There are so many Public Health ventures (for lack of a better term) in this world that we take for granted, especially here in our coddled milieu of the United States. Memories from my childhood detail very few instances of worry for my health and safety within my community. Yet, passively inhaling second-hand smoke has always piqued my aggravations. My educational conditioning opened my eyes to smoking’s potentially adverse health effects, half scaring me into a disgust of cigarettes and tobacco. Over time, Public Health measures, an amalgam of media, public policy, education, and resource allocation, has influenced the United States’ dependency on tobacco products, significantly reducing our exposure to passive and even direct smoke.
These same initiatives, though, have not been adopted by other countries in our world. Smoking has become an inherent part of many cultures; however, studies have consistently indicated that even non-smokers exposed to smoke have a higher risk for developing lung cancer. Takeshi Hirayama’s study – “Non-Smoking Wives of Heavy Smokers Have a Higher Risk of Lung Cancer: A Study From Japan” – followed 91,540 non-smoking Japanese wives between 1966 and 1979, monitoring their elevating risks for contracting lung cancer in correlation to the smoking habits of their husbands. Each individual over forty years of age was interviewed to find cigarette smoking practices (heavy smokers versus light smokers), alcohol consumption rates, occupations, and marital statuses over the course of the fourteen years. The study discerned a total of 346 deaths due to lung cancer, of which 174 were married women who didn’t smoke.
The results were conclusive: the dose-response relationship confirmed a relationship between the level of smoking and risk for lung cancer in the wives exposed – the greater the exposure (heavy smoke exposure), the greater the risk for developing lung cancer. The study even observed different classes and cultures within Japan, notably the urban versus rural populations. A greater risk for development of lung cancer in non-smoking wives within rural populations was evident, probably attributable to the increased hours of exposure to second-hand smoke in rural society. For all populations, though, the risk of lung cancer increases, not the incidence because cancer is randomly activated.
This cohort study was observational and in many ways advantageous because of the reduction of recall bias and the large groups of populations that could be followed. The variance allowed for an increased collection of data within several groups, which could finally be compared and assessed. Essentially, Hirayama’s study cites passive smoking as correlated to the increased risk of lung cancer.
Passive smoking, whether in Japan or another country, is an environmental health issue because of this very fact. Cigarettes and other tobacco smoke-based products, which directly affect the smoker, are inadvertently released into the air, a shared “commons,” if you will. The carcinogens burned in a cigarette are agents carried through the vector of air attach to particles, all of which we inhale. Consequently, even if we make the purposeful and personal decision to not to smoke, we can still be exposed to the toxic chemicals carried in a cigarette. This renders second-hand smoke as a compromiser of the community’s environment, and subsequently our health. As proven by Hirayama’s study, our exposure to even passive smoking can substantially increase our risk of developing lung cancer.
Even though evidence is there for the increased risk of development of lung cancer, smoking cannot cause lung cancer; it can only make us more susceptible to developing it. Correlations in this study and in others have shown that the risk for development of cancer and the continued exposure to second hand smoke might actually be a cause of lung cancer. This is supported by the small fraction of lung cancers attributed to chance. Cancer is random, though. Yet, reducing any risk of contracting it is a Public Health initiative that must be taken.
Smoking not only affects the health of an individual, but also the health of the community. And even if it may be my personal bias that interferes with my objective thoughts, direct smoke and passive smoke alike will continue to be environmental health issues until Public Health measures are accepted globally.
Good post Kavya. I noticed a number of problems with your usage of terms and some of your assertions. For example, you cannot really "contract" cancer. You used the phraze "develop cancer" later, which is much more appropriate. More importantly, please be careful when you use technical jargon, such as "variance" or "correlation". The epidemiological and statistical meanings of these are quite specifically and precisely defined and are somewhat different than in lay usage. For example, in this study you described there was a clear association between second-hand smoke and lung CA, not merely a correlation. A correlation is when one thing changes when another thing changes. There is no requirement for one thing to come first before another may happen, etc. Association denotes a much stronger relationship and one that is related in time between 2 variables or a variable and an outcome. Finally, I think you have misunderstood the relationship of a risk factor as a cause of disease, cancer in particular. Smoking certainly causes cancer in a sense that by smoking you increase your risk for lung cancer and this study is yet another that adds to that evidence. The random nature (random model) of cancer as an outcome points to the fact that there is no "safe" dose and that any exposure will increase you RISK of cancer and the dose-response relationship is usually linear, whereas in a deterministic model (non-cancer outcomes, such as infection, heart disease, etc) there is a safe dose of exposure, where you will not develop an outcome, but past a certain dose you will observe an increase in incidence of the outcome as a function of dose (dose-response relationship). I suggest you read up on these important concepts. Otherwise, a very good job.
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