates on the one of the three areas of specialization that the applicant has studied.
In addition, there are two subspecialty areas of certification:
- Medical toxicology (MT)
- Undersea and hyperbaric medicine (UHB), formerly "undersea medicine"
These certifications require sitting for an examination following successful completion of an MT or UHB fellowship and prior board certification in one of the 24 ABMS-recognized specialties

# Rose's theorem
Rose's Theorem states that "a large number of people at small risk may give rise to more cases of disease than a small number who are at high risk."