CLO5

Article 1

Section 1

Source: HCT Libraries page -Discover-Electronic Resources

Search terms: Smoking Cause of Cancer

Section 2

Title: Smoking Cause Specific Lung Cancer—Evidence from Non-Smoking Lung Adenocarcinoma

Abstract

Introduction: Smoking and non-smoking lung cancer have many differences in clinical feature. But those may be the result of interference due to differences in pathological type, as most smoking patients suffer squmous cell lung cancer and non-smoking tend to get adenocarcinoma. This study was conducted on the specific histological type—lung adenocarcinoma—to avoid histological bias and to reveal the true effect of smoking.

Methods: A total of 2222 patients with lung adenocarcinoma confirmed by histological or cytological evidence were enrolled from January 1, 1999 to December 31, 2004. Differences in clinical features and prognosis between non-smoking and smoking patients were analyzed. Chi-square test was used for univariate comparisons. Univariate probability of survival was computed using Kaplan-Meier estimate and compared to using the log-rank test. Cox proportional hazards regression analysis was used to evaluate the risk of death.

Results: There were 777 current smokers (34.96%), 197 former smokers (8.87%) and 1248 non-smoking patients (56.17%). 860 non-smoking patients (68.91%) were female, compared with 6.31% among current smokers and 4.06% among former smokers (p < 0.001). Non-smoking patients had an earlier age at diagnosis (p < 0.001) and a better response to chemotherapy (p < 0.001) compared to current smoking patients. Current smoking correlated with lower cell differentiation (p < 0.001) and worse prognosis (p = 0.0024). After multivariate analysis, smoking was identified as an independent negative prognostic factor (HR, 1.302; 95% CI, 1.011 - 1.6780, p = 0.041). No difference in prognosis was observed according to smoking conditions in smoking patients.

Conclusions: Significant differences exist in clinical features and prognosis between non-smoking and smoking lung adenocarcinoma patients. There is a strong evidence that non-smoking lung adenocarcinoma should be regard as different disease.

Reference

Li, N., Qu, B., Shao, K., Chen, Z., Tan, F., Tan, X., . . . He, J. (2012). Smoking cause specific lung cancer-evidence from non-smoking lung adenocarcinoma. Journal of Cancer Therapy, 3(4), 435-441.

Section 3

Population

This article describes a population of Chinese Academy of Medical Sciences (CAMS). Patients had primary lung adenocarcinoma diagnosed between January 1 1999 and December 31 2004. A total of 2222 patients were enrolled and met study se- lection criteria. 777 patients (34.96%) were current smokers, 1248 patients (56.17%) were never smokers, and 197 patients (8.87%) who quit smoking for at least one year were termed as “former smokers”.

Research Approach

The article used chi-square test was used for univariate comparisons of patients, disease and treatment-related characteristics and Cox proportional hazards regression analysis was used to evaluate the risk of death between current, former and never smoking patients.

Participant selection

Current respective study was conducted in the Cancer hospital, Chinese Academy of Medical Sciences (CAMS). Patients had primary lung adenocarcinoma diagnosed between January 1 1999 and December 31 2004. Patients who were smokers during diagnosis or stop smoking less than 1 year were collected in “current smoker” group. Patients who quit smoking more than one year were classified as “former smoker”. Patients who have a lifetime exposure of less than 100 cigarettes or never smoked in the past were termed as “never smoker”.

Main results

Non-smoking patients had a better response to chemotherapy compared to current smoking patients. Current smoking correlated with lower cell differentiation and worse prognosis. The risk of dying for current smokers remained higher compared with never smokers after adjusting for gender, clinical stage, treatment and family history.

This article, although describes that the chances of treatment and survival for non-smokers are higher than those of smoking patients but the number of non-smoking patients are higher and also there is not much difference between prognosis in smoking and non-smoking patients.

Article 2

Section 1

Source:HCT Libraries page >Discover>Electronic Resources

Search terms: Smoking Hazards

Section 2

Title: 21st-Century Hazards of Smoking and Benefits of Cessation in the United States

Abstract

Background: Extrapolation from studies in the 1980s suggests that smoking causes 25% of deaths among women and men 35 to 69 years of age in the United States. Nationally representative measurements of the current risks of smoking and the benefits of cessation at various ages are unavailable.

Methods: We obtained smoking and smoking-cessation histories from 113,752 women and 88,496 men 25 years of age or older who were interviewed between 1997 and 2004 in the U.S. National Health Interview Survey and related these data to the causes of deaths that occurred by December 31, 2006 (8236 deaths in women and 7479 in men). Hazard ratios for death among current smokers, as compared with those who had never smoked, were adjusted for age, educational level, adiposity, and alcohol consumption.

Results: For participants who were 25 to 79 years of age, the rate of death from any cause among current smokers was about three times that among those who had never smoked (hazard ratio for women, 3.0; 99% confidence interval [CI], 2.7 to 3.3; hazard ratio for men, 2.8; 99% CI, 2.4 to 3.1). Most of the excess mortality among smokers was due to neoplastic, vascular, respiratory, and other diseases that can be caused by smoking. The probability of surviving from 25 to 79 years of age was about twice as great in those who had never smoked as in current smokers (70% vs. 38% among women and 61% vs. 26% among men). Life expectancy was shortened by more than 10 years among the current smokers, as compared with those who had never smoked. Adults who had quit smoking at 25 to 34, 35 to 44, or 45 to 54 years of age gained about 10, 9, and 6 years of life, respectively, as compared with those who continued to smoke.

Conclusions: Smokers lose at least one decade of life expectancy, as compared with those who have never smoked. Cessation before the age of 40 years reduces the risk of death associated with continued smoking by about 90%.

Reference

Jha, P., M.D., Ramasundarahettige, C., M.Sc, Landsman, V., PhD., Rostron, B., PhD., Thun, M., M.D., Anderson, R. N., PhD., . . . Peto, R., F.R.S. (2013). 21st-century hazards of smoking and benefits of cessation in the United States. The New England Journal of Medicine, 368(4), 341-50.

Section 3

Population

The population used in the research were 216,917 adults in the U.S. National Health Interview Survey (NHIS) between 1997 and 2004 that were linked to the National Death Index. One adult (≥18 years of age) is randomly selected from each selected household for a detailed interview on health and other behaviors.

Research Approach

The research approach is qualitative and involved interviews. The survey uses a stratified, multistage sample design that permits representative sampling of households and a detailed interview on health and other behaviors.

Participant selection

The NHIS sample is drawn from each state and the District of Columbia. One adult (≥18 years of age) is randomly selected from each selected household and a detailed interview on health and other behaviors. Mortality among survey participants through the end of 2006 was assessed by means of periodic matching of their records to the National Death Index.

Main results

The author concludes that hazard ratios for deaths from all causes among former smokers, as compared with those who had never smoked, were similar for women and men. The effect of smoking cessation at younger ages was especially favorable. For smokers who quit at 25 to 34 years of age, survival curves were nearly identical to those for participants who had never smoked, meaning that those who quit smoking gained about 10 years of life, as compared with those who continued to smoke. Survival curves were somewhat worse for smokers who had quit at 35 to 44 years of age than for those who had never smoked; still, smokers who quit smoking could expect to gain about 9 years of life, as compared with those who continued to smoke. Thus, cessation at about 39 years of age reduced the excess risk of death from any cause by about 90%.

Article 3

Section 1

Source:HCT Libraries page >Discover>Electronic Resources

Search terms: Smoking Causes

Section 2

Title: Cigarette Smoking Causes Hearing Impairment among Bangladeshi Population

Abstract

Lifestyle including smoking, noise exposure with MP3 player and drinking alcohol are considered as risk factors for affecting hearing synergistically. However, little is known about the association of cigarette smoking with hearing impairment among subjects who carry a lifestyle without using MP3 player and drinking alcohol. We showed here the influence of smoking on hearing among Bangladeshi subjects who maintain a lifestyle devoid of using MP3 player and drinking alcohol. A total of 184 subjects (smokers: 90; non-smokers: 94) were included considering their duration and frequency of smoking for conducting this study. The mean hearing thresholds of non-smoker subjects at 1, 4, 8 and 12 kHz frequencies were 5.63±2.10, 8.56±5.75, 21.06±11.06, 40.79±20.36 decibel (dB), respectively and that of the smokers were 7±3.8, 13.27±8.4, 30.66±12.50 and 56.88±21.58 dB, respectively. The hearing thresholds of the smokers at 4, 8 and 12 kHz frequencies were significantly (p5 years) showed higher level of auditory threshold (62.16±19.87 dB) at 12 kHz frequency compared with that (41.52±19.21 dB) of the subjects smoked for 1-5 years and the difference in auditory thresholds was statistically significant (p<0.0002). In this study, the Brinkman Index (BI) of smokers was from 6 to 440 and the adjusted odds ratio showed a positive correlation between hearing loss and smoking when adjusted for age and body mass index (BMI). In addition, age, but not BMI, also played positive role on hearing impairment at all frequencies. Thus, these findings suggested that cigarette smoking affects hearing level at all the frequencies tested but most significantly at extra higher frequencies.

Reference

Sumit, A. F., Das, A., Sharmin, Z., Ahsan, N., Ohgami, N., Kato, M., & Akhand, A. A. (2015). Cigarette smoking causes hearing impairment among bangladeshi population. PLoS One, 10(3)

Section 3

Population

The population of 184 people surveyed who agreed to participate in audiometric testing. The ages of participants were 18 to 60 years. The participants were excluded who used alcohols, portable music players with earphones or who had a previous history of ear diseases. The respondents were assessed through an audiometric examination which was conducted in a sound-proof room using an iPod with earphone for a measurement of hearing level at 1, 4, 8 and 12 kHz frequencies.

Research Approach

A quantitative approach is used as the outcomes are presented numerically.  The chi-square method and logistic regression analysis were used with hearing level as dependent variable and smoking, age and Body Mass Index (BMI) as independent variables.

Main results

The hearing level is quantified relative to 'normal' hearing in dB, with higher values of dB indicating worse hearing. The average auditory thresholds for smokers were found significantly higher than non-smokers at 8 and 12 kHz frequencies. However, the difference was not found significant (p = 0.06) between smoker and nonsmoker older than 40 years at the extra higher frequency (12 kHz). As hearing loss was more profound for the older age group (nonsmoker: 76.9%, smoker: 92.7%) at that frequency, significant difference probably was not obtained.

The discussion section describes that smoking cigarettes increased the risk of hearing impairment. The average auditory thresholds were slightly increased with increasing smoking amount but the difference in hearing thresholds among the smoker subgroups at all the frequencies tested.

Section 4

Article 1

Ranking: Middle

Article 2

Ranking: Best

Article 3

Ranking: Bottom

In case of the highest ranking article which is article 2.The detailed interview regarding health and behaviors makes it possible understand the maximum information about the hazards of smoking. Smoking is the cause of premature death. It provides a clear picture of life expectancy for smokers and non-smokers. It shows that smokers loses a decade of life by smoking continuously throughout the life. The analysis used age group stratification, gender, race, alcohol consumption, and education level. These classes describes many angles for understanding the smoking behaviors and risks associated with continuous smoking. Most of the hazards associated with smoking were identified as neoplastic, lungs, cardiovascular, or respiratory diseases. It further described that smoking cessation will improve the life expectancy. It also shows that the difference of age gain from quitting smoking at an earlier stage is greater than the gain from a later stage.

There are useful insights about the quitting of smoking for the governments and policy makers as knowing that the quitting of smoking between the ages of 25-35 is better chances of decreasing the risk of fatal diseases caused by smoking. Hence, the focus and efforts of government for urging the smokers to quit smoking should be made extensively during these years. By this way, the life expectancy and better health can be promoted in the society.