Reduced incidence of diabetes during the COVID-19 pandemic in Alberta: A time-segmented longitudinal study of Alberta's Tomorrow Project

AIM

To characterize the impact of the COVID-19 pandemic on diabetes diagnosis using data from Alberta's Tomorrow Project (ATP), a population-based cohort study of chronic diseases in Alberta, Canada.

MATERIALS AND METHODS

The ATP participants who were free of diabetes on 1 April 2018 were included in the study. A time-segmented regression model was used to compare incidence rates of diabetes before the COVID-19 pandemic, during the first two COVID-19 states of emergency, and in the period when the state of emergency was relaxed, after adjusting for seasonality, sociodemographic factors, socioeconomic status, and lifestyle behaviours.

RESULTS

Among 43 705 ATP participants free of diabetes (65.5% females, age 60.4 ± 9.5 years in 2018), the rate of diabetes was 4.75 per 1000 person-year (PY) during the COVID-19 pandemic (up to 31 March 2021), which was 32% lower (95% confidence interval [CI] 21%, 42%; p < 0.001) than pre-pandemic (6.98 per 1000 PY for the period 1 April 2018 to 16 March 2020). In multivariable regression analysis, the first COVID-19 state of emergency (first wave) was associated with an 87.3% (95% CI -98.6%, 13.9%; p = 0.07) reduction in diabetes diagnosis; this decreasing trend was sustained to the second COVID-19 state of emergency and no substantial rebound (increase) was observed when the COVID-19 state of emergency was relaxed.

CONCLUSIONS

The COVID-19 public health emergencies had a negative impact on diabetes diagnosis in Alberta. The reduction in diabetes diagnosis was likely due to province-wide health service disruptions during the COVID-19 pandemic. Systematic plans to close the post-COVID-19 diagnostic gap are required in diabetes to avoid substantial downstream sequelae of undiagnosed disease.

Factors associated with change in moderate or severe symptoms of anxiety and depression in community-living adults and older adults during the COVID-19 pandemic

OBJECTIVES

Few are the longitudinal studies on the changes in moderate or severe symptoms of anxiety or depression (MSS-ANXDEP) from before to during the COVID-19 pandemic in Canada. The aim was to study the change in MSS-ANXDEP and associated sociodemographic, economic, psychosocial, health behaviour and lifestyle, and clinical factors.

METHODS

The current sample includes 59,997 adults aged ≥ 35 years participating in the 2018 and 2020 health surveys of the 5 established cohorts of the Canadian Partnership for Tomorrow's Health (CanPath). MSS-ANXDEP was based on a cutoff score ≥ 10 on the 7-item Generalized Anxiety Disorder Scale and Patient Health Questionnaire (PHQ-8). Change in MSS-ANXDEP was categorized as follows: no MSS-ANXDEP, remitted, incident, and persistent. Multinomial regressions were used to study MSS-ANXDEP as a function of sociodemographic, economic, psychosocial, health behaviours and lifestyle, and clinical factors.

RESULTS

Sociodemographic and economic (i.e. age, gender, cohort, race/ethnicity, lower income, decreased in income, work status, being an essential worker), lifestyle and health behaviours (i.e. smoking, cannabis and alcohol use, drinking more alcohol), psychosocial (i.e. provide help to others, information and instrumental support, and change in relationships with friends, family, and partner) and clinical factors (i.e. lifetime mental disorder and multimorbidity) were associated with remitted, incident, and persistent MSS-ANXDEP.

CONCLUSION

Health and socio-economic factors were associated with changes in symptoms of anxiety and depression during the pandemic, further increasing inequities in mental health needs. Public health campaigns on the importance of healthy behaviours should continue and health policies should reduce economic and social barriers to integrated substance use and mental health care.

Factors associated with mental health service use during the pandemic: Initiation and barriers

BACKGROUND

Scarce are the studies focusing on initiation of new mental health service use (MHSU) and distinguishing individuals who have sought services but have been unsuccessful in accessing these.

AIMS

Assessing the factors associated with initiating new MHSU as compared to no MHSU due to self-reported no need, no MHSU due to health system and personal barriers and MHSU using resources already in place.

METHODS

The sample included participants (n = 16,435) in the five established regional cohorts of the Canadian Partnership for Tomorrow's Health (CanPath) who responded to the CanPath COVID-19 health surveys (May-December 2020 and January-June 2021). Multinomial regression analyses were carried out to study MHSU since the pandemic (March 2020) as a function of predisposing, enabling and need factors. Analyses were carried out in the overall sample and restricted to those with moderate and severe symptoms (MSS) of depression and/or anxiety (n = 2,237).

RESULTS

In individuals with MSS of depression and/or anxiety, 14.4% reported initiating new MHSU, 22.0% had no MHSU due to barriers and personal reasons and 36.7% had no MHSU due to self-reported no need. Age, living alone, lower income, a decrease in income during the pandemic and health professional status were associated with MHSU. Younger adults were more likely to initiate MHSU during the pandemic than older adults who reported not being comfortable to seek mental health care or self-reported no need. Individuals living alone and with lower income were more likely to report not being able to find an appointment for mental health care.

CONCLUSIONS

Awareness campaigns focusing on older adults that explain the importance of seeking treatment is needed, as well as sensitising health professionals as to the importance of informing and aiding individuals at risk of social isolation and lower socio-economic status as to available mental health resources and facilitating access to care.

Development of the Canadian Eating Practices Screener to assess eating practices based on 2019 Canada's Food Guide recommendations

In 2019, Health Canada released a new iteration of Canada's Food Guide (2019-CFG), which, for the first time, highlighted recommendations regarding eating practices, i.e., guidance on where, when, why, and how to eat. The objective of this study was to develop a brief self-administered screener to assess eating practices recommended in the 2019-CFG among adults aged 18-65 years. Development of the screener items was informed by a review of existing tools and mapping of items onto 2019-CFG recommendations. Face and content validity were assessed with experts in public health nutrition and/or dietary assessment (n = 16) and individuals from Government of Canada (n = 14). Cognitive interviews were conducted with English-speaking (n = 16) and French-speaking (n = 16) adults living in Canada to assess face validity and understanding of the screener items. While some modifications were identified to improve relevance or clarity, overall, the screener items were found to be relevant, well-constructed, and clearly worded. This comprehensive process resulted in the Canadian Eating Practices Screener/Questionnaire court canadien sur les pratiques alimentaires, which includes 21 items that assess eating practices recommended in the 2019-CFG. This screener can facilitate monitoring and surveillance efforts of the 2019-CFG eating practices as well as research exploring how these practices are associated with various health outcomes.

Non-fasting lipids and cardiovascular disease in those with and without diabetes in Alberta's Tomorrow Project: A prospective cohort study

AIMS

Non-fasting remnant cholesterol (RC) is a novel marker of cardiovascular disease (CVD) risk, however, data on this relationship in Canadians with diabetes (at high risk of CVD) is lacking. The objective of this analysis was to determine the relationship of RC with CVD in individuals with and without diabetes in the Alberta's Tomorrow Project (ATP) cohort.

METHODS

Non-fasting lipid data collected as part of the ATP was linked to administrative health records (October 2000-March 2015) to ascertain incident CVD and prevalent diabetes. Participants without prevalent CVD or incident diabetes and who had complete, non-negative non-fasting lipid data collected with triglycerides <4.5 mmol/L were included (n = 13,631). The relationship between non-fasting RC and incident CVD diagnoses was assessed by Cox proportional hazards regression, after stratification by diabetes status.

RESULTS

Participants were 69.8% women with a mean age of 61.6 ± 9.7 years, and 6.5% had prevalent diabetes. Non-fasting RC was higher in participants with diabetes compared to those without (mean 0.94 ± 0.41 mmol/L vs. 0.77 ± 0.38 mmol/L, p < 0.0001) and was associated with increased risk of incident CVD among those without diabetes (adjusted hazard ratio (aHR) 1.22, 95% CI 1.03-1.43, p = 0.02). Although a similar trend was observed in participants with diabetes it did not reach statistical significance (aHR 1.31, 95% CI 0.84-2.05, p = 0.23).

CONCLUSIONS

Elevated non-fasting RC predicted increased CVD risk in middle and older-aged adults without diabetes; similar trends were observed in participants with diabetes and require further testing in a larger sample.

Development of the Canadian Food Intake Screener to assess alignment of adults' dietary intake with the 2019 Canada's Food Guide healthy food choices recommendations

NOVELTY

The Canadian Food Intake Screener was developed to rapidly assess alignment of adults' dietary intake over the past month with the Food Guide's healthy food choices recommendations. The screener was developed and evaluated through an iterative process that included three rounds of cognitive interviews in each of English and French, along with ongoing feedback from external advisors and face and content validity testing with a separate panel of content experts. The 16-question screener is intended for use with adults, aged 18-65 years, with marginal and higher health literacy in research and surveillance contexts in which comprehensive dietary assessment is not possible.

Nonfasting remnant cholesterol and cardiovascular disease risk prediction in Albertans: a prospective cohort study

BACKGROUND

European studies have shown that nonfasting remnant cholesterol can be a strong predictor of cardiovascular disease risk and may contribute to identifying residual risk; however, Canadian data are lacking on nonfasting remnant cholesterol. In this study, we aimed to determine the relation between nonfasting remnant cholesterol, low-density lipoprotein (LDL) cholesterol and cardiovascular disease among people in Alberta.

METHODS

In this retrospective analysis, we used data from Alberta's Tomorrow Project, a large prospective cohort that enrolled Albertans aged 35-69 years (2000-2015). Participants with consent to data linkage, with complete nonfasting lipid data and without existing cardiovascular disease were included. The nonfasting remnant cholesterol and LDL cholesterol relation with a composite cardiovascular disease outcome of major incident cardiovascular diagnoses, ascertained by linking to Alberta Health databases, was determined by multivariable logistic regression, adjusting for age, sex, statin use, comorbidities, and LDL cholesterol or remnant cholesterol.

RESULTS

The final sample of 13 988 participants was 69.4% female, and the mean age was 61.8 (standard deviation [SD] 9.7) years. Follow-up time was approximately 15 years. Mean remnant cholesterol was significantly higher among individuals with versus without cardiovascular disease (0.87 [SD 0.40] mmol/L v. 0.78 [SD 0.38] mmol/L, standardized mean difference [SMD] -0.24), and mean LDL cholesterol was significantly lower (2.69 [SD 0.93] mmol/L v. 2.88 [SD 0.84] mmol/L, SMD 0.21). The odds of incident composite cardiovascular disease were significantly increased per mmol/L increase in remnant cholesterol (adjusted odds ratio [OR] 1.48, 95% confidence interval [CI] 1.27-1.73) but significantly decreased per mmol/L increase in LDL cholesterol (adjusted OR 0.73, 95% CI 0.68-0.79).

INTERPRETATION

In this large Albertan cohort of predominantly older females, nonfasting remnant cholesterol had a positive relation with cardiovascular disease incidence, whereas LDL cholesterol did not. These findings support the clinical utility of measuring non-fasting remnant cholesterol to detect cardiovascular disease risk.

An ecological analysis of walkability and housing affordability in Canada: Moderation by city size and neighbourhood property type composition

The neighbourhood built environment can support the physical activity of adults regardless of their individual-level socioeconomic status. However, physical activity supportive (walkable) neighbourhoods may not be accessible to those with lower incomes if homes in walkable neighbourhoods are too expensive. The objectives of this study were: 1) to estimate the associations between neighbourhood walkability and home values in Canadian cities, and 2) to test whether these associations differ by city size and residential property type composition within neighbourhoods. We linked built environment data from the 2016 Canadian Active Living Environments (Can-ALE) index with neighbourhood-level structural home characteristics and sociodemographic data from the 2016 Canadian census for 33,026 neighbourhoods across 31 Census Metropolitan Areas. We used multilevel linear regression models to estimate covariate-adjusted associations between neighbourhood walkability and natural-log median home values and tested city size and neighbourhood property type composition as moderators. There were no statistically significant associations between walkability and home values overall. The associations between neighbourhood walkability and home values were jointly moderated by city size and property type composition. For small and medium sized cities, within neighbourhoods containing a high proportion of detached homes, walkability was negatively associated with home values (b = -0.05, 95% CI: -0.10, -0.01; and, b = -0.04, 95% CI: -0.06, -0.02, for small and medium cities, respectively). However, for extra-large cities, within neighbourhoods containing a high proportion of detached homes, walkability was positively associated with home values (b = 0.06, 95% CI: 0.01, 0.10). Our findings suggest that, based on housing affordability, higher walkable neighbourhoods are likely accessible to lower income households that are situated in small and medium Canadian cities. In larger cities, however, municipal interventions (e.g., inclusionary zoning or targeted development of subsidized or social housing) may be needed to ensure equitable access to walkable neighbourhoods for lower income households.

The Canadian Food Intake Screener for assessing alignment of adults' dietary intake with the 2019 Canada's Food Guide healthy food choices recommendations: Scoring system and construct validity

The Canadian Food Intake Screener/Questionnaire court canadien sur les apports alimentaires was developed to rapidly assess alignment of adults' dietary intake over the past month with the 2019 Canada's Food Guide's healthy food choices recommendations. From July to December 2021, adults (n=154) aged 18-65 years completed the screener and up to two 24-hour dietary recalls. The screener scoring system was aligned with the Healthy Eating Food Index-2019 (HEFI-2019), to the extent possible. ANOVA compared screener scores among subgroups with known differences in diet quality. Using the recall data, the National Cancer Institute multivariate method was used to model HEFI-2019 components, with the screener score as a covariate, and the correlation coefficient between screener and total HEFI-2019 scores was estimated. The mean screener score was 35 points (SD=4.7; maximum, 65), ranging from 25 (1st percentile) to 45 (99th percentile). Differences in scores in hypothesized directions were evident by gender identity (p=0.06), perceived income adequacy (p=0.07), education (p=0.02), and smoking status (p=0.003). The correlation between screener and HEFI-2019 scores was 0.53 (SE=0.12). The screener's moderate construct validity supports its use for rapid assessment of alignment of adults' intake with the healthy food choices recommendations when comprehensive dietary assessment is not possible.

Mental health service use and associated predisposing, enabling and need factors in community living adults and older adults across Canada

OBJECTIVES

Using Andersen's model of health care seeking behavior, we examined the predisposing, enabling, and need factors associated with mental health service use (MHSU) during the first wave of the COVID-19 pandemic across Canada.

METHODS

The sample included n = 45,542 participants in the 5 established regional cohorts of the Canadian Partnership for Tomorrow's Health (CanPath) and who responded to the CanPath COVID-19 health survey (May-December 2020), with complete data on MHSU. Multivariable logistic regression analyses were carried out to study MHSU as a function of predisposing, enabling, and need factors. Analyses were stratified by regional cohort.

RESULTS

Among the need factors, individuals reporting moderate/severe symptoms of depression and anxiety and poorer self-rated mental health were more likely to report MHSU. Among the enabling factors, receipt of informational/financial/practical support was associated with increased MHSU. While income was not consistently associated with MHSU, reported decrease in income was marginally associated with reduced MHSU. Among the predisposing factors, identifying as female or other gender minority was associated with increased MHSU, as was the presence of past-year cannabis use. In contrast, older age and alcohol consumption were associated with reduced MHSU.

CONCLUSION

Need factors were consistently associated with MHSU. Although income inequities in MHSU were not observed, changes such as reduced income during the pandemic may lead to barriers in accessing mental health services. Future research should focus on better identifying contextual enabling factors and policies that overcome financial barriers to MHSU.

Impact of Co-morbidity on Hospitalization and Emergency Room Visits in People with Diabetes: A Longitudinal Study of Alberta’s Tomorrow Project

OBJECTIVE

Our aim in this study was to characterize the impact of comorbidities, including number and types, on hospitalization and emergency room (ER) visits in people with diabetes.

METHODS

Incident cases of diabetes from Alberta's Tomorrow Project with >24 months of follow-up were included. Comorbidities, classified by Elixhauser conditions, were updated every 12 months after diagnosis. A generalized estimating equation model was used to examine the association (by incidence rate ratio [IRR]) between time-varying comorbidity profile and hospitalization and ER visits per year of follow-up after adjusting for sociodemographic factors, lifestyle behaviours, and historic health-care utilization in the previous 5 years.

RESULTS

Among 2,110 incident cases of diabetes (51.0% females; median age at diagnosis: 59.5 years; median follow-up: 7.19 years), the average number of Elixhauser comorbidities was 1.9±1.6 in the first year of diagnosis and 3.3±2.0 in year 15 after diagnosis. The number of comorbidities in the previous year was positively associated with risk of hospitalization (IRR=1.33 [95% confidence interval {CI}: 1.04 to 1.70] and 2.14 [95% CI: 1.67 to 2.74] for 1 or 2 and ≥2 comorbidities, respectively) and ER visits (IRR=1.31 [95% CI: 1.15 to 1.50] and 1.62 [95% CI: 1.41 to 1.87] for 1 or 2 and ≥2 comorbidities, respectively) in the subsequent year. Cardiovascular diseases, peripheral vascular diseases, cancer, liver disease, fluid and electrolyte disorders, and depression were the conditions most typically associated with increased health-care utilization.

CONCLUSIONS

The number of comorbidities was a major risk factor of health-care utilization for people with diabetes. Vascular diseases, cancer, and conditions closely related to diabetic frailty (e.g. fluid and electrolyte disorders and depression) were the main drivers of hospital care and ER visits.

Associations between neighborhood walkability and walking following residential relocation: Findings from Alberta's Tomorrow Project

Introduction

Cross-sectional studies consistently find that the neighborhood built environment (e.g., walkability) is associated with walking. However, findings from the few existing longitudinal residential relocation studies that have estimated associations between changes in neighborhood built characteristics and walking are equivocal. The study objective was to estimate whether changes in neighborhood walkability resulting from residential relocation were associated with leisure, transportation, and total walking levels among adults.

Methods

This study included longitudinal data from the "Alberta's Tomorrow Project"-a province-wide cohort study (Alberta, Canada). The analysis included data collected at two time points (i.e., baseline and follow-up) from 5,977 urban adults. The International Physical Activity Questionnaire (IPAQ) captured self-reported walking. We estimated neighborhood walkability, an index capturing intersection, destination, and population counts for the 400 m Euclidean buffer around participants' homes. Using household postal codes reported at baseline and follow-up, we categorized participants into three groups reflecting residential relocation ("non-movers:" n = 5,679; "movers to less walkability:" n = 164, and; "movers to more walkability:" n = 134). We used Inverse-Probability-Weighted Regression Adjustment to estimate differences [i.e., average treatment effects in the treated (ATET)] in weekly minutes of leisure, transportation, and total walking at follow-up between residential relocation groups, adjusting for baseline walking, sociodemographic characteristics, and walkability. The median time between baseline and follow-up was 2-years.

Results

The three residential relocation groups mainly included women (61.6-67.2%) and had a mean age of between 52.2 and 55.7 years. Compared to "non-movers" (reference group), weekly minutes of transportation walking at follow-up was significantly lower among adults who moved to less walkable neighborhoods (ATET: -41.34, 95 CI: -68.30, -14.39; p < 0.01). We found no other statistically significant differences in walking between the groups.

Discussion

Our findings suggest that relocating to less walkable neighborhoods could have detrimental effects on transportation walking to the extent of adversely affecting health. Public health strategies that counteract the negative impacts of low walkable neighborhoods and leverage the supportiveness of high walkable neighborhoods might promote more walking.

Cross-sectional and longitudinal associations between the built environment and walking: effect modification by socioeconomic status

BACKGROUND

Although socioeconomic status (SES) has been shown to modify associations between the neighborhood built environment and physical activity, contradictory results exist. Objectives of this cross-sectional and longitudinal analysis were to: 1) examine whether overall neighborhood walkability and specific built characteristics were associated with walking among adults at a single point in time and after they relocate neighborhoods, and 2) test for effect modification of these associations by SES.

METHODS

We linked longitudinal data from 703 adults who relocated urban neighborhoods between two waves of Alberta's Tomorrow Project (2008-2015) to neighborhood built environment data. We created a walkability index from measures of population counts, street connectivity, and destination diversity within 400 m of participants' homes. In cross-sectional analyses, we used generalized linear models to estimate associations between built characteristics and minutes walked per week at baseline. For the longitudinal analyses, we used fixed-effects linear regression models to estimate associations between changes in built characteristics and minutes walked per week. We also assessed if indicators of SES (individual education or household income) modified both sets of associations.

RESULTS

Most cross-sectional and longitudinal associations were small and statistically non-significant. Neighborhood population count (b = 0.03, 95% CI: 0.01, 0.07) and street connectivity (b = - 1.75, 95% CI: - 3.26, - 0.24) were cross-sectionally associated with walking duration among the overall sample. None of the longitudinal associations were statistically significant among the overall sample. There was limited evidence of effect modification by SES, however, we found negative cross-sectional associations between street connectivity and walking among adults with lower education and income, and a positive association between percent change in walkability and change in walking among lower educated adults.

CONCLUSIONS

Despite population count and street connectivity being associated with walking at baseline, changes in these built environment variables were not associated with changes in walking following residential relocation. Our findings also provide evidence, albeit weak, that changes in neighborhood walkability, resulting from residential relocation, might more strongly affect walking among low SES adults. Further longitudinal research is needed to examine built environment characteristics with walking for different purposes and to test for inequitable socioeconomic impacts.

Anti-Hyperglycemic Medication Adherence and Health Services Utilization in People with Diabetes: A Longitudinal Study of Alberta's Tomorrow Project

BACKGROUND

Little is known about the long-term (>2 years) relationship between the time-varying drug adherence and healthcare utilization for patients with diabetes.

OBJECTIVE

To characterize the relationship between time-varying anti-hyperglycemic medication adherence and healthcare utilization in patients with diabetes, using data from Alberta's Tomorrow Project, a population-based cohort study in Alberta, Canada.

METHODS

Incident cases of diabetes with at least 24 months of follow-up were included in the study. Anti-hyperglycemic drug adherence was measured by proportion of days covered (PDC) in the past 12 months for each year after diagnosis. The rate of healthcare utilization was assessed for the subsequent 12 months, 36 months and 60 months. A time-varying, negative binomial generalized estimating equation model was used to examine the association between medication adherence and healthcare utilization.

RESULTS

Among 2155 incident cases of diabetes, average age at diagnosis was 59.6±9.3, 51.0% were female and average duration of follow-up was 7.3±3.7 (range, 2.0-16.2) years. The proportion of patients taking anti-hyperglycemic medications was 47.6% during the first year of diagnosis, which increased to 77.3% by the end of follow-up. Compared to adherent patients (PDC≥0.8), non-adherent patients (PDC<0.8) had substantially higher rate of all-cause hospitalization [incident rate ratio, IRR=1.48 (1.22-1.79), ED visits [1.30 (1.15-1.47)] and GP visits [1.17 (1.08-1.27)] in the subsequent 12 months. However, these associations became weaker with longer follow-up [eg, IRR=1.18 (0.98-1.39) and 1.05 (0.94-1.18) for all-cause hospitalization in the subsequent 36 and 60 months, respectively].

CONCLUSION

Poor adherence among diabetic patients was associated with substantially higher rate of healthcare utilization in the short term (eg, 12 months); however, this association weakened over a longer period (eg, 36-60 months).

Chronic disease surveillance in Alberta's tomorrow project using administrative health data

Introduction

Alberta’s Tomorrow Project (ATP) is the largest population-based prospective cohort study of cancer and chronic diseases in Alberta, Canada. The ATP cohort data were primarily self-reported by participants on lifestyle behaviors and disease risk factors at the enrollment, which lacks sufficient and accurate data on chronic disease diagnosis for longer-term follow-up.

Objectives

To characterize the occurrence rate and trend of chronic diseases in the ATP cohort by linking with administrative healthcare data.

Methods

A set of validated algorithms using ICD codes were applied to Alberta Health (AH) administrative data (October 2000-March 2018) linked to the ATP cohort to determine the prevalence and incidence of common chronic diseases.

Results

There were 52,770 ATP participants (51.2±9.4 years old at enrollment and 63.7% females) linked to the AH data with average follow-up of 10.1±4.4 years. In the ATP cohort, hypertension (18.5%), depression (18.1%), chronic pain (12.8%), osteoarthritis (10.1%) and cardiovascular diseases (8.7%) were the most prevalent chronic conditions. The incidence rates varied across diseases, with the highest rates for hypertension (22.1 per 1000 person-year), osteoarthritis (16.2 per 1000 person-year) and ischemic heart diseases (13.0 per 1000 person-year). All chronic conditions had increased prevalence over time (p < for trend tests), while incidence rates were relatively stable. The proportion of participants with two or more of these conditions (multi-morbidity) increased from 3.9% in 2001 to 40.3% in 2017.

Conclusions

This study shows an increasing trend of chronic diseases in the ATP cohort, particularly related to cardiovascular diseases and multi-morbidity. Using administrative health data to monitor chronic diseases for large population-based prospective cohort studies is feasible in Alberta, and our approach could be further applied in a broader research area, including health services research, to enhance research capacity of these population-based studies in Canada.

Effect of Cognitive Reserve on the Association of Vascular Brain Injury With Cognition: Analysis of the PURE and CAHHM Studies

BACKGROUND AND OBJECTIVES

To determine whether cognitive reserve attenuates the association of vascular brain injury with cognition.

METHODS

Cross-sectional data were analyzed from 2 harmonized studies: the Canadian Alliance for Healthy Hearts and Healthy Minds (CAHHM) and the Prospective Urban and Rural Epidemiology (PURE) study. Markers of cognitive reserve were education, involvement in social activities, marital status, height, and leisure physical activity, which were combined into a composite score. Vascular brain injury was defined as nonlacunar brain infarcts or high white matter hyperintensity (WMH) burden on MRI. Cognition was assessed using the Montreal Cognitive Assessment Tool (MoCA) and the Digit Symbol Substitution Test (DSST).

RESULTS

There were 10,916 participants age 35-81. Mean age was 58.8 years (range 35-81) and 55.8% were female. Education, moderate leisure physical activity, being in a marital partnership, being taller, and participating in social groups were each independently associated with higher cognition, as was the composite cognitive reserve score. Vascular brain injury was associated with lower cognition (β -0.35 [95% confidence interval [CI] -0.53 to -0.17] for MoCA and β -2.19 [95% CI -3.22 to -1.15] for DSST) but the association was not modified by the composite cognitive reserve variable (interaction p = 0.59 for MoCA and p = 0.72 for DSST).

CONCLUSIONS

Both vascular brain injury and markers of cognitive reserve are associated with cognition. However, the effects were independent such that the adverse effects of covert vascular brain injury were not attenuated by higher cognitive reserve. To improve cognitive brain health, interventions to both prevent cerebrovascular disease and promote positive lifestyles are needed.

A Prospective Analysis of Plasma Phospholipid Fatty Acids and Breast Cancer Risk in 2 Provinces in Canada

BACKGROUND

Studies suggest that fatty acid status influences breast cancer etiology, yet the roles of individual fatty acids in breast cancer risk are unclear, specifically when central adiposity and menopausal status are considered.

OBJECTIVES

This study examined the associations of fatty acid status with breast cancer risk including location, menopausal status, and waist-to-hip ratio as key variables.

METHODS

Prediagnostic plasma phospholipid fatty acids were measured in women with breast cancer (n = 393) and age-matched controls (n = 786) from a nested case-control prospective study within Alberta's Tomorrow Project (ATP) and British Columbia Generations Project (BCGP) cohorts. Binary logistic regression models were used to evaluate associations of fatty acids and breast cancer risk with subgroup analysis for menopausal status and waist-to-hip ratio.

RESULTS

Women from BCGP had a higher n-3 (ɷ-3) fatty acid status compared with the ATP (6.4% ± 0.08% vs. 5.3% ± 0.06%; P < 0.001), so subsequent analysis was blocked by cohort. Overall, fatty acids had inconsistent associations with risk. In the ATP among premenopausal women, total long-chain n-3 fatty acids (ORQ4vsQ1 = 1.78; 95% CI: 0.58, 5.43; P-trend = 0.007, P-interaction = 0.07) were positively associated with breast cancer risk, whereas in BCGP, DHA (ORQ4vsQ1 = 0.66; 95% CI: 0.28, 1.53; P-trend = 0.03, P-interaction = 0.05) and total long-chain n-3 fatty acids (ORQ4vsQ1 = 0.66; 95% CI: 0.28, 1.54; P-trend = 0.03) were associated with decreased cancer risk when the waist-to-hip ratio was <0.85.

CONCLUSIONS

Our findings suggest that regional variations in fatty acid status influence breast cancer risk, resulting in positive associations of total long-chain n-3 fatty acids in premenopausal ATP women and negative associations of these fatty acids in BCGP women with a waist-to-hip ratio below guidelines. This study highlights the complexity and difficulty in using fatty acid status to predict breast cancer risk in diverse populations without the consideration of other risk factors.

High-throughput LC-MS method to investigate postprandial lipemia: considerations for future precision nutrition research

Elevated postprandial lipemia is an independent risk factor for cardiovascular disease, yet methods to quantitate postmeal handling of dietary lipids in humans are limited. This study tested a new method to track dietary lipid appearance using a stable isotope tracer (²H₁₁-oleate) in liquid meals containing three levels of fat [low fat (LF), 15 g; moderate fat (MF), 30 g; high fat (HF), 60 g]. Meals were fed to 12 healthy men [means ± SD, age 31.3 ± 9.2 yr, body mass index (BMI) 24.5 ± 1.9 kg/m²] during four randomized study visits; the HF meal was administered twice for reproducibility. Blood was collected over 8 h postprandially, triglyceride (TG)-rich lipoproteins (TRL), and particles with a Svedberg flotation rate >400 (S_f > 400, n = 8) were isolated by ultracentrifugation, and labeling of two TG species (54:3 and 52:2) was quantified by LC-MS. Total plasma TRL-TG concentrations were threefold greater than S_f > 400-TG. Both S_f > 400- and TRL-TG 54:3 were present at higher concentrations than 52:2, and singly labeled TG concentrations were higher than doubly labeled. Furthermore, TG 54:3 and the singly labeled molecules demonstrated higher plasma absolute entry rates differing significantly across fat levels within a single TG species (P < 0.01). Calculation of fractional entry showed no significant differences in label handling supporting the utility of either TG species for appearance rate calculations. These data demonstrate the utility of labeling research meals with stable isotopes to investigate human postprandial lipemia while simultaneously highlighting the importance of examining individual responses. Meal type and timing, control of prestudy activities, and effects of sex on outcomes should match the research goals. The method, optimized here, will be beneficial to conduct basic science research in precision nutrition and clinical drug development.NEW & NOTEWORTHY A novel method to test human intestinal lipid handling using stable isotope labeling is presented and, for the first time, plasma appearance and lipid turnover were quantified in 12 healthy men following meals with varying amounts of fat. The method can be applied to studies in precision nutrition characterizing individual response to support basic science research or drug development. This report discusses key questions for consideration in precision nutrition that were highlighted by the data.

Administering a combination of online dietary assessment tools, the Automated Self-Administered 24-Hour Dietary Assessment Tool, and Diet History Questionnaire II, in a cohort of adults in Alberta's Tomorrow Project

BACKGROUND

Evidence suggests that combining tools that gather short- and long-term dietary data may be the optimal approach for the assessment of diet-disease associations in epidemiologic studies. Online technology can reduce the associated burdens for researchers and participants, but feasibility must be demonstrated in real-world settings before wide-scale implementation.

OBJECTIVE

The objective of this study was to determine the feasibility and acceptability of combining web-based tools (the Automated Self-Administered 24-hour Dietary Assessment Tool [ASA24-2016] and the past-year Diet History Questionnaire II [DHQ-II]) in a subset of participants in Alberta's Tomorrow Project, a prospective cohort.

DESIGN

For this feasibility study, invitations were mailed to 550 randomly selected individuals enrolled in Alberta's Tomorrow Project. Consented participants (n = 331) were asked to complete a brief sociodemographic and health questionnaire, four ASA24-2016 recalls, the DHQ-II, and an evaluation survey.

PARTICIPANTS/SETTING

The study was conducted from March 2016 to December 2016 in Alberta, Canada. The majority of participants, mean age (SD) = 57.4 (9.8) years, were women (70.7%), urban residents (85.5%), and nonsmokers (95.7%).

MAIN OUTCOME MEASURES

Primary outcomes were number of ASA24-2016 recalls completed, response rate of DHQ-II completion, and time to complete each assessment.

STATISTICAL ANALYSES

The Wilcoxon signed rank sum test was used to assess differences in completion time.

RESULTS

One-third (n = 102) of consenting participants did not complete any ASA24-2016 recalls. The primary reason to withdraw from the feasibility study was a lack of time. Among consenting participants, 51.9% (n = 172), 41.1% (n = 136), and 36.5% (n = 121) completed at least two ASA24-2016 recalls, the DHQ-II, and at least two ASA24-2016 recalls plus the DHQ-II, respectively. Median (25th to 75th percentile) completion times for participants who completed all recalls were 39 minutes (25 to 53 minutes) for the first ASA24-2016 recall and 60 minutes (40 to 90 minutes) for the DHQ-II.

CONCLUSIONS

Findings indicate combining multiple ASA24-2016 recalls and the DHQ-II is feasible in this subset of Alberta's Tomorrow Project participants. However, optimal response rates may be contingent on providing participant support. Completion may also be sensitive to timing and frequency of recall administration.

Associations between the built environment and physical activity among adults with low socio-economic status in Canada: a systematic review

OBJECTIVE

To synthesize literature on the associations between the built environment and physical activity among adults with low socio-economic status (SES) in Canada.

METHODS

Using a pre-specified study protocol (PROSPERO ID: CRD42019117894), we searched seven databases from inception to November 2018, for peer-reviewed quantitative studies that (1) included adults with low SES living in Canada and (2) estimated the association between self-reported or objectively measured built characteristics and self-reported or objectively measured physical activity. Study quality was assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Findings were synthesized using a narrative approach.

SYNTHESIS

Of the 8338 citations identified by our search, seven studies met the inclusion criteria. Most studies included adults living in one province (Alberta, British Columbia, Ontario, or Quebec), with one study including a national sample. All studies were cross-sectional, and none controlled for residential self-selection. Sampling designs and data collection strategies were heterogeneous. Sample sizes ranged between 78 and 37,241 participants. Most studies measured SES using household income. Street connectivity, greenness, destination density, and walkability were positively associated with physical activity. Relative to the objectively measured built environment, associations between the self-reported built environment and physical activity were less consistent. Studies were of fair to good quality.

CONCLUSION

Findings suggest that the neighbourhood built environment is associated with physical activity among adults with low SES in Canada. More rigorous study designs are needed to determine whether or not the built environment and physical activity are causally related within this vulnerable population.

Associations between the neighbourhood characteristics and body mass index, waist circumference, and waist-to-hip ratio: Findings from Alberta's Tomorrow Project

This study estimated the associations between neighbourhood characteristics and self-reported body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) risk categories among Canadian men and women. Using data from the Alberta's Tomorrow Project (n = 14,550), we estimated 3- and 4-way intersections, business destinations, population count, and normalized difference vegetation index (NDVI) within a 400 m radius of participant's home. Intersections, business destinations, and population count (z-scores) were summed to create a walkability score. Four-way intersections and walkability were negatively associated with overweight and obesity. Walkability was negatively associated with obesity. NDVI was negatively associated with high-risk WHR and population count and walkability positively associated with high-risk WHR. Among men, population count and walkability were negatively associated with obesity, and business destinations and walkability were negatively associated with overweight and obesity. Among women, NDVI was negatively associated with overweight (including obesity), obesity, and high-risk WC. Interventions promoting healthy weight could incorporate strategies that take into consideration local built environment characteristics.

A population-based study of the associations between neighbourhood walkability and different types of physical activity in Canadian men and women

Few Canadian studies have examined whether or not associations between neighbourhood walkability and physical activity differ by sex. We estimated associations between perceived neighbourhood walkability and physical activity among Canadian men and women. This study included cross-sectional survey data from participants in 'Alberta's Tomorrow Project' (Canada; n = 14,078), a longitudinal cohort study. The survey included socio-demographic items as well as the International Physical Activity Questionnaire (IPAQ) and the abbreviated Neighbourhood Environment Walkability Scale (NEWS-A), which captured perceived neighbourhood built characteristics. We computed subscale and overall walkability scores from NEWS-A responses. Covariate-adjusted generalized linear models estimated the associations of participation (≥10 min/week) and minutes of different types of physical activity, including transportation walking (TW), leisure walking (LW), moderate-intensity physical activity (MPA), and vigorous-intensity physical activity (VPA) with walkability scores. Walkability was positively associated with participation in TW, LW, MPA and VPA and minutes of TW, LW, and VPA. Among men, a negative association was found between street connectivity and VPA participation. Additionally, crime safety was negatively associated with VPA minutes among men. Among women, pedestrian infrastructure was positively associated with LW participation and overall walkability was positively associated with VPA minutes. Notably, overall walkability was positively associated with LW participation among men and women. Different perceived neighbourhood walkability characteristics might be associated with participation and time spent in different types of physical activity among men and women living in Alberta. Interventions designed to modify perceptions of neighbourhood walkability might influence initiation or maintenance of different types of physical activity.

Validation of drug prescription records for senior patients in Alberta's Tomorrow Project: Assessing agreement between two population-level administrative pharmaceutical databases in Alberta, Canada

PURPOSE

To assess agreement between the Pharmaceutical Information Network (PIN), a newly implemented medication data repository in Alberta, Canada, and the Alberta Blue Cross (ABC) database, a long established database with medication records of all senior patients in Alberta.

METHODS

PIN data (2008-2015) were cross-validated with ABC medication records for senior participants (older than 65 years old) in Alberta's Tomorrow Project (ATP), a longitudinal cohort study in Alberta. The completeness and accuracy of PIN were respectively calculated as the percentage of ABC records coexisting (concordant) in PIN and the percentage of concordant records having mutually agreeable information on drug quantity. Generalized linear models were used to examine potential association of PIN completeness and accuracy with sociodemographic factors.

RESULTS

A total of 1 218 191 drug prescription records from 13 143 ATP participants were captured by PIN and ABC in 2008-2015, among which 91.6% were from PIN, 82.5% from ABC, and 74.2% coexisted in PIN and ABC. The overall completeness of PIN in capturing ABC medication records was 89.9%, with small variations (less than ±5%) across types of drugs. The completeness of PIN was improved on average by 1.3% annually over time (P < .001). PIN had 100% accuracy as defined by drug quantity data agreeable with ABC records. No significant associations were observed with age, sex, ethnicity, rural/urban areas, and socioeconomic status of the participants.

CONCLUSIONS

Cross-validated with the ABC dataset, our study showed that irrespective of drug type, PIN has a fairly good completeness (approximately 90%) and accuracy (100%) in capturing the ABC claimed medications for senior patients in Alberta.

Anthropometric changes and risk of diabetes: are there sex differences? A longitudinal study of Alberta's Tomorrow Project

OBJECTIVES

To characterise the sex-specific difference in the association between anthropometric changes and risk of diabetes in the general population in Canada.

SETTING AND PARTICIPANTS

From 2000 to 2008, Alberta's Tomorrow Project (ATP) invited Alberta's residents aged 35-69 years to a prospective cohort study. A total of 19 655 diabetes-free ATP participants having anthropometrics measured at the baseline and follow-ups were included.

DESIGN AND OUTCOME MEASURES

A longitudinal study design was used to examine the association between anthropometric changes and risk of diabetes and the sex difference in this association. Changes in weight, body mass index (BMI), waist circumference (WC) and waist-hip-ratio (WHR) were calculated as the difference between baseline and follow-up measures. Diabetes cases were identified using the Canadian National Diabetes Surveillance System algorithm with administrative healthcare data (2000-2015) linked to the ATP cohort. The sex-specific association between anthropometric changes and incidence of diabetes were examined by multivariable Cox regression models.

RESULTS

Changes in weight, BMI, WC and WHR over time were positively associated with incidence of diabetes in both men and women. The sex difference in risk of diabetes associated with 1 standard deviation (SD) increase in anthropometrics was 0.07 (95% CI -0.02 to 0.14) for weight, 0.08 (95% CI -0.03 to 0.17) for BMI, 0.07 (95% CI -0.02 to 0.15) for WC and 0.09 (95% CI 0.03 to 0.13) for WHR. Similar results were found in sex difference in the associations with changes per 5% and changes per categories (5% loss, ±5%, 5% gain).

CONCLUSIONS

The positive association between anthropometric changes and risk of diabetes was generally stronger in men than in women. However, this sex-specific difference of approximately 10% of the total risk associated with anthropometric changes had limited significance. For population-based public health programmes aiming to control obesity and incidence of diabetes, it may not be necessary to set up sex-specific goals for anthropometric reduction.

Systemic use of antibiotics and risk of diabetes in adults: A nested case-control study of Alberta's Tomorrow Project

AIMS

Previous observational studies using administrative health records have suggested an increased risk of diabetes with use of antibiotics. However, unmeasured confounding factors may explain these results. This study characterized the association between systemic use of antibiotics and risk of diabetes in a cohort of adults in Canada, accounting for both clinical and self-reported disease risk factors.

MATERIALS AND METHODS

In this nested case-control study, we used data from Alberta's Tomorrow Project (ATP), a longitudinal cohort study in Canada, and the linked administrative health records (2000-2015). Incident cases of diabetes were matched with up to 8 age and sex-matched controls per case. Conditional logistic regression was used to examine the association between antibiotic exposures and incident diabetes after sequentially adjusting for important clinical and lifestyle factors.

RESULTS

This study included 1676 cases of diabetes and 13 401 controls. Although 17.9% of cases received more than 5 courses of antibiotics, compared to 13.8% of controls (P < .0001), the association between antibiotic use and risk of diabetes was progressively reduced as important clinical and lifestyle factors were accounted for. In fully adjusted models, compared to participants with 0 to 1 courses of antibiotics, participants receiving more antibiotics had no increased risk of diabetes [Odds Ratio, 0.97 (0.83-1.13) for 2 to 4 courses and 0.98 (0.82-1.18) for ≥5 courses].

CONCLUSIONS

After adjustment for clinical and difficult-to-capture lifestyle data, we found no association between systemic use of antibiotics and risk of diabetes. Our results suggest that those positive associations observed in previous studies using only administrative records might have been confounded.

Patterns and predictors of adherence to colorectal cancer screening recommendations in Alberta's Tomorrow Project participants stratified by risk

Background

Colorectal cancer (CRC) screening is an important modifiable behaviour for cancer control. Regular screening, following recommendations for the type, timing and frequency based on personal CRC risk, contributes to earlier detection and increases likelihood of successful treatment.

Methods

To determine adherence to screening recommendations in a large provincial cohort of adults, participants in Alberta’s Tomorrow Project (n = 9641) were stratified based on increasing level of CRC risk: age (Age-only), family history of CRC (FamilyHx), personal history of bowel conditions (PersonalHx), or both (Family/PersonalHx) using self-reported information from questionnaires. Provincial and national guidelines for timing and frequency of screening tests were used to determine if participants were up-to-date based on their CRC risk. Screening status was compared between enrollment (2000–2006) and follow-up (2008) to determine screening pattern over time.

Results

The majority of participants (77%) fell into the average risk Age-only strata. Only a third of this strata were up-to-date for screening at baseline, but the proportion increased across the higher risk strata, with > 90% of the highest risk Family/PersonalHx strata up-to-date at baseline. There was also a lower proportion (< 25%) of the Age-only group who were regular screeners over time compared to the higher risk strata, though age, higher income and uptake of other screening tests (e.g. mammography) were associated with a greater likelihood of regular screening in multinomial logistic regression.

Conclusions

The low (< 50%) adherence to regular CRC screening in average and moderate risk strata highlights the need to further explore barriers to uptake of screening across different risk profiles.

Changes in body mass index and incidence of diabetes: A longitudinal study of Alberta's Tomorrow Project Cohort

Although obesity is a known risk factor for diabetes, the impact of body mass index (BMI) changes over time, especially BMI reduction, on diabetes development is less than clear. The objective of this study is to characterize the association between BMI changes over time and incidence of diabetes in a cohort of adults in Alberta. From 2000 to 2008, Alberta's Tomorrow Project (ATP) enrolled participants aged 35-69 to a population-based prospective cohort study. BMI was calculated from self-reported height and weight; change in BMI (∆BMI) was calculated as the difference between baseline and follow-up measurements. Diabetes cases were identified using the Canadian National Diabetes Surveillance System algorithm applied to linked administrative data (2000-2015). Multivariable Cox regression was used to examine the association between ∆BMI and incidence of diabetes. In a subset of the ATP cohort (n=19,164), 1168 incident cases of diabetes were identified during 198,853person-years of follow-up. Overall, BMI increase was associated with increased risk and BMI reduction was associated with reduced risk of diabetes. Particularly, compared to minimal BMI change (±5%), moderate (5%-10%) reduction in BMI was associated with 34% (95% CI: 12%-51%) reduction in risk of diabetes in participants with obesity; whereas 10% or greater increase in BMI was associated with an increased risk of diabetes of 64% or more in participants with overweight and obesity; in participants with normal and underweight, BMI changes was not apparently associated with risk of diabetes. Public health programs promoting weight loss, even at a moderate extent, would reduce risk of diabetes.

Diet quality is associated with reduced incidence of cancer and self-reported chronic disease: Observations from Alberta's Tomorrow Project

The objective of this study was to assess diet quality using the Healthy Eating Index-2005 Canada (HEI-2005-Canada) and its association with risk of cancer and chronic disease in a sample of Alberta's Tomorrow Project (ATP) participants. Food frequency questionnaires completed by 25,169 participants (38% men; mean age 50.3 (9.2)) enrolled between 2000 and 2008 were used to calculate HEI-2005-Canada scores. Data from a subset of participants (n=10,735) who reported no chronic disease at enrollment were used to investigate the association between HEI-2005-Canada score and development of self-reported chronic disease at follow-up (2008). Participants were divided into HEI-2005-Canada score quartiles. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for cancer and chronic disease incidence. In this cohort, mean HEI-2005-Canada scores for men and women were 50.9 and 55.5 (maximum range 0-100), respectively. In men, higher HEI-2005-Canada score (Q4 vs. Q1) was associated with lower cancer risk (HR (95% CI) 0.63 (0.49-0.83)) over the course of follow-up (mean (SD)=10.4 (2.3) years); the same was not observed in women. In contrast, higher overall HEI-2005-Canada score (Q4 vs. Q1) was associated with lower risk of self-reported chronic disease (0.85 (0.75-0.97)) in both men and women over follow-up (4.2 (2.3) years). In conclusion, in this cohort better diet quality was associated with a lower risk of cancer in men and lower risk of chronic disease in both sexes. Future studies with longer follow-up and repeated measures of diet may be helpful to elucidate sex-specific associations between dietary quality and disease outcomes.

Design, methods and demographics from phase I of Alberta's Tomorrow Project cohort: a prospective cohort profile

BACKGROUND

Prospective cohorts have the potential to support multifactorial, health-related research, particularly if they are drawn from the general population, incorporate active and passive follow-up and permission is obtained to allow access by researchers to data repositories. This paper describes Phase I of the Alberta's Tomorrow Project cohort, a broad-based research platform designed to support investigations into factors that influence cancer and chronic disease risk.

METHODS

Adults aged 35-69 years living in Alberta, Canada, with no previous cancer diagnosis other than nonmelanoma skin cancer were recruited to the project by telephone-based random digit dialling. Participants were enrolled if they returned a Health and Lifestyle Questionnaire. Past year diet and physical activity questionnaires were mailed 3 months after enrolment. Consent was sought for active follow-up and linkage with administrative databases. Depending on enrolment date, participants were invited to complete up to 2 follow-up questionnaires (2004 and 2008).

RESULTS

Between 2001 and 2009, 31 072 (39% men) participants (mean age 50.2 [± 9.2] yr) were enrolled and 99% consented to linkage with administrative databases. Participants reported a wide range of educational attainment and household income. Compared with provincial surveillance data from the Canadian Community Health Survey, Alberta's Tomorrow Project participants had higher body mass index, lower prevalence of smoking and similar distribution of chronic health conditions. Follow-up questionnaires were completed by 83% and 72% of participants in 2004 and 2008, respectively. Robust quality control measures resulted in low frequencies of missing data.

INTERPRETATION

Alberta's Tomorrow Project provides a robust platform, based on a prospective cohort design, to support research into risk factors for cancer and chronic disease.

Polychlorinated biphenyl serum concentrations, lifestyle and time-to-pregnancy

BACKGROUND

Consumption of fish contaminated with polychlorinated biphenyls (PCBs) and prenatal PCB serum concentrations have been associated with a longer time-to-pregnancy (TTP). However, the relationship between preconception serum PCBs concentrations and TTP has not been previously studied.

METHODS

Eighty-three women (contributing 442 menstrual cycles) planning pregnancies completed daily diaries regarding menstruation, intercourse, home pregnancy test results, and reported use of alcohol and cigarettes. TTP denoted the number of observed menstrual cycles required for pregnancy. Preconception blood specimens underwent toxicologic analysis for 76 PCB congeners via gas chromatography with electron capture; serum lipids were quantified with enzymatic methods. A priori, PCB congeners were summed into a total and three groupings-estrogenic, anti-estrogenic and other-and entered into discrete analogs of Cox models with time-varying covariates to estimate fecundability odds ratios (FOR) and corresponding 95% confidence intervals (CIs).

RESULTS

Estrogenic and anti-estrogenic PCB concentrations (ng/g serum) conferred reduced FORs in fully adjusted models (0.32; 95% CI 0.03, 3.90 and 0.01: 95% CI < 0.00, 1.99, respectively). Reduced FORs (0.96) were observed for alcohol consumption standardized to a 28-day menstrual cycle in the same adjusted model (FOR = 0.96; 95% CI 0.93, 1.00).

CONCLUSIONS

These data suggest that environmental exposures including those amenable to change, such as alcohol consumption, may impact female fecundity. The findings are sensitive to model specification and PCB groupings, underscoring the need to further assess the impact of chemical mixtures on sensitive reproductive outcomes, such as TTP, especially in the context of lifestyle factors which are amenable to change, thereby improving reproductive health.

Longitudinal study of babies born to mothers enrolled in a preconception prospective pregnancy study: study design and methodology, New York State Angler cohort study

Persistent environmental chemicals such as organochlorine pesticides and polychlorinated biphenyls (PCBs) have been associated with alterations in fetal development and child health including subtle differences in developmental status. Previous prospective studies have ascertained prenatal or postnatal exposures but none have been designed to assess exposures at critical windows including preconception. To address this gap, we followed infants born to mothers recruited prior to conception in the New York State Prospective Pregnancy Study to assess feasibility issues including acceptability of a relatively invasive study protocol during the child's first 2 years of life. Longitudinal measurements on health, development, and growth were obtained from 53 live-born infants; 49 families consented to standardized in-home neurodevelopmental and psychosocial evaluations at 12 and 24 months of age. Nineteen participating parents consented to the collection of blood from infants for lead thyroid and PCB levels. Despite the intensive data collection protocol over 2 years coupled with the mothers having completed an intensive prospective pregnancy protocol, we found parents readily open to continued participation in a longitudinal study involving their children. Suggestions for conducting in-home assessments include use of a consistent contact nurse, comprehensive parent-friendly developmental assessment tools with some interim assessment by parent report, and periodic team visits.

Alcohol consumption and lung cancer: a review of the epidemiologic evidence

A role for alcohol consumption in lung cancer etiology has been suggested in some studies, but this possible relationship has been often regarded with skepticism, with any indication of an association being attributed to confounding by cigarette smoking. The purpose of this work was to review the epidemiological evidence for an association of alcohol and lung cancer and to identify gaps in that research. The studies reviewed here provide some indication that alcohol and particularly beer intake may increase lung cancer risk after controlling for cigarette smoking. Although the evidence is not conclusive, it warrants additional consideration of alcohol as a risk factor in lung cancer etiology, independent of cigarette smoking. Recommendations for future studies are provided.

Infecundity and consumption of polychlorinated biphenyl-contaminated fish

Biologic capacity for reproduction, or fecundity, may be threatened by environmental contaminants, especially compounds capable of disrupting endocrine pathways. Telephone interviews that focused on reproductive events were conducted with female members of the New York State Angler Cohort Study who became pregnant between 1991 and 1993 and who reported known time to pregnancy (N = 895; 73%). Consumption of polychlorinated biphenyl-contaminated Lake Ontario sportfish and other factors were ascertained in 1991. The authors classified the women as follows: (a) fecund (time to pregnancy < or =12 cycles; n = 723); (b) having resolved infecundity (time to pregnancy > 12 cycles; n = 81); or (c) having unresolved infecundity (time to pregnancy > 12 cycles without pregnancy; n = 94). Adjusted odds ratios for duration of fish consumption for both resolved and unresolved infecundity were elevated (1.46 and 1.19, respectively), although confidence intervals included unity. Frequency of recent fish consumption was associated with an increased risk for select categories, although confidence intervals included one.

Parental consumption of contaminated sport fish from Lake Ontario and predicted fecundability

Wildlife studies suggest that consumption of contaminated fish from the Great Lakes may expose humans to polychlorinated biphenyls and persistent chlorinated pesticides. To assess whether time to pregnancy or fecundability is affected, we conducted a telephone survey in 1993 with female members of the New York State Angler Cohort Study who were considering pregnancy between 1991 and 1994 (N = 2,445). Among the 1,234 (50%) women who became pregnant, 895 (73%) had a known time to pregnancy. Upon enrollment into the cohort in 1991, both partners reported duration and frequency of Lake Ontario sport fish consumption. We estimated lifetime exposure to polychlorinated biphenyls from recent consumption and used a discrete-time analog of Cox proportional hazards analysis to estimate conditional fecundability ratios and 95% confidence intervals (CIs) for fish consumption among couples with complete exposure data who discontinued birth control to become pregnant (N = 575). Maternal consumption of fish for 3-6 years was associated with reduced fecundability (fecundability ratio = 0.75; 95% CI = 0.59-0.91), as was more than a monthly fish meal in 1991 (fecundability ratio = 0.73; 95% CI = 0.54-0.98). Our findings suggest that maternal but not paternal consumption of contaminated fish may reduce fecundability among couples attempting pregnancy.

Innovative multidisciplinary research in environmental epidemiology: the challenges and needs

The ability of epidemiology to determine the relationships between health and environmental insults has become exceedingly difficult. The multifactorial nature of disease and the diversity of the insults, which include biologic, physical, social and cultural factors, combined with genetic susceptibility, suggest the need to develop better models of multidisciplinary epidemiologic investigation. This paper highlights the needs of an environmental epidemiologic team, discusses ways to incorporate new ideas across disciplines and to integrate constructs and paradigms of social, ecological, cultural and population determinants with individual-based exposure assessments. Innovation will be the key to the survival and increasing importance of epidemiology in addressing the public health needs of the future, but what are the ways to enhance and encourage creativity in environmental epidemiology? The process of self-renewal and continuing education will be highlighted. Additionally, the complexity of the problems and the need for clear supervision and control of multidisciplinary research efforts require a forum of communication and an 'information-processing approach' beyond those in traditional epidemiologic studies. New approaches in data management and medical informatics must be incorporated into the epidemiologic investigative framework. Methods to be included should focus on opportunities for computer-supported sharing of ideas. Such capabilities minimise the geographic distances and the disparate knowledge and training of the investigators and bring the team closer to the objectives and functions inherent in multidisciplinary investigation.

Apolipoprotein E genetic polymorphism, serum lipoproteins, and breast cancer risk

Apolipoprotein E (apoE) is a polymorphic gene involved in lipid metabolism with three common variant alleles (epsilon2, epsilon3, and epsilon4). The epsilon4 allele has been associated with elevated levels of cholesterol as well as greater risk of coronary heart disease and Alzheimer's disease. In this case-control study we examined whether apoE genotype affected the association between serum lipids and breast cancer risk. In a subset of a study in western New York, 260 women with incident, primary breast cancer and 332 community controls were interviewed and provided blood samples. Polymerase chain reaction-restriction fragment length polymorphism analyses of the apoE polymorphism were performed. Participants were classified as apoE2 (epsilon2, epsilon2 or epsilon2, epsilon3), apoE3 (epsilon3, epsilon3), or apoE4 (epsilon4, epsilon4 or epsilon4, epsilon3). No unconditional logistic regression was used to compute adjusted odds ratios (ORs) and 95% confidence intervals (CI). Compared with women with the apoE3 genotype, there were no associations with risk for women with the apoE2 (OR=1.0; 95% CI=0. 91-1.64) or apoE4 genotype (OR=0.97; 95% CI=0.63-1.54). Higher serum levels of total cholesterol, HDL cholesterol, and LDL cholesterol were not associated with risk, either in the total sample or among subgroups of women defined by apoE genotype. Women with the highest serum triglyceride levels had an increase in risk (OR=1.63; 95% CI=1. 03-2.59) compared to women with the lowest levels. This effect was not apparent among women with the apoE2 or apoE3 genotype, but much stronger among women with the apoE4 genotype (OR=4.69; 95% CI=1. 49-14.7). These data suggest that the apoE4 genotype may modify the association between serum triglycerides and breast cancer risk.

Alcohol dehydrogenase 3 genotype modification of the association of alcohol consumption with breast cancer risk

OBJECTIVES

Because alcohol dehydrogenase 3 (ADH3) is rate-limiting in alcohol oxidation and is polymorphic, we examined ADH3 genotype in relation to alcohol intake and breast cancer risk.

METHODS

We conducted a case-control study among Caucasian women aged 40-85 with incident, pathologically confirmed breast cancer and controls, frequency-matched on age and county. Queries included alcohol intake in the past 20 years. Genomic DNA was genotyped for the exon VIII ADH polymorphism by PCR followed by restriction enzyme digestion. Computation of odds ratios (OR) and 95% confidence intervals (CI) was by unconditional logistic regression.

RESULTS

We found increased risk among pre- (OR 2.3, 95%, CI 1.2-4.3) but not postmenopausal women (OR 1.1, 95% CI 0.7-1.7) associated with ADH3(1-1) compared to ADH3(1-2) and ADH3(2-2) genotypes. Risk was increased for premenopausal women with the ADH3(1-1) genotype and alcohol intake above the median (OR 3.6, 95% CI 1.5-8.8) compared to lighter drinkers with the ADH3(2-2) or ADH3(1-2) genotypes. ORs were close to null for premenopausal women in other drinking and genotype groups and for postmenopausal women categorized by genotype and alcohol consumption.

CONCLUSION

Among premenopausal women there may be a group more genetically susceptible to an alcohol consumption effect on breast cancer risk.

Work and leisure time physical activity and mortality in men and women from a general population sample

PURPOSE

The purpose of this study was to examine the long-term relationships between total physical activity and mortality from all causes and coronary heart disease (CHD) in the general population.

METHODS

A prospective design was used, following participants for 29 years, beginning in 1960. The study population consisted of a randomly selected sample of white male (n = 698) and female (n = 763) residents of Buffalo, New York with a 79.0% participation rate and follow-up rates of 96.0% and 90.2% in males and females, respectively. At baseline, comprehensive information was obtained regarding participants' usual physical activity at work and during leisure time.

RESULTS

As of December 31, 1989, three hundred and two (43.3%) men and 276 (41.0%) women died, 109 (15.6%) and 81 (10.6%) from CHD, respectively. In men, a significant interaction was found between activity and body mass index (BMI) for both outcomes. In women, a significant activity by age interaction was observed. In non-obese men (BMI<27.02), activity was inversely associated with all-cause [relative risk (RR) = 0.59; 95% confidence interval (CI), 0.39-0.89] and CHD mortality (RR = 0.39; 95% CI, 0.18-0.83), independent from the effects of age and education. No such associations were found in obese men and increased risks could not be ruled out. Among women, younger participants (age <60 years) had a significantly reduced risk of CHD death with increased activity (RR = 0.26; 95% CI, 0.07-0.99). No other significant associations were observed.

CONCLUSIONS

Physical activity favorably influences mortality risks in non-obese men and younger women. Gender-specific factors should be considered for potential effect modification.

Risk of premenopausal breast cancer in association with occupational exposure to polycyclic aromatic hydrocarbons and benzene

OBJECTIVES

This study examined the relationship between risk of premenopausal breast cancer and occupational exposure to benzene and polycyclic aromatic hydrocarbons (PAH) and whether the proposed relationship between PAH and breast cancer differed by tumor estrogen receptor (ER) status.

METHODS

In a case-referent study of premenopausal breast cancer, occupational histories and other information were obtained through interviews, and job-exposure matrices were used to assess exposure to PAH and benzene.

RESULTS

A dose-response relationship for the probability of exposure to benzene [low: odds ratio (OR) 1.64, 95% confidence interval (95% CI) 0.64-4.21; high: OR 1.95, 95% CI 1.14-3.33) and to PAH (low: OR 1.56, 95% CI 0.78-3.12; high: OR 2.40, 95% CI 0.96-6.01). Risk increased with duration of exposure to benzene, but not to PAH. A dose-response relationship was not evident for the intensity of exposure to benzene or to PAH. When analyses were stratified by tumor ER status, PAH exposure was related to a greater increase in the risk of ER-positive (OR 2.27, 95% CI 1.14-4.54) than ER-negative (OR 1.12, 95% CI 0.47-2.64) breast cancer. Risk of ER-positive, but not ER-negative, tumors increased with the probability of exposure to PAH.

CONCLUSIONS

The findings suggest an association between risk and occupational exposure to benzene. Although it was difficult to study PAH independently of benzene, there was some suggestion of an association between PAH exposure and ER-positive tumors. These data should be interpreted with caution because of the limitations of this study, including low-response rates and small numbers of exposed persons.

Comparison of PCB congeners and pesticide levels between serum and milk from lactating women

Samples of blood and milk were obtained from lactating women participating in the New York State Angler study. A total of seven women gave one blood and one milk sample at time intervals between blood and milk collection different for each woman. The time between samples varied from 3 to 318 days. One subject provided a second milk sample 219 days after the first milk sample. The samples were analyzed for 69 PCB congeners, DDE (a metabolite of DDT), Mirex, and hexachlorobenzene (HCB). Lipid content was determined by gravimetric analysis. The congener profiles in serum and milk were similar for each individual but different among all subjects. The sum of the concentrations of the congeners present above the limit of detection was used to estimate the total PCB concentration that was in the range of 2.6 to 5.8 ng/g of serum and 3.5 to 14.1 ng/g of milk. The ratio of serum to milk concentrations varied from 0.18 to 1.66 with a mean of 0.65+/-0.49 showing no consistency among individuals prior to adjusting the data for lipid content. The total PCB levels normalized for lipid content were 320-728 ng/g of serum lipid and 239-428 ng/g of milk lipid. The range of the lipid adjusted serum/milk ratio was 1.1 to 2.8 and the mean+/-SD serum/milk ratio was 1.9+/-0.5. The ranges of lipid adjusted serum concentration of DDE, HCB, and Mirex were 95 to 591, 8 to 48, and 3 to 29 ng/g lipid, respectively. The ranges of lipid adjusted milk concentration of DDE, HCB, and Mirex were 90 to 577, 11 to 22, and 1 to 10 ng/g lipid, respectively. For DDE, HCB, and Mirex, the means of the individual lipid adjusted serum to milk ratios were 1.5+/-0.7, 2.5+/-1.5, and 5. 3+/-4.6, respectively. Considerable differences were found among lipid adjusted concentrations of these environmental pollutants in serum and milk samples from the same individual. This suggests that body burden estimates in lactating women using different matrices may not be equivalent even when lipid adjusted values are used.

An evaluation of proposed frameworks for grouping polychlorinated biphenyl (PCB) congener data into meaningful analytic units

BACKGROUND

Polychlorinated biphenyls (PCBs) have been associated with a variety of health outcomes. Enhanced laboratory techniques can provide a relatively large number of individual PCB congeners for investigation. However, to date there are no established frameworks for grouping a large number of PCB congeners into meaningful analytic units.

METHODS

In a case-control study of serum PCB levels on breast cancer risk, measured levels of 56 PCB congener peaks were available for analysis. We considered several approaches for grouping these compounds based on 1) chlorination, 2) factor analysis, 3) enzyme induction, 4) enzyme induction and occurrence, and 5) enzyme induction, occurrence, and other toxicological aspects. The utility of a framework was based on the mechanism of biologic actions within each framework, lack of collinearity among congener groups, and frequency of detection of PCB congener groups in measured serum levels of 192 healthy postmenopausal women.

RESULTS

Most participants had detectable levels for the proposed PCB congeners groups, using degree of chlorination as a grouping framework. In addition, the previously proposed grouping approach based on enzyme induction, occurrence, and other toxicological aspects was an applicable alternative to the crude approach of grouping by degree of chlorination. Grouping these congeners with respect to P450 enzyme induction activity, and the previously proposed framework based on enzyme induction and occurrence, did not fit these data as well, because only a small proportion of participants had detectable levels for the congener groups with the greatest toxicological potential. Statistical grouping did not result in an interpretable and meaningful clustering of these exposures.

CONCLUSIONS

In these data, grouping with respect to degree of chlorination and the previously proposed framework based on enzyme induction, occurrence, and other toxicological aspects were the most useful approaches to reducing a large number of PCB congeners into meaningful analytic units. Factors affecting the utility of the proposed grouping frameworks are discussed.

Risk of premenopausal breast cancer and patterns of established breast cancer risk factors among teachers and nurses

BACKGROUND

Contrasting results have been published regarding the risk of breast cancer among teachers and nurses. Confounding by reproductive factors may explain the increased risk observed among women in these occupations as information on those factors were not available in most studies.

METHODS

We examined the risk of premenopausal breast cancer among teachers and nurses using occupational histories in a case-control study where information on established risk factors was available.

RESULTS

Having ever held a teaching job was not related to breast cancer (OR = 0.74, 95% CI = 0.44-1.28) and women who worked for 10 years or less in this occupation had a non-significant deficit of risk (OR = 0.52, 95% CI = 0.27-1.02). No elevation in risk was found in association with having ever been a nurse (OR = 0.85, 95% CI = 0.45-1.61) or with duration of nursing. Although direct comparison of established risk factors among teachers and nurses and other women in the study showed some evidence of differential distribution, especially when comparing teachers to other women, adjustment for reproductive variables and other breast cancer risk factors did not change the results of this study.

CONCLUSION

These findings suggest that teachers and nurses are not at an increased risk of breast cancer. This study also suggests that established risk factors for premenopausal breast cancer may not explain the elevation of risk found in other studies of teachers and nurses. However, this conclusion is limited by the fact that in the present study teachers and nurses had lower than expected breast cancer risk with or without adjustment for established risk factors. Limitations of this study such as low response rates and limited statistical power should be considered in the interpretation of these findings.

Manganese superoxide dismutase (MnSOD) genetic polymorphisms, dietary antioxidants, and risk of breast cancer

Oxidative stress, resulting from the imbalance between prooxidant and antioxidant states, damages DNA, proteins, cell membranes, and mitochondria and seems to play a role in human breast carcinogenesis. Dietary sources of antioxidants (chemical) and endogenous antioxidants (enzymatic), including the polymorphic manganese superoxide dismutase (MnSOD), can act to reduce the load of oxidative stress. We hypothesized that the valine-to-alanine substitution that seems to alter transport of the enzyme into the mitochondrion, changing its efficacy in fighting oxidative stress, was associated with breast cancer risk and that a diet rich in sources of antioxidants could ameliorate the effects on risk. Data were collected in a case-control study of diet and breast cancer in western New York from 1986 to 1991. Caucasian women with incident, primary, histologically confirmed breast cancer were frequency-matched on age and county of residence to community controls. Blood specimens were collected and processed from a subset of participants in the study (266 cases and 295 controls). Using a RFLP that distinguishes a valine (V) to alanine (A) change in the -9 position in the signal sequence of the protein for MnSOD, we characterized MnSOD genotypes in relation to breast cancer risk. We also evaluated the effect of the polymorphism on risk among low and high consumers of fruits and vegetables. Premenopausal women who were homozygous for the A allele had a 4-fold increase in breast cancer risk in comparison to those with 1 or 2 V alleles (odds ratio, 4.3; 95% confidence interval, 1.7-10.8). Risk was most pronounced among women below the median consumption of fruits and vegetables and of dietary ascorbic acid and alpha-tocopherol, with little increased risk for those with diets rich in these foods. Relationships were weaker among postmenopausal women, although the MnSOD AA genotype was associated with an almost 2-fold increase in risk (odds ratio, 1.8; confidence interval, 0.9-3.6). No appreciable modification of risk by diet was detected for these older women. These data support the hypothesis that MnSOD and oxidative stress play a significant role in breast cancer risk, particularly in premenopausal women. The finding that risk was greatest among women who consumed lower amounts of dietary antioxidants and was minimal among high consumers indicates that a diet rich in sources of antioxidants may minimize the deleterious effects of the MnSOD polymorphism, thereby supporting public health recommendations for the consumption of diets rich in fruits and vegetables as a preventive measure against cancer.

Paternal Lake Ontario fish consumption and risk of conception delay, New York State Angler Cohort

The aquatic ecosystems of the Great Lakes are contaminated with a variety of compounds, some of which are considered reproductive toxicants. Few studies of paternal fish consumption and reproductive endpoints have been undertaken and serve as the impetus for study. Standardized telephone interviews were conducted with 2445 female members of the New York State Angler Cohort (82% response) to update reproductive profiles and to ascertain specific information on time-to-pregnancy (TTP). The study sample includes women with a known TTP and paternal fish consumption data (n=785). Conception delay was defined as more than 12 cycles of unprotected intercourse to achieve pregnancy. Paternal fish consumption was assessed by three measures: frequency of Lake Ontario sport fish meals in 1991, numbers of years eating fish, and estimated PCB exposure from fish consumption. Adjusted ORs for number of fish meals, based on logistic regression, ranged from 0.69 to 0.80; from 0.61 to 0.82 for number of years eating fish; and from 0.44 to 1.14 for quartiles of estimated PCB exposure from fish consumption. All confidence intervals included one. These findings suggest that, based on paternal self-reports, Lake Ontario fish consumption does not increase the risk of conception delay.

Polychlorinated biphenyls, cytochrome P4501A1 polymorphism, and postmenopausal breast cancer risk

In experimental systems, polychlorinated biphenyls (PCBs) induce cytochrome P4501A1 (CYP1A1), which is involved in metabolism of steroid hormones and polycyclic aromatic hydrocarbons in humans. A genetic polymorphism coding for a valine to isoleucine substitution in exon 7 has been associated with lung cancer risk in Japanese populations. In a previous study, we found no association between CYP1A1 genotype and breast cancer risk. However, we were interested in determining whether genotype would relate to risk when PCB body burden was taken into account. In a subset of a case-control study in western New York, 154 postmenopausal women with incident, primary, histologically confirmed postmenopausal breast cancer and 192 community controls were interviewed and underwent phlebotomy. Serum levels of 56 PCB peaks were determined by high resolution gas chromatography with electron capture. PCR-RFLP analyses of the CYP1A1 polymorphism were performed. Unconditional logistic regression was used to compute adjusted odds ratios and 95% confidence intervals. Among women with serum PCB levels above the median of the distribution in the control group, there was increased risk of breast cancer associated with the presence of at least one valine allele, compared with women who were homozygous for the isoleucine alleles (odds ratio, 2.93; 95% confidence interval, 1.17-7.36). Among women with low PCB body burden, no association between CYP1A1 genotype and breast cancer risk was observed. Adjustment for serum lipids and body mass index did not affect the magnitude of the observed associations. PCB body burden may modify the effect of the polymorphism on postmenopausal breast cancer risk through increased CYP1A1 enzyme induction or by activation by specific PCB congeners. These results should be considered preliminary, pending replication by other studies.