Non-modifiable Risk Factors for Lung Cancer
There are a number of non-modifiable risk factors (factors that cannot be controlled) for lung cancer. These risk factors include age, race, and sex (gender).
Age & Lung Cancer Risk
Lung cancer risk increases with age. During aging, the body's internal repair processes slow down and metabolism changes, resulting in a higher risk for cancer development (carcinogenesis). According to the American Cancer Society, the average age of people who have lung cancer is 60 years old. Lung cancer is uncommon in people under the age of 40. Most cases of lung cancer occur in people over 50 years of age.
Some experts suggest that lung cancer develops as the result of the accumulation of several genetic mutations, many of which may be caused by tobacco carcinogens. This collection of genetic mutations is affected by the age-related length of exposure to carcinogens, as well as each person's susceptibility and the intensity and variety of exposure(s).
Race & Lung Cancer Risk
In the United Stats, there are several variations in smoking habits among different races and ethnic groups. For example, more African American men than Caucasian men smoke, but they smoke fewer cigarettes per day on average. African American and Caucasian women have reported similar smoking rates.
Although menthol cigarettes are more widely used among African Americans, African Americans have higher lung cancer rates than Caucasians, even after findings have been adjusted for differences in smoking habits. Differences in socioeconomic backgrounds may account for some of the variations in lung cancer rates among African American and Caucasian populations within the United States (e.g., the highest rate of age-adjusted lung cancer incidence is found in African American citizens of New Orleans, many of whom belong to low socioeconomic groups).
In Japan, recent lung cancer incidence has risen eightfold in women and tenfold in men. Rates of lung cancer in central and eastern Europeans are higher than ever recorded. The causes for these increases are unknown, and it may be that genetic differences are the source of different lung cancer risk among various racial and ethnic groups.
Gender & Lung Cancer Risk
In the United States, the higher incidence of lung cancer in men probably mirrors the higher rate of men who smoke as compared to women who smoke. Historically, men and women in the United States have differed in their cigarette smoking habits—including the frequency of smoking, age when starting to smoke, and patterns and intensity of smoking.
The highest reported female smoking rates occurred in the 1970s, although such figures did not equal smoking rates in men. Some studies have noted sex-specific differences in lung cancer rates even after adjustment for smoking. In addition, incidence of lung cancer in men who do not smoke are higher than in women nonsmokers. Other factors, such as sex-linked genetic susceptibility or sex hormones, may be responsible for some of the gender-related differences in lung cancer risk.