1.
The study was conducted by following the rate of
mortality due to lung cancer in 91,540 Japanese women above 40, who did not
smoke themselves, but had heavily smoking husbands. The study analyzed data
from 29 health center districts in Japan during a span of 14 years, from 1966 –
1979. In order to gather data, almost the entire census population was
interviewed. The population’s risk-factor records, residence lists, and death
certificates were followed as well. The main result of the study was that the
wives of heavy smokers displayed a much higher rate of mortality from lung
cancer. Lung cancer rates also showed a correlation with both age and the
husband’s line of work, with the highest risk being associated with agriculture
with husbands of age 40-59. Additionally, the greater the dose of cigarettes
smoked daily by the husbands, the greater amount of lung cancer seen in their
non-smoking wives. Although smoking does affect the lung cancer prevalence in
their wives, it appeared as though no other types of cancer were brought on by
this exposure to passive smoke.
2.
I think that it is extremely important to notice
that it is not only those who are directly taking part in cigarette smoking
that are suffering from disease and mortality as a result. Just being around a
smoker, as in the case of non-smoking wives of heavy smokers, has resulted in a
greatly increased risk of dying from lung cancer. Thus, cigarette smoking has
far greater and more detrimental consequences than to just the direct partaker.
Anyone who is even in a close distance of a smoker on a regular basis can
develop fatal cancers, which could mean that one person’s decision could affect
his or her entire family. Additionally, I found it interesting that the wives
of husbands who were involved in agriculture were most affected. I would think
that those in more city areas, where people are more congested and there is
more smoke to be subject to, rather than rural areas where there are less
people and more open spaces, would cause the wives to be more heavily affected.
But, as raised by the study itself as a possible reason, couples may spend more
time together in a rural area and thus could be around the smoking more, which
I would have never thought of.
3.
There are a few advantages of using this type of
study design. Firstly, the data analyzed in this study was collected using
government-based records. By using actual records, such as death certificates,
rather than phone surveys for example, the numbers are very accurate, since
people cannot possibly lie or alter the data. Additionally, the study collected
data for 91-99% of the census population, which is a huge amount of data
points. With this amount of data collected, and with it being from the majority
of the population in a wide area, the study is much more accurate.
4.
I believe that the results of this study support
secondhand smoke as a cause of long cancer. The results are accurate because
the study was conducted using a very large sample, with 91-99% of the census
population of Japan being included. Thus, the results are very representative
of the general population and precise as well. In addition, the data displayed
a correlation between exposure and disease, with the wives exposed to passive
smoking as having a much higher chance of developing lung cancer over wives who
were not exposed. Also, as the amount of exposure increased, as in the dose of
cigarettes the husbands smoke daily, the likelihood of getting lung cancer
increased as well. With all these correlations in place, it is very clear that
passive smoking surely increases the rate mortality due to lung cancer.
Your summary was good but I think it's important to note in the beginning that wives of non-smokers were also included in the study as comparison models to wives of former smokers and wives of heavy smokers. You do imply this later in the paragraph but it'd be good to explicitly state it. I agree with your explanation of how one smoker does not just harm himself but also his immediate family. I would also add that a smoker also harms the public if he/she is allowed to smoke outside the home in public areas. Regarding the advantages of the study used, your points are all valid but I would also add that the long period of time during which the study was conducted also contributes to its accuracy. Though the study does prove a high correlation between living with smokers and increased risk of lung cancer, correlation does not necessarily mean causation.
ReplyDeleteI really liked that you pointed out that smoking affects others, as the study found. That was mainly one of the things that jumped out at me as well. I found interesting that you brought up the agricultural lifestyle that was talked about in the study; I did not think much of this but my initial opinion was also that it is odd for rural livers to be more affected than "city-folk." I, too, agreed with the conclusion that you reached.
ReplyDeleteYou also did a good job in explaining why the support was accurate, but also remember that an important factor was that there was a control in comparing these wives with smoker husbands to wives with non-smoker husbands. This added more significance to the data.
Alyssa,
ReplyDeleteExcellent summary of the article. In your answer to question 2, you mention the importance of transferred risk of lung disease from one person's behavior to another person who may not engage in this behavior. This is a good point - I wonder if we can consider other cases like this in public health? (there are many...spread of STD's, etc etc.)
For question 3, to which study design do you refer? This study is prospective in nature, and you're right about following a LOT of people. One of the most important points about this is it follows folks for a long time. Because of this, it could get pretty expensive. A case-control study might be a cheaper, more focused way of doing this study, but as you point out, would not have been so broad a study.
Question 4 challenges you to consider what determines causality. So, this is really getting at Hill's criteria, which is in your text book. Recall that these criteria include strength of association, consistency, specificity, temporality, etc., and all of these can be considered when deciding if the relationship between 2nd hand smoking and lung cancer is causal.
Erin