begin to deteriorate. Age further carries with it the
specter of lifestyle choices and their health conse-
quences, often compounding health risk. With
increasing age, for example, the body becomes less
efficient in its ability to use INSULIN. This increases
the risk for type 2 diabetes. Physical inactivity and
EATING HABITS may further challenge the body’s
insulin efficiency, as well as contribute to OBESITY,
an independent risk factor for diabetes. In combi-
nation, these circumstances significantly boost the
likelihood of developing diabetes in older age.
Cardiovascular function also becomes less efficient
with age, as blood vessels lose elasticity (often as a
result of ATHEROSCLEROSIS).
Gender Some health conditions, of course,
affect only men (prostate and testicular disorders)
or only women (cervical, ovarian, and uterine dis-
orders as well as PREGNANCY-related conditions).
Other health conditions may predominantly affect
one over the other gender, such as breast cancer.
Popular perception erroneously holds that some
health problems, such as cardiovascular disease
and colorectal cancer, are primarily health risks for
men. Though men are more likely than women to
develop cardiovascular disease earlier in life, car-
diovascular disease is the leading cause of death
and disability among men and women alike. Doc-
tors diagnose more women than men with colo-
rectal cancer each year.
Health history PERSONAL HEALTH HISTORYsignifi-
cantly influences future health circumstances and
often integrates with lifestyle (modifiable risk fac-
tors). Some health conditions are purely of heredi-
tary origin, such as CYSTIC FIBROSIS, HEMOPHILIA,or
congenital heart malformations. Some acquired
conditions may result in residual health effects,
such as chronic OTITISmedia (middle ear INFECTION)
that may have consequential HEARING LOSS. Other
conditions may reflect a genetic predisposition as
well as lifestyle choices, such as DIABETES AND CAR-
DIOVASCULAR DISEASE.
Advances in genetics and molecular medicine
are making it possible to determine whether a per-
son has a hereditary health condition. Though
such knowledge does not change the risk for
developing the condition, it does allow the person
and his or her doctor to establish a plan for man-
aging the condition. Making changes in lifestyle
may delay the condition’s development or further
mitigate its the adverse effects.Modifiable (Mutable) Health Risk Factors
Cigarette smoking, eating habits, and physical
activity are the primary modifiable risk factors for
health. Other health risk factors include occupa-
tion, recreational activities, ALCOHOLuse, substance
abuse, seat belt use, helmet use, and preventive
health measures such as vaccination and safer sex
practices. Modifiable health risk factors may
directly cause disease, such as cigarette smoking,
or contribute to the circumstances that allow
health conditions to develop, as with diabetes.
Cigarette smoking Since the 1950s, research
has linked cigarette smoking with a growing list of
health conditions. There are no known health
benefits of cigarette smoking. The leading health
consequences of smoking are cardiovascular dis-
ease and lung cancer. Smoking also causes or con-
tributes to dozens of other health conditions along
the entire continuum of life: it influences CONCEP-
TION, pregnancy, childhood health (ENVIRONMENTAL
CIGARETTE SMOKE), nutrition, chronic diseases,
numerous cancers, and LIFE EXPECTANCY.
Eating habits The advent of fast food and
processed food in the 1960s forever changed eat-
ing habits in the United States. Three decades later
two thirds of the American population was over-
weight, a significant general health risk. Most fast
foods and processed foods combine low nutri-
tional content and excessive portion sizes.
Fast-food meals often feature “deals” that offer
more food for a small increase in price, giving the
impression of value. Processed foods, such as
quick-prepare meals and snack items, come in
packaging often implies the product is a single
serving when instead the package contains two,
three, or even four servings. When fast foods and
processed foods are the mainstay of a person’s eat-
ing habits, CALORIEconsumption often is two to
four times what it should be.
Fewer than 20 percent of Americans eat the
American Cancer Society’s recommended 9 to 12
daily servings of fruits and vegetables, yet more
than a third exceed the American Heart Associa-
tion’s guideline limiting dietary fat consumption to
30 percent of total calories. Most Americans need28 Preventive Medicine