Association between smoking, insulin resistance and beta-cell function in a North-western First Nation.

AIMS: Aboriginal peoples have a high prevalence of smoking and are at major risk for diabetes. The role of insulin resistance vs. compromised beta-cell function in the link between smoking and glycaemic disease is not clear. This study tested whether relations between insulin resistance and beta-cell function differ between current smokers, former smokers and non-smokers, and if having diabetes modifies smoking-related effects. METHODS: A community-based diabetes screening initiative was mounted for a North-western First Nation (Interior Salishan) in rural British Columbia, Canada. Respondents were on-reserve Aboriginal people (n=156), all adults 18+ years. Glycaemic status was determined by oral glucose tolerance test. Fasting values for glucose and insulin were used to estimate beta-cell function and insulin resistance by homeostasis model assessment (HOMA). Analyses adjusted for age, sex, alcohol intake, education, body mass index and physical activity. RESULTS: For normoglycaemic persons (n=119) current smokers relative to non-smokers had high beta-cell values [difference (95% confidence interval) 19.5 (17.1, 21.9)], while former smokers had low beta-cell values [difference -22.8 (-20.3, -25.3)] (P<0.0001). For diabetic persons (n=37) differences were of equivalent direction but greater magnitude (P<0.0001). Insulin resistance was for normoglycaemic persons highest for current smokers, and for diabetic persons lowest for current smokers (P=0.021). CONCLUSIONS: Former smoking is associated with low beta-cell function, and current smoking with high beta-cell function, independent of diabetes in the North-western First Nation surveyed. Associations between smoking and insulin resistance vary according to glycaemic status. Smoking may have diametric acute and post-cessation effects on beta-cell function and insulin resistance.

Application of Karasek's demand/control model a Canadian occupational setting including shift workers during a period of reorganization and downsizing.

PURPOSE: To apply Karasek's Job Content Model to an analysis of the relationships between job type and perceived stress and stress behaviors in a large company during a period of reorganization and downsizing. DESIGN: Cross-sectional mail-out, mail-back survey. SETTING: A large Canadian telephone/telecommunications company. SUBJECTS: Stratified random sample (stratified by job category) of 2200 out of 13,000 employees with a response rate of 48.8%. MEASURES: Responses to 25 of Karasek's core questions were utilized to define four job types: low-demand and high control = "relaxed"; high demand and high control = "active"; low demand and low control = "passive", and high demand and low control = "high strain." These job types were compared against self-reported stress levels, perceived general level of health, absenteeism, alcohol use, exercise level, and use of medications and drugs. Similar analyses were performed to assess the influence of shift work. RESULTS: Employees with "passive" or "high strain" job types reported higher levels of stress (trend test p < .0001); poorer health (trend test P = .006); and higher levels of absenteeism (trend test p < .0001). More shift workers reported themselves in poor or fair health (chi-square p = .018) and reported high levels of stress at home (chi-square p = .002) than nonshift workers. The relationships between job type and levels of stress, health and absenteeism, however, held for nonshift workers as well. CONCLUSIONS: Job types with high demand and low control were associated with increased stress, increased absenteeism, and poorer self-concept of health. The demand/control model of Karasek and Theorell was validated in this setting with respect to stress and some stress-associated attitudes and behaviors.

Dispositional risk factors for smoking-stage transitions: a social influences program as an effect modifier.

A cognitive-developmental model postulates three predominant adolescent dispositions (self-definition, social compliance, and affect regulation) which may impede or facilitate transitions in stages of smoking. The purpose of the present prospective study was to build on the findings supporting this model. One hundred schools were randomly assigned to either receive or not receive a social influences smoking prevention program. A baseline survey, including smoking behavior and dispositional items, was administered in the sixth grade in 1990, interventions were delivered in the sixth and seventh grades, and a survey was administered following the seventh grade intervention. Principal component patterns, based on dispositional items, were very similar for grades 6 and 7, did not vary by gender, and the components (rebelliousness, rejection of adult authority, personal dissatisfaction, and peer approval) were correlated. All smoking-stage transitions were positively related to rebelliousness for boys. The relationship of the dispositional scores with smoking-stage transitions was more complex for girls. Receiving the program modified the effects of the dispositional risk scores, particularly for girls.

Social environment and smoking initiation.

This paper reports exploratory research to predict smoking initiation prospectively as a function of both personal (peer and family) and more macro (school and community) social environment. At the macro level, older peer smoking by school system and school board by school system were significant predictors of smoking onset. At the personal level, the effect of gender varied with time. Males began to smoke earlier than females, but females had higher onset rates in the period from the end of Grade 7 to the end of Grade 9. Significant sibling and peer influences replicate the consistent findings in the smoking initiation area. Implications for the longitudinal study of the smoking onset process are given.