武汉市私立学校中学生吸烟状况的初步分析

目的　了解私立学校中学生的吸烟状况 ,为加强青少年吸烟行为的干预措施提供依据。方法　以美国南加州大学提供的“青少年控烟项目调查问卷”为基础 ,对武汉市 8所私立学校 1 30 7名中学生进行问卷调查。以尝试吸烟率、吸过一整支烟的吸烟率、过去 30d吸烟率、吸过 1 0 0支烟吸烟率描述学生的吸烟行为。结果　中学生的初始吸烟年龄平均为 1 1 .2岁 ;尝试吸烟率为 54 .0 % ,吸过 1整支烟的比例为 2 2 .0 % ,过去 30d内吸烟率为 1 9.4 % ,吸烟 >1 0 0支的学生占 4 .4 % ;吸烟情况分析中 ,54 .1 %的学生是在好奇的情况下抽烟 ;吸烟来源中 ,46 .0 %的学生报告香烟是从朋友或同学那里得到的。结论　私立学校中学生的吸烟状况严重 ,加强对吸烟行为的早期预防教育和干预控制刻不容缓     

Cigarette smoking among Beijing (Peking) high schoolers

Students smoking at 2 key middle schools and 6 ordinary middle schools in Beijing, China were surveyed to determine the form in which high schoolers start smoking, and how long they have smoked. The patterns and causes of smoking were analyzed. The investigation was made from March to May 1981. 430 boys and 423 girls were selected from key schools and 1396 boys and 1394 girls from ordinary schools. Ages ranged from 13-17. All subjects completed a questionnaire in the classroom. To increase the reliability of the survey, names were kept secret. The students surveyed were classified into groups according to their smoking status: current regular smokers; occasional smokers; ex-smokers; and nonsmokers. In the key schools, there were only 4 smokers among 430 students, accounting for 0.9% of the total. Of these, 1 was Senior Class 2, 2 Senior Class 1, and 1 Junior Class 3. In the ordinary schools, 10% were smokers. 19.7% of the boys and 0.4% of the girls smoked. Among the boys, the higher the class, the more numerous the smokers. The smoking rate was 8.2% in the 1st year of junior high but rose to 34% in senior class 2; the difference was statistically significant. "Special occasion" smokers were few, only 5.5% of the students. In junior class, the number of regular smokers was about 2/3 to 4/5 that of occasional smokers. And by senior class 2 the number of regular smokers had risen to about 3 times that of the occasional smokers. In every grade, there were students who had given up smoking. Most had been occasional smokers. Some high schoolers had started to smoke in primary school and had a 4-5 year history of smoking, but most had only picked up smoking for 1-2 years after announcement of the Rules for High School Students prohibiting smoking. There were 3 smoking patterns: smoking without inhaling; inhaling the smoke deeply into the lungs, then expiring through the mouth or nostrils; and combining patterns 1 and 2. Of 265 students, 128 used the 1st pattern, 121 the second, and only 16 combined both patterns. The most common cause of smoking was curiosity. Next was lack of high ideals and dedication followed by boredom. The smoking rate in students whose parents were smokers was significantly higher than in those whose parents were nonsmokers. The difference was significant among all classes except junior class 1. To reduce smoking among high school students, it is necessary to go beyond the existing rules which prohibit smoking and emphasize political and ideologic education. Students must be taught about the dangers of smoking as early as possible, preferably in primary schools.     

Multiple Correlates of Cigarette Use Among High School Students

A cross-sectional survey research design measured factors related to cigarette use among 2,212 senior high school students. Results showed 14.3% of the sample smoked cigarettes at least occasionally, with 5.3% reporting they were daily smokers. About 12.8% indicated they were ex-smokers. Males and females smoked at almost equal rates, and the percentage of 10th grade student smokers was slightly higher (16.4%) than the percentage of juniors and seniors who smoked. Approximately 22% of Hispanic students, 15% of Caucasian students, and 4.5% of African-American students reported smoking cigarettes at least occasionally. An initial regression analysis used 21 variables to predict cigarette smoking. A more parsimonious regression model (R2 = .28), using variables from the initial regression analysis with significance levels of .01 or less, indicated the most important predictors of cigarette use were ethnic group, attitude toward females who smoke, close friends' use of cigarettes, personal use of marijuana, best friend's use of cigarettes, personal use of alcohol, and school self-esteem. Implications for school health programs are addressed.     

Prevalence of cigarette smoking among Australian secondary school students in 1993

Abstract: The prevalence of cigarette smoking in Australian secondary school students in 1993 was estimated from a survey of 22 696 12- to 17-year-old students from 332 secondary schools (and feeder schools) in all states and the Northern Territory. Self-administered questionnaires were answered anonymously by groups of up to 20 students selected randomly from school rolls, a method that replicated previous surveys in 1984, 1987 and 1990. Current smoking (smoking at least one cigarette in the week preceding the survey) at 12 years of age was 8 per cent in boys and 7 per cent in girls, but in those 17 years of age the prevalence was much higher (28 per cent of boys, 31 per cent of girls). Age was also associated with the mean number of cigarettes smoked per week by current smokers (8.6 in boys and 7.0 in girls at age 12 and 43.8 in boys and 32.0 in girls at age 17). After controlling for sex, age, school type and state of residence, the percentage of 12- to 15-year-olds who were current smokers rose from 15.7 per cent to 17.5 per cent between 1990 and 1993, an effect that was more pronounced in boys. On the other hand, the mean number of cigarettes smoked by 12- to 15-year-old current smokers dropped from 23 per week to 19.5, and the reduced consumption was greatest in boys. Furthermore, there was no increase in the proportion of students who smoked on three or more days per week, which suggests the increase was limited to occasional, casual or social smoking.     

Risks of lung cancer, chronic bronchitis, ischaemic heart disease, and stroke in relation to type of cigarette smoked.

In a case control study of over 12 000 inpatients aged 35-74, risk of lung cancer, chronic bronchitis, and, particularly in those aged 35-54, ischaemic heart disease was positively associated with the number of manufactured cigarettes smoked daily and was negatively associated with long term giving up. Risk of stroke was not clearly related to smoking. Among manufactured cigarette smokers, lung cancer risk tended to be lowest in those who had always smoked filter cigarettes. This pattern was, however, evident only in men who additionally smoked pipes, cigars or handrolled cigarettes and in women, not being seen in men who smoked only manufactured cigarettes. Risk of lung cancer was not clearly related to time of switch to filter cigarettes. A markedly lower risk of chronic bronchitis was seen in men, but not women, who smoked filter rather than plain cigarettes. Heart disease risk did not vary by type of cigarette smoked 10 years before admission, but, compared with those who had never smoked filter cigarettes, those who had ever smoked filter cigarettes had a higher risk in men and a lower risk in younger women. Compared with the general population, markedly more controls were ex-smokers, suggesting incipient disease, whether or not smoking related, may alter smoking habits, thus affecting the interpretability of the findings. Control smokers were also relatively much more likely to report smoking plain cigarettes than expected. This comparison, not made in other studies relating risk to type of cigarette smoked, indicates that great care must be taken in verifying validity of reported smoking habits. While our findings are compatible with other evidence that risk of lung cancer and chronic bronchitis is probably reduced by switching from plain to filter cigarettes, they underline the difficulties in obtaining valid evidence from epidemiological studies.     

广州市城乡结合部初中生吸烟行为特点的调查

目的:了解城乡结合部青少年吸烟行为的特点。方法:用自填式调查表对6所中学3 956名初中生进行流行病学调查。结果:初中生的尝试吸烟率为20.4%(男30.4%,女8.9%),不规律吸烟率14.7%(男21%,女7.7%),规律吸烟率5.7%(男9.4%,女1.2%)。吸烟率在不同性别和年级间存在差异,不同生源地的初中生吸烟率也有所区别。大部分尝试吸烟行为发生于10~14岁,初吸烟年龄中位数为12岁。吸第一支烟最主要的原因是“好奇尝试(70.3%),最主要的影响人是同伴(46.3%)。73%的规律吸烟者在过去1个月吸过烟,27%的只吸了1~5天。现在吸烟者的日均吸烟量平均值为5.12支,中位数为3支。46.6%的吸烟者只将烟雾吸入口腔。获得香烟的主要方式是别人给的,吸烟主要发生于伙伴聚会时。59%的规律吸烟者曾经戒过烟,主要是由于健康的缘故,戒烟成功率为28.8%。48.9%的现在吸烟者表明目前有戒烟的打算。结论:城乡结合部已成为烟草流行的重灾区,此趋势在青少年已有所表现。青少年控烟工作要联合政府、社会、家庭和学校等方多力量,结合其心理特征开展诸如同伴教育、提供戒烟辅助等有效措施。     

Evidence for compensation in smokers of low yield cigarettes

To determine the relation of smoking low yield cigarettes (tar yield less than 15.0 mg and nicotine yield less than 1.0 mg per cigarette) to the number of cigarettes smoked per day, we analysed information provided on self-administered questionnaires by 7706 current, regular cigarette smokers. The mean age at starting to smoke and the mean number of years of smoking were not consistently different in smokers of low yield compared with smokers of high yield cigarettes. In contrast, at all ages in both men and women, smokers of low yield cigarettes smoked significantly more cigarettes per day than smokers of high yield cigarettes. The differences in the number of cigarettes smoked per day between smokers of low and high yield cigarettes were small--about 3 cigarettes per day in men and about 1 1/2 cigarettes per day in women. However, these small differences might translate to the smoking of as many as one billion more packs of cigarettes per year in the United States alone. The potential beneficial effect of the smoking of cigarettes whose yield per cigarette is lower must be weighed against a possible adverse effect of the smoking of more cigarettes if the relation between smoking low yield cigarettes and smoking more cigarettes is causal.     

Density of tobacco retail outlets near schools and smoking behaviour among secondary school students

Objective: To investigate whether the density of tobacco retail outlets near schools in Victoria, Australia, is associated with adolescent smoking behaviour. Methods: Cross‐sectional survey data of 2,044 secondary school students aged 12–17 years was combined with tobacco outlet audit data. Associations between students' self‐reported tobacco use and the density of tobacco outlets near schools was examined using multilevel logistic and negative binomial regression models, with cigarette price at local milk bars and key socio‐demographic and school‐related variables included as covariates. Results: Increased tobacco retail outlet density was associated with a significant increase in the number of cigarettes smoked in the previous seven days among students who smoked in the past month (IRR=1.13; 95% CI 1.02–1.26), but not the odds of smoking in the past month in the larger sample (OR=1.06; 95% CI 0.90–1.24), after controlling for local mean price of cigarettes and socio‐demographic and school‐related variables. Conclusions and implications: This study suggests there is a positive association between tobacco retail outlet density and cigarette consumption among adolescent smokers, but not smoking prevalence, in the Australian context. There is value in considering policy measures that restrict the supply of tobacco retail outlets in school neighbourhoods as a means of reducing youth cigarette consumption.     

The epidemiology of cigarette smoking in Hong Kong Chinese women

BACKGROUND: Smoking in women is a well-recognized public health problem. In many developed countries, cigarette smoking is now the single most important preventable cause of premature death in women. There are relatively few data on the epidemiology of cigarette smoking in Asian women, and this study examined the prevalence of and factors predisposing Chinese women to smoke cigarettes in Hong Kong. METHOD: A territory-wide random telephone survey of 26,716 households in Hong Kong was conducted. A total of 1064 current smokers and 291 ex-smokers were identified in these household, and in-depth interviews of 791 current smokers, 221 ex-smokers, and 1012 controls were conducted. RESULTS: The prevalence of cigarette smoking was 4.5% in women who were 25 years or younger, 2.6% in women aged 46-65 years, and 2.2% in women aged 65 years or older. Sixty-four percent of current smokers started when they were 19 years or younger. The main reasons for the initiation of cigarette smoking were the influence of friends, curiosity, feeling bored, or being idle. Current smokers and ex-smokers tended to have positive images of women who smoked. The following risk factors were found to be significant for cigarette smoking: less than university education, unemployment, being divorced, having a husband who smoked, and a low score on the perceived harms of cigarette smoking. CONCLUSION: Cigarette smoking is more prevalent in younger women in Hong Kong; and psychosocial issues should be addressed to prevent future epidemics.     

The relationship of white blood cell count to other cardiovascular risk factors

Baseline data for the 12,866 men from the Multiple Risk Factor Intervention Trial was used to study factors related to white blood cell (WBC) count. White blood cell count was significantly higher in smokers (7853 cells/mm3) and ex-smokers (7091 cells/mm3) who stopped smoking less than one year before than in ex-smokers who stopped more than one year before (6255 cells/mm3) and those who never smoked (6094 cells/mm3). In current cigarette smokers, white blood cell count was significantly related to number of cigarettes smoked, degree of inhalation, and duration of smoking (p less than 0.001 for each). In addition, white blood cell count was higher in non-cigarette smokers who smoked pipes, cigars, or cigarillos than among men who did not smoke tobacco (p less than 0.001). White blood cell count was lower in blacks (by 877 cells/mm3) and Orientals (by 634 cells/mm3) than in whites. Leukocyte count also showed a strong inverse association with high density lipoprotein (HDL)-cholesterol, a positive association with triglycerides independent of cigarette use, and a positive association with low density lipoprotein (LDL)-cholesterol in smokers only. Leukocyte counts were inversely related to total family income and alcohol consumption. We conclude that elevated leukocyte count is independently associated with other risk factors for coronary heart disease (CHD) such as amount and duration of smoking as well as an atherogenic profile, and these relationships should be considered when using white blood cell count as a predictor of coronary heart disease.     

Characteristics of tobacco smoking in schools in Andorra]

1600 schoolchildren aged 13 to 18 answered an anonimus, self administered questionnaire, in a cross sectional study to estimate the prevalence of cigarette smoking in the high grades schools in Andorra. 46.6% answered they did smoke cigarettes, either daily (11.2%) or occasionally (35.4%). Ten per cent of actual smokers did already smoke at age 10, and 50% at age 13. More girls (48.8%) than boys (44.4%) smoked (p less than 0.05) but boys smoked a greater number of cigarettes (p less than 0.001). Ninety five percent smoked Virginia tobacco, and little more than 50% used filter tipped cigarettes. Two thirds of smokers inhaled the smoke of cigarettes; this was more common among daily smokers. Again two thirds of smokers answered they would be prepared to quit smoking. 31% of those who had tried smoking said they believed they would smoke in the future, while only 5.6% of those that never smoked previously said so (p less than 0.001). Actual smokers answered they believed that they would not smoke in the future much less often than non smokers. Parents let boys smoke more than girls when the children started doing so, particularly before age thirteen and after age fifteen. These are the first available data about the community studied describing some features of its cigarette smoking habit. Their knowledge may well help to plan disease protection and health promotion developments addressed to youngsters in Andorra.     

Behavioral aspects of cigarette smoking among industrial college men of Shanghai, China.

A questionnaire survey was conducted among 7,665 students and staff in the factory-operated industrial colleges in Shanghai, China. Response rate was 95.7 per cent. The proportion of smokers among the men was 50.5 per cent; only 0.33 per cent of the women reported they were smokers. Male smokers began smoking upon entering the work force, where social interaction encourages cigarette smoking. Seventy per cent of the male smokers smoked fewer than 10 cigarettes per day. Only 4.3 per cent perceived themselves as very addicted; 3.4 per cent reported they had no confidence in their ability to control the amount they smoke. The Chinese smokers are more likely to succeed in giving up cigarette smoking for at least one day, as well as for longer periods, compared to US smokers. The number of cigarettes smoked may be related to the individual's purchasing power. For China, strategic timeliness in legislative action and education is urgently needed to combat the high prevalence of cigarette smoking in males, at extremely high risk.     

Smoking habits and risk of fatal stroke: 18 years follow up of the Oslo Study.

STUDY OBJECTIVE: To examine the risk of fatal stroke in relation to smoking habits in men screened for the Oslo study. DESIGN: The Oslo study is a prospective, cohort study of the epidemiology and preventive aspects of cardiovascular diseases in middle aged men. Screening started in May 1972 and results after 18 years of follow up are reported. PARTICIPANTS: There were 16209 men aged 40-49 years, of whom 16173 had no stroke history. Eighty five men died from stroke, of whom 48 were daily cigarettes smokers, 7 were pipe and cigar smokers, 15 smoked cigarettes and pipe or cigars daily, 11 were previous cigarette smokers, and 4 had never smoked cigarettes. MAIN RESULTS: Results of proportional hazards regression analysis adjusted for age, diastolic blood pressure, and glucose concentration showed the following rate ratios (RR) (95% confidence interval) of smoking groups compared with those who had never smoked or had previously smoked: combined cigarette and cigar or pipe smokers, RR = 6.1 (3.0, 12.5); cigarettes only, RR = 4.1 (2.3,7.4); and pipe and/or cigars only RR = 2.2 (0.9,5.5). The overall, age adjusted risk of smoking cigarettes daily was 3.5 and was found to increase with increasing cigarette consumption. Regardless of their smoking group, stroke cases had increased diastolic (DBP) and systolic blood pressure (SBP) when compared with men who had not had a stroke. The absolute differences in DBP and SBP between stroke cases and others for never and previous cigarette smokers versus daily smokers were twice as large: DBP, 12.1 mmHg versus 6.5 mmHg respectively and SBP, 16.0 mmHg versus 7.1 mmHg respectively. A high BMI increased the risk of fatal stroke of never and previous cigarette smokers. Men being treated for hypertension at the time of screening had three times the crude risk of fatal stroke of men who were not taking hypertensive treatment. CONCLUSIONS: Daily cigarette smoking increased the risk of fatal stroke three and a half times. Combined cigarette and pipe or cigar smoking had a higher risk than smoking cigarettes only. An increased risk was found in relation to increased daily cigarette consumption.     

高中生吸烟行为特征及与其他危险行为关系分析

目的了解蚌埠市高中生的吸烟特征,为制定有效的干预措施提供科学依据。方法采取分层随机整群抽样,在蚌埠市区12所中学高中班中随机抽取11所中学22个班的全体学生进行问卷调查。结果3 131名高中生中,有800名高中生曾经吸过一整支烟,曾经吸烟率为25.6%,男生高于女生,其中,35.8%的学生吸一整支烟时的年龄<13岁,15~16岁是青少年尝试吸烟的高发年龄。8.9%的高中生曾有过经常性吸烟行为。在调查前30 d,4.6%的学生在学校吸烟,男生高于女生;4.9%的学生平均每天吸烟≥2支,男生高于女生;获得香烟的方式以在商店买烟为主,占50.5%。多因素logistic回归分析表明:最近12个月打架,厌学情绪、最近30 d饮酒、谈恋爱、性行为、最近7 d上网吧、参加校内运动队、性别对高中生吸烟影响最大。结论应及早对青少年进行控制吸烟的健康教育,使他们认识到吸烟的危害,自觉抵制烟草。同时对其他相关危险行为进行干预,以发挥干预措施的综合效应,提高控烟效果。     

Evaluation of the level of nicotine dependence among adolescent smokers

The questionnaire containing ten items evaluated the degree of dependence in students-volunteers from Brno secondary and vocational schools (ages ranging from 15 to 17 years) and the anamnestic data were compared with the specific (urinary cotinine) and non-specific (CO in the air exhaled) biological tests of exposure to smoking. The sample of 147 students examined contained 42% non-smokers, 25% occasional smokers and almost 33% of those who smoked every day. Almost 10% children smoked more than 10 cigarettes a day, and more than 20% children stated that they smoked 60 and more cigarettes a week. In accordance with the pre-developed degrees of dependence, compiled by the scores of the individual responses, 59% of the respondents (including the non-smokers) were ranked among the non-dependent. The second most frequent group contained the "strongly dependent" (almost 17% of all persons, e.g. 30% of smokers), 3.4% of examined persons (6% of smokers) were ranked in the sub-group of persons with a very high degree of dependence. Highly positive correlations were found between the evaluation of the dependence degree according to the anamnestic data and the exposure bio-markers (urinary cotinine/creatinine and CO in the air exhaled): the values of correlation coefficients were 0.615 and 0.764, resp. Both bio-markers also correlated negatively with the time of the last exposure to both active and passive smoking. The individual items in the dependence questionnaire had positive correlations with the objective exposure indicators which had statistical significance. The strongest relationship was observed in the question about the first morning cigarette--the highest correlation coefficients, being followed by signs evaluating the smoking frequency and the usual number of cigarettes smoked per day and in a week. The lowest relationships concerned the occasions for smoking and the unpleasant symptoms associated with the withdrawal. The anamnestic questionnaire could explain 42.6% of urinary cotinine level variability (converted to the density measured by creatinine content) and 65.8% of variability of CO content in the air exhaled. It was demonstrated that regular adolescent smokers at the ages between 15 to 17 years inhaled the cigarette smoke and the young smokers' inner exposure to nicotine had been proved as well. In this age group, there are many individuals who have a strong or a very strong dependence on nicotine. As a result, it is necessary to promote smoking cessation and nicotine dependence treatment by recommending pharmaceuticals of substantial nicotine therapy.     

Electronic Cigarette Use Among Korean Adolescents: A Cross-Sectional Study of Market Penetration,Dual Use,and Relationship to Quit Attempts and Former Smoking

PurposeAs elsewhere, in South Korea electronic cigarettes (e-cigarettes) are marketed, in part, as a smoking cessation aid. We assessed the prevalence of e-cigarette use among Korean adolescents and the relationship between e-cigarette use and current (past 30-day) smoking, cigarettes/day, attempts to quit conventional cigarettes, and ceasing to use cigarettes.MethodsData from the 2011 Korean Youth Risk Behavior Web-based Survey of 75,643 students aged 13–18 years were analyzed with logistic regression.ResultsA total of 9.4% (8.0% ever–dual users who were concurrently using e-cigarettes and smoking conventional cigarettes and 1.4% ever–e-cigarette only users) of Korean adolescents have ever used e-cigarettes and 4.7% were current (past 30-day) e-cigarette users (3.6% dual users and 1.1% e-cigarettes only). After adjusting for demographics, current cigarette smokers were much more likely to use e-cigarettes than were nonsmokers. Among current cigarette smokers, those who smoked more frequently were more likely to be current e-cigarette users. The odds of being an e-cigarette user were 1.58 times (95% confidence interval, 1.39–1.79) higher among students who had made an attempt to quit than for those who had not. It was rare for students no longer using cigarettes to be among current e-cigarette users (odds ratio, .10; confidence interval, .09–.12).ConclusionsSome Korean adolescents may be responding to advertising claims that e-cigarettes are a cessation aid: those who had made an attempt to quit were more likely to use e-cigarettes but less likely to no longer use cigarettes. E-cigarette use was strongly associated with current and heavier cigarette smoking.     

Cigarette smoking and small irregular opacities.

A survey of chemical workers by chest roentgenograms was designed to determine whether exposure to acrylic dust and/or cigarette smoking was associated with diffuse abnormalities suggestive of pneumoconiosis. The films were examined without knowledge of dust exposure or smoking habits. The International Labour Office (ILO) classification and standard films were used. Workers with exposure to asbestos were excluded. There was no relation between prevalence of abnormalities and exposure to dust. Among 181 workers 28 had s and/or t small irregular opacities with profusion of 0/1 (23), 1/0 (three), or 1/1 (two). These findings were present in 20% of smokers compared with 2.2% of non-smokers. The prevalence increased with increasing age to 31.6% among smokers aged 50-64. Prevalence was 10% among ex-smokers of cigarettes. Among current cigarette smokers, prevalence was 5.3% in those who smoked less than one pack per day, 31.3% in heavier cigarette smokers, and 52.9% in 17 heavy cigarette smokers aged 50-64. Profusions of 0/1 and 1/0 are classified as "suspect" pneumoconiosis according to the ILO guidelines. The data in this study indicate that such abnormalities are directly related to age and smoking habits among workers not exposed to hazardous dust.     

Cigarette smoking and small irregular opacities.

A survey of chemical workers by chest roentgenograms was designed to determine whether exposure to acrylic dust and/or cigarette smoking was associated with diffuse abnormalities suggestive of pneumoconiosis. The films were examined without knowledge of dust exposure or smoking habits. The International Labour Office (ILO) classification and standard films were used. Workers with exposure to asbestos were excluded. There was no relation between prevalence of abnormalities and exposure to dust. Among 181 workers 28 had s and/or t small irregular opacities with profusion of 0/1 (23), 1/0 (three), or 1/1 (two). These findings were present in 20% of smokers compared with 2.2% of non-smokers. The prevalence increased with increasing age to 31.6% among smokers aged 50-64. Prevalence was 10% among ex-smokers of cigarettes. Among current cigarette smokers, prevalence was 5.3% in those who smoked less than one pack per day, 31.3% in heavier cigarette smokers, and 52.9% in 17 heavy cigarette smokers aged 50-64. Profusions of 0/1 and 1/0 are classified as "suspect" pneumoconiosis according to the ILO guidelines. The data in this study indicate that such abnormalities are directly related to age and smoking habits among workers not exposed to hazardous dust.     

Cigarette smoking and coronary heart disease in Puerto Rico

Cigarette smoking habits were assessed in over 9000 men, aged 45–64 years, who participated in a prospective study of coronary heart disease (CHD) in Puerto Rico beginning in 1965. Fewer Puerto Rican men smoked cigarettes, and they smoked fewer cigarettes per day than in comparable studies in the mainland United States. Even in this lower-smoking, low-CHD population, cigarette smoking showed a significant independent association with the incidence of myocardial infarction (MI) over an 8-year period both in the rural and urban areas; however, this association was not statistically significant for other manifestations of CHD. Pipe and cigar smokers had a risk of MI similar to nonsmokers. Those men who used filter cigarettes or who stated that they did not inhale showed the same risk of MI as other cigarette smokers. Ex-smokers had a risk of MI intermediate to that of nonsmokers and current smokers. The risk of MI did not increase with an increase in the number of cigarettes smoked, but the risk of MI in smokers as a group relative to those who had never smoked was 3.4 in the rural area and 2.0 in the urban area. These results emphasize that there is an excess risk of MI in those cigarette smokers who report that they used filter cigarettes, did not inhale, or smoked a small number of cigarettes a day.     

Cigarette smoking and birthweight: type of cigarette smoked and a possible threshold effect

The effects on birthweight of the number of cigarettes smoked and their tar, nicotine and carbon monoxide yields were investigated prospectively in 1309 pregnant women of whom 414 were smokers. Several approaches to modelling the effect of smoking were tried. These suggested that while both yield and quantity smoked were important, yield had the greatest effect. This led to an empirical approach whereby consistent smokers were divided into four categories according to whether they smoked a low or high quantity of cigarettes per day and whether they smoked low or high yield cigarettes. Using these four groups it emerged that women smoking a low quantity of low yield cigarettes had babies of a similar mean birthweight to those of non-smokers whereas those smoking a low quantity of high yield cigarettes had babies whose birthweight was reduced to the same degree (6% or more) as those of mothers who smoked higher quantities. This apparent threshold was estimated as 13 cigarettes/day and 15 mg/cigarette carbon monoxide. We conclude that brand smoked is at least as important as quantity and that in this population there is evidence for a threshold for tobacco smoke intake below which no discernible effect on birthweight is seen.