Erratum to: Association between Modifiable Risk Factors and Levels of Blood-Based Biomarkers of Alzheimer's and Related Dementias in the Look AHEAD Cohort.

[This corrects the article DOI: 10.14283/jarlife.2024.1.].

Association between Modifiable Risk Factors and Levels of Blood-Based Biomarkers of Alzheimer's and Related Dementias in the Look AHEAD Cohort.

Background: Emerging evidence suggests that a number of factors can influence blood-based biomarker levels for Alzheimer's disease (AD) and Alzheimer's related dementias (ADRD). We examined the associations that demographic and clinical characteristics have with AD/ADRD blood-based biomarker levels in an observational continuation of a clinical trial cohort of older individuals with type 2 diabetes and overweight or obesity. Methods: Participants aged 45-76 years were randomized to a 10-year Intensive Lifestyle Intervention (ILI) or a diabetes support and education (DSE) condition. Stored baseline and end of intervention (8-13 years later) plasma samples were analyzed with the Quanterix Simoa HD-X Analyzer. Changes in Aß42, Aß40, Aß42/Aß40, ptau181, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) were evaluated in relation to randomization status, demographic, and clinical characteristics. Results: In a sample of 779 participants from the Look AHEAD cohort, we found significant associations between blood-based biomarkers for AD/ADRD and 15 of 18 demographic (age, gender, race and ethnicity, education) and clinical characteristics (APOE, depression, alcohol use, smoking, body mass index, HbA1c, diabetes duration, diabetes treatment, estimated glomerular filtration rate, hypertension, and history of cardiovascular disease) . Conclusions: Blood-based biomarkers of AD/ADRD are influenced by common demographic and clinical characteristics. These factors should be considered carefully when interpreting these AD/ADRD blood biomarker values for clinical or research purposes.

The renin-angiotensin aldosterone system and osteoporosis: findings from the Women's Health Initiative.

New users of RAAS inhibitors, including ACE inhibitors and ARBs, have a small increased risk for fracture in the first 3 years of use, with a reduced risk of fracture with longer duration of use. INTRODUCTION: Pharmacological inhibitors of the renin-angiotensin aldosterone system (RAAS) are used to treat hypertension. However, the relationship of these medications to osteoporosis is inconsistent, and no study has included simultaneous measurements of both incident fractures and bone mineral density (BMD). METHODS: The association of RAAS inhibitor use (n = 131,793) with incident fractures in new users of these medications in women in the Women's Health Initiative over a minimum median follow-up of 6.5 years was assessed by Cox proportional hazard models. The association of incident fractures by a cumulative duration of use of these medications (< 3 years.) and (> 3 years.) was also estimated. Subgroup analysis of fracture risk by RAAS inhibitor use confined to women with hypertension was also performed (n = 33,820). The association of RAAS inhibitor use with changes in BMD of the hip was estimated by linear regression in 8940 women with dual energy X-ray absorptiometry measurements. RESULTS: There was no significant association between RAAS inhibitor use and all fractures in the final adjusted multivariable models including hip BMD (HR 0.86 (0.59, 1.24)). However, among users of RAAS inhibitors, including ACE inhibitors and angiotensin receptor blockers (ARBs), hazard ratios for all incident fracture sites in final multivariable models including hip BMD showed dramatic differences by duration of use, with short duration of use (3 years or less) associated with a marked increased risk for fracture (HR 3.28 (1.66, 6.48)) to (HR 6.23 (3.11, 12.46)) and use for more than 3 years associated with a reduced fracture risk (HR 0.40 (0.24, 0.68) to (HR 0.44 (0.20, 0.97)) . Findings were similar in the subgroup of women with a history of hypertension. There was no significant change in BMD of the hip by RAAS inhibitor use. CONCLUSIONS: In postmenopausal women, use of RAAS inhibitors, including ACE inhibitors and ARBs, is associated with an increased risk for fracture among new users of these medications in the first 3 years of use. However, long-term use (> 3 years) is associated with a reduced risk. Consideration for fracture risk may be part of the decision-making process for initiation of these medications for other disease states.

Oral bisphosphonate use and lung cancer incidence among postmenopausal women.

Background: Bisphosphonates are common medications for the treatment of osteoporosis in older populations. Several studies, including the Women's Health Initiative (WHI), have found inverse associations of bisphosphonate use with risk of breast and endometrial cancer, but little is known about its association with other common malignancies. The objective of this study was to evaluate the association of bisphosphonate use on the incidence of lung cancer in the WHI. Patients and methods: The association between oral bisphosphonate use and lung cancer risk was examined in 151 432 postmenopausal women enrolled into the WHI in 1993-1998. At baseline and during follow-up, participants completed an inventory of regularly used medications including bisphosphonates. Results: After a mean follow-up of 13.3 years, 2511 women were diagnosed with incident lung cancer. There was no evidence of a difference in lung cancer incidence between oral bisphosphonate users and never users (adjusted hazard ratio = 0.91; 95% confidence intervals, 0.80-1.04; P = 0.16). However, an inverse association was observed among those who were never smokers (hazard ratio = 0.57, 95% confidence interval, 0.39-0.84; P < 0.01). Conclusion: In this large prospective cohort of postmenopausal women, oral bisphosphonate use was associated with significantly lower lung cancer risk among never smokers, suggesting bisphosphonates may have a protective effect against lung cancer. Additional studies are needed to confirm our findings.

Mode of birth in twins: data and reflections.

Our primary objective was to compare neonatal and maternal outcomes in women with twin pregnancies, beyond 32 weeks, having a planned vaginal birth or a planned caesarean section (CS). This was a retrospective cohort study from a single tertiary centre over nine years. 534 sets of twins ≥32 + 0 weeks of gestation were included. 401 sets were planned vaginally and 133 sets were planned by CS. We compared a composite adverse perinatal outcome (perinatal mortality or serious neonatal morbidity; five minute APGAR score ≤4, neurological abnormality and need for intubation) and a composite maternal adverse outcome (major haemorrhage, trauma or infection) between the groups. There were no significant differences. Given the similarity of these results with several other larger studies of twin birth, we sought to look at reasons why there is still a rising rate of CS for twin births. We further make suggestions for keeping this rate to a sensible minimum. Impact statement What is already known on this subject? The largest randomised controlled study comparing planned vaginal birth with planned CSs for lower risk twins between 32 and 39 weeks of gestation, showed no added safety from planned CS. However, in most of the Western countries this conclusion has failed to increase the number of planned vaginal births for lower risk twins. What do the results of this study add? This observational study from a single tertiary centre provides external validation of the twin trial results in a practical day-to-day setting. It also provides insights as to how planned vaginal birth can be developed and maintained, with a key focus on safety and maternal participation in decision making. It does focus on consent and providing accurate data. What are the implications of these findings for clinical practice and/or further research? There are good grounds to encourage vaginal birth for low-risk twin pregnancies. The trend of rising caesarean rates in low-risk twin pregnancies worldwide will erode important skills for the conduct of vaginal births without any clear benefit for mothers or babies. The current situation demands careful thought about implementing innovative training opportunities for younger obstetricians. Finally, we need intelligent responses to many non-evidence-based factors which can drive clinical practice.

Benefit/risk for adjuvant breast cancer therapy with tamoxifen or aromatase inhibitor use by age, and race/ethnicity.

In early adjuvant breast cancer trial reports, aromatase inhibitors more effectively reduced breast recurrence with lower risk of thromboembolic events and endometrial cancer than tamoxifen, while aromatase inhibitors had higher fracture and cardiovascular disease risk. We used data from updated patient-level meta-analyses of adjuvant trials in analyses to summarize the benefits and risks of these agents in various clinical circumstances. Baseline incidence rates for health outcomes by age and race/ethnicity, absent aromatase inhibitor, or tamoxifen use were estimated from the Women's Health Initiative. Aromatase inhibitor and tamoxifen effects on distant recurrence were obtained from a meta-analysis of the Arimidex, Tamoxifen, Alone or in Combination (ATAC) and Breast International Group (Big-1-98) clinical trials. Impact on other health outcomes were obtained from meta-analyses of randomized trials comparing aromatase inhibitor to tamoxifen use and from placebo-controlled chemoprevention trials. All health outcomes were given equal weight when modeling net benefit/risk for aromatase inhibitor compared to tamoxifen use by breast cancer recurrence risk, age (decade), race/ethnicity, hysterectomy (yes/no), and by prior myocardial infarction. Over a 10-year period, the benefit/risk index was more favorable for aromatase inhibitor than for tamoxifen as adjuvant breast cancer therapy in almost all circumstances regardless of patient age, race/ethnicity, breast cancer recurrence risk, or presence or absence of a uterus. Only in older women with prior myocardial infarction and low recurrence risk was an advantage for tamoxifen seen. Using a benefit/risk index for endocrine adjuvant breast cancer therapy in postmenopausal women, benefit was higher for aromatase inhibitor use in almost all circumstances.

Status Report--Retracing the history of the early development of national chronic disease surveillance in Canada and the major role of the Laboratory Centre for Disease Control (LCDC) from 1972 to 2000.

TITRE: Rapport d'étape - Historique des débuts de la surveillance nationale des maladies chroniques au Canada et rôle majeur du Laboratoire de lutte contre la maladie (LLCM) de 1972 à 2000. INTRODUCTION: La surveillance de la santé consiste en l'utilisation systématique et continue de données sur la santé recueillies régulièrement en vue d'orienter les mesures de santé publique en temps opportun. Ce document décrit la création et l'essor des systèmes nationaux de surveillance au Canada et les répercussions de ces systèmes sur la prévention des maladies chroniques et des blessures. En 2008, les auteurs ont commencé à retracer l'historique des débuts de la surveillance nationale des maladies chroniques au Canada, en commençant à 1960, et ils ont poursuivi leur examen jusqu'en 2000. Une publication de 1967 a retracé l'historique de la création du Laboratoire d'hygiène de 1921 à 1967. Notre étude fait suite à cette publication et décrit l'historique de l'établissement de la surveillance nationale des maladies chroniques au Canada, à la fois avant et après la création du Laboratoire de lutte contre la maladie (LCDC).

Multivitamin and mineral use and breast cancer mortality in older women with invasive breast cancer in the women's health initiative.

Multivitamin use is common in the United States. It is not known whether multivitamins with minerals supplements (MVM) used by women already diagnosed with invasive breast cancer would affect their breast cancer mortality risk. To determine prospectively the effects of MVM use on breast cancer mortality in postmenopausal women diagnosed with invasive breast cancer, a prospective cohort study was conducted of 7,728 women aged 50-79 at enrollment in the women's health initiative (WHI) in 40 clinical sites across the United States diagnosed with incident invasive breast cancer during WHI and followed for a mean of 7.1 years after breast cancer diagnosis. Use of MVM supplements was assessed at WHI baseline visit and at visit closest to breast cancer diagnosis, obtained from vitamin pill bottles brought to clinic visit. Outcome was breast cancer mortality. Hazard ratios and 95 % confidence intervals (CIs) for breast cancer mortality comparing MVM users to non-users were estimated using Cox proportional hazard regression models. Analyses using propensity to take MVM were done to adjust for potential differences in characteristics of MVM users versus non-users. At baseline, 37.8 % of women reported MVM use. After mean post-diagnosis follow-up of 7.1 ± 4.1 (SD) years, there were 518 (6.7 %) deaths from breast cancer. In adjusted analyses, breast cancer mortality was 30 % lower in MVM users as compared to non-users (HR = 0.70; 95 % CI 0.55, 0.91). This association was highly robust and persisted after multiple adjustments for potential confounding variables and in propensity score matched analysis (HR = 0.76; 95 % CI 0.60-0.96). Postmenopausal women with invasive breast cancer using MVM had lower breast cancer mortality than non-users. The results suggest a possible role for daily MVM use in attenuating breast cancer mortality in women with invasive breast cancer but the findings require confirmation.

Generalization of adiposity genetic loci to US Hispanic women.

BACKGROUND: Obesity is a public health concern. Yet the identification of adiposity-related genetic variants among United States (US) Hispanics, which is the largest US minority group, remains largely unknown. OBJECTIVE: To interrogate an a priori list of 47 (32 overall body mass and 15 central adiposity) index single-nucleotide polymorphisms (SNPs) previously studied in individuals of European descent among 3494 US Hispanic women in the Women's Health Initiative SNP Health Association Resource (WHI SHARe). DESIGN: Cross-sectional analysis of measured body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) were inverse normally transformed after adjusting for age, smoking, center and global ancestry. WC and WHR models were also adjusted for BMI. Genotyping was performed using the Affymetrix 6.0 array. In the absence of an a priori selected SNP, a proxy was selected (r(2)0.8 in CEU). RESULTS: Six BMI loci (TMEM18, NUDT3/HMGA1, FAIM2, FTO, MC4R and KCTD15) and two WC/WHR loci (VEGFA and ITPR2-SSPN) were nominally significant (P<0.05) at the index or proxy SNP in the corresponding BMI and WC/WHR models. To account for distinct linkage disequilibrium patterns in Hispanics and further assess generalization of genetic effects at each locus, we interrogated the evidence for association at the 47 surrounding loci within 1 Mb region of the index or proxy SNP. Three additional BMI loci (FANCL, TFAP2B and ETV5) and five WC/WHR loci (DNM3-PIGC, GRB14, ADAMTS9, LY86 and MSRA) displayed Bonferroni-corrected significant associations with BMI and WC/WHR. Conditional analyses of each index SNP (or its proxy) and the most significant SNP within the 1 Mb region supported the possible presence of index-independent signals at each of these eight loci as well as at KCTD15. CONCLUSION: This study provides evidence for the generalization of nine BMI and seven central adiposity loci in Hispanic women. This study expands the current knowledge of common adiposity-related genetic loci to Hispanic women.

A rolling stone gathers no moss, but resistant plants must gather their moses.

The detection of pathogenic microbes by plant resistance (R) proteins and the subsequent activation of R protein-mediated immunity constitute an important layer in the plant innate immune system. Most R genes encode proteins with nucleotide-binding (NB) and leucine-rich repeat (LRR) domains. The autoimmune mutant suppressor of npr1, constitutive 1 (snc1), that constitutively activates resistance signaling, is a unique model used in our laboratory to dissect the details of TIR (Toll/Interleukin1 receptor)-NB-LRR, protein-mediated defense responses. Suppressor screens of snc1 yielded 15 modifier of snc1 (mos) complementation groups containing second-site mutations, and resulted in the identification of 13 novel MOS genes via either positional cloning or T-DNA tagging. Characterizations of the mos mutants have revealed important roles for transcriptional regulation, RNA processing, protein modifications, and nucleocytoplasmic trafficking in R protein-mediated immunity. The MOS genes have taught us a great deal about the complex mechanisms surrounding R protein activation. Future in-depth genetic and biochemical analyses will further enhance our knowledge of how R proteins are deliberately activated and how specific, targeted immunity is achieved in plants.

Evidence secondhand smoke causes breast cancer in 2005 stronger than for lung cancer in 1986.

OBJECTIVES: To compare the strength of evidence from epidemiologic studies of secondhand smoke of the US Surgeon General's 1986 conclusion that secondhand smoke caused lung cancer with the California Environmental Protection Agency's (CalEPA) similar 2005 conclusion on breast cancer in younger, primarily premenopausal women. METHODS: We reviewed each report for criteria used to assess causality: numbers of studies, statistically significant increases in risk, and pooled summary risk estimates. RESULTS: Both the Surgeon General and CalEPA used updated Bradford Hill criteria for assessing causality and found that the evidence met those criteria. Six of 13 lung cancer studies (46%) had statistically significant increases (one of three cohort studies). Pooled risk estimates for lung cancer for spousal exposure were 1.53 for 10 combined case-control studies and 1.88 for seven studies with dose-response results. The CalEPA reported 10 of 14 studies (71%) had statistically significant increases in breast cancer risk (two of four cohort studies). Pooled relative risk estimates for younger, primarily premenopausal women were 1.68 (95% CI: 1.33, 2.12) for all exposed women and 2.19 (1.68, 2.84) for five studies with better exposure assessment. CONCLUSIONS: The evidence from epidemiologic studies of secondhand smoke in 2005 for breast cancer in younger, primarily premenopausal women was stronger than for lung cancer in 1986.

Volumetric and areal bone mineral density measures are associated with cardiovascular disease in older men and women: the health, aging, and body composition study.

The associations of volumetric (vBMD) and areal (aBMD) bone mineral density measures with prevalent cardiovascular disease (CVD) and subclinical peripheral arterial disease (PAD) were investigated in a cohort of older men and women enrolled in the Health, Aging, and Body Composition Study. Participants were 3,075 well-functioning white and black men and women (42% black, 51% women), aged 68-80 years. Total hip, femoral neck, and trochanter aBMD were measured using dual-energy X-ray absorptiometry. Quantitative computed tomography was used to evaluate spine trabecular, integral, and cortical vBMD measures in a subgroup (n = 1,489). Logistic regression was performed to examine associations of BMD measures with CVD and PAD. The prevalence of CVD (defined by coronary heart disease, PAD, cerebrovascular disease, or congestive heart failure) was 29.8%. Among participants without CVD, 10% had subclinical PAD (defined as ankle-arm index <0.9). Spine vBMD measures were inversely associated with CVD in men (odds ratio of integral [OR(integral)] = 1.34, 95% confidence interval [CI] 1.10-1.63; OR(trabecular )= 1.25, 95% CI 1.02-1.53; OR(cortical )= 1.36, 95% CI 1.11-1.65). In women, for each standard deviation decrease in integral vBMD, cortical vBMD, or trochanter aBMD, the odds of CVD were significantly increased by 28%, 27%, and 22%, respectively. Total hip aBMD was associated with subclinical PAD in men (OR = 1.39, 95% CI 1.03-1.84) but not in women. All associations were independent of age and shared risk factors between BMD and CVD and were not influenced by inflammatory cytokines (interleukin-6 and tumor necrosis factors-alpha). In conclusion, our results provide further evidence for an inverse association between BMD and CVD in men and women. Future research should investigate common pathophysiological links for osteoporosis and CVD.

Cross-sectional correlates of fasting hyperinsulinaemia in post-menopausal women of different ethnic origin.

AIMS: In a large ethnically diverse nationwide sample of post-menopausal women we explored the relationship between fasting insulin levels, ethnicity, and a wide range of anthropometric, socio-economic, and lifestyle factors. METHODS: Subjects were post-menopausal women aged 50-79 years without diagnosed diabetes mellitus comprising a subsample (n = 3500) of the Women's Health Initiative (WHI) Clinical Trial and Observational Study. In a cross-sectional survey at baseline, we analysed the association between ethnicity and fasting insulin using analysis of covariance procedures and identified independent correlates of hyperinsulinaemia, defined by the 75th percentile cut point for each ethnic group. RESULTS: Fasting insulin levels were higher among African-American and Hispanic women than among non-Hispanic White or Asian women. These differences persisted after adjustment for age, educational attainment, total and central body obesity, adult weight change, family history of diabetes, smoking status, alcohol consumption, use of menopausal hormone therapy and physical activity. Higher levels of body mass index, waist-hip ratio, adult weight gain, and lower levels of total and moderate or strenuous recreational activity were independent correlates of fasting hyperinsulinaemia. Habitual walking was also inversely associated with fasting insulin. CONCLUSIONS: In this cross-sectional analysis, fasting insulin levels were higher among African-American and Hispanic post-menopausal women as compared with non-Hispanic White and Asian women. In addition, obesity, adult weight gain, and low levels of moderate or strenuous physical activity were independently associated with hyperinsulinaemia.

Specific fatty acid intake and the risk of pancreatic cancer in Canada.

The possible association of specific fatty acid (FA) intake and pancreatic cancer risk was investigated in a population-based case-control study of 462 histologically confirmed cases and 4721 frequency-matched controls in eight Canadian provinces between 1994 and 1997. Dietary intake was assessed by means of a self-administered food frequency questionnaire. Unconditional logistic regression was used to assess associations between dietary FAs and pancreatic cancer risk. After adjustment for age, province, body mass index, smoking, educational attainment, fat and total energy intake, statistically significant inverse associations were observed between pancreatic cancer risk and palmitate (odds ratios (ORs)=0.73; 95% confidence intervals (CIs) 0.56-0.96; P-trend=0.02), stearate (OR=0.70; 95% CI 0.51-0.94; P-trend=0.04), oleate (OR=0.75; 95% CI 0.55-1.02; P-trend=0.04), saturated FAs (OR=0.67; 95% CI 0.50-0.91; P-trend=0.01), and monounsaturated FAs (OR=0.72; 95% CI 0.53-0.98; P-trend=0.02), when comparing the highest quartile of intake to the lowest. Significant interactions were detected between body mass index and both saturated and monounsaturated FAs, with a markedly reduced risk associated with intake of stearate (OR=0.36; 95% CI 0.18-0.70; P-trend=0.001), oleate (OR=0.36; 95% CI 0.19-0.72; P-trend=0.002), saturated FAs (OR=0.35; 95% CI 0.18-0.67; P-trend=0.002), and monounsaturated FAs (OR=0.32; 95% CI 0.16-0.63; P-trend<0.0001) among subjects who are obese. The results suggest that substituting polyunsaturated FAs with saturated or monounsaturated FAs may reduce pancreatic cancer risk, independently of total energy intake, particularly among obese subjects.

Alcohol, tobacco and breast cancer--collaborative reanalysis of individual data from 53 epidemiological studies, including 58,515 women with breast cancer and 95,067 women without the disease.

Alcohol and tobacco consumption are closely correlated and published results on their association with breast cancer have not always allowed adequately for confounding between these exposures. Over 80% of the relevant information worldwide on alcohol and tobacco consumption and breast cancer were collated, checked and analysed centrally. Analyses included 58,515 women with invasive breast cancer and 95,067 controls from 53 studies. Relative risks of breast cancer were estimated, after stratifying by study, age, parity and, where appropriate, women's age when their first child was born and consumption of alcohol and tobacco. The average consumption of alcohol reported by controls from developed countries was 6.0 g per day, i.e. about half a unit/drink of alcohol per day, and was greater in ever-smokers than never-smokers, (8.4 g per day and 5.0 g per day, respectively). Compared with women who reported drinking no alcohol, the relative risk of breast cancer was 1.32 (1.19-1.45, P<0.00001) for an intake of 35-44 g per day alcohol, and 1.46 (1.33-1.61, P<0.00001) for >/=45 g per day alcohol. The relative risk of breast cancer increased by 7.1% (95% CI 5.5-8.7%; P<0.00001) for each additional 10 g per day intake of alcohol, i.e. for each extra unit or drink of alcohol consumed on a daily basis. This increase was the same in ever-smokers and never-smokers (7.1% per 10 g per day, P<0.00001, in each group). By contrast, the relationship between smoking and breast cancer was substantially confounded by the effect of alcohol. When analyses were restricted to 22 255 women with breast cancer and 40 832 controls who reported drinking no alcohol, smoking was not associated with breast cancer (compared to never-smokers, relative risk for ever-smokers=1.03, 95% CI 0.98-1.07, and for current smokers=0.99, 0.92-1.05). The results for alcohol and for tobacco did not vary substantially across studies, study designs, or according to 15 personal characteristics of the women; nor were the findings materially confounded by any of these factors. If the observed relationship for alcohol is causal, these results suggest that about 4% of the breast cancers in developed countries are attributable to alcohol. In developing countries, where alcohol consumption among controls averaged only 0.4 g per day, alcohol would have a negligible effect on the incidence of breast cancer. In conclusion, smoking has little or no independent effect on the risk of developing breast cancer; the effect of alcohol on breast cancer needs to be interpreted in the context of its beneficial effects, in moderation, on cardiovascular disease and its harmful effects on cirrhosis and cancers of the mouth, larynx, oesophagus and liver.

Health Opportunities with Physical Exercise (HOPE): social contextual interventions to reduce sedentary behavior in urban settings.

Physical activity interventions targeting social and physical environments of the urban poor hold promise in improving health outcomes in underserved communities. This study randomly assigned overweight, sedentary, economically disadvantaged adults to one of three intervention conditions at The Hope and Healing Center, a large inner-city health facility providing numerous options for exercise. Within the tenets of Social Action Theory, the Health Opportunities with Physical Exercise (HOPE) trial will test the efficacy of two behavior change models, social support and patient-provider interaction, to increase physical activity. In addition to a standard care condition, in which patients have open access to Hope and Healing physical activity programming, patients were assigned to one of two behavior change interventions. Those assigned to patient-peer receive face-to-face, systematic and scheduled encouragement from study-trained 'peer' interventionists at the facility. Patients assigned to patient-provider receive face-to-face, systematic and scheduled encouragement provided by study-trained 'provider' interventionists also at the facility. The primary outcomes of change in exercise behavior will be documented by self-reported physical activity and confirmed by fitness testing at baseline, 6, 12 and 24 months during the 1 year of active intervention and 1 year of relapse prevention follow-up. Intervention conditions will be compared on psychosocial mediators including motivational appraisals, ratings of social support, rapport, problem solving and self-efficacy for overcoming barriers to increased physical activity. Novel aspects of this intervention include: (1) delivery of socially based physical activity interventions to an economically disadvantaged urban population, (2) reduction of environmental barriers to be physically active and (3) emphasis on social interactions influencing health habit change. Results of this study have the potential to identify mechanisms of behavior change that could be adopted by physical activity interventions aimed at reducing sedentary behavior and health disparities in high-risk, underserved populations.

Risk factors for male breast cancer in Canada, 1994-1998.

Relatively little attention has been paid to the aetiology of male breast cancer and the current understanding of female breast cancer, primarily related to reproductive events, cannot be readily transferred to understanding the cancer in males. However, since male breast cancer occurs in the absence of factors related to childbearing and menstruation, its aetiology may provide special insights into the causes of breast cancer in women. We examined lifestyle risk factors for male breast cancer as part of a Canadian, multi-site, population-based, case-control study. Eighty-one newly diagnosed, histologically confirmed cases and 1905 male controls aged 42-74 were analysed using unconditional logistic regression. Increased risks were found for men with a mother or sister with breast cancer (adjusted odds ratio (OR) 3.65, 95% confidence interval (95% CI) 1.62-8.19). Higher physical activity levels (moderate, and strenuous recreational plus occupational) were associated with a decreased risk of male breast cancer (highest quartile, adjusted OR 0.48, 95% CI 0.26-0.91). Similarly, higher risks were associated with higher weight 2 years before interview (2.19, 95% CI 1.08-4.43), maximum weight (OR 2.66) and higher body mass index (OR 1.60). Higher vegetable consumption and coffee consumption were associated with decreased risk, whereas higher beta-carotene, vitamin E and calcium supplementation were associated with statistically significant increased risk. The small number of cases and multiple comparisons preclude strong conclusions, but our study is consistent with studies suggesting obesity and family history increase risk, and physical activity decreases risk of breast cancer.

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, > or =28.3 kg/m(2)) 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 < or =2.9% loss (> or =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 > or =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.