Anthony J. G. Hanley

Physical activity, anthropometric factors and risk of pancreatic cancer: Results from the Canadian enhanced cancer surveillance system

To explore the hypothesis that insulin resistance may be an etiologic factor in pancreatic cancer, we assessed the pancreatic cancer risk associated with anthropometric factors and physical activity, both of which are important determinants of insulin sensitivity in humans. Three hundred and twelve patients with histologically confirmed pancreatic cancer were compared to 2,919 controls in a population‐based, case‐control study in 7 of the 10 Canadian provinces. Participants were asked to report their exposure status for the period 2 years before interview. Men in the highest quartile of body mass index (BMI, ≥28.3 kg/m2) were at increased risk of pancreatic cancer [adjusted odds ratio (OR) = 1.90, 95% confidence interval (CI) 1.08–3.35]. In addition, men who reported a decrease in weight of at least 2.9% from their lifetime maximum were at reduced risk compared to those reporting a ≤2.9% loss (≥10.2% loss, OR = 0.51, 95% CI 0.30–0.86). BMI 2 years before interview was not associated with pancreatic cancer risk among women, though those reporting a ≥12.5% decrease in weight from their lifetime maximum had substantially lower risk compared to those in the baseline quartile (OR = 0.53, 95% CI 0.29–0.99). After adjustment for age, province of residence, dietary intake and anthropometric factors, men in the highest quartile of the composite moderate and strenuous physical activity index were at reduced risk of pancreatic cancer (OR = 0.53, 95% CI 0.31–0.90). Physical activity did not appear to be associated with pancreatic cancer among women, though a tendency for reduced risk with increasing levels of strenuous activity was suggested (p for trend = 0.06). Our findings support the hypothesis that insulin resistance is an etiologic factor in the development of pancreatic neoplasms among men and possibly women.

The impact of diabetes on cardiovascular risk factors and outcomes in a native Canadian population

We measured cardiovascular disease (CVD) risk factors and their relationship to glucose intolerance in a Native Canadian population with very high rates of Type 2 diabetes mellitus. Five hundred and twenty five study-eligible Ojibwa-Cree individuals age 18 and over in the community of Sandy Lake, Canada who had participated in a population-based survey were studied. Diabetes status, plasma concentrations of total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), calculated low density lipoprotein-cholesterol (LDL-C), waist/hip ratio (WHR), BMI, systolic and diastolic BP, and history of smoking were compared to a standard national population. Extremely high rates of obesity (BMI and WHR) were identified in the study population and were associated with increasing glucose intolerance for both males and females. Rates of smoking exceeded 70 and 80% in females and males, respectively. Interestingly, despite obesity individuals who had normal glucose tolerance had significantly lower rates of high risk TC, TG, LDL-C, and HDL-C levels compared to a national Canadian population survey. However, with worsening glucose intolerance, TC, TG, LDL-C and HDL-C dramatically deteriorated in comparison to nationally published levels. These changes in cardiovascular risk factors, as a consequence of diabetes, appear to result in increased clinical outcomes. Admission to hospital for Ischemic Heart Disease (IHD) for Sandy Lake residents increased from a rate of 34.8/10,000 to 109.1/10,000 in 15 years. Although this and similar populations have historically reported low rates of CVD, the impact of diabetes on lipid risk factor is having devastating consequences on cardiovascular outcomes. This trend is expected to continue unless the high rates of diabetes can be modified.

Exercise Interventions in Obese Youth : Are They Effective?

Given the increasing prevalence of childhood obesity, effective and cost-efficient strategies to enhance childrens physical activity levels are needed. Unfortunately, exercise interventions evaluated to date have had little impact on overweight and obesity in youth. Physical activity counseling interventions have emerged as an effective and inexpensive alternative to traditional, structured exercise programs in adults, and may be an interesting option for the treatment of obesity in youth.

Association between AGT codon 235 polymorphism and variation in serum concentrations of creatinine and urea in Canadian Oji-Cree

Finding the genetic determinants of intermediate quantitative traits, such as serum creatinine and urea, might aid in finding the determinants of disease phenotypes, such as renal failure, that are, in part, defined according to threshold values imposed upon such traits. We evaluated the association between common variation in the gene encoding angiotensinogen, AGT, and the serum concentrations of creatinine and urea in non‐diabetic Canadian Oji‐Cree. We determined genotypes of the AGT codon 235 polymorphism among 502 non‐diabetic Oji‐Cree. We used multivariate analysis of variance to identify significant determinants of variation in serum concentrations of creatinine and urea and of systolic and diastolic blood pressure. We found significant associations between the AGT codon 235 genotype and serum concentrations of creatinine and urea (p=0.017 and 0.049, respectively) and systolic blood pressure (p=0.041). Compared with subjects with the other two genotypes, homozygotes for AGT T235/T235 had significantly lower serum concentrations of creatinine and urea and significantly higher mean systolic blood pressure. The findings suggest that the AGT T235 allele is a determinant of intermediate traits related to renal function in these aboriginal Canadians.