In the developed world, chronic obstructive pulmonary disease is one of the most serious causes of mortality and morbidity. The epidemiology of the disease is examined by European Respiratory Society president Giovanni Viegi.
COPD was the fifth leading cause of death worldwide in 2001, according to the World Health Organization. Because distinct phenotypic entities in epidemiology are sometimes referred to as COPD, prevalence and mortality data do not equally include chronic bronchitis, emphysema, and asthma.

Even though the phatophysiologic mechanisms and cellular patterns of bronchial asthma and COPD are distinct, persistent chronic asthma may develop into an irreversible form of airway obstruction. In that case, asthma must be examined in conjunction with COPD.

A DANGEROUS DISEASE According to the WHO's statistics, COPD was the cause of 2,676,000 deaths in 2001.

Due to the various distributions of tabagism and other risk factors, there are significant variations in COPD mortality rates between nations. Even in Europe, where the disease kills between 200,000 and 300,000 people each year, remarkable differences can be seen.

In Europe, COPD was the cause of death for 4.1% of men and 2.4% of women in 1997, according to the WHO. In addition, female COPD mortality increased in North European nations between 1980 and 1990. In the adult population of the United States, smoking was the cause of just under 65,000 COPD deaths per year between 1995 and 1999. COPD was the cause of roughly half of the 37,782 respiratory deaths in Italy in 2000.

HIGH MORBIDITY In Europe, between 4% and 6% of adults have COPD in a clinically relevant form, but two thirds only have minor ventilatory impairments. Age is associated with a proportional rise in prevalence. The multicenter European Community Respiratory Health Survey (ECRHS), which included 18,000 participants ranging in age from 20 to 44, found a mean prevalence of 2.6% of Chronic Bronchitis Drugs Development Market across all 16 countries.

Due to smoking's decline and the aging of the population, both the individual and social burden of COPD will rise in the coming decades, with women bearing the brunt.
Estimating COPD's actual prevalence in the general population, which can vary significantly depending on the diagnostic tools used, is a major issue. respiratory symptoms as reported by the patient, the diagnosis made by the physician, or the presence of impairments in lung function.

Due to the various criteria that the major international scientific societies use to define bronchial obstruction, variation within a population may be substantial even when COPD diagnosis is based on an objective verification like spirometry.

Clearly, it is necessary to establish a uniform criterion that is accepted by all respiratory medicine societies and validated by epidemiology. Even with the introduction of the GOLD criterion for COPD diagnosis, this goal has not yet been achieved, either in terms of providing information about the prognostic value for patients or applying it to the entire population, regardless of age.

Underdiagnosis of COPD is yet another significant aspect of the epidemiology. Considered surveys indicate that underdiagnosis ranges from 25% to 50% in the scientific literature. About 18% of the people who were studied either had obstructive spirometric findings or were diagnosed with chronic bronchitis, asthma, or emphysema. This suggests that the disease may be more common than expected.

A few researchers have come up with the idea of early diagnosis studies on the basis of their intuition that many people with COPD do not know they have the condition, which delays the start of treatment and allows the disease to progress to more severe stages. A spirometric examination of smokers, for instance, might reveal subjects with obstructive findings.

There are two categories of factors that increase the likelihood of COPD developing: both external and internal. The subject's level of susceptibility to the development of the disease is determined by these factors, either on their own or together.

EXOGENEOUS RISK FACTORS Tobacco use, occupational exposure, indoor and outdoor pollution, socioeconomic status, and diet are examples of exogenous risk factors.

SMOKING TOBACCO Tobacco use is without a doubt the most significant risk factor for COPD development and death. Smoking was responsible for the deaths of 4.83 million people in the year 2000, or 12% of all adult deaths. Men account for 88.5 percent of COPD deaths in industrialized nations, while women account for 61.5 percent.

In point of fact, a fifty-year follow-up study conducted by British physicians revealed that, on average, ten years earlier than nonsmokers, approximately two thirds of smokers die from smoke-related causes. Additionally, current smokers have a COPD mortality rate that is 12.7 times higher than that of nonsmokers. These rates rise in direct proportion to the average number of cigarettes smoked per day.
The starting age, average number of cigarettes smoked per day, and number of years smoked each play a different role in the genesis of the pulmonary damage. Recent epidemiological studies indicate that COPD signs and symptoms are present in 40%–50% of smokers, despite the fact that the disease affects only 10%–20% of those who smoke.

Work-related exposure to pollutants may contribute to the development of COPD over time. The metallurgical, mining, building, agricultural, textile, chemical, paper, and food industries all have workers who are particularly vulnerable to this risk.

Work-related exposure has been linked to a faster decline in lung function and a higher prevalence of respiratory symptoms and/or chronic diseases. Workplace exposure and smoking tobacco appear to work together.

According to recent studies, the population attributable risk of chronic bronchitis and COPD-related lung function impairments is approximately 15% and 18%, respectively, of the total.

Fossil fuel smoke, sulfur dioxide (SO2), nitrogen oxides (NOx), and ozone (O3) are typical outdoor pollutants. It appears that chronic bronchitis and impairments in lung function are correlated with prolonged exposure to high levels of air pollution.

The scientific community has shown a great deal of interest in the study of the effects of suspended particulates with aerodynamic diameters of 10 m (PM10) or 2.5 m (PM2.5) on cardio-respiratory-related deaths.

According to the findings of a recent epidemiological survey, an increase of 6% in mortality risk is associated with an increase in suspended particulates of 10 g/m3.

POLLUTION INDOORS In the developed world, people spend the majority of their time inside buildings, which means they are constantly exposed to the extremely harmful effects of pollutants inside buildings. Environmental Tobacco Smoke (ETS), Particulate Matter (PM), and biomass combustion are the indoor pollutants most closely associated with the risk of COPD development.
Children's FEV1 physiological growth rate has been shown to decrease as a result of ETS exposure in research. COPD may develop in adulthood as a result of inadequate respiratory system maturation during childhood. Adult exposure to ETS has been clearly linked in European studies to the diagnosis of COPD or chronic bronchitis.

Both in children and adults, an increased incidence of respiratory symptoms and impairments in lung function have been linked to increases in PM concentrations, primarily as a result of inhaling tobacco smoke and combustion processes.
SOCIO-ECONOMIC CONDITION This term includes indicators like income, household life, occupation, and education. Numerous epidemiological studies have demonstrated a link between COPD risk and socioeconomic status.

DIET A great deal of research focuses on the role that eating habits play as a risk factor. Antioxidants appear to, in general, have preventative properties linked to reducing aging-related physiological deterioration. A number of epidemiological studies have demonstrated a link between regular consumption of fruits and vegetables and a lower risk of developing COPD.

Studies have looked into whether flavonoids, micronutrients like magnesium and selenium, omega-3 fatty acids, and moderate alcohol consumption can protect the respiratory system. Lung function decline and a higher prevalence of COPD have been linked to excessive drinking.

ENDOGENEOUS RISK FACTORS Gender, genetics, childhood respiratory issues, and family history are all endogenous risk factors.

GENETIC FACTORS It is common knowledge that a serum protease linked to an increased risk of inhibitor deficit-1-antitrypsin panacinar type pulmonary emphysema in young subjects with a genetic recessive trait (ZZ) whose phenotypic expression is influenced by smoking can be induced by Mendelian transmission. Even the Z allele heterozygosity condition is considered a risk factor for COPD development on its own.

COPD AND GENDER In many parts of the world, men are more likely than women to have COPD. This is usually due to fewer people smoking tobacco and fewer people working around toxic substances. In fact, as reported, for instance, in the United States, the recent rise in women's smoking has coincided with a rise in COPD prevalence.

CHILDHOOD RESPIRATORY PROBLEMS Numerous epidemiological studies have demonstrated that the development of COPD is independently influenced by respiratory conditions that affect children.
FAMILY HISTORY Impairments in lung function have traditionally been linked to family history. This aggregation, which sometimes occurs without smoking, may indicate a genetic predisposition to disease development, which requires additional research.

COPD COSTS Direct costs include pharmacological treatment, hospital admissions, outpatient visits, and domestic assistance. The disease's disabling effects, which result in lost workdays, account for the majority of indirect costs.

In 2000, it was estimated that COPD would cost $30.4 billion in the United States. The annual cost of COPD in the European Union is approximately €38.8 billion.

The burden of COPD in developed nations appears to be substantial and will undoubtedly rise in the coming years. Public health specialists, pneumologists, and primary care physicians need to work harder to improve the quality of preventive medical services given the worldwide high prevalence of smokers under the age of 45.