Article 19: Lung Cancer Occurrence in Never-Smokers: An Analysis of 13 Cohorts and 22 Cancer Registry Studies

Passive smoking is the inhalation of smoke, called second-hand smoke (SHS) or environmental tobacco smoke (ETS), from cigarette or tobacco smoking of other people. It occurs when cigarette or tobacco smoke saturates any setting, causing its inhalation by people within those surroundings. Scientific proof shows that contact to second-hand tobacco smoke causes illness, disability, and even death.

For a lengthy time, contact to other people’s smoke was not considered a risk to health, but current research has shown that the dangers of passive smoking are grave. It has now been verified that those who inhale other people’s smoke, either exhaled by the smoker or inhaled directly from the burning cigarette, are at risk of all the same diseases as the active smoker. This has strengthened the case for a smoking ban in public places, already enforced in Ireland and now in Wales.

In 2005, it was estimated that exposure to second-hand smoke kills more than 3,000 adult non-smokers from lung cancer, approximately 46,000 from coronary heart disease, and an estimated 430 newborns from sudden infant death syndrome. In addition, second-hand smoke causes other respiratory problems in non-smokers such as coughing, phlegm, and reduced lung function. According to the CDC’s National Health Interview Survey in 2000, more than 80 percent of the respondents aged 18 years or older believe that second-hand smoke is harmful and non-smokers should be protected in their workplaces.

The Study used 13 different cohorts and 22 Cancer Registry studies across the Pacific Rim to evaluate the incidence and mortality rates of occurrence of lung Cancer in non-smokers and current smokers, in races such as African-Americans and Asians residing in Asia, and those European descents. The study also included the age, sex, and race data on lung cancer cases.

A 2004 study by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) concluded that non-smokers are exposed to the same carcinogens as active smokers. But the study said that the molecular profile of lung tumors in non-smokers differs from those of smokers, thus, non-smokers have better responses in therapy and higher chances of surviving.

The study results show that (1) men had higher death from lung cancer than in women in all age and racial groups. (2) Men and women incidence rate were at same level at the standardized age excluding African-American Respondents. (3) African-American and Asians living in Asia have higher death rates than in European descents. (4) There are no trends seen in the comparison of incidence and mortality rates amid US women aged 40-69 years old during 1930’s (contemporary times) where few women smoke. (5) Lung cancer incidence rates were higher and more unpredictable among women in East Asia than in other geographical areas with low female smoking.

The study has limited uncertainties about the accuracy and completeness of data gathered in the cohort and cancer registry studies. The potential errors in the classification of exposure and the availability of data to examine the risk in relation to race of the African-American respondents who have sparse data gave the study a data gap. Missed diagnoses certainly contributed to the low record rates of lung cancer incidences and mortality in Africa which complicated the result of the study to compare the occurrence of lung cancer in non-smokers in all countries who take part in the study.

Moreover, the study merely included age, sex, and race of the respondents which discounted the other known risk factors of lung cancer risks in various settings. These include exposure to other carcinogens, radiations, combustion products, environmental and/or medical settings.



REFERENCE:
1. International Agency for Research on Cancer (2004). "Tobacco Smoke and Involuntary Smoking". Retrieved last June 21, 2009, from http://en.wikipedia.org/wiki/Passive_smoking#Third-hand_smoke
2. U.S. Department of Health and Human Services (2006). The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General—Executive Summary. Retrieved June 21, 2009, from http://www.surgeongeneral.gov/library/secondhandsmoke/report/executivesummary.pdf
3. Jamison, W. (2007) Dangers of Passive Smoking. Retrieved June 21, 2009, from http://ezinearticles.com/?Dangers-of-Passive-Smoking&id=539114

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article 19 . post comments here

Many people are stunned because she was not a smoker and her death came so suddenly. There are still an increasing number of patients who do not have a smoking history, so-called 'never smokers'. While cigarette smoking is an undisputed cause of lung cancer, not all cases of lung cancer occur in smokers or former smokers. Although not every non-smoker suffering from lung cancer will have an identifiable risk factor for development of the disease, a number of conditions and circumstances have been identified that will increase a non-smoker's chance of developing lung cancer.

What are the risk factors for lung cancer?

Gender: Unfortunately, women seem to be more vulnerable to lung cancer. Research has shown that female smokers are more susceptible to the cancer-causing chemicals found in cigarettes. In another study, a gene linked to abnormal lung cancer cell growth was found to be more active in women than in men. It did not matter whether the women smoked or not.

A family history of lung cancer: Evidence suggests that there is a lung cancer gene which predisposes offspring to develop lung cancer. However, the evidence is far from conclusive as the situation is made difficult by the fact that offspring of smokers have been exposed to a smoking environment since childhood and would therefore have a greater risk for developing the disease.

Scarring from previous lung disease : Scarring in lungs caused by tuberculosis or other lung disease can be a risk factor for lung cancer.

Second-hand smoke: Exposure to second-hand smoke has been shown to be a definite risk factor. Your risk increases by 30 percent from daily exposure to second-hand smoke. This is probably the most significant risk factor for lung cancer in non-smokers.

Exposure to radon: Radon is an odorless gas than can seep out of the soil into buildings. Worse yet, the gas can seep from the soil into water near residential communities. Radon has been implicated as a potential cause of lung cancer.

Air pollution: Long-term occupational exposure to diesel exhaust fumes may increase lung cancer risk by 47%. Air pollution in general is a risk factor in the general population.

Past Cancer Treatment: Researchers in Sweden who looked at the medical records of 140,000 breast cancer patients found that there was an increase of lung cancer 5 to 20 years after breast cancer treatment. Suspicion is that radiotherapy in the chest area may have made the lungs more susceptible to the disease.

Estrogen Replacement fuel the growth of non small-cell lung cancer.

What preventative measures can we take?

Diet: An apple a day may keep lung cancer away. A Finnish study suggests that apples not only keep doctors away, but provide protection for the lungs as well. This study found that people who ate the most apples were 58 % less likely to develop lung cancer. Other studies suggest that lung cancer risk is lower among smokers and non smokers who ate at least 5 servings of vegetables and fruits daily.

Beta Carotene: A high intake of beta carotene compounds can lower your lung cancer risk; however, studies also show that the beta carotene is only effective when the compounds are ingested from whole foods such as peaches, melon, carrots, mangoes, dark leafy vegetables, squash etc. The opposite effect seems to take place with beta carotene supplements. A Finnish study reported 18% more lung cancer cases among heavy smokers who took beta carotene supplements. And a National Cancer Study on the effects of vitamin A and beta carotene was halted because smokers taking the supplements had 28% more lung cancer than those taking a placebo.

Selenium and Vitamin C: Taking selenium supplements on a long- term basis has been shown to decrease the incidence of lung cancer. In one study, people taking 55-200 mcg of the mineral daily had a 46% lower rate of lung cancer. As well, studies indicate that people who take less than 90 mg of vitamin C on a daily basis may have a 90% higher risk of lung cancer than those who take 140mg or more.

Avoid second-hand smoke and check your house for radon.

Quote:

There are never guarantees in life, but it makes perfectly good sense to take some preventative measures as these can not only improve your overall quality of health and life but also prevent lung cancer.

REFERENCES:
1.www.medicinenet.com/script/main/art.asp?articlekey=53012
2.cancer.about.com/od/lungcancer/a/nonsmokers.htm

Certainly, a non-smoker’s chance of developing lung cancer would increase through a number of conditions and circumstances.

In the study of the World health organization, I have read and it states that “Involuntary smoking involves exposure to the same numerous carcinogens and toxic substances that are present in tobacco smoke produced by active smoking, which is the principal cause of lung cancer.
More than 50 studies of involuntary smoking and lung cancer risk in never-smokers, have been published during the last 25 years. These studies have been carried out in many countries. Most showed an increased risk, especially for persons with higher exposures.
This evidence is sufficient to conclude that involuntary smoking is a cause of lung cancer in never-smokers. The magnitudes of the observed risks are reasonably consistent with predictions based on studies of active smoking in many populations.

Secondhand smoke is a known carcinogen (a substance that causes cancer). Many research studies show that inhaling secondhand smoke causes lung cancer in adults who do not smoke. Approximately 3,000 nonsmokers die of lung cancer each year.
The Surgeon General estimates that living with a smoker increases the chance of getting lung cancer by up to 30%. And a recent large study showed that the risk of lung cancer is nearly twice as high when the first exposure to secondhand smoke occurs before age 25, compared with later in life. (American Society of Clinical Oncology, 2009)


References:

World Health Organization, International Agency For Research of Cancer,(2004), Tobacco Smoke and Involuntary Smoking, volume 83, Volume 83 - Chapter 5.2: Human carcinogenicity data, http://www.greenfacts.org/en/tobacco/3-tobacco-smoking/6-passive-smoking-cancer.htm#1p0

American Society of Clinical Oncology ( 2009), Second Hand Smoke and Cancer,www.cancer.net.

Passive smoking is the inhalation of smoke from another’s smoking. Studies have consistently shown a significant increased in the relative risk of acquiring lung cancer among those who are exposed to secondhand tobacco smoke, especially spouses of smokers and never smokers at the workplace. The risk of lung cancer for passive smokers goes up the more cigarette smoke they are exposed to. Studies also revealed that the epidemiological and biochemical evidence on exposure to environmental tobacco smoke provides compelling confirmation that breathing other people’s tobacco smoke is a cause of lung cancer. Carcinogens in environmental tobacco smoke are inhaled and pass into the blood. Experimental exposure of non-smokers to tobacco smoke increased the urinary concentration of a tobacco specific carcinogen, and non-smokers exposed to environmental tobacco smoke have raised blood concentrations of tobacco specific carcinogen. Aside from passive smoking, there are other factors that cause lung cancer to non-smokers. These are radon gas, asbestos, viruses, genetic risk and other contact to some chemicals.

I conclude that involuntary smoking is a cause of lung cancer in never-smokers. So I agree that cigarette should be stop to prevent the risk of lung cancer.