86 resultados para Multivariate Adaptive Regression Splines (MARS)


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This study developed a gluten-free granola and evaluated it during storage with the application of multivariate and regression analysis of the sensory and instrumental parameters. The physicochemical, sensory, and nutritional characteristics of a product containing quinoa, amaranth and linseed were evaluated. The crude protein and lipid contents ranged from 97.49 and 122.72 g kg-1 of food, respectively. The polyunsaturated/saturated, and n-6:n-3 fatty acid ratios ranged from 2.82 and 2.59:1, respectively. Granola had the best alpha-linolenic acid content, nutritional indices in the lipid fraction, and mineral content. There were good hygienic and sanitary conditions during storage; probably due to the low water activity of the formulation, which contributed to inhibit microbial growth. The sensory attributes ranged from 'like very much' to 'like slightly', and the regression models were highly fitted and correlated during the storage period. A reduction in the sensory attribute levels and in the product physical stabilisation was verified by principal component analysis. The use of the affective test acceptance and instrumental analysis combined with statistical methods allowed us to obtain promising results about the characteristics of gluten-free granola.

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Mortality due to chronic diseases has been increasing in all regions of Brazil with corresponding decreases in mortality from infectious diseases. The geographical variation in proportionate mortality for chronic diseases for 17 Brazilian state capitals for the year 1985 and their association with socio-economic variables and infectious disease was studied. Calculations were made of correlation coefficients of proportionate mortality for adults of 30 years or above due to ischaemic heart disease, stroke and cancer of the lung, the breast and stomach with 3 socio-economic variables, race, and mortality due to infectious disease. Linear regression analysis included as independent variables the % of illiteracy, % of whites, % of houses with piped water, mean income, age group, sex, and % of deaths caused by infectious disease. The dependent variables were the % of deaths due to each one of the chronic diseases studied by age-sex group. Chronic diseases were an important cause of death in all regions of Brazil. Ischaemic heart diseases, stroke and malignant neoplasms accounted for more than 34% of the mortality in each of the 17 capitals studied. Proportionate cause-specific mortality varied markedly among state capitals. Ranges were 6.3-19.5% for ischaemic heart diseases, 8.3-25.4% for stroke, 2.3-10.4% for infections and 12.2-21.5% for malignant neoplasm. Infectious disease mortality had the highest (p < 0.001) correlation with all the four socio-economic variables studied and ischaemic heart disease showed the second highest correlation (p < 0.05). Higher socio-economic level was related to a lower % of infectious diseases and a higher % of ischaemic heart diseases. Mortality due to breast cancer and stroke was not associated with socio-economic variables. Multivariate linear regression models explained 59% of the variance among state capitals for mortality due to ischaemic heart disease, 50% for stroke, 28% for lung cancer, 24% for breast cancer and 40% for stomach cancer. There were major differences in the proportionate mortality due to chronic diseases among the capitals which could not be accounted for by the social and environmental factors and by the mortality due to infectious disease.

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OBJECTIVE: In order to determine the relationship between some maternal anthropometric indicators and birth weight, crown-heel length and newborn's head circumference, 92 pregnant women were followed through at the prenatal service of hospital in S. Paulo, Brazil. MATERIAL AND METHOD: The following variables were established for the mother: weight, height, mid-upper arm circumference, pre-pregnancy weight, gestational weight gain and Quetelet's index. For the newborn the following variables were recorded: birth weight, crown-heel length, head circumference and gestational age by Dubowitz's method. RESULTS: Significant associations were noted between gestational age and newborn variables. In addition, maternal mid-arm circumference (MUAC) and pre-pregnancy weight were found to be positively correlated to birth weight (r=0.399; r=0.378, respectively). The multivariate linear regression shows that gestational age, mother's arm circumference and pre-pregnancy weight continue to be significant predictors of birth weight. On the other hand, only gestational age and mother's age was associated with crown-heel length. Similarly MUAC was significantly associated with crown-heel length (r= 0.306; P=0.0030). CONCLUSION: Maternal mid-upper arm circumference is a potential indicator of maternal nutritional status. It could be used in association with other anthropometric measurements, instead of pre-pregnancy weight, as an alternative indicator to assess women at risk of poor pregnancy outcome.

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OBJECTIVE: Despite the intensive use of pesticides in agriculture there are few studies assessing the risk of respiratory conditions from this exposure. The study aimed at quantifying the prevalence of respiratory symptoms among farmers and evaluating its relationship with occupational use of pesticides and the prevalence of respiratory symptoms. METHODS: A cross-sectional study was conducted among 1,379 farmers from two municipalities of Southern Brazil in 1996. Frequency and type of chemical exposure and pesticide poisoning were recorded for both sexes. All subjects aged 15 years or older with at least 15 weekly hours of agricultural activity were interviewed. An adapted questionnaire developed by the American Thoracic Society was used for the assessment of respiratory symptoms. Multivariate logistic regression analysis was carried out. RESULTS: More than half (55%) of interviewees were male. The prevalence of asthma symptoms was 12% and chronic respiratory disease symptoms was 22%. Higher odds ratios for both asthma (OR=1.51; 95% CI: 1.07-2.14) and chronic respiratory disease (OR=1.34; 95% CI 1.00-1.81) symptoms were found in women. Logistic regression analysis identified associations between many forms of exposure to pesticides and increased respiratory symptoms. Occurrence of pesticide poisoning was associated with higher prevalence of asthma symptoms (OR=1.54; 95% CI: 1.04-2.58) and chronic respiratory disease symptoms (OR=1.57; 95% CI: 1.08-2.28). CONCLUSIONS: In spite of causality limitations, the study results provide evidence that farming exposure to pesticides is associated with higher prevalence of respiratory symptoms, especially when the exposure is above two days per month.

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OBJECTIVE: To assess the relationship of blood lead and hemoglobin, zinc protoporphyrin, and ferritin concentrations in children. METHODS: A cross-sectional study was carried out in 136 anemic and non-anemic children from two rural villages near a lead smelter in Adrianópolis, Southern Brazil, from July to September 2001. Hemoglobin electrophoresis was performed to exclude children with hemoglobin variants and thalassemia syndromes associated with anemia. Lead was determined by atomic absorption spectrophotometry; hemoglobin by automated cell counting; zinc protoporphyrin by hematofluorometry; ferritin by chemiluminescence. Student's t-test, Mann-Whitney test, and the c² test were used to assess the significance of the differences between the variables investigated in anemic and non-anemic children. Stepwise multivariate linear regression analysis was performed using two models for anemic and non-anemic children respectively. RESULTS: Lead was negatively associated to hemoglobin (p<0.017) in the first model, and in the second model lead was positively associated to zinc protoporphyrin (p<0.004) after controlling for ferritin, age, sex, and per capita income. There was an inverse association between hemoglobin and blood lead in anemic children. It was not possible to confirm if anemic children had iron deficiency anemia or subclinical infection, considering that the majority (90.4%) had normal ferritin. CONCLUSIONS: The study detected a relationship between anemia and elevated blood lead concentrations. Further epidemiological studies are necessary to investigate the impact of iron nutritional interventions as an attempt to decrease blood lead in children.

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OBJECTIVE: To assess the association between iron status at birth and growth of preterm infants. METHODS: Ninety-five premature babies (26 to 36 weeks of gestational age) born from July 2000 to May 2001 in a public hospital in Rio de Janeiro, Southeastern Brazil, were followed up for six months, corrected by gestational age. Iron measurements at birth were available for 82 mothers and 78 children: hemoglobin, hematocrit, mean corpuscular volume and plasma iron. All children received free doses of iron supplement (2 mg/kg/day) during the follow-up period and up to two years of age. Multivariate linear regression analyses with repeated measurements were performed to assess factors associated to linear growth. RESULTS: Growth was more pronounced up to 40 weeks of gestational age, increasing about 1.0 cm/week and then slowing down to 0.75 cm/week. The multivariate analysis showed growth was positively associated with birth weight (0.4 cm/100 g; p<0.001) and negatively associated with gestational age at birth (-0.5 cm/week; p<0.001). There was no association between cord iron and mother iron measurements and growth (p>0.60 for all measures). Only two children had anemia at birth, whereas 43.9% of mothers were anemic (hemoglobin <11 g/dl). Also, there was no correlation between anemia indicators of mothers and children at birth (r<0.15; p>0.20). CONCLUSIONS: Maternal anemia was not associated with anemia in preterm infants and iron status of mothers and children at birth was not associated with short-term growth of preterm infants.

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OBJECTIVE To examine factors associated with social participation and their relationship with self-perceived well-being in older adults. METHODS This study was based on data obtained from the National Socioeconomic Characterization (CASEN) Survey conducted in Chile, in 2011, on a probability sample of households. We examined information of 31,428 older adults living in these households. Descriptive and explanatory analyses were performed using linear and multivariate logistic regression models. We assessed the respondents’ participation in different types of associations: egotropic, sociotropic, and religious. RESULTS Social participation increased with advancing age and then declined after the age of 80. The main finding of this study was that family social capital is a major determinant of social participation of older adults. Their involvement was associated with high levels of self-perceived subjective well-being. We identified four settings as sources of social participation: home-based; rural community-based; social policy programs; and religious. Older adults were significantly more likely to participate when other members of the household were also involved in social activities evidencing an intergenerational transmission of social participation. Rural communities, especially territorial associations, were the most favorable setting for participation. There has been a steady increase in the rates of involvement of older adults in social groups in Chile, especially after retirement. Religiosity remains a major determinant of associativism. The proportion of participation was higher among older women than men but these proportions equaled after the age of 80. CONCLUSIONS Self-perceived subjective well-being is not only dependent upon objective factors such as health and income, but is also dependent upon active participation in social life, measured as participation in associations, though its effects are moderate.

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OBJECTIVE To analyze lifestyle risk factors related to direct healthcare costs and the indirect costs due to sick leave among workers of an airline company in Brazil. METHODS In this longitudinal 12-month study of 2,201 employees of a Brazilian airline company, the costs of sick leave and healthcare were the primary outcomes of interest. Information on the independent variables, such as gender, age, educational level, type of work, stress, and lifestyle-related factors (body mass index, physical activity, and smoking), was collected using a questionnaire on enrolment in the study. Data on sick leave days were available from the company register, and data on healthcare costs were obtained from insurance records. Multivariate linear regression analysis was used to investigate the association between direct and indirect healthcare costs with sociodemographic, work, and lifestyle-related factors. RESULTS Over the 12-month study period, the average direct healthcare expenditure per worker was US$505.00 and the average indirect cost because of sick leave was US$249.00 per worker. Direct costs were more than twice the indirect costs and both were higher in women. Body mass index was a determinant of direct costs and smoking was a determinant of indirect costs. CONCLUSIONS Obesity and smoking among workers in a Brazilian airline company were associated with increased health costs. Therefore, promoting a healthy diet, physical activity, and anti-tobacco campaigns are important targets for health promotion in this study population.

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OBJECTIVE To analyze if dietary patterns during the third gestational trimester are associated with birth weight.METHODS Longitudinal study conducted in the cities of Petropolis and Queimados, Rio de Janeiro (RJ), Southeastern Brazil, between 2007 and 2008. We analyzed data from the first and second follow-up wave of a prospective cohort. Food consumption of 1,298 pregnant women was assessed using a semi-quantitative questionnaire about food frequency. Dietary patterns were obtained by exploratory factor analysis, using the Varimax rotation method. We also applied the multivariate linear regression model to estimate the association between food consumption patterns and birth weight.RESULTS Four patterns of consumption – which explain 36.4% of the variability – were identified and divided as follows: (1) prudent pattern (milk, yogurt, cheese, fruit and fresh-fruit juice, cracker, and chicken/beef/fish/liver), which explained 14.9% of the consumption; (2) traditional pattern, consisting of beans, rice, vegetables, breads, butter/margarine and sugar, which explained 8.8% of the variation in consumption; (3) Western pattern (potato/cassava/yams, macaroni, flour/farofa/grits, pizza/hamburger/deep fried pastries, soft drinks/cool drinks and pork/sausages/egg), which accounts for 6.9% of the variance; and (4) snack pattern (sandwich cookie, salty snacks, chocolate, and chocolate drink mix), which explains 5.7% of the consumption variability. The snack dietary pattern was positively associated with birth weight (β = 56.64; p = 0.04) in pregnant adolescents.CONCLUSIONS For pregnant adolescents, the greater the adherence to snack pattern during pregnancy, the greater the baby’s birth weight.

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The objective of this study was to assess vitamin A status and association between acute diarrhoea and plasma levels of vitamin A through cross-sectional comparison in children. Plasma vitamin A was measured by colorimetric method of Neeld & Pearson and RBP by radial immunodiffusion technique. Seventy eight children (aged 18-119 months), 26 with current history of diarrhoea and 52 children as controls (outpatient from the Santa Casa de Misericórdia Hospital in metropolitan area of São Paulo City, Brazil) were studied. Children with history of diarrhoea showed significant low levels (mean ± s.e.) as compared to controls, vitamin A (15.87 ± 1.4 µg/dl vs. 21.14 ± 1.15 µg/dl, p < 0.007) and RBP (1.70 ± 0.2 mg/dl vs. 2.52 ±0.11 mg/dl). Multivariate logistic regression adjusted by sex, age, nutritional status and mother education revealed association between diarrhoea and inadequate levels of vitamin A and RBP.

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Burn mortality statistics may be misleading unless they account properly for the many factors that can influence outcome. Such estimates are useful for patients and others making medical and financial decisions concerning their care. This study aimed to define the clinical, microbiological and laboratorial predictors of mortality with a view to focus on better burn care. Data were collected using independent variables, which were analyzed sequentially and cumulatively, employing univariate statistics and a pooled, cross-sectional, multivariate logistic regression to establish which variables better predict the probability of mortality. Survivors and non-survivors among burn patients were compared to define the predictive factors of mortality. Mortality rate was 5.0%. Higher age, larger burn area, presence of fungi in the wound, shorter length of stay and the presence of multi-resistant bacteria in the wound significantly predicted increased mortality. The authors conclude that those patients who are most apt to die are those with age > 50 years, with limited skin donor sites and those with multi-resistant bacteria and fungi in the wound.

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The identification of predictors for the progression of chronic Chagas cardiomyopathy (CCC) is essential to ensure adequate patient management. This study looked into a non-concurrent cohort of 165 CCC patients between 1985 and 2010 for independent predictors for CCC progression. The outcomes were worsening of the CCC scores and the onset of left ventricular dysfunction assessed by means of echo-Doppler cardiography. Patients were analyzed for social, demographic, epidemiologic, clinical and workup-related variables. A descriptive analysis was conducted, followed by survival curves based on univariate (Kaplan-Meier and Cox’s univariate model) and multivariate (Cox regression model) analysis. Patients were followed from two to 20 years (mean: 8.2). Their mean age was 44.8 years (20-77). Comparing both iterations of the study, in the second there was a statistically significant increase in the PR interval and in the QRS duration, despite a reduction in heart rates (Wilcoxon < 0.01). The predictors for CCC progression in the final regression model were male gender (HR = 2.81), Holter monitoring showing pauses equal to or greater than two seconds (HR = 3.02) increased cardiothoracic ratio (HR = 7.87) and time of use of digitalis (HR = 1.41). Patients with multiple predictive factors require stricter follow-up and treatment.

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SUMMARY American visceral leishmaniasis is a vector-borne zoonosis in expansion in Brazil. Dogs are the main urban reservoir. Departing from a case of canine visceral leishmaniasis (CVL) in Jacaré, Niterói, Rio de Janeiro State, an epidemiological canine and entomological study was performed to assess the extension of the disease at the location. Sample was collected around the case and the dogs identified by serological tests (rapid double platform immunochromatographic exams, immunoenzymatic assay/ELISA, indirect immunofluorescence/IFAT). The parasitological diagnosis was performed in animals positive in at least one of these tests. The entomological study was carried out by using light traps and manual collection. The associations between canine variables and outcome (ELISA and IFAT reagents) were assessed by the chi-square test and adjusted by multivariate logistic regression for those associations with p < 0.1 in the bivariate analysis. Seventeen cases of CVL were detected among 110 evaluated dogs (prevalence of 15.5%). Presence of ectoparasites (OR 6.5; 95% CI 1.1-37.4), animals with clinical signs (OR 9.5; 95% CI 1.2-76.6), and previous cases of CVL in the same house (OR 17.9; 95% CI 2.2-147.1) were associated with the outcome. Lutzomyia longipalpiswas not detected. Our results are indicative of an ongoing transmission in the area.

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INTRODUCTION: Multidrug-resistant Pseudomonas aeruginosa is a major threat in healthcare settings. The use of antimicrobials can influence the incidence of resistant strains by direct and indirect mechanisms. The latter can be addressed by ecological studies. METHODS: Our group attempted to analyze the relation between the use of antipseudomonal drugs and the incidence of MDR-PA among 18 units from a 400-bed teaching hospital. The study had a retrospective, ecological design, comprising data from 2004 and 2005. Data on the use of four antimicrobials (amikacin, ciprofloxacin, ceftazidime and imipenem) were tested for correlation with the incidence of MDR-PA (defined as isolates resistant to the four antimicrobials of interest) in clinical cultures. Univariate and multivariate linear regression analyses were performed. RESULTS: Significant correlations were determined between use and resistance for all antimicrobials in the univariate analysis: amikacin (standardized correlation coefficient = 0.73, p = 0.001); ciprofloxacin (0.71, p = 0.001); ceftazidime (0.61, p = 0.007) and imipenem (0.87, p < 0.001). In multivariate analysis, only imipenem (0.67, p = 0.01) was independently related to the incidence of multidrug-resistant strains. CONCLUSIONS: These findings share similarities with those reported in individual-based observational studies, with possible implications for infection control.

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INTRODUCTION: Neurocysticercosis is an infection of the human central nervous system caused by the metacestode larvae of Taenia solium. Neurocysticercosis is the most common parasitic disease in developing countries. Epilepsy is the most common clinical manifestation. Difficulties in confirming the diagnosis motivated the evaluation of the enzyme-linked immunosorbent assay on cerebral spinal fluid (CSF). METHODS: Twenty-two patients with NCC and 44 control patients were studied. CSF was analyzed using a commercial ELISA kit developed for NCC. Sensitivity and specificity were measured and a multivariate logistic regression was performed. RESULTS: Sensitivity and specificity of ELISA were 31.8% and 100%, respectively, with accuracy of 77.3%. Only the size of the lesions proved to be important for performance of the test. CONCLUSIONS: The results showed that ELISA contributes to the diagnosis of neurocysticercosis if the result is negative or if the patient has a lesion of 2 cm or more.