Use of multiple correspondence analysis and cluster analysis to study dietary behaviour: food consumption questionnaire in the SU.VI.MAX. cohort

Identifying Potential Factors Associated with High HIV viral load in KwaZulu-Natal, South Africa using Multiple Correspondence Analysis and Random Forest Analysis

Background

Sustainable Human Immunodeficiency Virus (HIV) virological suppression is crucial to achieving the Joint United Nations Programme of HIV/AIDS (UNAIDS) 95–95-95 treatment targets to reduce the risk of onward HIV transmission. Exploratory data analysis is an integral part of statistical analysis which aids variable selection from complex survey data for further confirmatory analysis.

Methods

In this study, we divulge participants’ epidemiological and biological factors with high HIV RNA viral load (HHVL) from an HIV Incidence Provincial Surveillance System (HIPSS) sequential cross-sectional survey between 2014 and 2015 KwaZulu-Natal, South Africa. Using multiple correspondence analysis (MCA) and random forest analysis (RFA), we analyzed the linkage between socio-demographic, behavioral, psycho-social, and biological factors associated with HHVL, defined as ≥400 copies per m/L.

Results

Out of 3956 in 2014 and 3868 in 2015, 50.1% and 41% of participants, respectively, had HHVL. MCA and RFA revealed that knowledge of HIV status, ART use, ARV dosage, current CD4 cell count, perceived risk of contracting HIV, number of lifetime HIV tests, number of lifetime sex partners, and ever diagnosed with TB were consistent potential factors identified to be associated with high HIV viral load in the 2014 and 2015 surveys. Based on MCA findings, diverse categories of variables identified with HHVL were, did not know HIV status, not on ART, on multiple dosages of ARV, with less likely perceived risk of contracting HIV and having two or more lifetime sexual partners.

Conclusion

The high proportion of individuals with HHVL suggests that the UNAIDS 95–95-95 goal of HIV viral suppression is less likely to be achieved. Based on performance and visualization evaluation, MCA was selected as the best and essential exploration tool for identifying and understanding categorical variables’ significant associations and interactions to enhance individual epidemiological understanding of high HIV viral load. When faced with complex survey data and challenges of variables selection in research, exploratory data analysis with robust graphical visualization and reliability that can reveal divers’ structures should be considered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01625-6.

Identification of New Biological Pathways Involved in Skin Aging From the Analysis of French Women Genome-Wide Data

Skin aging is an ineluctable process leading to the progressive loss of tissue integrity and is characterized by various outcomes such as wrinkling and sagging. Researchers have identified impacting environmental factors (sun exposure, smoking, etc.) and several molecular mechanisms leading to skin aging. We have previously performed genome-wide association studies (GWAS) in 502 very-well characterized French women, looking for associations with four major outcomes of skin aging, namely, photoaging, solar lentigines, wrinkling, and sagging, and this has led to new insights into the molecular mechanisms of skin aging. Since individual SNP associations in GWAS explain only a small fraction of the genetic impact in complex polygenic phenotypes, we have made the integration of these genotypes into the reference Kegg biological pathways and looked for associations by the gene set enrichment analysis (GSEA) approach. 106 pathways were tested for association with the four outcomes of skin aging. This biological pathway analysis revealed new relevant pathways and genes, some likely specific of skin aging such as the WNT7B and PRKCA genes in the “melanogenesis” pathway and some likely involved in global aging such as the DDB1 gene in the “nucleotide excision repair” pathway, not picked up in the previously published GWAS. Overall, our results suggest that the four outcomes of skin aging possess specific molecular mechanisms such as the “proteasome” and “mTOR signaling pathway” but may also share common molecular mechanisms such as “nucleotide excision repair.”

Small-Scale Coastal Fisheries in the Midst of Adaptation and Diversification: Insights from Southern Italy

The study looks at the problems facing coastal fishing communities. It highlights the impacts that, in the complex framework of the EU reforms, have manifested themselves on economic activities and on society. The aim of the paper is twofold: to examine small-scale artisanal fishing in an area of Southern Italy in order to develop resilience and diversification and at the same time to outline the profiles of local bluefish buyers to highlight development strategies for the sector. The research carried out through a direct survey by administering a questionnaire to fishermen operating in areas of Southern Italy and the data cross-referenced with the opinions of local consumers. A conjoint experiment, followed by a multiple correspondence analysis and cluster identification, was used to outline the profiles of local bluefish buyers. The results of the analysis reveal that the fish market and the restaurant sector are the main distribution channels preferred by fishermen. Furthermore, fishermen are very sensitive to environmental issues and are willing to collaborate and actively participate in the environmental protection of the sea. Consumers recognise the quality of local bluefish, and they implicitly perceive the sustainability of the method of capture. The results show the need to undertake synergistic actions for the fishing industry, capable of activating marketing strategies adequately to support, promote and develop the sector. The results of the study provide helpful information for food companies in order to better segment their market and target their consumers, as well as to effectively promote their product using brands, certifications and traceability.

Questionnaire data analysis using information geometry

The analysis of questionnaires often involves representing the high-dimensional responses in a low-dimensional space (e.g., PCA, MCA, or t-SNE). However questionnaire data often contains categorical variables and common statistical model assumptions rarely hold. Here we present a non-parametric approach based on Fisher Information which obtains a low-dimensional embedding of a statistical manifold (SM). The SM has deep connections with parametric statistical models and the theory of phase transitions in statistical physics. Firstly we simulate questionnaire responses based on a non-linear SM and validate our method compared to other methods. Secondly we apply our method to two empirical datasets containing largely categorical variables: an anthropological survey of rice farmers in Bali and a cohort study on health inequality in Amsterdam. Compare to previous analysis and known anthropological knowledge we conclude that our method best discriminates between different behaviours, paving the way to dimension reduction as effective as for continuous data.

Consumer Habits of Local Food: Perspectives from Northern Sweden

International studies are dealing with the promotion of sustainable food systems more frequently. Additionally, places of purchase and sharing in the choice of food to be consumed have become a network system for families. The aim of this work is to analyse the preferences of Swedish consumers for local/artisanal cheeses and the purchase motivations that guide their choices. We also studied the role played by consumers’ favourite shopping locations (retail store, hypermarket, city market, supply chain). On the one hand, we examined the attractiveness and the power exercised by the various stores and on the other hand, we viewed the consumer in relation to the frequency of purchase, and the confidence with the sales points. We interviewed 200 people in the city of Östersund, highlighting habits, consumption preferences and reasons for purchasing. A multiple correspondence analysis explores the reasons behind the purchase preferences of the local ‘Källarlagrad getost’ artisan cheese from the Slow Food brand. The representations of social network analysis are used to show the complex articulations that influence the choices of consumers in terms of type of cheese purchased/consumed and places of purchase/consumption. The results showed that Swedish consumers, in the purchase of cheeses, have a loyalty point at the point of sale, follow the advice of the seller and are attentive to the reputation of the product. Those who buy Källarlagrad getost are sensitive to safety, appreciate artisan cheeses and choose them for their versatility, have a strong connection with the territory and wish to contribute to supporting the local economy. Knowing these characteristics and preferences of Swedish consumers living in a city in the north of the country is important for marketing activities and for promoting tourism and sustainable gastronomy.

Western Dietary Pattern Is Associated with Irritable Bowel Syndrome in the French NutriNet Cohort

Background: Diet appears to play a key role in the pathogenesis of the irritable bowel syndrome (IBS). Some dietary patterns (DP) could increase the risk of triggering or worsening IBS symptoms. This cross-sectional study aimed to assess the association between a posteriori derived DP and IBS in a large French population, the web-based NutriNet-Santé cohort. Methods: Study population included participants of the NutriNet-Santé study who completed a questionnaire based on Rome III criteria assessing IBS. A principal component analysis (PCA) was performed to identify major DPs based on 29 food groups' consumption. Associations between DP quintiles and IBS were investigated with multivariable logistic regressions. Results: 44,350 participants were included, with 2423 (5.5%) presenting IBS. Three major DP were extracted using PCA, "healthy," "western," and "traditional." After adjustments on confounders, the "western" DP was positively associated with IBS (OR _{Q5 vs. Q1} = 1.38, 95% CI 1.19-1.61, p trend < 0.0001) and the "traditional" DP was positively associated with IBS in women (OR _{Q5 vs. Q1} = 1.29 95% CI 1.08-1.54, p trend = 0.001). Conclusions: In this study, a "western" DP-highly correlated with the consumption of fatty and sugary products and snacks-was associated with a moderate increased risk of IBS.

A comprehensive grid to evaluate case management's expected effectiveness for community-dwelling frail older people: results from a multiple, embedded case study

BACKGROUND

Case management is a type of intervention expected to improve the quality of care and therefore the quality of life of frail, community-dwelling older people while delaying institutionalisation in nursing homes. However, the heterogeneity, multidimensionality and complexity of these interventions make their evaluation by the means of classical approaches inadequate. Our objective was twofold: (i) to propose a tool allowing for the identification of the key components that explain the success of case management for this population and (ii) to propose a typology based on the results of this tool.

METHODS

The process started with a multiple embedded case study design in order to identify the key components of case management. Based on the results of this first step, data were collected among 22 case management interventions, in order to evaluate their expected effectiveness. Finally, multiple correspondence analyses was conducted to propose a typology of case management. The overall approach was informed by Wagner's Chronic Care Model and the theory of complexity.

RESULTS

The study identified a total of 23 interacting key components. Based on the clustering of response patterns of the 22 case management projects included in our study, three types of case management programmes were evidenced, situated on a continuum from a more "socially-oriented" type towards a more "clinically-oriented" type of case management. The type of feedback provided to the general practitioner about both the global geriatric assessment and the result of the intervention turned out to be the most discriminant component between the types.

CONCLUSION

The study design allowed to produce a tool that can be used to distinguish between different types of case management interventions and further evaluate their effect on frail older people in terms of the delaying institutionalisation, functional and cognitive status, quality of life and societal costs.

Relationships between students’ mental health and their perspectives of life at school

Purpose

– The purpose of this paper is to explore relationships between students’ self-reported mental health and their perspectives about life at school in metropolitan Adelaide, South Australia.

Design/methodology/approach

– The Strengths and Difficulties Questionnaire (SDQ) and a purpose designed Living and Learning at School Questionnaire (LLSQ) were administered to 1,715 early adolescents in school Years 7-9. Correspondence analysis, which is a perceptual mapping technique available in SPSS, was used to examine relationships between students’ SDQ subscale scores (Emotional Symptoms, Hyperactivity, Conduct Problems, Pro-social Skills) and the LLSQ subscale scores (Motivation, Learning Strategies, Coping with Schoolwork, Bullying, Numbers of Friends, Safety at School and Teacher Intervention in Bullying Events).

Findings

– The correspondence analysis produced a two-dimensional visual display (a perceptual map) showing that students’ abnormal, borderline and normal SDQ subscale scores were closely related to their low, medium and high LLSQ subscale scores, respectively. A clear Dimension (factor) emerged, showing a progression from mental health difficulties to strengths, in close association with students’ reports about their school experiences.

Research limitations/implications

– Caution should be exercised when using the results to interpret events in other contexts. The limitations of self-report methods must be considered.

Practical implications

– The two-dimensional visual display provides a powerful tool for dissemination of the findings of this study about students’ perspectives to system-level and school-based personnel. This can inform the selection of intervention programs, such as strategies for self-regulation of emotions and learning behaviours, fostering friendships, and supporting academic achievement, that are related to positive mental health.

Social implications

– This paper can inform school-level policies and practices, such as those relating to professional development to support teachers’ and students’ capabilities (e.g. to manage and prevent bullying) and thus influence the nature of the school experiences that shape students’ perceptions.

Originality/value

– This paper adds students’ perspectives to the emerging field concerned with designing programs for mental health promotion in schools.

Lifestyle domains as determinants of wheeze prevalence in urban and rural schoolchildren in Ecuador: cross sectional analysis

BACKGROUND

The acquisition of a modern lifestyle may explain variations in asthma prevalence between urban and rural areas in developing countries. However, the effects of lifestyle on asthma have been investigated as individual factors with little consideration given to the effects of lifestyle as a set of attributes. The aim of the present study was to identify modern lifestyle domains and assess how these domains might explain wheeze prevalence in urban and rural areas.

METHODS

We analysed data from cross-sectional studies of urban and rural schoolchildren in Esmeraldas Province, Ecuador. Variables were grouped as indicators of socioeconomic factors, sedentarism, agricultural activities and household characteristics to represent the main lifestyle features of the study population. We used multiple correspondence analyses to identify common lifestyle domains and cluster analysis to allocate children to each domain. We evaluated associations between domains and recent wheeze by logistic regression.

RESULTS

We identified 2-3 lifestyle domains for each variable group. Although wheeze prevalence was similar in urban (9.4%) and rural (10.3%) schoolchildren, lifestyle domains presented clear associations with wheeze prevalence. Domains relating to home infrastructure (termed transitional, rudimentary, and basic urban) had the strongest overall effect on wheeze prevalence in both urban (rudimentary vs. basic urban, OR = 2.38, 95% CI 1.12-5.05, p = 0.024) and rural areas (transitional vs. basic urban, OR = 2.02, 95% CI 1.1-3.73, p = 0.024; rudimentary vs. basic urban, OR = 1.88, 95% CI 1.02-3.47, p = 0.043). A high level of sedentarism was associated with wheeze in the rural areas only (OR = 1.64, 95% CI 1.23-2.18, p = 0.001).

CONCLUSIONS

We identified lifestyle domains associated with wheeze prevalence, particularly living in substandard housing and a high level of sedentarism. Such factors could be modified through programmes of improved housing and education. The use of lifestyle domains provides an alternative methodology for the evaluation of variations in wheeze prevalence in populations with different levels of development.

Physiotherapy practice in the private sector: organizational characteristics and models

Background

Even if a large proportion of physiotherapists work in the private sector worldwide, very little is known of the organizations within which they practice. Such knowledge is important to help understand contexts of practice and how they influence the quality of services and patient outcomes. The purpose of this study was to: 1) describe characteristics of organizations where physiotherapists practice in the private sector, and 2) explore the existence of a taxonomy of organizational models.

Methods

This was a cross-sectional quantitative survey of 236 randomly-selected physiotherapists. Participants completed a purpose-designed questionnaire online or by telephone, covering organizational vision, resources, structures and practices. Organizational characteristics were analyzed descriptively, while organizational models were identified by multiple correspondence analyses.

Results

Most organizations were for-profit (93.2%), located in urban areas (91.5%), and within buildings containing multiple businesses/organizations (76.7%). The majority included multiple providers (89.8%) from diverse professions, mainly physiotherapy assistants (68.7%), massage therapists (67.3%) and osteopaths (50.2%). Four organizational models were identified: 1) solo practice, 2) middle-scale multiprovider, 3) large-scale multiprovider and 4) mixed.

Conclusions

The results of this study provide a detailed description of the organizations where physiotherapists practice, and highlight the importance of human resources in differentiating organizational models. Further research examining the influences of these organizational characteristics and models on outcomes such as physiotherapists’ professional practices and patient outcomes are needed.

The Use of Multiple Correspondence Analysis to Explore Associations between Categories of Qualitative Variables in Healthy Ageing

The main focus of this study was to illustrate the applicability of multiple correspondence analysis (MCA) in detecting and representing underlying structures in large datasets used to investigate cognitive ageing. Principal component analysis (PCA) was used to obtain main cognitive dimensions, and MCA was used to detect and explore relationships between cognitive, clinical, physical, and lifestyle variables. Two PCA dimensions were identified (general cognition/executive function and memory), and two MCA dimensions were retained. Poorer cognitive performance was associated with older age, less school years, unhealthier lifestyle indicators, and presence of pathology. The first MCA dimension indicated the clustering of general/executive function and lifestyle indicators and education, while the second association was between memory and clinical parameters and age. The clustering analysis with object scores method was used to identify groups sharing similar characteristics. The weaker cognitive clusters in terms of memory and executive function comprised individuals with characteristics contributing to a higher MCA dimensional mean score (age, less education, and presence of indicators of unhealthier lifestyle habits and/or clinical pathologies). MCA provided a powerful tool to explore complex ageing data, covering multiple and diverse variables, showing if a relationship exists and how variables are related, and offering statistical results that can be seen both analytically and visually.

The prevalence of asthma and declared asthma in Poland on the basis of ECAP survey using correspondence analysis

Results of epidemiological and public health surveys are often presented in the form of cross-classification tables. It is sometimes difficult to analyze data described in this way and to understand relations between variables. Graphical methods such as correspondence analysis are more convenient and useful. Our paper describes an application of correspondence analysis to epidemiological research. We apply the basic concepts of correspondence analysis like profiles, chi-square distance to medical data concerning prevalence of asthma. We aim at describing the relationship between asthma, region, and age. The data presented in this paper come from Epidemiology of Allergy in Poland (ECAP) survey in years 2006-2008. Correspondence analysis shows that there is a fundamental difference in the structure of age groups for people with symptoms compared to those who have declared asthma (regardless of the level of symptoms of asthma and the level of declaration). The variable which best differentiates declared asthma in all regions is "wheezing and whistling." Correspondence analysis also shows significant differences between locations. Our analyses are performed in the R package "ca".

Dietary patterns obtained through principal components analysis: the effect of input variable quantification

Principal components analysis (PCA) is a popular method for deriving dietary patterns. A number of decisions must be made throughout the analytic process, including how to quantify the input variables of the PCA. The present study aims to compare the effect of using different input variables on the patterns extracted using PCA on 3-d diet diary data collected from 7473 children, aged 10 years, in the Avon Longitudinal Study of Parents and Children. Four options were examined: weight consumed of each food group (g/d), energy-adjusted weight, percentage contribution to energy of each food group and binary intake (consumed/not consumed). Four separate PCA were performed, one for each intake measurement. Three or four dietary patterns were obtained from each analysis, with at least one component that described 'more healthy' and 'less healthy' diets and one component that described a diet with high consumption of meat, potatoes and vegetables. There were no obvious differences between the patterns derived using percentage energy as a measurement and adjusting weight for total energy intake, compared to those derived using gram weights. Using binary input variables yielded a component that loaded positively on reduced fat and reduced sugar foods. The present results suggest that food intakes quantified by gram weights or as binary variables both resulted in meaningful dietary patterns and each method has distinct advantages: weight takes into account the amount of each food consumed and binary intake appears to describe general food preferences, which are potentially easier to modify and useful in public health settings.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Our systematic review has demonstrated that antioxidant supplements may increase mortality. We have now updated this review.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements for prevention of mortality in adults.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, LILACS, the Science Citation Index Expanded, and Conference Proceedings Citation Index-Science to February 2011. We scanned bibliographies of relevant publications and asked pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Random-effects and fixed-effect model meta-analyses were conducted. Risk of bias was considered in order to minimise the risk of systematic errors. Trial sequential analyses were conducted to minimise the risk of random errors. Random-effects model meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Seventy-eight randomised trials with 296,707 participants were included. Fifty-six trials including 244,056 participants had low risk of bias. Twenty-six trials included 215,900 healthy participants. Fifty-two trials included 80,807 participants with various diseases in a stable phase. The mean age was 63 years (range 18 to 103 years). The mean proportion of women was 46%. Of the 78 trials, 46 used the parallel-group design, 30 the factorial design, and 2 the cross-over design. All antioxidants were administered orally, either alone or in combination with vitamins, minerals, or other interventions. The duration of supplementation varied from 28 days to 12 years (mean duration 3 years; median duration 2 years). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects model meta-analysis (21,484 dead/183,749 (11.7%) versus 11,479 dead/112,958 (10.2%); 78 trials, relative risk (RR) 1.02, 95% confidence interval (CI) 0.98 to 1.05) but significantly increased mortality in a fixed-effect model (RR 1.03, 95% CI 1.01 to 1.05). Heterogeneity was low with an I(2)- of 12%. In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. Meta-regression analysis did not find a significant difference in the estimated intervention effect in the primary prevention and the secondary prevention trials. In the 56 trials with a low risk of bias, the antioxidant supplements significantly increased mortality (18,833 dead/146,320 (12.9%) versus 10,320 dead/97,736 (10.6%); RR 1.04, 95% CI 1.01 to 1.07). This effect was confirmed by trial sequential analysis. Excluding factorial trials with potential confounding showed that 38 trials with low risk of bias demonstrated a significant increase in mortality (2822 dead/26,903 (10.5%) versus 2473 dead/26,052 (9.5%); RR 1.10, 95% CI 1.05 to 1.15). In trials with low risk of bias, beta-carotene (13,202 dead/96,003 (13.8%) versus 8556 dead/77,003 (11.1%); 26 trials, RR 1.05, 95% CI 1.01 to 1.09) and vitamin E (11,689 dead/97,523 (12.0%) versus 7561 dead/73,721 (10.3%); 46 trials, RR 1.03, 95% CI 1.00 to 1.05) significantly increased mortality, whereas vitamin A (3444 dead/24,596 (14.0%) versus 2249 dead/16,548 (13.6%); 12 trials, RR 1.07, 95% CI 0.97 to 1.18), vitamin C (3637 dead/36,659 (9.9%) versus 2717 dead/29,283 (9.3%); 29 trials, RR 1.02, 95% CI 0.98 to 1.07), and selenium (2670 dead/39,779 (6.7%) versus 1468 dead/22,961 (6.4%); 17 trials, RR 0.97, 95% CI 0.91 to 1.03) did not significantly affect mortality. In univariate meta-regression analysis, the dose of vitamin A was significantly associated with increased mortality (RR 1.0006, 95% CI 1.0002 to 1.001, P = 0.002).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Beta-carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A. Antioxidant supplements need to be considered as medicinal products and should undergo sufficient evaluation before marketing.

Nutrition transition among adolescents of a south-Mediterranean country: dietary patterns, association with socio-economic factors, overweight and blood pressure. A cross-sectional study in Tunisia

BACKGROUND

The increase in the burden of chronic diseases linked to the nutrition transition and associated dietary and lifestyle changes is of growing concern in south and east Mediterranean countries and adolescents are at the forefront of these changes. This study assessed dietary intake and association with socio-economic factors and health outcomes among adolescents in Tunisia.

METHODS

Cross-sectional survey (year 2005); 1019 subjects 15-19 y. from a clustered random sample. Dietary intake was assessed by a validated semi-quantitative frequency questionnaire (134 items) as was physical activity; the Diet Quality Index International measured diet quality; dietary patterns were derived by multiple correspondence analysis from intakes of 43 food groups. Body Mass Index (BMI) ≥ 85th and 95th percentile defined overweight and obesity. Waist Circumference (WC) assessed abdominal fat. High blood pressure was systolic (SBP) or diastolic blood pressure (DBP) ≥ 90th of the international reference for 15-17 y., and SBP/DBP ≥ 120/80 mm Hg for 18-19 y.

RESULTS

Energy intake levels were quite high, especially for females. The macro-nutrient structure was close to recommendations but only 38% had a satisfactory diet quality. A main traditional to modern dietary gradient, linked to urbanisation and increased economic level, featured an increasing consumption of white bread, dairy products, sugars, added fats and fruits and decreasing consumption of oils, grains, legumes and vegetables; regarding nutrients this modern diet score featured a decreasing relationship with total fat and an increase of calcium intake, but with an increase of energy, sugars and saturated fat, while vitamin C, potassium and fibre decreased. Adjusted for age, energy and physical activity, this modern pattern was associated with increased overweight in males (2nd vs. 1st tertile: Prevalence Odds-Ratio (POR) = 4.0[1.7-9.3], 3rd vs. 1st: POR = 3.3[1.3-8.7]) and a higher WC. Adjusting also for BMI and WC, among females, it was associated with decreased prevalence of high blood pressure (2nd vs. 1st tertile: POR = 0.5[0.3-0.8], 3rd vs. 1st tertile: POR = 0.4[0.2-0.8]).

CONCLUSION

The dietary intake contrasts among Tunisian adolescents, linked to socio-economic differentials are characteristic of a nutrition transition situation. The observed gradient of modernisation of dietary intake features associations with several nutrients involving a higher risk of chronic diseases but might have not only negative characteristics regarding health outcomes.

Socioeconomic and Demographic Factors Associated With Health Care Choices in Taiwan

By using the data from the 2001 National Health Interview Survey and the National Heath Insurance database in Taiwan, this study aims at investigating the socioeconomic and demographic factors associated with different health care choices. This study incorporated hierarchical cluster analysis into multiple correspondent analysis to determine 5 attribute clusters of socioeconomic and demographic factors associated with different health care choices. This study found that older women with higher education levels were more likely to choose multiple sources of health care and that low- to middle-income people were more likely to use over-the-counter medications in pharmacies. In addition, people’s self-reported health care choices were inconsistent with their observed health care seeking behavior. The health policy authority may need to provide more health promotion education programs, especially for older women with higher educational levels, and funding incentives for quality of care provided rather than relying solely on reimbursements for episodic care.

Assessment of yellow fever epidemic risk: an original multi-criteria modeling approach

Background

Yellow fever (YF) virtually disappeared in francophone West African countries as a result of YF mass vaccination campaigns carried out between 1940 and 1953. However, because of the failure to continue mass vaccination campaigns, a resurgence of the deadly disease in many African countries began in the early 1980s. We developed an original modeling approach to assess YF epidemic risk (vulnerability) and to prioritize the populations to be vaccinated.

Methods and Findings

We chose a two-step assessment of vulnerability at district level consisting of a quantitative and qualitative assessment per country. Quantitative assessment starts with data collection on six risk factors: five risk factors associated with “exposure” to virus/vector and one with “susceptibility” of a district to YF epidemics. The multiple correspondence analysis (MCA) modeling method was specifically adapted to reduce the five exposure variables to one aggregated exposure indicator. Health districts were then projected onto a two-dimensional graph to define different levels of vulnerability. Districts are presented on risk maps for qualitative analysis in consensus groups, allowing the addition of factors, such as population migrations or vector density, that could not be included in MCA. The example of rural districts in Burkina Faso show five distinct clusters of risk profiles. Based on this assessment, 32 of 55 districts comprising over 7 million people were prioritized for preventive vaccination campaigns.

Conclusion

This assessment of yellow fever epidemic risk at the district level includes MCA modeling and consensus group modification. MCA provides a standardized way to reduce complexity. It supports an informed public health decision-making process that empowers local stakeholders through the consensus group. This original approach can be applied to any disease with documented risk factors.

This article describes the use of an original modeling approach to assess the risk of yellow fever (YF) epidemics. YF is a viral hemorrhagic fever responsible in past centuries for devastating outbreaks. Since the 1930s, a vaccine has been available that protects the individual for at least 10 years, if not for life. However, immunization of populations in African countries was gradually discontinued after the 1960s. With the decrease in immunity against YF in African populations the disease reemerged in the 1980s. In 2005, WHO, UNICEF, and the GAVI Alliance decided to support preventive vaccination of at-risk populations in West African endemic countries in order to tackle the reemergence of YF and reduce the risk of urban YF outbreaks. Financial resources were made available to scale up a global YF vaccine stockpile and to support countries with limited resources in the management of preventive vaccination campaigns. This article describes the process we used to determine the most at-risk populations using a mathematical model to prioritize targeted immunization campaigns. We believe that this approach could be useful for other diseases for which decision making process is difficult because of limited data availability, complex risk variables, and a need for rapid decisions and implementation.

[The concept of "patient type": utility for the care of surgical patients]

OBJECTIVE

To describe a model of surgical "patient type" by identifying the needs and characteristics of surgical patients.

METHOD

We performed a cross-sectional study of surgical patients with one or more diseases and similar needs and/or characteristics admitted to the surgical wards of a general hospital over a 10-month period. The variables analyzed were sociodemographic and clinical data, degree of autonomy, and Virginia Henderson's needs, which were identified through an interview performed in the postoperative period. Univariate analysis, stratified descriptive statistics and multiple correspondence analysis were performed.

RESULTS

A total of 270 medium- or low-complexity patients from different surgical specialties took part in the analysis. During the surgical process (pre- and post-operative), almost a half of the patients suffered from hypotension, heart rate showed no significant changes and the risk of developing a pressure ulcer was unmodified according to Norton's scale. The first statistical analysis classified the surgical patients into five groups and showed the relationship between the degree of autonomy (measured through Barthel's index) and the number of personal problems (assessed according to the Henderson model). A subsequent statistical analysis classified the patients into four groups or types, explaining 70% of the total variance.

CONCLUSIONS

Through the use of Virginia Henderson's model, a surgical patient type composed of four different groups was identified. The results of this study may be useful in the care of low- and medium-complexity patients in distinct surgical specialties.

Antioxidant supplements for preventing gastrointestinal cancers

BACKGROUND

Oxidative stress may cause gastrointestinal cancers. The evidence on whether antioxidant supplements are effective in preventing gastrointestinal cancers is contradictory.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements in preventing gastrointestinal cancers.

SEARCH STRATEGY

We identified trials through the trials registers of the four Cochrane Review Groups on gastrointestinal diseases, The Cochrane Central Register of Controlled Trials in The Cochrane Library (Issue 2, 2007), MEDLINE, EMBASE, LILACS, SCI-EXPANDED, and The Chinese Biomedical Database from inception to October 2007. We scanned reference lists and contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing antioxidant supplements to placebo/no intervention examining occurrence of gastrointestinal cancers.

DATA COLLECTION AND ANALYSIS

Two authors (GB and DN) independently selected trials for inclusion and extracted data. Outcome measures were gastrointestinal cancers, overall mortality, and adverse effects. Outcomes were reported as relative risks (RR) with 95% confidence interval (CI) based on random-effects and fixed-effect model meta-analysis. Meta-regression assessed the effect of covariates across the trials.

MAIN RESULTS

We identified 20 randomised trials (211,818 participants), assessing beta-carotene (12 trials), vitamin A (4 trials), vitamin C (8 trials), vitamin E (10 trials), and selenium (9 trials). Trials quality was generally high. Heterogeneity was low to moderate. Antioxidant supplements were without significant effects on gastrointestinal cancers (RR 0.94, 95% CI 0.83 to 1.06). However, there was significant heterogeneity (I(2) = 54.0%, P = 0.003). The heterogeneity may have been explained by bias risk (low-bias risk trials RR 1.04, 95% CI 0.96 to 1.13 compared to high-bias risk trials RR 0.59, 95% CI 0.43 to 0.80; test of interaction P < 0.0005), and type of antioxidant supplement (beta-carotene potentially increasing and selenium potentially decreasing cancer risk). The antioxidant supplements had no significant effects on mortality in a random-effects model meta-analysis (RR 1.02, 95% CI 0.97 to 1.07, I(2) = 53.5%), but significantly increased mortality in a fixed-effect model meta-analysis (RR 1.04, 95% CI 1.02 to 1.07). Beta-carotene in combination with vitamin A (RR 1.16, 95% CI 1.09 to 1.23) and vitamin E (RR 1.06, 95% CI 1.02 to 1.11) significantly increased mortality. Increased yellowing of the skin and belching were non-serious adverse effects of beta-carotene. In five trials (four with high risk of bias), selenium seemed to show significant beneficial effect on gastrointestinal cancer occurrence (RR 0.59, 95% CI 0.46 to 0.75, I(2) = 0%).

AUTHORS' CONCLUSIONS

We could not find convincing evidence that antioxidant supplements prevent gastrointestinal cancers. On the contrary, antioxidant supplements seem to increase overall mortality. The potential cancer preventive effect of selenium should be tested in adequately conducted randomised trials.

A heuristic index for selecting similar categories in multiple correspondence analysis applied to living donor kidney transplantation

This work introduces a heuristic index (the "tolerance distance") to define the "closeness" of two variable categories in multiple correspondence analysis (MCA). This index is a weighted Euclidean distance where weightings are based on the "importance" of each MCA axis, and variable categories were considered to be associated when their distances were below the tolerance distance. This approach was applied to a renal transplantation data. The analysed variables were allograft survival and 13 of its putative predictors. A bootstrap-based stability analysis was employed for assessing result reliability. The method identified previously detected associations within the database, such as that between race of donors and recipients, and that between HLA match and Cyclosporine use. A hierarchical clustering algorithm was also applied to the same data, allowing for interpretations similar to those based on MCA. The defined tolerance distance could thus be used as an index of "closeness" in MCA, hence decreasing the subjectivity of interpreting MCA results.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Animal and physiological research as well as observational studies suggest that antioxidant supplements may improve survival.

OBJECTIVES

To assess the effect of antioxidant supplements on mortality in primary or secondary prevention randomised clinical trials.

SEARCH STRATEGY

We searched The Cochrane Library (Issue 3, 2005), MEDLINE (1966 to October 2005), EMBASE (1985 to October 2005), and the Science Citation Index Expanded (1945 to October 2005). We scanned bibliographies of relevant publications and wrote to pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention. Included participants were either healthy (primary prevention trials) or had any disease (secondary prevention trials).

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Trials with adequate randomisation, blinding, and follow-up were classified as having a low risk of bias. Random-effects and fixed-effect meta-analyses were performed. Random-effects meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Sixty-seven randomised trials with 232,550 participants were included. Forty-seven trials including 180,938 participants had low risk of bias. Twenty-one trials included 164,439 healthy participants. Forty-six trials included 68111 participants with various diseases (gastrointestinal, cardiovascular, neurological, ocular, dermatological, rheumatoid, renal, endocrinological, or unspecified). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects meta-analysis (relative risk [RR] 1.02, 95% confidence interval [CI] 0.99 to 1.06), but significantly increased mortality in a fixed-effect model (RR 1.04, 95% CI 1.02 to 1.06). In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. In the trials with a low risk of bias, the antioxidant supplements significantly increased mortality (RR 1.05, 95% CI 1.02 to 1.08). When the different antioxidants were assessed separately, analyses including trials with a low risk of bias and excluding selenium trials found significantly increased mortality by vitamin A (RR 1.16, 95% CI 1.10 to 1.24), beta-carotene (RR 1.07, 95% CI 1.02 to 1.11), and vitamin E (RR 1.04, 95% CI 1.01 to 1.07), but no significant detrimental effect of vitamin C (RR 1.06, 95% CI 0.94 to 1.20). Low-bias risk trials on selenium found no significant effect on mortality (RR 0.91, 95% CI 0.76 to 1.09).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Vitamin A, beta-carotene, and vitamin E may increase mortality. Future randomised trials could evaluate the potential effects of vitamin C and selenium for primary and secondary prevention. Such trials should be closely monitored for potential harmful effects. Antioxidant supplements need to be considered medicinal products and should undergo sufficient evaluation before marketing.

Artificial and natural ultraviolet radiation exposure: beliefs and behaviour of 7200 French adults

BACKGROUND

Despite the increasing use of indoor tanning facilities, little is known regarding the behaviour of adults with respect to artificial and natural ultraviolet (UV) radiation exposure and the relationship between the two forms of exposure.

OBJECTIVES

To describe the beliefs and behaviour of French middle-aged volunteers regarding artificial and natural UV exposure.

METHODS

Cross-sectional study of a French national cohort using a self-completed questionnaire.

RESULTS

Participants were identified as 'indoor UV tanners' (n= 1076) and as 'non-users' (n= 6124). Predictor factors associated with indoor tanning were gender, age, smoking, phototype, region of residence, sun exposure during hobbies, voluntary sun exposure in particular during the hottest hours of the day, nudism practice, facial sunscreen habits, sunglass use, importance for lying in the sun and the claim 'ever heard of melanoma'.

LIMITATIONS

The quality of information may be limited by the data collection method.

CONCLUSION

Whereas indoor tanning should be discouraged, it seems that indoor tanners are also regular sunbathers unconcerned about the risk of photoageing and skin cancer occurrence. Moreover, indoor tanners seem to have more behavioural risk factors for cancer, such as smoking.

Practice patterns of physiotherapists in the treatment of work-related back pain

RATIONALE AND OBJECTIVES

Although physiotherapists (PTs) are one of the health professionals most involved in the treatment of back pain, their practice patterns have not been well studied. The study objectives were to identify the practice patterns of PTs treating workers suffering from acute/subacute back pain, with and without radiating pain below the knee, and to assess the relationship between these patterns and characteristics of PTs.

METHODS

PTs working in private clinics in the province of Quebec, Canada were invited to participate. Each PT used a self-administered questionnaire to record, for each treatment session, treatment objectives, interventions used and education given to two workers with back pain, one without radiating pain (n = 189 PTs) and one with radiating pain (n = 136 PTs). Multiple correspondence analysis with hierarchical classification was used to identify practice patterns of PTs. Multinomial logistic regressions were used to assess the relationship between practice patterns and PTs characteristics.

RESULTS

For workers without radiating pain, 51.9% of PTs focused their treatment on soft tissue mobilizations/massage and heat, 24.3% focused on the McKenzie approach and related interventions, and 23.8% focused on exercises and function. Similar results were found for workers with radiating pain. Most of the PT characteristics were not related to practice patterns.

CONCLUSIONS

The practices of PTs appeared to be separated into three distinct patterns. These practice variations suggest that there may be disagreement or uncertainty among PTs in the management of work-related back pain. The lack of evidence for the majority of interventions used by PTs and the difficulties of integrating evidence into clinical practice may be possible explanations.

Travellers to high UV-index countries: Sun-exposure behaviour in 7822 French adults

BACKGROUND

Travel health information includes warning on sun exposure, particularly for fair-skinned individuals travelling to tropical countries.

METHOD

A self-completed questionnaire on sun exposure behaviour was sent to the 12,741 French adults enrolled in the SU.VI.MAX cohort. Among the 7822 participants, 196 (110 women and 86 men) declared at least one visit to a high UV-index country over the past year for more than 1 month, subsequently referred to as long-term travellers. The remaining 7626 participants (non-travellers) accounted for 4862 women and 2764 men.

RESULTS

Women travellers declared more frequently skin exposure to the sun over the past year, practised tanning in high UV-index areas more than 2h daily, experienced intensive sun exposure than non-travellers. Moreover, they asserted that basking in the sun is very important. Comparable results were found in men. The use of sun protection products was similar in travellers and non-travellers, but women tended to use sunscreen products more often, more regularly and with a higher sun protection factor (SPF) than men.

CONCLUSIONS

Specific health education campaigns and pre-travel advice aiming to reduce sun exposure and to improve protective measures against ultraviolet (UV) radiation should be addressed to travellers to countries with high UV-index.

Daily protein intakes and eating patterns in young and elderly French

An adequate level of protein intake is required to limit the gradual body protein loss observed during ageing. Different factors (cohort age, sex, life conditions) may modify protein intake and distribution. However the precise amounts, as well as their daily distribution which affects protein utilisation and N retention, are unknown in both young and elderly individuals. The hypothesis was tested that protein intake and its distribution over daily meals could be different between the young and elderly. The consumption of six different protein-rich food groups by 292 healthy individuals aged 20–30 and 65–75 years was determined throughout each day for 1 week. The data of the total protein intake and protein intakes at each meal were analysed by ANOVA for each sex separately, using age group as the independent factor. The average protein intake of men was lower in the older age group whilst the opposite trend was seen in women. The distribution of protein intake was different between the two age groups: 56·5 % of the daily protein was eaten at lunch by the elderly but only 47 % (P<0·0001) by the younger subjects. In the elderly subjects, those eating larger amounts consumed a greater proportion of protein-rich foods at dinner than those eating small amounts (30·4 v. 26·2 %, P=0·05). A high level of protein intake was related to a higher meat-product consumption in both the elderly and young individuals. In conclusion, the pattern of protein intake differs significantly between age groups and sexes.

Emotions generated by meat and other food products in women

Eating behaviour depends partly on food preference, which is itself determined by different types of emotions. Among the emotions generated by food, disgust with red meat is common in women and can lead to reduced meat consumption. We tested the hypothesis that low meat intake is related to different negative emotions towards meat but does not affect the emotions expressed towards other food categories. Food intake of sixty women was followed throughout each day for 1 week and allowed us to assign women to two groups (low v. high meat-eating women). They were then invited to assess the intensity of twenty-six emotions described by words and induced by thirty food pictures. We determined the number of necessary dimensions to describe the space created by the twenty-six words. The results showed differences in emotions between the low and high meat-eating women. As expected, there were overall differences in the emotions generated by the thirty food pictures. Six clusters of emotions were necessary and sufficient to summarise the emotional space. These dimensions were described by ‘disappointment’, ‘satisfaction’, ‘guilt’, ‘doubt’, ‘amused’ and ‘indifference’. As expected, the low meat-eating women felt more ‘disappointment’, ‘indifference’ and less ‘satisfaction’ towards meat than did the high meat-eating women. However, the low meat-eating women also stated other negative emotions such as ‘doubt’ towards some starchy foods. The only foods that they liked more than high meat-eating women were pears and French beans. In conclusion, low meat consumption was associated with specific negative emotions regarding meat and other foods.

Patterns of dental crowding in the lower arch and contributing factors. A statistical study

OBJECTIVE

To investigate the patterns of dental crowding in the lower arch and their contributing morphological and functional factors.

MATERIALS AND METHODS

Pretreatment diagnostic materials from 168 patients exhibiting dental crowding were selected, and the patients, dental casts, lateral cephalograms, and occlusal forces were evaluated. The crowding in the lower dental arch was quantified and the patterns of crowding were identified. Crowding patterns in the anterior region were classified by cluster analysis. The relationship between the crowding patterns and morphological and functional factors was investigated by correspondence analysis.

RESULTS

The prevalence of dental crowding was highest in the anterior region and was related to the same tooth on each side (eg, right lateral incisor vs left lateral incisor). In the premolar and molar region, the prevalence of dental crowding was related to the adjacent tooth (eg, right first premolar vs second premolar). Three crowding patterns were found in the anterior region: (1) a "symmetry pattern," (2) a "rotation pattern," and (3) an "irregular pattern." The first pattern was related to the factors of discrepancy, whereas the latter two patterns were related to functional factors such as occlusal force and its center of gravity.

CONCLUSIONS

These results suggest that crowding patterns can be useful information for treatment planning and achieving dental stability.

Self-reported skin sensitivity in a general adult population in France: data of the SU.VI.MAX cohort

OBJECTIVE

This study aimed to examine the frequency of self-assessed facial skin sensitivity and its different patterns, and the relationship with gender and sun sensitivity in a general adult population.

METHODS

A standardized 11-item questionnaire investigating reactions experienced during the past year was developed. The questions explored different patterns of skin sensitivity: pattern I (blushing related to vascular reactivity), pattern II (skin reactions to certain environmental conditions), pattern III (skin reactions after substance contact), and for women pattern IV ('breakout of spots' related to menstrual cycle). Additional items were addressed for women and men, including sun sensitivity. The questionnaire was administered to a large middle-aged population involved in the 'Supplément en Vitamines et Minéraux Antioxydants' (SU.VI.MAX) cohort.

RESULTS

Sensitive facial skin was reported by 61% of the women (n = 5074) and 32% of the men (n = 3448), and the frequency decreased with age. The frequency of patterns I, II and III was greater for women (78, 72 and 58%, respectively) than for men (56, 48 and 28%) of comparable classes of age. The frequency of pattern IV was reported by 49% of premenopausal women, and skin reactions after shaving by 41% of the men. Sun sensitivity was found to be a major component of skin sensitivity. Factor analysis showed that individuals with fair phototype frequently evoked reactions associated with pattern I, and skin redness and burning sensations were related to certain environmental conditions (pattern II).

CONCLUSION

Skin sensitivity is a common concern that declines with age and is relevant for men as well as for women.

Antioxidant supplements for preventing gastrointestinal cancers

BACKGROUND

Oxidative stress may cause gastrointestinal cancers. The evidence on whether antioxidant supplements are effective in preventing gastrointestinal cancers is contradictory.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements in preventing gastrointestinal cancers.

SEARCH STRATEGY

We identified trials through the trials registers of the four Cochrane Review Groups on gastrointestinal diseases, The Cochrane Central Register of Controlled Trials on The Cochrane Library (Issue 1, 2003), MEDLINE, EMBASE, LILACS, and SCI-EXPANDED from inception to February 2003, and The Chinese Biomedical Database (March 2003). We scanned reference lists and contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing antioxidant supplements to placebo/no intervention examining the incidence of gastrointestinal cancers.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion and extracted data. The outcome measures were incidence of gastrointestinal cancers, overall mortality, and adverse events. Outcomes were reported as relative risks (RR) with 95% confidence interval (CI) based on fixed and random effects meta-analyses.

MAIN RESULTS

We identified 14 randomised trials (170,525 participants), assessing beta-carotene (9 trials), vitamin A (4 trials), vitamin C (4 trials), vitamin E (5 trials), and selenium (6 trials). Trial quality was generally high. Heterogeneity was low to moderate. Neither the fixed effect (RR 0.96, 95% CI 0.88 to 1.04) nor random effects meta-analyses (RR 0.90, 95% CI 0.77 to 1.05) showed significant effects of supplementation with antioxidants on the incidences of gastrointestinal cancers. Among the seven high-quality trials reporting on mortality (131,727 participants), the fixed effect (RR 1.06, 95% CI 1.02 to 1.10) unlike the random effects meta-analysis (RR 1.06, 95% CI 0.98 to 1.15) showed that antioxidant supplements significantly increased mortality. Two low-quality trials (32,302 participants) found no significant effect of antioxidant supplementation on mortality. The difference between the mortality estimates in high- and low-quality trials was significant by test of interaction (z = 2.10, P = 0.04). Beta-carotene and vitamin A (RR 1.29, 95% CI 1.14 to 1.45) and beta-carotene and vitamin E (RR 1.10, 95% CI 1.01 to 1.20) significantly increased mortality, while beta-carotene alone only tended to do so (RR 1.05, 95% CI 0.99 to 1.11). Increased yellowing of the skin and belching were non-serious adverse effects of beta-carotene. In four trials (three with unclear/inadequate methodology), selenium showed significant beneficial effect on gastrointestinal cancer incidences.

REVIEWERS' CONCLUSIONS

We could not find evidence that antioxidant supplements prevent gastrointestinal cancers. On the contrary, they seem to increase overall mortality. The potential cancer preventive effect of selenium should be studied in adequately conducted randomised trials.