Risk Factors and Preventive Measures
Occupational exposure is the risk factor for silico-
sis. Appropriate personal protective equipment in
combination with work-site dust management
methods has the potential to prevent nearly all
cases of silicosis. New cases of silicosis have
steadily declined in the United States since the
implementation of OSHA regulations limiting
exposure, a trend health experts expect to con-
tinue. Researchers believe the silica dust interferes
with the IMMUNE SYSTEM’s ability to protect against
certain kinds of infection, notably tuberculosis.
Health experts recommend annual tuberculosis
testing for everyone diagnosed with silicosis.
OCCUPATIONS AT RISK FOR SILICOSISabrasive blasting agricultural plowing
ceramics foundry core room
foundry shakeout glass etching
glass manufacturing jack hammering
masonry work mineral mining
pottery quarry work
road construction rock blasting
rock drilling rock tunneling
sandblasting soap and detergent
stone chipping and crushing manufacturing
stone cutting stone grinding
See also ANTHRACOSIS; ASBESTOSIS; BERYLLIOSIS;
BYSSINOSIS; PNEUMOCONIOSIS.
smoking and pulmonary disease Cigarette
smoking is the leading cause of health conditions
affecting the LUNGSand accounts for 90 percent of
LUNG CANCERin the United States. Cigarette smok-
ing is also the leading cause of many forms of CAR-
DIOVASCULAR DISEASE(CVD), including HYPERTENSION,
ATHEROSCLEROSIS, ISCHEMIC HEART DISEASE (IHD),
CORONARY ARTERY DISEASE(CAD), andPERIPHERAL VAS-
CULAR DISEASE (PVD). Though the correlation
between cigarette smoking and lung cancer has
been known since the 1940s and widely publi-
cized since the 1964 landmark report Smoking and
Health: Report of the Advisory Committee to the Surgeon
General of the Public Health Service, nearly 49 million
Americans currently smoke. About one in six has
at least one significant health condition that is a
direct consequence of smoking. The longer a per-
son smokes, the higher the risk for developing a
smoking-related health condition.Smoking and Pulmonary Function
The first few puffs of every cigarette paralyze the
cilia, the hairlike structures that line the airways
and sweep mucus from the lungs. NICOTINEfrom
the smoke immediately passes across the alveolar
membrane into the BLOOD, entering the circulation
within seconds. A potent central NERVOUS SYSTEM
STIMULANT and vasoconstrictor, nicotine causes
smooth MUSCLEfibers to contract, contributing to
cerebrovascular and cardiovascular disease such as
STROKEand HEART ATTACK. Nicotine remains active
in the circulation for about 20 minutes after the
last puff from the cigarette, keeping the airways
constricted.
One of the most hazardous chemicals in ciga-
rette smoke is carbon monoxide, which binds
more strongly with HEMOGLOBIN than oxygen.
Hemoglobin molecules will not release carbon
monoxide to bind with oxygen, thus carbon
monoxide blocks oxygen diffusion into the blood.
Carbon monoxide levels in the blood can reach
5 to 7 percent with smoking a single cigarette,
dropping OXYGEN SATURATIONto near 90 percent.
The other byproducts of combustion from ciga-
rette smoke can result in direct toxicity to the
lungs.Smoking and Obstructive Lung Diseases
Tar and smoke particulates that enter the airways
and lungs with each cigarette cause irritation and
INFLAMMATION. Over time SCARtissue replaces lung
tissue as the body attempts to repair itself from
repeated damage and protect itself from further
damage. This scar tissue gradually destroys the
alveoli and bronchioles, the lung’s smallest
structures, and eventually becomes pervasive
within the lungs. The consequence is CHRONIC
OBSTRUCTIVE PULMONARY DISEASE (COPD), which
accounts for more than 70 percent of pulmonary
disease related to smoking. COPD is the leading
reason for LUNG TRANSPLANTATION in the United
States and is also the leading form of noncancer
lung disease. Once the damage of COPD occurs, it
is permanent.230 The Pulmonary System