The effect of intramuscular injection of dinoprost or gonadotropin-releasing hormone in dairy cows on beef quality.

Intramuscular injections of drugs and vaccines cause tissue damage and subsequent effects on tenderness and consumer acceptability of beef. In the 2007 National Market Cow and Bull Beef Quality Audit, 100% of plants reported fabricating subprimal cuts such as rib eyes and tenderloins from cow and bull carcasses. Dairy beef quality should therefore be a consideration when injections are given to dairy animals. The discussion about injection site reactions and tenderness has focused on vaccines and antimicrobial drugs with little concern for the effects of reproductive hormones. The objective of this study was to quantify antemortem the effects of semimembranosis/semitendinosis muscle injection of dinoprost and GnRH in lactating dairy cows by estimating the weight of tissue damaged and comparing that with a drug known to cause extensive tissue damage, flunixin meglumine. Tissue damage was estimated from previously reported equations for grams of muscle tissue damage based on area under the curve of serum concentrations of the muscle enzyme creatine kinase over time. Dinoprost and flunixin injection both caused a significantly increased estimate of muscle tissue damaged compared with needle only (P = 0.0351 and 0.0355, respectively). Dinoprost and flunixin caused a marginally significant increased muscle tissue damage compared with GnRH (P = 0.1394 and 0.1475, respectively). No statistically significant difference was found between the estimated weight of muscle tissue damaged by flunixin compared with dinoprost (P = 1.0000), or by saline compared with GnRH (P = 0.7736) or needle only (P = 0.4902). The assumption that reproductive hormones are less damaging than vaccines and antimicrobial drugs should be examined more closely, including postmortem evaluation of injection site lesions and effects on tenderness.

New tobacco products: do smokers like them?

BACKGROUND: There is little information about smokers who tried potentially reduced exposure products (PREPs) (Eclipse, Omni, Advance Lights, Accord, or Ariva), why they tried them, if they liked these products, and if they will continue to use them. OBJECTIVES: The objectives of this qualitative study were to understand: (1) how smokers who tried PREPs learned about them, (2) reasons for first trying PREPs, (3) which PREP(s) they tried, (4) what they thought of the product at first trial, (5) reasons for continuing or discontinuing use, and (6) whether they would recommend PREPs to others. DESIGN: In October 2002, 16 focus group sessions were conducted with current cigarette smokers aged 30-50 years: eight groups in Chattanooga, Tennessee, and eight in Dallas, Texas. Specific focus groups were composed of white men, white women, African American men, African American women, Hispanic men, or Hispanic women. RESULTS: The majority of the participants learned about PREPs through advertising or promotion, family, friends, and co-workers; major reasons given for first trying PREPs were that the products were free or inexpensive, they wanted to stop smoking, they believed the product claims of fewer health risks, or they were curious; most of them tried Eclipse probably because the focus groups were conducted in the same cities where Eclipse was introduced; most participants did not like PREPs; most discontinued the use of PREPS, some who continued to use them did so infrequently and also kept smoking their regular brands of cigarettes; and most would not recommend PREPs, although a few might recommend them to specific groups (for example, new smokers, the young, women, curious or health conscious people). CONCLUSIONS: Although most established smokers did not like the PREPs they tried and will not recommend them to anyone, a minority of established smokers believe that there may be a market for these products.

Comprehensive tobacco control policies and the smoking behaviour of Canadian adults.

OBJECTIVE: To examine the associations of cigarette prices, restrictions on public smoking, and health education with the odds of adult smoking and amount smoked daily. DESIGN: Multi-level analysis of adult (age 25+) smoking patterns in Canada's National Population Health Survey, after adding administrative data on prices, bylaws, and health education according to the survey respondent's place of residence. SETTING/SUBJECTS: Population based sample of Canadians age 25+ in households (n = 14 355). OUTCOME MEASURES: Smoking status, amount consumed daily. ANALYSIS: Logistic regression for smoking status, multiple regression for amount smoked, with controls for age, education, marital status; separate analyses for men and women. RESULTS: Cigarette prices were positively associated with the odds of being a non-smoker and negatively with amount smoked, for adults of both sexes. Per capita health education expenditures were positively associated with the odds of being a non-smoker and negatively with amount smoked--for men but not women. The restrictiveness of municipal bylaws limiting public smoking was positively associated with the odds of being a non-smoker and negatively with amount smoked--for women but not men. These results are independent of age, education, and marital status. CONCLUSIONS: To be effective, tobacco control must comprise a mix of strategies as men and women respond differently to health education and restrictions on public smoking; taxation, reflected in higher cigarette prices, is the only one of these measures related to smoking for both sexes. This model permits calculations of the level of increase in each measure that is required to reduce the prevalence of smoking by a specified amount.

Heterogeneity among smokers and non-smokers in attitudes and behaviour regarding smoking and smoking restrictions.

OBJECTIVE: To determine if smokers and non-smokers cluster into meaningful, discrete subgroups with distinguishable attitudes and behaviours regarding smoking and smoking restrictions. DESIGN: Qualitative research with 45 smokers guided development of questionnaire items applied in a population based telephone survey of 432 current smokers and 1332 non-smokers in Ontario, Canada. METHODS: Cluster analysis of questionnaire items used to categorise adult smokers and non-smokers; comparison of clusters on sociodemographic characteristics and composite knowledge and attitude scores. RESULTS: Smokers clustered in three groups. "Reluctant" smokers (16%) show more concern about other people discovering that they smoke, but parallel "easygoing" smokers (42%) in supporting restrictions on smoking and not smoking around others. "Adamant" smokers (42%) feel restrictions have gone too far, and are less likely to accommodate non-smokers. Significant gradients across categories in the expected direction were observed with respect to smoking status, stage of change, knowledge, and attitude scores, and predicted compliance with restrictions, validating the proposed typology. Non-smokers also clustered into three groups, of which the "adamant" non-smokers (45%) are the least favourably disposed to smoking. "Unempowered" non-smokers (34%) also oppose smoking, but tend not to act on it. "Laissez-faire" non-smokers (21%) are less opposed to smoking in both attitude and behaviour. A significant gradient across categories in the expected direction was observed with respect to composite scores regarding knowledge of the health effects of active and passive smoking and a composite score on support for restrictions on smoking in public places. CONCLUSION: Recognition and consideration of the types of smokers and non-smokers in the population and their distinguishing characteristics could inform the development of tobacco control policies and programmes and suggest strategies to assist implementation.

Is smoking associated with the risk of developing Alzheimer's disease? Results from three Canadian data sets.

PURPOSE: To determine whether smoking is associated with Alzheimer's disease (AD). METHODS: Analyses were conducted using three Canadian data sets: the University of Western Ontario Dementia Study (200 cases, 163 controls), the Canadian Study of Health and Aging (258 cases, 258 controls), and the patient database from the Clinic for Alzheimer Disease and Related Disorders at the Vancouver Hospital and Health Sciences Centre (566 cases, 277 controls). The association between smoking and AD was investigated using bivariate analyses and multiple logistic regression models adjusted for the potential confounders age, sex, educational level, family history of dementia, head injury, and hypertension. RESULTS: The results of bivariate analyses were inconsistent across the three data sets, with smoking status a significant protective factor, a significant risk factor, or not associated with AD. The results of multiple logistic regression models, however, were consistent: any association between smoking status and AD disappeared in all three data sets after adjustment for confounders. CONCLUSIONS: Smoking status was consistently not associated with AD across all three data sets after adjustment for confounders. Failure to adjust for relevant confounders may explain inconsistent reports of the influence of smoking on AD. Any protective effect of smoking may be limited to specific AD subtypes (e.g., early onset AD).

Influence of a rural primary care clerkship on medical students' intentions to practice in a rural community.

The purpose of this study is to examine the relationship of a rural clerkship to medical students' interest in establishing careers in rural communities. The Association of American Medical Colleges Medical School Graduation Questionnaire (GQ) for years 1988 through 1997 was examined to compare the career plans of students graduating from Morehouse School of Medicine (MSM) with those of all students graduating from United States medical schools before the period 1988 through 1992 and after the period 1993 through 1997, after the inception of the rural clerkship at MSM. Select GQ data items examined include student demographics, medical school experiences, and career plans. Statistical analyses were used to compare pre- and post-clerkship responses for MSM students and to compare their responses with the national trends. Results indicate that, following a transition period, MSM students showed an increased preference for a future career in a rural community. A smaller upward trend in the national data was observed. There appears to be an association between the rural clerkship experience at MSM and the stated preferred career choices of the students.

Models of the relationship of stress, depression, and other psychosocial factors to smoking behavior: a comparison of a cohort of students in grades 6 and 8.

BACKGROUND: Six specific hypotheses regarding putative mechanisms by which stressful life events might lead to initiation of smoking among adolescents were proposed and tested on a Grade 6 cohort of students in Scarborough, Ontario, Canada. In addition, the data were used to determine the set of risk factors for initiation of smoking most pertinent to the experience of the cohort. METHODS: The same relationships were examined for the 1,543 students when they were in Grade 8 and compared to the earlier Grade 6 results. The hypotheses include the effects of personal resources (coping, self-esteem, social support, and mastery), social conformity, rebelliousness, attitudes, smoking environment factors, and gender differences. RESULTS: The hypotheses were not unequivocally supported, except for the hypotheses about attitudes and smoking environment as well as gender effects. Males and females differ with regard to the variables and interrelationships in both years and in the final models developed. In Grade 6, there are more smoking environment items for males than for females. By Grade 8, male smoking is influenced by mastery, social conformity, and rebelliousness, while for females environmental smoking and rebelliousness are important. CONCLUSION: Male and female students differ in how stress, depression, and smoking are related in the presence of psychosocial factors.

Smoking cessation among African Americans: what we know and do not know about interventions and self-quitting.

BACKGROUND: Many studies on cessation interventions and self-quitting have been conducted, but few have focused on African Americans. The purpose of this review was to critically evaluate the available studies and make recommendations for future research. METHODS: Articles published from 1988 to 1998 were collected using Medline and other data bases, as well as personal communication. Studies were divided into two categories: evaluations of specific cessation interventions and examinations of self-quit behaviors and related factors. Studies were tabulated using author/year, study design/sample size, variables/results, and comments. RESULTS: In the intervention studies, church-based programs may provide an effective location for cessation interventions, but the studies to date did not demonstrate unequivocal effectiveness. In clinic programs, there do not appear to be any interventions that are particularly effective. In community-based interventions, there were no differences for African and Caucasian Americans. With regard to self-quitting, sociodemographic variables were similarly related to cessation as in the general population, as were smoking history variables. All other categories did not contain enough information for firm conclusions to be drawn. CONCLUSIONS: There are some interventions that appear to be useful, but little information is available on self-quitting. More research is needed on the natural history of quitting, on the social norms for smoking among African American groups, and on the conceptual dimensions of race in the context of this research.

Does an interaction between smoking and drinking influence the risk of Alzheimer's disease? Results from three Canadian data sets.

Investigation of the relationship of smoking and drinking to Alzheimer's disease (AD) may advance research on the cause of AD and provide a basis for treatment. Pharmacological mechanisms for an involvement of smoking and drinking are plausible but epidemiologic reports are inconsistent. Evidence of behavioural and physiological interactions suggests that tobacco and alcohol use may not only individually affect AD, but may also modify each other's effects. A modelling strategy was developed to examine the interaction between smoking and drinking on the risk of AD. Three Canadian data sets were analysed: the University of Western Ontario Dementia Study (UWODS) (n=363); the Canadian Study of Health and Aging (CSHA) (n=516), and the database from the Clinic for Alzheimer Disease and Related Disorders at the Vancouver Hospital and Health Sciences Centre, University of British Columbia site (UBC) (n=843). Multiple logistic regression models were adjusted for the potential confounders age, age squared, sex, education, family history of dementia, head injury and hypertension. Analysis of the CSHA provided evidence consistent with the hypothesis that smoking and drinking influence each other's effects on AD, with smoking reducing the risk of AD among drinkers. A similar interaction was marginally significant (p=0.052) in the UWODS data set, but not significant in the UBC data. Extension of these analyses, particularly in longitudinal studies and within genetic risk groups, is needed to determine whether this interaction can be replicated. If so, research on the biological interactions of nicotine and alcohol may provide a basis for the development of therapeutic interventions as well as providing clues to the cause of this disorder.

Longitudinal tracking and retention in a school-based study on adolescent smoking: costs, variables, and smoking status.

Methods used to track a cohort of Grade 6 students through Grades 8 and 11, and costs involved for survey completion in school and by mail for ever and never smokers from the original group are detailed. At baseline, 1,598 students in Scarborough, Canada, completed a questionnaire on smoking, drinking, and health, and again in Grade 8 (N = 1,543/1,598) and Grade 11 (N = 1,454/1,598). In Grades 8 and 11, tracking and administering the questionnaire was more costly per participant when the survey was administered by mail than in school. Average completion costs were highest for Grade 11 students who used tobacco at baseline ($52.44). Students categorized as ever smokers in Grade 6 were harder to locate at each phase of testing, which suggests that this group should be identified at baseline so that closer tracking procedures may be employed between data collection points.

Stress-coping and other psychosocial risk factors: a model for smoking in grade 6 students.

Smoking uptake by adolescents is best studied by a following a cohort of children as they proceed through adolescence. In this analysis of the first stage of such a study, several hypotheses about psychosocial factors that may modify the initiation of smoking in adolescents were examined in 1,552 11- and 12-year-olds in a school system in Scarborough, Canada. Investigation of the stress-coping hypothesis and other possible effect modifiers as they relate to ever-smoking revealed that stress (measured by number of life events) was important for both males and females (p = .0163 and .0056, respectively). However, the mechanisms underlying smoking appear to be different for males and females, even at this young age. In models adjusting for several factors simultaneously, rebelliousness was found to be the most important factor (p = .0001) followed by attitudes toward the effect of second-hand smoke (p = .0063) for males, whereas for females, mother smoking was the most important factor (p = .0001) followed by rebelliousness (p = .0102). Implications for design of prevention programs are discussed.

Effectiveness of physicians-in-training counseling for smoking cessation in African Americans.

This study examined the effectiveness of smoking cessation counseling by physicians-in-training (residents) with African-American patients. One hundred fifty-eight family and internal medicine residents at a large urban public general hospital participated in the study; two thirds of the residents underwent a 2-hour smoking cessation training program. Ninety-two of the trained physicians counseled from 1 to 18 patients. The majority of physicians were male, with 8% being current smokers. Over a 26-month period, 1086 patients were randomly assigned to intervention and control (usual care) groups. Mean patient age was 44 years, mean years smoking was 25, and mean number of cigarettes smoked per day was 14. There were no differences in biochemically validated smoking cessation rates between the intervention and control groups at 3 or 12 months postenrollment (2% versus 1.8% and 2.2% versus 2.8%, respectively). Losses to follow-up were high at both 3 and 12 months (38% and 40% respectively). Implications for future trials in minority populations are discussed. A brief physician-based smoking cessation message does not appear to be an effective strategy for use with African-American smokers in a large urban public general hospital.

Smoking initiation and cessation in African Americans attending an inner-city walk-in clinic.

OBJECTIVES: Data collected from a population of African Americans were analyzed to examine patterns of smoking initiation, smoking cessation, and factors related to smoking cessation. METHODS: Over a 4-month period, all (N = 2,928) patients attending an inner-city medicine clinic were recruited to participate in a smoking intervention trial. Over 99% participated, providing information on their smoking experiences, including smoking status (current, former, or never a smoker), duration of regular smoking, and year of quitting when applicable. Data on African Americans with complete information on these variables (n = 2,428) were analyzed with respect to initiation and duration of smoking. RESULTS: More than half of African-American smokers in the population studied initiated regular smoking after age 19. Later age of initiation of smoking and female gender were associated with short duration smoking (i.e., quitting before 10 years of regular smoking); these variables, but not age, were identified as significant factors in a Cox Proportional Hazards model with duration of smoking as the outcome variable. CONCLUSIONS: A sizable opportunity for primary prevention of regular smoking appears to exist among African Americans aged 20 to 30 years as evidenced by patterns of smoking initiation in the population studied. The importance of age at initiation of regular smoking to the duration of smoking is demonstrated in this population over a wide range of duration.

The degree and type of relationship between psychosocial variables and smoking status for students in grade 8: is there a dose-response relationship?

BACKGROUND: While most research focuses on simply analyzing the differences between smokers and non-smokers, dose-response analyses may be used to find evidence of the nature of the association between psychosocial variables and involvement with smoking in adolescence. METHODS: For the study, 1,614 grade 8 students from Scarborough, Ontario, Canada, completed a self-administered questionnaire that included items on sociodemographic characteristics, experience with smoking, lifestyle, health and weight, work status, and social involvement as well as parental education, occupation, and family and peer smoking. A series of scales measuring self-esteem, stress, coping, social support, mastery, social conformity, and rebelliousness was incorporated. RESULTS: Dose-response relationships were evidenced for all categories of variables and were demonstrated for the total group and, in most cases, for males and females when analyzed separately. CONCLUSIONS: Relationships between variables are not "all or none," but may vary depending on amount or level of other factors. These relationships provide insight into the mechanisms underlying initiation to, maintenance of, and cessation of smoking and should be taken into account in programs to reduce or prevent adolescent tobacco use.

Psychosocial factors related to adolescent smoking: a critical review of the literature.

OBJECTIVE: To extend the analysis of psychosocial risk factors for smoking presented in the United States surgeon general's 1994 report on smoking and health, and to propose a theoretical frame of reference for understanding the development of smoking. DATA SOURCES: General Science Index, Medline, PsycLIT, Sociofile, Sociological Abstracts, and Smoking and Health. Holdings of the Addiction Research Foundation of Ontario Library as well as the authors' personal files. STUDY SELECTION: Reviewed literature focused on studies that examined the association of sociodemographic, environmental, behavioural, and personal variables with smoking. DATA SYNTHESIS: Adolescent smoking was associated with age, ethnicity, family structure, parental socioeconomic status, personal income, parental smoking, parental attitudes, sibling smoking, peer smoking, peer attitudes and norms, family environment, attachment to family and friends, school factors, risk behaviours, lifestyle, stress, depression/distress, self-esteem, attitudes, and health concerns. It is unclear whether adolescent smoking is related to other psychosocial variables. CONCLUSIONS: Attempts should be made to use common definitions of outcome and predictor variables. Analyses should include multivariate and bivariate models, with some attempt in the multivariate models to test specific hypotheses. Future research should be theory driven and consider the range of possible factors, such as social, personal, economic, environmental, biological, and physiological influences, that may influence smoking behaviour. The apparent inconsistencies in relationships between parental socioeconomic status and adolescent disposable income need to be resolved as does the underlying constructs for which socioeconomic status is a proxy.

Health behaviours and socio-economic status in Ontario, Canada.

Data from the 1990 Ontario Health Survey were used to investigate the association of socioeconomic status with the likelihood of meeting current recommendations for four health behaviours (smoking, fat intake, alcohol consumption, and physical activity level) in adults living in Ontario (Canada). Health behaviours were categorised as 'unhealthy' if they did not meet current recommendations in Ontario (smoking, fat intake > 30% of dietary energy, alcohol intake > 14 units per week, low level of leisure-time physical activity). Two summary variables based on the number of 'unhealthy' behaviours were also examined: the crude number of 'unhealthy' behaviours reported and the likelihood of reporting 3 or 4 'unhealthy' behaviours. Four measures of socio-economic status were used: educational achievement, household income status, source of household income, and occupational prestige. Multiple logistic and linear regression analyses were performed to explore the association of each 'unhealthy' behaviour and of the summary variables with socio-economic status indicators (taken independently or simultaneously), controlling for demographic characteristics. Except for the positive relationship between income status and high alcohol intake, measures of 'unhealthy' behaviours were inversely associated with the socio-economic indices, suggesting that individuals in lower socioeconomic groups are at an increased risk for health problems.

The relationship of cigarette prices and no-smoking bylaws to the prevalence of smoking in Canada.

OBJECTIVES: The aim of this study was to analyze the association of cigarette prices and no-smoking bylaws with the prevalence of smoking. METHODS: Data on individual smoking status were taken from two national household surveys in Canada. Current cigarette price, the 1-year and 10-year increase in price, and the extent of local restrictions on public smoking were added to the model. Logistic regression was used to estimate the odds of being a smoker. RESULTS: The odds ratio for being a smoker was 1.21 where no-smoking by-laws were relatively infrequent and 1.26 when cigarettes were relatively inexpensive, after adjusting for individual age, sex, education, and marital status. CONCLUSIONS: Both cigarette prices and no-smoking bylaws are effective in controlling smoking; either alone will likely have less impact than the two measures together.

Are psychosocial factors related to smoking in grade-6 students?

The associations of psychosocial characteristics with both gender and smoking behavior were explored in a sample of 1552 grade-six students from 107 schools in one Ontario, Canada, school district. Ever smokers were more likely to have spending money: a part-time job; to have missed school in previous 2 months; perceive themselves to be below average or average in school; to have a mother, a father, and a sibling who smoke; to have consumed low alcohol and alcoholic beverages; and agree with fewer positive statements concerning second-hand smoke and the addictive properties of smoking. Ever smokers had more close friends who tried smoking, spent more time with friends, scored higher on depression, rebelliousness, and social conformity scales, reported more life events in the past year, and had lower scores for social support. More boys than girls had ever smoked (18.9% vs. 14.7%). Gender differences were found for sociodemographic, attitudes, social bonding, and psychosocial factors.

Quitting smoking: why, how, and what might help.

OBJECTIVE: To examine reasons for quitting smoking, methods used in quitting, reasons for continuing smoking and potential aids to quitting in the population of Ontario, Canada. DESIGN: Two population-based, telephone interview surveys, conducted by random-digit dialing. SUBJECTS: Adults aged 18 years of age and older in 1983 (n = 1383) and 1991 (n = 1421). MAIN OUTCOME MEASURES: Information was obtained from former smokers on why and how they quit smoking, and from continuing smokers on why they smoked and what might help them quit. RESULTS: The proportion of current smokers in the population decreased from 35.5% in 1983 to 27.2% in 1991. In both surveys, former smokers cited a variety of reasons for quitting, including personal health concerns, social and environmental factors, personal attitude factors, cost, and health education messages. Responses concerning the most important reason also revealed a range of factors; "advice of a physician" was not prominent among them. When questioned about methods used in quitting, most former smokers in both surveys responded that they "just decided to quit". Very few reported using other aids such as cessation clinics or nicotine gum. More smokers in 1991 than in 1983 reported that they continued smoking for enjoyment, to satisfy a craving or addiction, and for relaxation. With regard to what might help them quit, continuing smokers in both surveys cited a wide variety of potential aids, including information on harmful effects, more restrictions on smoking and on sales, cessation clinics, programmes on radio/TV, and higher taxes. CONCLUSIONS: These findings support a multifaceted approach to tobacco control.

The use of differential display-PCR to isolate and characterize a Legionella pneumophila locus induced during the intracellular infection of macrophages.

The differential display (DD)-PCR technique has been modified to identify prokaryotic cDNA fragments that are differentially induced by facultative intracellular bacteria in response to the intracellular environment of eukaryotic cells. Several DD-PCR fragments identified from the intracellular bacterium Legionella pneumophila were induced at 4 h post-infection of the U937 macrophage-like cells. From these, a 700 bp fragment was cloned and sequenced. Neither the DNA sequence nor the predicted protein sequence from the open reading frame has similarity to other sequences in genetic databases. Transcription of the chromosomal locus containing the 700 bp fragment (eml, for early stage macrophage-induced locus) was induced by intracellular bacteria during the first few hours post-infection of macrophages but the expression was downregulated by 12 h post-infection. Transcription of eml was not growth phase-related in vitro, and was not affected by in vitro stress stimuli. A 3.7 kb EcoRI genomic fragment containing the 700 bp DD-PCR product was cloned. Six mini-Tn 10 insertions in the 3.7 kb EcoRI fragment were recombined into the L. pneumophila chromosome. Compared to the wild-type strain, five of the eml isogenic mutants had a similar phenotype of reduced cytopathicity to the U937 cells, showed a 100-fold increase in killing by macrophages during the first 5 h of the intracellular infection, and showed a 100-fold increase in killing during the first 24h of infection of the amoeba Hartmanella vermiformis. The 6th mutant had a phenotype indistinguishable from the wild-type strain. The cytopathicity defect of the mutants to the U937 cells was restored to wild-type levels by complementation of the mutants with a plasmid containing the 3.7 kb EcoRI fragment. These data showed that the 3.7 kb fragment containing eml is a novel L. pneumophila locus whose expression is uniquely induced by non-stress stimuli during early stages of the intracellular infection of phagocytic cells. Expression of this locus is required for survival of L. pneumophila within macrophages and within amoebae during early stages of the infection.