Association between aluminum in drinking water and incident Alzheimer's disease in the Canadian Study of Health and Aging cohort.

Epidemiological evidence linking aluminum in drinking water and Alzheimer's disease (AD) has been inconsistent, with previous studies often limited by small sample sizes. The present study addresses this issue using data from the Canadian Study of Health and Aging (CSHA), a prospective cohort of 10,263 subjects followed-up from 1991-1992 through 2001-2002. Participants' residential histories were linked to municipal drinking water sources in 35 Canadian municipalities to obtain ecologic pH, aluminum, fluoride, iron and silica concentrations in drinking water. Cox proportional hazards models were used to examine associations between aluminum and incident AD [Hazard Ratios (HRs), 95% confidence intervals (CIs)], adjusting for age, gender, history of stroke, education, and high blood pressure. A total of 240 incident AD cases were identified during follow-up of 3, 638 subjects derived from the CSHA cohort with complete data on all covariates. With categorical aluminum measurements, there was an increasing, but not statistically significant, exposure-response relationship (HR = 1.34, 95% CI 0.88-2.04, in the highest aluminum exposure category; p = 0.13 for linear trend). Similar results were observed using continuous aluminum measurements (HR=1.21, 95% CI 0.97-1.52, at the interquartile range of 333.8 µg/L; p = 0.09 for linear trend). In a subsample genotyped for ApoE-ε4, there was some evidence of an association between aluminum and AD (p = 0.03 for linear trend). Although a clear association between aluminum in drinking water and AD was not found, the linear trend observed in ApoE-ε4 subsample warrants further examination.

Cancer-Related Pain: A Longitudinal Study of Time to Stable Pain Control and Its Clinicodemographic Predictors.

CONTEXT: Multidimensional assessment is pivotal in managing cancer-related pain. OBJECTIVES: The objectives of this study were to determine time to stable pain control (SPC) and identify its baseline clinicodemographic predictors in patients with cancer pain. METHODS: This is a prospective longitudinal study of patients attending a cancer pain clinic. Scheduled clinic attendances and weekly investigator-led phone calls enabled monitoring of patients' daily pain diary, opioid use, and other analgesic interventions. Baseline clinicodemographic variables were examined in survival analyses, which included the construction of accelerated failure time models with time ratios [TRs, (95% CIs)], based on time to SPC (pain intensity ≤3 and <3 breakthrough opioid doses over three consecutive days) for variable categories. RESULTS: Of 319 participants, 22 died before achieving SPC and were censored in the survival analysis. The median survival time (95% CI) to SPC was 22 (19-25) days. In multivariable analysis, compared to their respective reference categories, female sex (P = 0.001), substance abuse (P < 0.001), a neuropathic pain component (P < 0.001), and use of ≥1 adjuvant analgesic (P = 0.022) each had TRs > 1 (1.03-2.54), whereas soft tissue pain (P < 0.001) had a TR = 0.71 (0.62-0.82), reflecting longer and shorter time to SPC, respectively. CONCLUSION: SPC is achievable for most patients with cancer pain. Recognition of strong predictors of time to SPC, such as substance abuse, a neuropathic pain component, soft tissue pain, and current use of adjuvant analgesia, may help to triage care services based on therapeutic need and guide analgesic interventions.

Determinants of neurological disease: Synthesis of systematic reviews.

Systematic reviews were conducted to identify risk factors associated with the onset and progression of 14 neurological conditions, prioritized as a component of the National Population Health Study of Neurological Conditions. These systematic reviews provided a basis for evaluating the weight of evidence of evidence for risk factors for the onset and progression of the 14 individual neurological conditions considered. A number of risk factors associated with an increased risk of onset for more than one condition, including exposure to pesticides (associated with an increased risk of AD, amyotrophic lateral sclerosis, brain tumours, and PD; smoking (AD, MS); and infection (MS, Tourette syndrome). Coffee and tea intake was associated with a decreased risk of onset of both dystonia and PD. Further understanding of the etiology of priority neurological conditions will be helpful in focusing future research initiatives and in the development of interventions to reduce the burden associated with neurological conditions in Canada and internationally.

Off-label use of cancer therapies in women diagnosed with breast cancer in the United States.

PURPOSE: To determine the level of off-label cancer therapy use in a population of female breast cancer patients and to establish whether this use was evidence-based. METHODS: A study was conducted by sampling Cerner's data warehouse for all women diagnosed with breast cancer between January 2000 and June 2009 who received at least one cancer therapy approved by the US-FDA during the study period. Drug encounters were considered off-label if the circumstances of use did not match the age or medical diagnoses specified on the product label at the time of study. The level of evidence for the use of these drugs in a breast cancer setting was evaluated from randomized phase III trials using a tiered approach. RESULTS: The study included 2,663 women with a median age of 59 years. A total of 1,636 off-label encounters were recorded, representing 13.0% of all encounters. Of the 65 cancer therapies investigated, 55.4% were prescribed off-label. The drugs with the highest off-label use were, in a descending order, vinorelbine, carboplatin, bevacizumab, leuprolide, liposomal doxorubicin and cisplatin. Most off-label encounters were evidence-based and more likely to be associated with private insurance coverage, younger age, ethnicities other than Caucasian, smaller treatment centres and drugs with limited labeled indications that have a longer market history. CONCLUSIONS: Off-label prescribing is common practice in oncology and is an integral component of breast cancer treatment strategies. While this practice tends to be associated with specific socio-demographic factors and disease characteristics, the majority of off-label encounters appear to be evidence-based.

The impact of taxation reduction on smoking in youth between 1990 and 1999: results from a reconstructed cohort analysis of the Canadian Community Health Surveys.

BACKGROUND: Increases in taxation can contribute to smoking control. In the early 1990's, tobacco smuggling rates in Canada increased dramatically. Governments responded with a substantial reduction in taxes on tobacco products. This study examines the impact of these tax changes on smoking in youth in Canada. METHODS: Data on smoking from three consecutive cycles of the Canadian Community Health Surveys were combined and analyzed using a reconstructed cohort approach. Age, sex and calendar year specific rates of smoking experimentation and the onset of daily smoking were estimated for youth. Estimates apply to the entire Canadian population. RESULTS: There was a strong increase in smoking in youth in the years following the reduction in tobacco taxes. The increase was stronger in women. The rates returned to pre-1990 rates by about 2002. The number of excess daily smokers for people born between 1977 and 1985 that can be linked to the taxation reduction is about 190,000. INTERPRETATION: There is strong evidence that reduction of tobacco taxes to combat smuggling had an adverse impact on smoking rates in youth.

Estimates of global mortality attributable to particulate air pollution using satellite imagery.

BACKGROUND: Epidemiological studies of the health effects of air pollution have traditionally relied upon ground-monitoring stations to measure ambient concentrations. Satellite derived air pollution measures offer the advantage of providing global coverage. OBJECTIVE: To undertake a global assessment of mortality associated with long-term exposure to fine particulate air pollution using remote sensing data. METHODS: Global PM(2.5) exposure levels were derived from the MODIS and MISR satellite instruments. Relative risks and attributable fractions of mortality were modeled using previously developed concentration-response functions for the association between PM(2.5) and mortality. RESULTS: The global fraction of adult mortality attributable to the anthropogenic component of PM(2.5) (95% CI) was 8.0% (5.3-10.5) for cardiopulmonary disease, 12.8% (5.9-18.5) for lung cancer, and 9.4% (6.6-11.8) for ischemic heart disease. CONCLUSION: This study demonstrates the feasibility of using satellite derived pollution concentrations in assessing the population health impacts of air pollution at the global scale. This approach leads to global estimates of mortality attributable to PM(2.5) that are greater than those based on fixed site ground-level measures of urban PM(2.5), but more similar to estimates based on global chemical transport model simulations of anthropogenic PM(2.5).

Readiness to shop for low-fat foods: a population study.

BACKGROUND: Stages of change are related to dietary fat consumption. Few studies have examined stage occupation within the context of purchasing low-fat foods. OBJECTIVE: To determine the stage-prevalence of individuals for purchasing low-fat foods; identify the frequency of misclassification into action and maintenance (A/M) stages for purchasing for low-fat foods; and explain the demographic and cognitive-variable differences between pseudo (or false positive) A/M and true A/M individuals. DESIGN: Data were collected using a self-administered questionnaire among English-speaking adults (n=1,001) who were randomly sampled by mail. STATISTICAL ANALYSES PERFORMED: Descriptive statistics were used to compare the characteristics of the stage groups. Groups were compared using chi(2) tests and Student t test. RESULTS: Of those who reported being in A/M stages, 32% were misclassified by the staging algorithm and were not true A/M low-fat food purchasers. CONCLUSIONS: Individuals who are in A/M stages for buying low-fat foods still purchase high-fat foods. Stage misclassification may be a persistent problem in studies of dietary change using the Transtheoretical Model.

Applying the stages of change to multiple low-fat dietary behavioral contexts. An examination of stage occupation and discontinuity.

Consuming a diet lower in total fat is important for the prevention of many chronic diseases. Individual and population-based programs targeting this behavior must be theoretically grounded and consider the context within which dietary behavior change may be attempted. To identify the factors differentiating stage of readiness to follow a low-fat diet, a sample (N=1216) of adults was surveyed using 4 different staging algorithms to assess stages of change and associated social-cognitive variables (pros, cons, and temptation). Approximately 75% of the sample occupied the Action/Maintenance stages for all staging algorithms. In general, pros increased and cons decreased with higher stage occupation. Temptation decreased from the early pre-action to the action stages for the different staging algorithms. When developing programs to decrease dietary-fat intake, social-cognitive variables associated with stage transition for behaviors related to consuming a low-fat diet may have relevance to researchers and clinicians.

Occupations and lung cancer: a population-based case-control study in British Columbia.

An investigation based on a large population-based case-control study in British Columbia, Canada, was conducted to identify high-risk occupations for lung cancer by histological subtypes. Subjects were 14,755 male incident cancer cases for whom lifetime occupational histories and information on smoking and relevant covariates were collected. Occupational associations for 2998 lung cancer cases, including histological subtypes, were assessed by logistic regression using other cancer cases, excluding smoking-related cancers, as controls. An excess risk of lung cancer was found among workers in metal processing, bakers, and ship deck crew for all histological subtypes, and construction workers, chefs and cooks, and medical workers for specific histological subtypes. Occupational associations that are unique to histological subtypes of lung cancer were identified. Owing to a scarcity of literature in this area, future research needs to focus on confirming these histological associations, and identifying the risk from key exposures found within these occupations (e.g., medical radiation, electromagnetic fields, and cooking fumes).

The efficacy of stage-matched and standard public health materials for promoting physical activity in the workplace: the Physical Activity Workplace Study (PAWS).

PURPOSE: To compare the effects of stage-matched and standard print materials for physical activity (PA) change. DESIGN: Participants were randomized into (1) a stage-matched intervention group (n = 165), (2) a standard intervention group (n = 176), or (3) a no-contact control group (n = 166). The stage-matched and standard intervention groups both received materials at baseline, 3 months, and 6 months. Assessments of all three groups were conducted at baseline, 6, and 12 months. SETTING: Canadian worksites. SUBJECTS: Employees (N = 507). INTERVENTIONS: Five motivationally targeted booklets were developed for the stage-matched group. The standard group received Canada's Physical Activity Guide and handbook. MEASURES: The main dependent variable was PA, expressed as metabolic equivalent (MET) minutes and measured using the Godin Leisure-Time Exercise Questionnaire. Demographic characteristics and stages of change for PA were also assessed. RESULTS: At 12 months mean weekly MET minutes for combined moderate and vigorous activity increased from baseline by 223, 67, and 78 for the stage-matched, standard, and control groups, respectively; however, differences were not significant (p > .05). Women in the stage-matched group over the 12-month period significantly increased their activity by 327 weekly MET minutes whereas the standard and control groups declined their activity (F = 3.01, p < .05). CONCLUSION: PA stage-matched materials delivered in the workplace are efficacious for women but not men. Future interventions should explore the use of these intervention materials in conjunction with multilevel strategies, and particular attention should be paid to possible gender differences.

Co-morbidity, functionality and time since diagnosis as predictors of physical activity in individuals with type 1 or type 2 diabetes.

Physical activity plays a key role in diabetes management, and in reducing the risk factors related to the development of co-morbid conditions. This study examined predictors of physical activity (Static Model) and activity change (Change Model) for individuals with type 1 (T1D) or type 2 diabetes (T2D) in a population sample of 1662 adults (510 type 1; 1152 type 2) using self-reported measures of co-morbidities, perceived difficulties in performing tasks of daily living (TDL), time since diagnosis, and selected demographic factors. Since the motivation for physical activity could be influenced by the initial diagnosis of diabetes, analyses were conducted separately for newly diagnosed individuals (diagnosed with diabetes < or =1 year), and those that have been diagnosed for sometime (diagnosed with diabetes >1 year). In the Static Model, a younger age (beta=-.11, p<.05) and having less perceived difficulties in performing TDL (beta=-.12, p<.05) were associated with a higher physical activity in individuals with type 1 diabetes. The presence of difficulties in TDL (beta=-.08, p<.05) and co-morbidities (beta=-.08, p<.05) were associated with physical activity participation in type 2 individuals diagnosed for >1 year, but not in newly diagnosed individuals. A shorter duration of disease (beta=-.07, p<.05), a higher body mass index (BMI) (beta=.09, p<.05) and female gender (beta=.07, p<.05) was associated with physical activity increase in individuals with type 2 diabetes. A higher BMI predicted physical activity change in both newly diagnosed individuals and those diagnosed for sometime. However, both genders were equally likely to increase their physical activity among newly diagnosed individuals. Although the magnitude of the study results are relatively modest, they could potentially guide and encourage future investigations in this area that could lead to useful insights in designing PA intervention programs for these specific populations.

Chlorination disinfection by-products and pancreatic cancer risk.

Chlorination disinfection by-products (CDBPs) are produced during the treatment of water with chlorine to remove bacterial contamination. CDBPs have been associated with an increased risk of bladder cancer. There is also some evidence that they may increase the risk of pancreatic cancer. We report results from a population-based case-control study of 486 incident cases of pancreatic cancer and 3,596 age- and sex-matched controls. Exposure to chlorination by-products was estimated by linking lifetime residential histories to two different databases containing information on CDBP levels in municipal water supplies. Logistic regression analysis found no evidence of increased pancreatic cancer risk at higher CDBP concentrations (all odds ratios < 1.3). Null findings were also obtained assuming a latency period for pancreatic cancer induction of 3, 8, or 13 years.

Cancer incidence patterns among Chinese immigrant populations in Alberta.

This study examines the incidence of cancer among Chinese immigrants to Alberta in comparison to the incidence in Canadian-born Alberta residents and in people of Chinese origin still living in China. Cancer cases among Chinese immigrants and Canadian-born Alberta residents were identified from the Alberta Cancer Registry (1974-1993). Incidence rates for Shanghai (1975-1992) were obtained from the International Agency for Research on Cancer (IARC) publications. Direct age-standardized incidence rates (ASIRs) were calculated using the "world standard population." Descriptive analysis and Poisson regression modelling were employed to obtain the rate ratios for certain cancer sites among the three populations. For males, the overall incidence of cancer (excluding non-melanoma skin cancer) was lowest in Chinese immigrants while being similar in Canadian-born Alberta residents and Chinese living in Shanghai (197 vs. 224 and 232/100,000). For females, the overall incidence in Chinese immigrants was lower than Canadian-born Alberta residents but similar to that in Chinese living in Shanghai (154 vs 200 and 150/100,000). For cancers that are common in China (stomach and esophagus), the incidence rates for Chinese immigrants were more similar to those for Canadian-born residents than to rates for Shanghai. However, the incidence of liver cancer was very high in the immigrants, suggesting the possible presence of an initiating event during childhood or early adulthood. For cancers that are traditionally uncommon in China (breast and prostate), rates for immigrants were mid-way between those of the two comparison groups. This study supports observations that the risk of cancer in immigrants tends towards the risk of people in the new host country.

Dietary risk factors for testicular carcinoma.

Although testicular cancer is a relatively rare lesion, accounting for only 1.1% of all malignant neoplasms in males in Canada, it is the most common cancer among Canadian men 20-45 years of age. Knowledge of the causes of testicular cancer risk in general, and more specifically, its association with diet, remain limited. Data from 601 cases of testicular cancer and 744 population-based controls collected in 8 of the 10 Canadian provinces between 1994-97 were used to explore the relationship between diet and testicular cancer risk. We systematically examined 17 food groups, 15 nutrients and 4 individual foods based on data collected through a 69-item food-frequency questionnaire. Our results suggest that high dairy product intake, in particular high intake of cheese (odds ratio [OR] = 1.87; 95% confidence interval [CI] 1.22-2.86; p-trend < 0.001), is associated with an elevated risk of testicular cancer in Canadian males.