OBJECTIVE: To assess the efficacy of a school-based intervention programme to reduce the prevalence of overweight in 6 to 10-year-old children. DESIGN: Cluster-randomized, controlled study. SUBJECTS: A total of 3135 boys and girls in grades 1-4 were included in the study. METHODS: Ten schools were selected in Stockholm county area and randomized to intervention (n=5) and control (n=5) schools. Low-fat dairy products and whole-grain bread were promoted and all sweets and sweetened drinks were eliminated in intervention schools. Physical activity (PA) was aimed to increase by 30 min day(-1) during school time and sedentary behaviour restricted during after school care time. PA was measured by accelerometry. Eating habits at home were assessed by parental report. Eating disorders were evaluated by self-report. RESULTS: The prevalence of overweight and obesity decreased by 3.2% (from 20.3 to 17.1) in intervention schools compared with an increase of 2.8% (from 16.1 to 18.9) in control schools (P
One in three young people use cannabis in Canada. Cannabis use can be associated with a variety of health problems which occur primarily among intensive/frequent users. Availability and effectiveness of conventional treatment for cannabis use is limited. While Brief Interventions (BIs) have been shown to result in short-term reductions of cannabis use risks or problems, few studies have assessed their longer-term effects. The present study examined 12-month follow-up outcomes for BIs in a cohort of young Canadian high-frequency cannabis users where select short-term effects (3 months) had previously been assessed and demonstrated.
N=134 frequent cannabis users were recruited from among university students in Toronto, randomized to either an oral or a written cannabis BI, or corresponding health controls, and assessed in-person at baseline, 3-months, and 12-months. N=72 (54%) of the original sample were retained for follow-up analyses at 12-months where reductions in 'deep inhalation/breathholding' (Q=13.1; p
To assess associations between the intake of different types of alcoholic beverages and the 32-year incidence of myocardial infarction, stroke, diabetes, and cancer, as well as mortality, in a middle-aged female population.
Gothenburg, Sweden, population about 430 000.
Representative sample of a general population of women (1462 in total) aged 38 to 60 years in 1968-1969, followed up to the ages of 70 to 92 years in 2000-2001.
Associations between alcohol intake and later risk of mortality and morbidity from myocardial infarction, stroke, diabetes, and cancer, studied longitudinally.
During the follow-up period, 185 women developed myocardial infarction, 162 developed stroke, 160 women became diabetic, and 345 developed cancer. Women who drank beer had a 30% lower risk (hazards ratio (HR) 0.70, 95% confidence interval (CI) 0.50-0.95) of developing myocardial infarcion and almost half the risk (HR 0.51 CI 0.33-0.80). A significant association between increased risk of death from cancer and high spirits consumption was also shown (hazards ratio [HR] 1.47, CI 1.06-2.05).
Women with moderate consumption of beer had a reduced risk of developing myocardial infarction. High spirits consumption was associated with increased risk of cancer mortality.
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The objective of this study was to evaluate the impact of the 2005 British Columbia Ministry of Health Smoking Cessation Mass Media Campaign on short-term smoking behavior.
National cross-sectional data are used with a quasi-experimental approach to test the impact of the campaign.
Findings indicate that prevalence and average number of cigarettes smoked per day deviated upward from trend for the rest of Canada (P = .08; P = .01) but not for British Columbia. They also indicate that British Columbia smokers in lower risk groups reduced their average daily consumption of cigarettes over and above the 1999-2004 trend (-2.23; P = .10), whereas smokers in the rest of Canada did not, and that British Columbia smokers in high-risk groups did not increase their average daily consumption of cigarettes over and above the 1999-2004 trend, whereas smokers in the rest of Canada did (2.97; P = .01).
The overall poorer performance of high-risk groups is attributed to high exposure to cigarette smoking, which reduces a smoker's chances of successful cessation. In particular, high-risk groups are by definition more likely to be exposed to smoking by peers, but are also less likely to work in workplaces with smoking bans, which are shown to have a substantial impact on prevalence. Results suggest that for mass media campaigns to be more effective with high-risk groups, they need to be combined with other incentives, and that more prolonged interventions should be considered.
To provide updated, evidence-based recommendations for the prevention and management of hypertension in adults.
For lifestyle and pharmacological interventions, evidence was reviewed from randomized controlled trials and systematic reviews of trials. Changes in cardiovascular morbidity and mortality were the primary outcomes of interest. However, for lifestyle interventions, blood pressure lowering was accepted as a primary outcome given the lack of long-term morbidity and mortality data in this field. For treatment of patients with kidney disease, the progression of kidney dysfunction was also accepted as a clinically relevant primary outcome.
A Cochrane collaboration librarian conducted an independent MEDLINE search from 2005 to August 2006 to update the 2006 Canadian Hypertension Education Program recommendations. In addition, reference lists were scanned and experts were contacted to identify additional published studies. All relevant articles were reviewed and appraised independently by both content and methodological experts using prespecified levels of evidence.
Dietary lifestyle modifications for prevention of hypertension, in addition to a well-balanced diet, include a dietary sodium intake of less than 100 mmol/day. In hypertensive patients, the dietary sodium intake should be limited to 65 mmol/day to 100 mmol/day. Other lifestyle modifications for both normotensive and hypertensive patients include: performing 30 min to 60 min of aerobic exercise four to seven days per week; maintaining a healthy body weight (body mass index of 18.5 kg/m2 to 24.9 kg/m2) and waist circumference (less than 102 cm in men and less than 88 cm in women); limiting alcohol consumption to no more than 14 units per week in men or nine units per week in women; following a diet reduced in saturated fat and cholesterol, and one that emphasizes fruits, vegetables and low-fat dairy products, dietary and soluble fibre, whole grains and protein from plant sources; and considering stress management in selected individuals with hypertension. For the pharmacological management of hypertension, treatment thresholds and targets should take into account each individual's global atherosclerotic risk, target organ damage and any comorbid conditions: blood pressure should be lowered to lower than 140/90 mmHg in all patients and lower than 130/80 mmHg in those with diabetes mellitus or chronic kidney disease. Most patients require more than one agent to achieve these blood pressure targets. In adults without compelling indications for other agents, initial therapy should include thiazide diuretics; other agents appropriate for first-line therapy for diastolic and/or systolic hypertension include angiotensin-converting enzyme (ACE) inhibitors (except in black patients), long-acting calcium channel blockers (CCBs), angiotensin receptor blockers (ARBs) or beta-blockers (in those younger than 60 years of age). First-line therapy for isolated systolic hypertension includes long-acting dihydropyridine CCBs or ARBs. Certain comorbid conditions provide compelling indications for first-line use of other agents: in patients with angina, recent myocardial infarction, or heart failure, beta-blockers and ACE inhibitors are recommended as first-line therapy; in patients with cerebrovascular disease, an ACE inhibitor plus diuretic combination is preferred; in patients with nondiabetic chronic kidney disease, ACE inhibitors are recommended; and in patients with diabetes mellitus, ACE inhibitors or ARBs (or, in patients without albuminuria, thiazides or dihydropyridine CCBs) are appropriate first-line therapies. All hypertensive patients with dyslipidemia should be treated using the thresholds, targets and agents outlined in the Canadian Cardiovascular Society position statement (recommendations for the diagnosis and treatment of dyslipidemia and prevention of cardiovascular disease). Selected high-risk patients with hypertension who do not achieve thresholds for statin therapy according to the position paper should nonetheless receive statin therapy. Once blood pressure is controlled, acetylsalicylic acid therapy should be considered.
All recommendations were graded according to strength of the evidence and voted on by the 57 members of the Canadian Hypertension Education Program Evidence-Based Recommendations Task Force. All recommendations reported here achieved at least 95% consensus. These guidelines will continue to be updated annually.
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The present article is a summary of the theme, the key recommendations for management of hypertension and the supporting clinical evidence of the 2010 Canadian Hypertension Education Program (CHEP). In 2010, CHEP emphasizes the need for health care professionals to stay informed about hypertension through automated updates at www.htnupdate.ca. A new interactive Internet-based lecture series will be available in 2010 and a program to train community hypertension leaders will be expanded. Patients can also sign up to receive regular updates in a pilot program at www.myBPsite.ca. In 2010, the new recommendations include consideration for using automated office blood pressure monitors, new targets for dietary sodium for the prevention and treatment of hypertension that are aligned with the national adequate intake values, and recommendations for considering treatment of selected hypertensive patients at high risk with calcium channel blocker/angiotensin-converting enzyme inhibitor combinations and the use of angiotensin receptor blockers.
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Cox proportional hazards regression models are frequently used to determine the association between exposure and time-to-event outcomes in both randomized controlled trials and in observational cohort studies. The resultant hazard ratio is a relative measure of effect that provides limited clinical information.
A method is described for deriving absolute reductions in the risk of an event occurring within a given duration of follow-up time from a Cox regression model. The associated number needed to treat can be derived from this quantity. The method involves determining the probability of the outcome occurring within the specified duration of follow-up if each subject in the cohort was treated and if each subject was untreated, based on the covariates in the regression model. These probabilities are then averaged across the study population to determine the average probability of the occurrence of an event within a specific duration of follow-up in the population if all subjects were treated and if all subjects were untreated.
Risk differences and numbers needed to treat.
Absolute measures of treatment effect can be derived in prospective studies when Cox regression is used to adjust for possible imbalance in prognostically important baseline covariates.
PURPOSE: Evaluate the effects of radiotherapy after sector resection for ductal carcinoma in situ of the breast (DCIS) in patient groups as defined by age, size of the lesion, focality, completeness of excision and mode of detection. PATIENTS AND METHODS: A total of 1,067 women in Sweden were randomly assigned to either postoperative radiotherapy (RT) or control from 1987 to 1999, and 1,046 were followed for a mean of 8 years. The main outcome was new ipsilateral breast cancer events and distant metastasis-free survival analyzed according to intention to treat. RESULTS: There were 64 ipsilateral events in the RT arm and 141 in the control group corresponding to a risk reduction of 16.0 percentage points at 10 years (95% CI, 10.3% to 21.6%) and a relative risk of 0.40 (95% CI, 0.30 to 0.54). There was no statistically significant difference in distant metastasis-free survival. There was an effect modification by age, yielding a low effect of RT in women younger than 50, but substantial protection in women older than 60 years. The age effect was not confounded by focality, lesion size, completeness of excision, or detection mode. There was no group as defined by our stratification variables that had a low risk without radiotherapy. CONCLUSION: Our results indicate that younger women have a low protective effect of conventional RT after sector resection. Older women benefit substantially. We caution that the age effect was seen in a subgroup analysis. Further search with conventional clinical variables for a low risk group that does not need RT does not seem fruitful.
Logistic regression models are frequently used in cohort studies to determine the association between treatment and dichotomous outcomes in the presence of confounding variables. In a logistic regression model, the association between exposure and outcome is measured using the odds ratio (OR). The OR can be difficult to interpret and only approximates the relative risk (RR) in certain restrictive settings. Several authors have suggested that for dichotomous outcomes, RRs, RR reductions, absolute risk reductions, and the number needed to treat (NNT) are more clinically meaningful measures of treatment effect.
We describe a method for deriving clinically meaningful measures of treatment effect from a logistic regression model. This method involves determining the probability of the outcome if each subject in the cohort was treated and if each subject was untreated. These probabilities are then averaged across the study cohort to determine the average probability of the outcome in the population if all subjects were treated and if they were untreated.
Risk differences, RRs, and NNTs were derived using a logistic regression model.
Clinically meaningful measures of effect can be derived from a logistic regression model in a cohort study. These methods can also be used in randomized controlled trials when logistic regression is used to adjust for possible imbalance in prognostically important baseline covariates.
Acarbose for the prevention of Type 2 diabetes, hypertension and cardiovascular disease in subjects with impaired glucose tolerance: facts and interpretations concerning the critical analysis of the STOP-NIDDM Trial data.
Research Centre, Centre hospitalier de l'Université de Montréal-Hôtel-Dieu, Department of Medicine, University of Montreal, 3850 St. Urbain Street, Rm 8-202, Montreal, Quebec H2W 1T7, Canada. firstname.lastname@example.org
The STOP-NIDDM Trial has shown that acarbose treatment in subjects with impaired glucose tolerance is associated with a significant risk reduction in the development of diabetes, hypertension and cardiovascular complications. Kaiser and Sawicki have accused the investigators of the STOP-NIDDM Trial of major biases in the conduct of the study, of manipulating the data and of conflict of interest. The aim of this paper is to present data and explanations refuting these allegations. In the STOP-NIDDM Trial, 61 subjects were excluded from the efficacy analysis before unblinding for legitimate reasons: failure to satisfy major entry criteria (n=17) and lack of post-randomisation data (n=44). Blinding and randomisation were carried out by an independent biostatistician. Titration of placebo/acarbose is well described in the protocol and in the study design paper. Of the study population, 9.3% had a fasting plasma glucose of > or =7.0 mmol/l at screening and could have been diabetic according to the new diagnostic criteria. However, even if these subjects are excluded, patients having acarbose treatment still saw a significant risk reduction in the development of diabetes (p=0.0027). The changes in weight are consistent in different publications and are related to different times of follow-up and assessment. Weight change does have an effect on the development of diabetes, but acarbose treatment is still effective even after adjusting for this (p=0.0063). The cardiovascular endpoints were a clearly designated assessment in the original protocol, and only those defined in the protocol and ascertained by the independent Cardiovascular Event Adjudication Committee were used in the analysis. Hypertension was defined according to the most recent diagnostic criteria. The STOP-NIDDM Trial results are scientifically sound and credible. The investigators stand strongly behind these results demonstrating that acarbose treatment is associated with a delay in the development of diabetes, hypertension and cardiovascular complications in a high-risk population with IGT.