Development and validation of a Brief Diet Quality Assessment Tool in the French-speaking adults from Quebec

Background

The objective of this study was to develop and validate a short, self-administered questionnaire to assess diet quality in clinical settings, using the Alternative Healthy Eating Index (AHEI) as reference.

Methods

A total of 1040 men and women (aged 44.6 ± 14.4 y) completed a validated web-based food frequency questionnaire (webFFQ) and had their height and weight measured (development sample). Participants were categorized arbitrarily according to diet quality (high: AHEI score ≥ 65/110, low: AHEI score < 65/110) based on dietary intake data from the webFFQ. The Brief Diet Quality Assessment Tool was developed using a classification and regression tree (CART) approach and individual answers to the webFFQ among participants considered to have a plausible energy intake (ratio of reported energy intake to basal metabolic rate ≥ 1.2 and < 2.4; n = 1040). A second sample of 3344 older adults (aged 66.5 ± 6.4 y) was used to test the external validity of the Brief Diet Quality Assessment Tool (external validation sample).

Results

The decision tree included sequences of 3 to 6 binary questions, yielding 21 different pathways classifying diet quality as being high or low. In the development sample, the area under the receiver operating characteristic (ROC) curve of the predictive model was 0.92, with sensitivity, specificity and agreement values of 89.5, 83.9 and 87.2%. Compared with individuals having a low-quality diet according to the Brief Diet Quality Assessment Tool (mean AHEI 56.7 ± 11.4), individuals classified as having a high-quality diet (mean AHEI 71.3 ± 11.0) were significantly older, and had lower BMI, percent body fat and waist circumference, and had lower blood pressure, triglycerides, cholesterol/HDL ratio and fasting insulin as well as higher HDL-cholesterol concentrations (all P < 0.05). Similar results were observed in the external validation sample, although overall performance of the Brief Diet Quality Assessment Tool was slightly lower than in the development sample, with an area under the ROC curve of 0.79 and sensitivity, specificity and agreement values of 73.0, 69.0 and 71.3%, respectively.

Conclusion

The CART approach yielded a simple and rapid Brief Diet Quality Assessment Tool that identifies individuals at risk of having a low-quality diet. Further studies are needed to test the performance of this tool in primary care settings.

Electronic supplementary material

The online version of this article (10.1186/s12966-019-0821-6) contains supplementary material, which is available to authorized users.

A test for the correct specification of marginal structural models

Marginal structural models (MSMs) allow estimating the causal effect of a time-varying exposure on an outcome in the presence of time-dependent confounding. The parameters of MSMs can be estimated utilizing an inverse probability of treatment weight estimator under certain assumptions. One of these assumptions is that the proposed causal model relating the outcome to exposure history is correctly specified. However, in practice, the true model is unknown. We propose a test that employs the observed data to attempt validating the assumption that the model is correctly specified. The performance of the proposed test is investigated with a simulation study. We illustrate our approach by estimating the effect of repeated exposure to psychosocial stressors at work on ambulatory blood pressure in a large cohort of white-collar workers in Québec City, Canada. Code examples in SAS and R are provided to facilitate the implementation of the test.

A descriptive review of variable selection methods in four epidemiologic journals: there is still room for improvement

A review of epidemiological papers conducted in 2009 concluded that several studies employed variable selection methods susceptible to introduce bias and yield inadequate inferences. Many new confounder selection methods have been developed since then. The goal of the study was to provide an updated descriptive portrait of which variable selection methods are used by epidemiologists for analyzing observational data. Studies published in four major epidemiological journals in 2015 were reviewed. Only articles concerned with a predictive or explicative objective and reporting on the analysis of individual data were included. Method(s) employed for selecting variables were extracted from retained articles. A total of 975 articles were retrieved and 299 met eligibility criteria, 292 of which pursued an explicative objective. Among those, 146 studies (50%) reported using prior knowledge or causal graphs for selecting variables, 34 (12%) used change in effect estimate methods, 26 (9%) used stepwise approaches, 16 (5%) employed univariate analyses, 5 (2%) used various other methods and 107 (37%) did not provide sufficient details to allow classification (more than one method could be employed in a single article). Despite being less frequent than in the previous review, stepwise and univariable analyses, which are susceptible to introduce bias and produce inadequate inferences, were still prevalent. Moreover, 37% studies did not provide sufficient details to assess how variables were selected. We thus believe there is still room for improvement in variable selection methods used by epidemiologists and in their reporting.

Factors Leading Municipal Authorities to Implement Preventive Interventions for Lyme Disease

The aim of this study is to document climate change adaptation interventions targeting Lyme disease at the municipal level in the province of Quebec (Canada). This exploratory study relies on the theory of planned behavior and certain constructs from the health belief model to identify the factors leading municipal authorities to implement preventive interventions for Lyme disease (PILD). Data were obtained from an online survey sent, during the summer of 2018, to municipal officers in 820 municipalities in Quebec, in all health regions where the population is at risk of contracting Lyme disease (response rate = 36%). The questionnaire was used to measure the implementation of PILD, the intention to implement these interventions, attitudes, perceived social pressure, perceived control (levers and barriers) over interventions, perceived effectiveness of preventive measures, risk, and perceived vulnerability. Results of structural equation analyses showed that attitudes were significantly associated with municipal authorities' intention to implement PILD, while the intention to implement PILD was a significant predictor of the implementation of PILD. Additional analyses showed that perceived barriers added a moderating effect in the intention-implementation relationship. The prediction of behaviors or practices that municipal authorities could implement to prevent Lyme disease will enable the evaluation over time of the evolution of Quebec municipalities' adaptation to Lyme disease. Moreover, the examination of the associations of specific psychosocial factors revealed important implications for the design of effective behavior-change interventions, which would allow health officials doing awareness work to create personalized interventions better suited to municipal officers and their specific contexts.

Assessment of the healthy worker survivor effect in the relationship between psychosocial work-related factors and hypertension

Objectives

The healthy worker survivor effect (HWSE) usually leads to underestimation of the effects of harmful occupational exposures. HWSE is characterised by the concomitance of three associations: (1) job status–subsequent exposure, (2) job status–disease and (3) previous exposure–job status. No study has reported the coexistence of these associations in the relationship between psychosocial work-related factors and health. We assessed if HWSE is present when measuring the effects of cumulative exposure to psychosocial work-related factors on the prevalence of hypertension in white-collar workers.

Methods

Data were obtained from two timepoints (1991–1993 at baseline and 1999–2001 at follow-up) of a prospective cohort study. At baseline, the population was composed of 9188 white-collar employees (women: 49.9%) in Quebec City. Job strain as psychosocial work-related factor and blood pressure were measured using validated methods. Job status (retirees vs employees) at follow-up was self-reported. Multiple multilevel robust Poisson regressions were used to estimate prevalence ratios of hypertension and risk ratios of retirement separately by gender. We performed multiple imputations to control selection bias due to missing values.

Results

Retirement eliminated the subsequent exposure to job strain de facto and was associated with the reduction in the prevalence of hypertension in younger (−33%) and older (−11%) men and in older women (−39%). Job strain was associated with job status in younger men and in women of any age.

Conclusion

Data showed the presence of HWSE in younger men and older women given the coexistence of the three structural associations.

Development and validation of five behavioral indices of flood adaptation

BACKGROUND

In the current context of climate change, climate forecasts for the province of Quebec (Canada) are a lengthening of the thunderstorm season and an increase in episodes of intense precipitations. These changes in the distribution of precipitations could heighten the intensity or frequency of floods, a natural hazard that concerns 80% of Quebec's riverside municipalities. For the health and safety of the at-risk population, it is very important to make sure they have acquired necessary adaptive behaviors against flooding hazard. However, there has been no assessment of these flood adaptation behaviors to date. Thus, the aim of this study was to develop and validate five indices of adaptation to flooding.

METHODS

A sample of 1951 adults completed a questionnaire by phone. The questionnaire, specifically developed for this study, measured whether they did or did not adopt the behaviors that are proposed by public health officials to protect themselves against flooding.

RESULTS

The results of the item, confirmatory factor, and multiple correspondence analyses contributed to the development of five indices corresponding to the adaptation behaviors to adopt according to the chronology of events: (a) pre-alert preventive behaviors, (b) behaviors to carry out after the alert is issued, (c) behaviors to adopt during a flood not requiring evacuation, (d) behaviors to adopt during a flood requiring evacuation, and (e) post-flood behaviors. The results of this study also showed that people who perceive a risk of flooding in their home in the next 5 years tend to adopt more preventive behaviors and adaptation behaviors than those who perceive little or no risk at all. They also reveal that people who feel more adverse effects on their physical or mental health tend to adopt more adaptive behaviors than those who feel little or no adverse effects on their health.

CONCLUSION

Across a series of psychometric analyses, the results showed that these flood adaptation indices could properly measure a vast range of adaptive behaviors according to the chronology of events. Therefore, researchers, public health agencies, and professionals can use them to monitor the evolution of individuals' adaptive behaviors during floods.

Impact of vaccine delays at the 2, 4, 6 and 12 month visits on incomplete vaccination status by 24 months of age in Quebec, Canada

BACKGROUND

Timeliness in the administration of recommended vaccines is often evaluated using vaccine delays and provides more information regarding the susceptibility of children to vaccine-preventable diseases compared with vaccine coverage at a given age. The importance of on-time administration of vaccines scheduled at the first visit is well documented, but data are scarce about the impact of vaccine delays at other visits on vaccination status by 24 months of age. Using vaccine delays for the first three doses of DTaP-containing vaccines and for the first dose of measles-containing vaccines as markers of timeliness at the 2, 4, 6 and 12 month visits, we estimated the proportion of incomplete vaccination status by 24 months of age attributable to a vaccine delay at each of these visits.

METHODS

We used the data from six cross-sectional coverage surveys conducted in the Province of Quebec from 2006 to 2016 which included 7183 children randomly selected from the universal health insurance database. A vaccine dose was considered delayed if received 30 days or more after the recommended age. The impact of new vaccine delays at each visit on incomplete vaccination status by 24 months of age was estimated with the attributable risk in the population.

RESULTS

The proportion of children with vaccine delay was 5.4% at 2 months, 13.3% at 4 months, 23.1% at 6 months and 23.6% at 12 months. Overall, 72.5% of all 2-year-old children with an incomplete status by 24 months were attributable with a vaccine delay, of which 16.1% were attributable with a first vaccine delay at 2 months, 10.6% at 4 months, 14.0% at 6 months and 31.8% at 12 months.

CONCLUSIONS

While great emphasis has been put on vaccine delays at the first vaccination visit, the prevalence of vaccine delays was greater with later visits and most children with an incomplete vaccination status by 24 months had a vaccine delay occurring during these later visits. Interventions to improve timeliness should address vaccine delays at each visit and not only focus on the first visit.

Comparing external and internal validation methods in correcting outcome misclassification bias in logistic regression: A simulation study and application to the case of postsurgical venous thromboembolism following total hip and knee arthroplasty

PURPOSE

We assessed the validity of postsurgery venous thromboembolism (VTE) diagnoses identified from administrative databases and compared Bayesian and multiple imputation (MI) approaches in correcting for outcome misclassification in logistic regression models.

METHODS

Sensitivity and specificity of postsurgery VTE among patients undergoing total hip or knee replacement (THR/TKR) were assessed against chart review in six Montreal hospitals in 2009 to 2010. Administrative data on all THR/TKR Quebec patients in 2009 to 2010 were obtained. The performance of Bayesian external, Bayesian internal, and MI approaches to correct the odds ratio (OR) of postsurgery VTE in tertiary versus community hospitals was assessed using simulations. Bayesian external approach used prior information from external sources, while Bayesian internal and MI approaches used chart review.

RESULTS

In total, 17 319 patients were included, 2136 in participating hospitals, among whom 75 had VTE in administrative data versus 81 in chart review. VTE sensitivity was 0.59 (95% confidence interval, 0.48-0.69) and specificity was 0.99 (0.98-0.99), overall. The adjusted OR of VTE in tertiary versus community hospitals was 1.35 (1.12-1.64) using administrative data, 1.45 (0.97-2.19) when MI was used for misclassification correction, and 1.53 (0.83-2.87) and 1.57 (0.39-5.24) when Bayesian internal and external approaches were used, respectively. In simulations, all three approaches reduced the OR bias and had appropriate coverage for both nondifferential and differential misclassification.

CONCLUSION

VTE identified from administrative data had low sensitivity and high specificity. The Bayesian external approach was useful to reduce outcome misclassification bias in logistic regression; however, it required accurate specification of the misclassification properties and should be used with caution.

Just how much does it cost? A cost study of chronic pain following cardiac surgery

OBJECTIVE

The study objective was to determine use of pain-related health care resources and associated direct and indirect costs over a two-year period in cardiac surgery patients who developed chronic post-surgical pain (CPSP).

METHODS

This multicentric observational prospective study recruited patients prior to cardiac surgery; these patients completed research assistant-administered questionnaires on pain and psychological characteristics at 6, 12 and 24 months post-operatively. Patients reporting CPSP also completed a one-month pain care record (PCR) (self-report diary) at each follow-up. Data were analyzed using descriptive statistics, multivariable logistic regression models, and generalized linear models with log link and gamma family adjusting for sociodemographic and pain intensity.

RESULTS

Out of 1,247 patients, 18%, 13%, and 9% reported experiencing CPSP at 6, 12, and 24 months, respectively. Between 16% and 28% of CPSP patients reported utilizing health care resources for their pain over the follow-up period. Among all CPSP patients, mean monthly pain-related costs were CAN$207 at 6 months and significantly decreased thereafter. More severe pain and greater levels of pain catastrophizing were the most consistent predictors of health care utilization and costs.

DISCUSSION

Health care costs associated with early management of CPSP after cardiac surgery seem attributable to a minority of patients and decrease over time for most of them. Results are novel in that they document for the first time the economic burden of CPSP in this population of patients. Longer follow-up time that would capture severe cases of CPSP as well as examination of costs associated with other surgical populations are warranted.

SUMMARY

Economic burden of chronic post-surgical pain may be substantial but few patients utilize resources. Health utilization and costs are associated with pain and psychological characteristics.

Masked hypertension incidence and risk factors in a prospective cohort study

Aims

Masked hypertension may affect up to 30% of the general population and is associated with a high cardiovascular disease risk. No previous study has examined the incidence of masked hypertension and its risk factors. The study aim was to determine the incidence of masked hypertension and to examine its related risk factors.

Methods

This is a cohort study including 1836 initially normotensive participants followed up on average for 2.9 years. Blood pressure was measured using Spacelabs 90207. Manual blood pressure was defined as the mean of the first three readings taken at rest. Ambulatory blood pressure was defined as the mean of the next readings recorded every 15 minutes during daytime working hours. Masked hypertension incidence at follow-up was defined as manual blood pressure less than 140 and less than 90 mmHg and ambulatory blood pressure at least 135 or at least 85 mmHg. Generalised estimating equations were used.

Results

The cumulative incidence of masked hypertension was 10.3% and was associated with male gender (relative risk (RR) 1.51, 95% confidence interval (CI) 1.18–1.94), older age (RR40–49 years 1.56, 95% CI 1.16–2.11, RR≥50 years 1.50, 95% CI 1.06–2.10), higher education (RRcollege 1.31, 95% CI 1.03–1.65), body mass index (RR≥27 1.43, 95% CI 1.11–1.85), smoking (RR 1.51, 95% CI 1.09–2.010) and alcohol intake (RR≥6/week 1.65, 95% CI 1.13–2.03).

Conclusion

The present study is the first to identify risk factors for the incidence of masked hypertension. Current guidelines for hypertension detection recommend ambulatory blood pressure in patients with an elevated blood pressure reading at the clinic. As it is impractical to measure ambulatory blood pressure in all normotensive patients, factors identified in the present study should be considered for the screening of at-risk individuals and for primary prevention of masked hypertension.

Development and validation of a dietary screener for carbohydrate intake in endurance athletes

BACKGROUND

Studies have shown that the majority of endurance athletes do not achieve the minimal recommended carbohydrate (CHO) intake of 6 g/kg of body weight (BW), with potentially negative impacts on recovery and performance. The purpose of this study was to develop and validate a rapid and easy to use dietary screener to identify athletes who do and do not achieve a CHO intake > 6 g/kg BW in the context of endurance sports.

METHODS

The dietary screener was developed using multiple logistic regression modeling of data from a sample of 1571 non-athlete adults (826 women and 745 men, mean age 44.75 ± 14.2 years) among whom dietary intake was assessed using a validated web-based food frequency questionnaire (web-FFQ). Three models were developed based on whole food intake using the 5, 10 and 15 most significant variables predicting CHO intake. The three models were then validated in a target population of non-elite endurance athletes having taken part in multisport events (n = 175, 64 women and 111 men, mean age 37.1 ± 11.3 years) and compared using sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively) and c-statistics.

RESULTS

The 15-variables model provided significantly better accuracy in predicting CHO intake adequacy in non-elite endurance athletes (c-statistic = 0.94) compared with the 10- and 5-variables model (c-statistic = 0.90 and 0.71 respectively). The 15-variables model predicts CHO intake adequacy in the target population of endurance athlete with a sensitivity of 89.5%, a specificity of 87.3% and PPV and NPV of 77.3 and 94.5%, respectively.

CONCLUSION

We have successfully developed a short and valid dietary screener that identifies endurance athletes at risk of not achieving a CHO intake > 6 g/kg BW. Use of this rapid screener may help alleviate the highly prevalent issue of suboptimal CHO consumption in the endurance sports realm.

Dynamics of Ferrofluid Drops on Magnetically Patterned Surfaces

The motion of liquid drops on solid surfaces is attracting a lot of attention because of its fundamental implications and wide technological applications. In this article, we present a comprehensive experimental study of the interaction between gravity-driven ferrofluid drops on very slippery oil-impregnated surfaces and a patterned magnetic field. The drop speed can be accurately tuned by the magnetic interaction, and more interestingly, drops are found to undergo a stick-slip motion whose contrast and phase can be easily tuned by changing either the strength of the magnetic field or the ferrofluid concentration. This motion is the result of the periodic modulation of the external magnetic field and can be accurately analyzed because the intrinsic pinning due to chemical defects is negligible on oil-impregnated surfaces.

Saturated Fats from Butter but Not from Cheese Increase HDL-Mediated Cholesterol Efflux Capacity from J774 Macrophages in Men and Women with Abdominal Obesity

Background

Recent evidence suggests that the association between dietary saturated fatty acids (SFAs) and coronary artery disease risk varies according to food sources. How SFAs from butter and cheese influence HDL-mediated cholesterol efflux capacity (CEC), a key process in reverse cholesterol transport, is currently unknown.

Objective

In a predefined secondary analysis of a previously published trial, we have examined how diets rich in SFAs from either cheese or butter influence HDL-mediated CEC, compared with diets rich in either monounsaturated fatty acids (MUFAs) or polyunsaturated fatty acids (PUFAs).

Methods

In a randomized crossover controlled consumption trial, 46 men and women with abdominal obesity consumed 5 isocaloric diets, each for 4 wk. Two diets were rich in SFAs either from cheese (CHEESE) or butter (BUTTER) [12.4-12.6% of energy (%E) as SFAs, 32%E as fat, 52%E as carbohydrates]. In 2 other diets, SFAs (5.8%E) were replaced with either MUFAs from refined olive oil (MUFA) or PUFAs from corn oil (PUFA). Finally, a lower fat and carbohydrate diet was used as a control (5.8%E as SFAs, 25.0%E as fat, 59%E as carbohydrates; CHO). Post-diet HDL-mediated CEC was determined ex vivo using radiolabelled J774 macrophages incubated with apolipoprotein B-depleted serum from the participants.

Results

Mean (±SD) age was 41.4 ± 14.2 y, and waist circumference was 107.6 ± 11.5 cm in men and 94.3 ± 12.4 cm in women. BUTTER and MUFA increased HDL-mediated CEC compared with CHEESE (+4.3%, P = 0.026 and +4.7%, P = 0.031, respectively). Exploring the significant diet × sex interaction (P = 0.044) revealed that the increase in HDL-mediated CEC after BUTTER compared with CHEESE was significant among men (+6.0%, P = 0.047) but not women (+2.9%, P = 0.19), whereas the increase after MUFA compared with CHEESE was significant among women (+9.1%, P = 0.008) but not men (-0.6%, P = 0.99).

Conclusion

These results provide evidence of a food matrix effect modulating the impact of dairy SFAs on HDL-mediated CEC with potential sex-related differences that deserve further investigation. This trial was registered at clinicaltrials.gov as NCT02106208.

Importance of the lipid-related pathways in the association between statins, mortality, and cardiovascular disease risk: The Multi-Ethnic Study of Atherosclerosis

PURPOSE

Estimating how much of the impact of statins on coronary heart diseases (CHD), cardiovascular disease (CVD), and mortality risk is attributable to their effect on low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and triglycerides.

METHODS

A semi-parametric g-formula estimator together with data from the Multi-Ethnic Study of Atherosclerosis (a prospective multi-center cohort study) was utilized to perform a mediation analysis. A total of 5280 participants, men and women of various race/ethnicities from multiple sites across the United States, were considered in the current study.

RESULTS

The adherence adjusted total relative risk reduction (RRR) estimate (95% confidence interval) of statins on CHD was 14% (-16%, 37%), and the indirect component through LDL was 23% (-4%, 58%). For CVD, the total RRR was 23% (2%, 40%), and the indirect component through LDL was 5% (-13%, 25%). The total RRR of mortality was 18% (-1%, 35%), and the indirect component through LDL was -4% (-17%, 12%). The estimated indirect components through HDL and triglycerides were close to zero with narrow confidence intervals for all 3 outcomes.

CONCLUSIONS

The estimated effect of statins on mortality, CVD, and CHD appeared to be independent of their estimated effect on HDL and triglycerides. Our study provides evidence that the preventive effect of statins on CHD could be attributed in large part to their effect on LDL. Our g-formula estimator is a promising approach to elucidate pathways, even if it is hard to make firm conclusions for the LDL pathway on mortality and CVD.

Venae Comitantes Fistulae: An Option in Patients with Difficult Hemodialysis Access

Objectives

To evaluate the outcome of use of venae comitantes vessels in the formation of arterio-venous fistulae as vascular access for hemodialysis, in patients with limited venous anatomy.

Methods

Twenty patients who underwent arterio-venous anastomosis between brachial artery and venae comitantes were identified (2002 – 2005) and the notes reviewed.

Results

There was early failure in two (10%) patients (immediate postoperative period) and a further four (20%) failed late (mean 26 weeks, range 7–60). One patient developed a steal syndrome with radial nerve dysfunction requiring ligation of the fistula. Six (30%) patients utilised their fistulae for dialysis successfully without additional surgery and a further 6(30%) required surgical intervention to exteriorise the fistulae by the use of interposition grafts to allow successful use.

Conclusion

Venae Comitantes arterial fistulae offer an option in patients with limited venous anatomy for standard reconstruction. If access surgery utilizes such veins second stage procedures are often required with overall 70% use.