Hey everyone!
I’m back again and this week I’m going to be talking a little bit about second-hand smoke and it’s implications. Everyone in our class was required to read about a study done in Japan that helped to determine the relationship between second-hand smoke and lung cancer. It took place over 14 years and was conducted in 29 health center districts in Japan. 91,450 non-smoking wives aged 40 years and older were followed up between 1966 and 1979 and their mortality rates due to lung cancer were measured in relation to the smoking habits of their husbands. It was found that wives of heavy smokers were found to have a higher risk of developing lung cancer. The husbands’ smoking habits did not affect the wives’ risk of dying from other cancers such as stomach or cervical. There was also evidence that the risk of developing emphysema and asthma is increased in non-smoking wives of heavy smokers but the statistics were not significant enough. This study also compared the effect of passive smoking to direct smoking and found that passive smoking had an effect of one half to one third that of direct smoking.
The type of study is called a cohort study. In a cohort study, large numbers of people are questioned about their lifestyle and various exposures. They are then followed over a period of time to see weather those exposed are more likely to develop a certain disease or diseases. There are many advantages to these types of studies. Some of these include the fact that you have an opportunity to study many possible outcomes from one specific exposure. Another advantage is that both the incidence rate (absolute risk) and the relative risk can be calculated. Also, in this specific study, detailed questions about lifestyle were asked of the husbands and wives independently rather than together. This allowed for no subjective bias to be formed.
Second-hand smoke is definitely an environmental health issue rather than behavioral. In class on Monday, our lecturer, Dr. Jonathan Links, addressed this very issue. He talked about the difference between direct smoking and second hand smoke. Direct smoking would require a behavioral intervention. But, in order for cigarette smoke in the air to be regulated, an environmental intervention would be needed to stop people from having to breathe in other people’s smoke. From a personal standpoint, it definitely affects me and bothers me when I have to stand next to people who are smoking. The smell can sometimes make me feel extremely nauseous and I’ll often have to move.
I think that the results of this study definitely support the idea that second-hand smoke can be and is a cause of lung cancer. There is a huge amount of evidence showing the relation ship between the two. It was clearly proven in the statistics that the wives of heavy smokers had a higher mortality rate from lung cancer compared to the wives of non-smokers.
I found this week’s assignment to be really interesting and I hope you did too! Until next week!
Excellent discussion. The article divulged the dangers of second-hand smoke utilizing a prospective cohort study (identifying an exposure--exposure to cigarette smoke--and then following the participants to see who develops a disease--in this case lung cancer). One advantage to this study was the ability to calculate the risk directly. I agree that second-hand smoke is an environmental issue given the proven health hazards. Association (aka correlation) and causation do not always imply each other but in this study the implication was supported with a dose-response relationship between exposure and cancer, temporal relationship between exposure to smoke and cancer, and lack of specificity to other cancers.
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