A centuries-old discipline, epidemiology has generated an array of concepts that can help researchers with understanding a health issue at hand. Today, modern epidemiology hinges on two basic assumptions (Bhopal, 2016). Firstly, the occurrence of the disease is not random, as there are factors, commonly classified into the host, agent, and environmental, that predispose individuals to contract infections or develop conditions (Bhopal, 2016). Secondly, it is the study of populations that can pinpoint the risk factors and causes as well as introduce preventive solutions. Doing the latter requires an adequate understanding of epidemiological concepts, such as occurrence, morbidity, mortality, and others.
The analysis of morbidity and mortality due to acute and chronic conditions makes up the basis of epidemiological studies (Bhopal, 2016). Morbidity refers to the signs and symptoms of the illness as well as the impairments that it causes; mortality is death caused by a specific condition. Crude mortality and morbidity rates rely on the absolute number of disease cases while specific rates control the numbers by factors, such as age, gender, race, and others. Lastly, adjusted rates are useful for drawing comparisons between populations displaying different characteristics.
Similarly, disease occurrence, or how often a disease occurs in a population, can be measured in a variety of ways (Bhopal, 2016). Incidence rates calculate the occurrence of disease cases in a given population within a specific timeframe. This measure is important for evaluating the effectiveness of interventions, such as disease prevention programs. In contrast, prevalence rates refer to the number of cases at a given point in time and provide an insight into the existing burden of disease.
The frequency of disease occurrence within a given population can be classified as endemic, epidemic, or pandemic (Bhopal, 2016). Endemic occurrence refers to the usual manifestation of a certain condition. For instance, one may assume that occurrence is endemic if a small, stable percentage of people contract a disease each year. However, if the numbers dramatically rise and affect larger portions of populations, the disease might have reached an epidemic stage. Later, global populations may find themselves suffering from or at a high risk of developing a condition, which may indicate an ongoing pandemic.
With the exclusion of skin cancer, lung cancer is the second most common type of cancer for both sexes in the United States. The most common cancer types for the two groups are gender-specific: prostate and breast cancer for men and women, respectively. As per the materials provided by the Center for Disease Control and Prevention (2020), lung and bronchus cancer do not have symptoms that would allow for instantly making a differential diagnosis. Conversely, different patients have different symptoms, and in some cases, if lung and bronchus cancer metastasized, signs specific to that part of the body are not uncommon. Frequently, lung and bronchus manifest themselves through unending coughing, chest pain, wheezing, tiredness, unexplainable weight loss, and coughing up blood (Center for Disease Control and Prevention, 2020). Many lung cancer patients have repeated episodes of pneumonia and swollen lymph nodes in the middle part of the chest area.
According to the American Cancer Society, the crude morbidity rate for lung cancer is 2020 in 228,820 new cases, whereas the crude mortality rate is 135,720 (Siegel, Miller & Jemal, 2020). As for specific rates, lung cancer occurred more frequently in males than females: 116,300 vs 112,520 cases respectively. The same goes for lung cancer mortality: in 2020, more men (72,500) than women (63,220) died from the condition (Siegel et al., 2020). When adjusting for age, the death rate for lung cancer is higher for males than for females: 46.7 vs 31.9 per 100,000 persons (American Lung Association, 2020). The American Cancer Society reports that lung and bronchus cancer predominantly affects older people, as only a small fraction of the patients are under 45 years old. Most lung and bronchus cancer patients are over 65; the average age of diagnosis is 70 (American Cancer Society, 2020). These statistics are pertinent to the prevalence rates as they reflect the state of the lung cancer burden as of 2020.
While lung and bronchus cancer remains the leading cause of death, on a larger scale, both the morbidity and the mortality rates are declining. In 1999, 189,471 cases of lung and bronchus cancer were reported; by 2017, the number had reached 221,222 morbidity cases (Centers for Disease Control and Prevention, 2017). Even though there is an increase in absolute (crude) numbers, it is only the adjusted rates that can reveal the truth. The morbidity rate in 1999 was 70.6 per 100,000 people, while in 2017, it was down to 55.2 per 100,000 (Centers for Disease Control and Prevention, 2017). The decline may be explained by the decreasing prevalence of smoking as well as the introduction of comprehensive control measures, such as early detection and treatment.
American Cancer Society. (2020). Key statistics for lung cancer. Web.
American Lung Association. (2020). Lung cancer fact sheet. Web.
Bhopal, R. S. (2016). Concepts of epidemiology: Integrating the ideas, theories, principles, and methods of epidemiology. Oxford University Press.
Centers for Disease Control and Prevention. (2017). Changes over time: lung and bronchus. Web.
Center for Disease Control and Prevention. (2020). What are the symptoms of lung cancer? Web.
Siegel, R.L., Miller, K.D., & Jamel, A. (2020). Cancer statistics, 2020. CA: A Cancer Journal for Clinicians, 70, 7–30. Web.