The dimension reduction power of ClustOfVar: application of the variable cluster analysis technique in a mixed data health database

ackground/Objective: Technological evolution is increasingly making real the elements necessary for the daily practice of personalized medicine, an improved vision of health care whose decisions regarding prognosis, diagnosis and therapeutic strategies depend on the patient's various characteristics. This approach leads to the collection and use of information that is broad in extension and complexity, for which dimensionality reduction techniques are imperative, in order to simplify and understand it. This paper aims to show the value of the ClustOfVar technique, a variable clustering technique capable of dealing with mixed data, resulting in data reduction. Through its hierarchical and non-hierarchical approaches, it replaces sample variables with representative synthetic variables. This dimensional reduction can be extended to individuals by applying Ward's method. Methods: The cleaning process of anthropometric, obstetric, vital signs and pubertal status data from 700 participants of the Generation XXI cohort and/or their mothers led to variables being removed (181 down to 105 variables, 82 quantitative and 23 qualitative). Then, the hierarchical technique of the ClustOfVar package was applied, which started by building a hierarchy of variables. The optimal number of clusters was then determined, considering the aggregation level plot and the bootstrap methodology, and each cluster was characterized. The partition into clusters was then tried with the non-hierarchical process. Once the partition was defined, Ward's method was applied, dividing the participants into clusters. We finished with their description according to the synthetic variables. Results: The partition in 8 clusters of variables suggested by the hierarchical technique was chosen, with the first and third cluster being filled mainly by maternal characteristics (relating mainly to menstruation and physical measurements, respectively). While cluster 2 mixes maternal and individual characteristics, cluster 4 contains only patient variables at birth. Cluster 5 is the most diverse, with anthropometric and related measurements of vital signs and blood macromolecules. Cluster 6 has total mass and fat measurements. Finally, cluster 7 is related to pubertal status variables, and cluster 8 includes cholesterol variables. The clustering of individuals results in the creation of specific profiles for each of the 8 clusters of individuals. Conclusions: The ClustOfVar technique accomplishes a data transformation relevant to the dispersion of personalized medicine. However, it lacks the ability to deal with high proportions of missing data and its bootstrap process is very time-consuming.publishe

Socioeconomic position early in adolescence and mode of delivery later in life: findings from a portuguese birth cohort

Objective: This study assessed the influence of socioeconomic position at 12 years of age (SEP-12) on the variability in cesarean rates later in life. Methods: As part of the Portuguese Generation XXI birth cohort we evaluated 7358 women with a singleton pregnancy who delivered at five Portuguese public hospitals serving the region of Porto (April/2005–September/2006). Based on the twelve items that described socioeconomic circumstances at age 12, a latent class analysis was used to classify women’s SEP-12 as high, intermediate and low. Multiple Poisson regression was used to estimate adjusted risk ratio (RR) and respective 95% confidence interval (95% CI). Results: The cesarean rates in high, intermediate and low SEP-12 were, respectively, 40.9%, 37.5% and 40.5% (p=0.100) among primiparous women; 14.2%, 11.6% and 15.5% (p=0.04) among multiparous women with no previous cesarean and 78.6%, 72.2% and 70.0% (p=0.08) among women with a previous cesarean. A low to moderate association between SEP-12 and cesarean rates was observed among multiparous women with a previous cesarean, illustrating that women from higher SEP-12 were more likely to have a surgical delivery (RR=1.12;95%CI:1.01-1.24 comparing high with low SEP-12 and RR=1.03:95%CI:0.94-1.14 comparing intermediate with low SEP-12) not explained by potential mediating factors. No such association was found either in primiparous or in multiparous women without a previous cesarean. Conclusions: The association between SEP-12 and cesarean rates suggests the effect of past socioeconomic context on the decision concerning the mode of delivery, but only among women who experienced a previous cesarean. Accordingly, it appears that early-life socioeconomic circumstances drive cesarean rates but the effect can be modified by lived experiences concerning childbirth

Sex-Heterogeneity on the Association between Dietary Patterns at 4 Years of Age with Adiposity and Cardiometabolic Risk Factors at 10 Years of Age

Funding: Generation XXI was funded by the Health Operational Programme–Saúde XXI, Community Support Framework III and the Regional Department of Ministry of Health. This study was also supported through FEDER–COMPETE and through national funding from the Foundation for Science and Technology–FCT (Portuguese Ministry of Education and Science) within the project “FOCAcCIa: (POCI-01-0145-FEDER-031949), and through a Researcher Contract (Andreia Oliveira IF/01350/2015). It had also support from the Epidemiology Research Unit (EPI-Unit: UIDB/04750/2020; POCI-01-0145-FEDER-006862) and Laboratory for Integrative and Translational Research in Population Health (ITR: LA/P/0064/2020).To evaluate the association of dietary patterns (DP) at 4 years with adiposity and cardiometabolic risk factors at 10 years, considering sex-heterogeneity. This prospective analysis included 3823 children enrolled in the population-based birth cohort, Generation XXI (Porto-Portugal, 2005–2006). Diet at 4 years was assessed by FFQ, with three DP being identified: high in energy-dense foods (EDF), intermediate in snacks (snacking), and healthier (reference). BMI at 10 years was considered as the Z-score according to the WHO. Other adiposity indicators—fat mass percentage (FM%), fat mass index (FMI), and waist-to-height ratio (WHtR)—were converted to z-scores using the sample’s sex-specific means and standard deviations, as were the cardiometabolic risk factors (systolic and diastolic blood pressure, lipid profile, and insulin resistance). The associations of DP at 4 years with later adiposity or cardiometabolic factors were estimated by linear regression or by multinomial logistic regression models. In fully adjusted models, the EDF DP was significantly positively associated with the BMI (EDF vs. healthier: β = 0.139; 95% CI: 0.031, 0.246, P-interaction = 0.042) and obesity (OR = 2.68; 95% CI 1.55, 4.63, P-interaction = 0.005) only in girls, among whom, it increased insulin (β = 0.165; 95% CI: 0.020, 0.311) and HOMA-IR (β = 0.159; 95% CI: 0.013, 0.306) at 10 years. An EDF DP at 4 years is associated with later adiposity, insulin, and HOMA-IR in girls.publishersversionpublishe

Anthropometric Indices Based on Waist Circumference as Measures of Adiposity in Children

Objective: The aim of this study was to compare the accuracy of body fat patterns and single measures in assessing body fat and to clarify the use of indices based on waist circumference as measures of adiposity in children. Methods: This study included 2,531 7-year-old children from the Generation XXI birth cohort (Porto, Portugal). Anthropometrics were obtained by trained personnel and whole-body dual-energy x-ray absorptiometry (DXA) scans were performed. Results: Principal component analysis identified two body fat patterns. Pattern 1 (BMI, fat mass index from tetra-polar bioelectric impedance, and waist-to-height ratio) showed strong correlations with DXA fat mass index (r = 0.85; P < 0.001), and pattern 2 (waist-to-hip, waist-to-thigh, and waist-to-weight ratios) showed moderate correlations with DXA central fat (r = 0.35; P < 0.001). Compared with single measures, body fat patterns showed similar correlations with DXA-derived measures. Conclusions: Compared with single anthropometric indices, body fat patterns seem to add little value for estimating body fat in children. Waist-to-height ratio seems to be a proxy for total fat, while waist-to-hip, waist-to-thigh, and waist-to-weight ratios seem to be proxies for central fat. Further studies should address the predictive ability of waist-to-weight ratio to identify children at risk of developing cardiometabolic disease, as this was the first time describing its potential usefulness.Generation XXI was funded by FEDER through the Operational Programme Competitiveness and Internationalization and with national funding from the Foundation for Science and Technology, FCT (Portuguese Ministry of Science, Technology and Higher Education) (POCI-01-0145-FEDER-021177), under the project PTDC/SAU-EPI/121532/2010 and Unidade de Investigação em Epidemiologia, Instituto de Saúde Pública da Universidade do Porto Epidemiology Research Unit (EPIUnit) (POCI-01-0145-FEDER-006862; Ref. UID/DTP/04750/2013). SS received a grant from the Foundation for Science and Technology (SFRH/BD/81123/2011). AO receives funds from the FCT Investigator Programme (IF/01350/2015), with FEDER funds through the Operational Programme Competitiveness and Internationalization and national funding from the Foundation for Science and Technology, FCT, cofunded by the FCT and the POPH/FSE Program. The funders had no role in the design, analysis, or writing of this article

PG.SGA (cotada) como indicador de prognóstico em oncologia

[Resumo][Abstract

Testing an adaptation of the EPIC physical activity questionnaire in Portuguese adults: a validation study that assesses the seasonal bias of self-report

Background: No self-report method to measure different types and intensities of physical activity (PA) in adults has been tested in the Portuguese population. We assessed the validity, reproducibility and seasonal bias on past-year PA reporting. Subjects and methods: A sample of 953 Portuguese adults was evaluated between 2001 and 2003. A 4x7-day PA diary was used as a reference method to evaluate the validity of the EPIC questionnaire adapted for the Portuguese population (n = 114). Spearman’s correlation coefficients were calculated and agreement was tested using Bland–Altman plots. Trigonometric linear models were used to assess the seasonal variation. Results: Correlations between the questionnaire and the diaries were 0.56, 0.50, 0.88 and 0.78 for total, rest, occupational and leisure-time PA, respectively. The coefficients for reproducibility (2–3 months interval) ranged between 0.80 for leisure and 0.91 for occupational. Visualizing Bland–Altman plots, only rest PA revealed a tendency towards an increase in differences with increasing rest reported. Males interviewed in April and August reported the highest and lowest mean of leisure-time PA, respectively. For professional activities, the probability of amplitude being over one-half standard deviation was 33%. Conclusions: The questionnaire is a valid and reproducible instrument for the brief assessment of usual energy expenditure in adults, detailing different types of PA. In males, seasonal bias on reporting leisure-time and professional PA was found

Latent models in the development and improvement of tools for health outcomes measurement

Saúde PúblicaDoctoral Programme in Public Healt

A short form of the neonatal intensive care unit family needs inventory

AbstractObjectiveThe identification of parental needs in Neonatal Intensive Care Units is essential to design and implement family-centered care. This article aims to validate the Neonatal Intensive Care Units Family Needs Inventory for the Portuguese population, and to propose a Short Form.MethodsA linguistic adaptation of the Neonatal Intensive Care Units Family Needs Inventory, a self-report scale with 56-items, was performed. The instrument was administered to 211 parents of infants hospitalized in all level III Neonatal Intensive Care Units in the North of Portugal, 15–22 days after admission (July of 2013–June of 2014). The number of items needed to achieve reliability close to 0.8 was calculated using by the Spearman–Brown formula. The global goodness of fit of the scale was evaluated using the comparative fit index. Construct validity was assessed through association of each dimension score with socio-demographic and obstetric characteristics.ResultsExploratory factor analysis revealed two dimensions, one focused on parents’ needs and another on the infant's needs. To compose the Short Form Inventory, items with ceiling effect were eliminated and 22 items were submitted to confirmatory analysis, which supported the existence of two dimensions (CFI=0.925). The Short Form showed a high degree of reliability (alpha≥0.76). Less educated and older parents more frequently attributed a significantly higher importance to parent-centered needs, while parents of multiples revealed a tendency to value infant-centered needs.ConclusionsThe Short Form of the Neonatal Intensive Care Units Family Needs Inventory is a brief, simple, and valid instrument with a high degree of reliability. Further studies are needed to explore associations with practices of family-centered care