Smoking, Diet and Cancer Death - Essay Example

Cancer epidemiology - smoking and dietary factors on cumulative incidence of death Background: Little is known about smoking habits and effect of dietary factors on cancer death. Methods: A total of 5870 adults in Italy enrolled in the EPIC-Turin cohort study were followed for smoking status and dietary factors in relation to cancer-related deaths. T-test and Chi-square test were used to compare the group difference while binary logistic regression models were used to calculate adjusted odd ratios and 95% confidence intervals (CIs) for smoking habits on cancer-related death and also the effect of dietary factors on cancer-related death. Results: The odds of dying for women that never smoked was estimated at 0.36 times (95% CI = 0.16 - 0.80, p = 0.013) as likely in cancer-related death than women who were either former smokers or still smoking. Current smoking habit is particularly harmful to men, as the estimated odds ratio was 2.1 times (95% CI = 1.28 - 3.48, p = 0.004) as likely in cancer-related deaths than men who either never smoked or former smokers. For women with former smoking habits, the estimated odds of dying was 2.56 times larger (95% CI = 1.15 - 5.72, p = 0.022) than their counterparts who never smoked. The odds of dying for daily vegetable consumption in women who were former smokers was 2.81 times (95% CI = 1.15 - 6.31, p = 0.021)higher and the odds of dying for total consumption of fruit and vegetables over 400g daily in women were former smokers was 2.80 times higher (95% CI =1.24 - 6.30, P = 0.013). Conclusions: The association between smoking habits and cancer-related death is confirmed but it varies on smoking status related to gender. The fruits and vegetable consumption habits have small-scale protective effect on cancer-related death. Further study can explore on single gender group with smoking determinants like intensity and daily quantity. Introduction With estimated 8.2 million cases of deaths and 14 million new cases reported in 2012, cancer remains as one of the most widespread chronic illnesses in the world (The International Agency for Research on Cancer (IARC, 2012). Lung cancer, followed by liver cancer, stomach caner, bowel cancer and breast cancer were the five leading causes of cancer deaths worldwide. Europe was one of the continents that reported the highest cancer mortality in 2012, in which men died more in lung cancer, followed by bowel cancer, prostate cancer and stomach cancer, while women were more prone to breast cancer, bowel cancer, and lung cancer, pancreas cancer and stomach cancer (IARC, 2012). As such, cancer prevention measures should be prioritized. For the common causes of cancer, more than 30% of the cases are attributable to lifestyle factors which are also considered as preventable risk factors, such as tobacco smoking, high BMI, unhealthy diet (especially low fruit and vegetable intake), physical inactivity and heavy alcohol consumption (World Health Organization, 2015). To modify the risk of cancer development and reduce cancer mortality, it is vital to improve on the preventable risk factors especially the ones that are most prevalent among the population and more influenced by daily lifestyle such as tobacco smoking and dietary factors. Tobacco smoking Tobacco smoking is the most worldwide recognized risk factor in cancer epidemiology (WHO, 2015). It is associated with 16 types of cancers. For example, lung cancer,cervix cancer, kidney cancer, bladder cancer, and responsible for about 20% of global cancer deaths and 70% of global lung cancer deaths. Smoking habits which can be defined by smoking status, smoking duration or smoking intensity,is critical to measure cancer risks. Studies show that people who never smoked tend to have a longer life expectancy than current smokers; people who quit smoking earlier are alsoable to gain extra years of life expectancy than current smokers (WHO, 2015). For cancer risk assessment, the number of cigarettes smoked per day could help estimate the risk of lung cancer; the incidence of renal pelvis cancer in current smokers is more than threefold times higher than former smokers; pancreatic cancer was also more likely to report in current smokers than former smokers and people who never smoked. The risk of bladder cancer was still significantly lower in the first 4 years when people decided to give up smoking. For female-dominated cancers, a recent cohort study revealed that the risk between smoking and risk of invasive breast cancer in postmenopausal women was found much higher in current smokers than former smokers (Petrucelli, Daly & Feldman, 2009). Gender difference in smoking is gradually changing especially with regards to smoking ratio between boys and girls. Compared with men who smoke nearly 5 times more than women, the 2006 Global Youth Tobacco Survey found that boys aged between 13 and 15 years old smoked only 2 to 3 times more than girls (WHO, 2009). In some of the European countries, the prevalence of female smoking over 15 years old has a significant proportion in adult population with 47% female smoking rate in Austria, 34% in Greece and 32% in France. The rise of smoking among women are said to be caused by social factors such as increasing attainment of economic resources and education skills, and change in cigarette campaign promoting women’s emancipation. Overall, it can be noted that a combined effect of smoking and other preventable risk factors could have a multiplicative effect on cancer risk and cancer mortality. For example, people with heavy smoking and drinking habits are found to have higher risk of developing pharyngeal and oral cancer than people without both of the habits. In othersstudies, cancer risks are found to be associated with obesity and smoking. The same combined effect could occur between smoking and unhealthy diet, although the effect of dietary factors itself on cancer risk is still far from conclusive. For instance, there are evidences continually suggesting that fruit and vegetable intake could reduce the cancer risk but this was found not to be convinced by the WCRF/AICR second expert report in 2007. Dietary factors Dietary factor is another important risk factor in cancer prevention beside tobacco smoking. Growing evidences suggest that a healthy diet such as high fibre food intake is found to be associated with reduction of cancer risks. A healthy diet guideline is currently recommended by World Health Organisation in which an adult should intake at least 400g of fruit and vegetables daily to induce the protective effect against malnutrition and noncommunicable diseases such as cancers. Other kinds of food such as red meat and processed meat are found to be associated with increased risk of cancers of the stomach, colon and rectum. The challenge in dietary factors remains in determining the right combination of diets to induce health protective effect. Moreover, the protective effect induced by dietary factors may vary across gender and the types of cancers. For example, fruits and vegetables intake have shown strong protective effect on cancers related to mouth, pharynx and larynx, oesophagus stomach, lung,but little effect was found on cancers related to nasopharynx, lung, colorectum, ovary, endometrium, pancreas and liver. Several Japanese studies have reported a significant association between salt intake and rate of gastric cancerin men only but a Hawaii cohort study found that such association was only linked to women. In addition, residual cofounding may have been involved with the plausible finding among the dietary factors.For instance,high intake of fibre foods is often reported of a protective effect in reducing the risk of colorectal cancer, but fibre intakes are also highly associated with existing healthy behaviours. Aim of the study The aim of this study was to investigate two main risk factors to cancers among a group of 5872 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC). In the light of the finding, the study will explore the impact of smoking habits on cumulative incidence of death and identify dietary variables that protect against cumulative incidences of death. Methodology Data source This analysis was based on data from a subset of European Prospective Investigation into Cancer and Nutrition (EPIC) cohort project completed in Turin, Italy. The aim of the EPIC project was to determine the relationships between lifestyle factors and health factors, especially cancers. For EPIC-Turin project, it was one of 23 EPIC study centres which recruited a total of 10,604 men and women living in the city of Turin. The project started in 1993 and ended in 1998; the follow-up period was begun in 1998 and completed in 2006.One of the main objectives of EPIC-Turin project was to determine the impact of tobacco smoking and dietary factors in relation to cancers. The data set comprised total of 5872 participants, some of whom were blood donors and healthy volunteers. Although the recruitment method for EPIC-Turin project was not provided in the original assignment, the process was expected to involve with blood donation services, local cancer registry and local health authority. In the review of the EPIC project, various recruitment methods were said to target local population. This included postal recruitment, telephone recruitment and personal contact recruitment. It was assumed that the same recruitment method was adopted in the project of EPIC-Turin. The general study design of EPIC project consisted of two repeat measurements obtained through diet questionnaires. These were collected at the start and end of a one-year period. Data scheme The dataset contains both numeric and categorical variables. The numeric variables include ages, BMI, and mean daily consumption of vegetables, legumes, fruits, and meat (measured in grams). The categorical variables include the highest levels of education attained (described as 1 = none or primary school, 2 = technical or professional school, 3 = secondary school, 4 = university), smoking status (described as 1 = never smoker, 2 = former smoker, 3 = current smoker, 4 = unknown), the genders of participants (described as 1 = male, 2 = female), and the died (described as 0 = alive, 1 = died). For the purposes of identifying how certain ranges within the variables like BMI and dietary factors could impact the overall regression models, BMIand a group of dietary factors wereconverted into categorical variable before placing into the regression models. The conversion of BMI set the measure of participants into three categories, including 1 = normal, 2 = overweight,3 = obese. A measurement range of dietary factors was grouped and defined as healthy diet. This new categorical variable would divide participants into two groups: 0 = mean daily consumption of fruit and vegetables ≤400g but mean daily consumption of meat and legumes ≥160g, and 1 = mean daily consumption of fruit and vegetables ≥400g but mean daily consumption of meat and legumes ≤160g. Statistical Analyses Descriptive statistics were used to provide an overall comparison of participants with different smoking status. This comparison included ages, education levels, weight, gender, diet and death. Continuous variables were estimated using t-test and categorical variables were estimated using Chi-square test. A P value Read More