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Dive into the research topics where Fernando Mazzili Louzada is active.

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Featured researches published by Fernando Mazzili Louzada.


Chronobiology International | 2007

Clock polymorphisms and circadian rhythms phenotypes in a sample of the Brazilian population

Mario Pedrazzoli; Fernando Mazzili Louzada; Danyella Silva Pereira; Ana Amélia Benedito-Silva; Alberto Remesar Lopez; Bruno Jacson Martynhak; Anna Ligia Korczak; Bruna Del Vechio Koike; A.A. Barbosa; Vania D'Almeida; Sergio Tufik

A Clock polymorphism T to C situated in the 3′ untranslated region (3′‐UTR) has been associated with human diurnal preference. At first, Clock 3111C had been reported as a marker for evening preference. However these data are controversial, and data both corroborating and denying them have been reported. This study hypothesizes that differences in Clock genotypes could be observed if extreme morning‐type subjects were compared with extreme evening‐type subjects, and the T3111C and T257G polymorphisms were studied. The possible relationship between both polymorphisms and delayed sleep phase syndrome (DSPS) was also investigated. An interesting and almost complete linkage disequilibrium between the polymorphisms T257G in the 5′ UTR region and the T3111C in the 3′ UTR region of the Clock gene is described. Almost always, a G in position 257 corresponds to a C in position 3111, and a T in position 257 corresponds to a T in position 3111. The possibility of an interaction of these two regions in the Clock messenger RNA structure that could affect gene expression was analyzed using computer software. The analyses did not reveal an interaction between those two regions, and it is unlikely that this full allele correspondence affects Clock gene expression. These results show that there is no association between either polymorphism T3111C or T257G in the Clock gene with diurnal preference or delayed sleep phase syndrome (DSPS). These controversial data could result from the possible effects of latitude and clock genes interaction on circadian phenotypes.


Chronobiology International | 2004

High Risk for Obstructive Sleep Apnea in Truck Drivers Estimated by the Berlin Questionnaire: Prevalence and Associated Factors

C. R. C. Moreno; F. A. Carvalho; C. Lorenzi; L. S. Matuzaki; S. Prezotti; P. Bighetti; Fernando Mazzili Louzada; G. Lorenzi-Filho

The health issues that attract our attention when analyzing the truck driver population are the high prevalence of sedentary habits, inadequate diet, obesity, and proportion of hypertensive. All these are either considered risk factors for or a consequence of Obstructive Sleep Apnea (OSA). The objective of this study was to investigate the risk for OSA among 10,101 truck drivers and to correlate it with potentially related factors, such as serum glucose and cholesterol levels, smoking habits, alcohol and drug consumption, and self-reported physical activity. The drivers were invited to participate in the campaign “Saúde na Boléia” (Health Behind the Wheel) promoted by a Brazilian company responsible for the maintenance of approximately 360 km of roads in the country. Drivers who spontaneously stopped at the campaign booths placed along the roads were invited to answer a questionnaire covering sociodemographic data such as age, alcohol, and drug consumption. All participants completed a Berlin Questionnaire and were classified as low- or high-risk subjects for OSA based on questions about snoring, tiredness during the day, and the presence of hypertension or obesity. Blood collection was accomplished at the same site by nurses and/or nursing students collaborating with the campaign for subsequent laboratory studies. Approximately 26% of the truck drivers were found to be at high-risk group for OSA. An adjusted multiple logistic model found the independent risk factors of smoking (OR = 1.16; p = 0.014) and drug use (OR = 1.32; p < 0.0001) were associated with high risk for OSA. The presence of self-reported occasional (OR = 0.62; p < 0.0001) and regular (OR = 0.53; p < 0.0001) physical activity was found to be an independent factor protective of OSA. Educational programs, including ones aimed at improving ones health habits, such as engagement in physical exercise, should be considered in the development of initiatives to reduce the risk for OSA among the truck driver population.


Chronobiology International | 2006

Short Sleep Is Associated with Obesity Among Truck Drivers

Claudia Roberta de Castro Moreno; Fernando Mazzili Louzada; Liliane Reis Teixeira; Flavio Notarnicola da Silva Borges; G. Lorenzi-Filho

Recent studies suggest that short‐sleep duration is independently associated with obesity in the general population. The population of truck drivers is of particular interest, because they frequently work irregular shifts that in turn are associated with short‐sleep duration. In addition, truck drivers have a high prevalence of sedentary habits, poor diet, and obesity. The present study aimed at verifying the association between sleep patterns and factors associated with obesity in this population. The study sample consisted in 4,878 truck drivers who participated in a campaign promoted by a highway company in the State of São Paulo, Brazil. This campaign offered highway truck drivers a medical and laboratorial evaluation. The truck drivers completed a questionnaire concerning demographic data, sleep duration, consumption of medications, and medical problems, such as diabetes, cardiopathy, and hypertension; as well as the Berlin questionnaire, which is able to discriminate low and high risk for obstructive sleep apnea. Blood samples were collected to measure glucose and cholesterol levels. Also, body weight and height were registered to calculate the body mass index (BMI). The mean age (±SD) of the truck drivers studied was 40±10 years. Out of the truck drivers analyzed, 28.3% (n=1,379) had a BMI ≥30.0 Kg/m2 (obesity). Among the 4,878 drivers included in the study, 1,199 (24.6%) were on medications and 334 (6.8%) were diabetic. Drivers (26.9%) with the greater BMI had a short sleep length. The independent factors associated with obesity were sleep duration <8 h/day (OR=1.24), age >40 years (OR=1.20), glucose levels >200 (OR=2.02), cholesterol levels >240 (OR=1.57), snoring (OR=1.74), and hypertension (OR=2.14). Smoking was not associated with obesity (OR=0.69), and diabetes was considered a control variable. In conclusion, this study supports the hypothesis that short sleep duration as well as age >40 years are independently associated with obesity. This particular combination (short‐sleep duration and obesity) is independently associated with several healthcare problems, including high levels of cholesterol, glucose, snoring, and hypertension. However, due to the cross‐sectional nature of this study, no cause–effect relationship can be drawn from these results.


Brazilian Journal of Medical and Biological Research | 2008

Influence of chronotype and social zeitgebers on sleep/wake patterns

Anna Ligia Korczak; Bruno Jacson Martynhak; Mario Pedrazzoli; A.f. Brito; Fernando Mazzili Louzada

Inter-individual differences in the phase of the endogenous circadian rhythms have been established. Individuals with early circadian phase are called morning types; those with late circadian phase are evening types. The Horne and Ostberg Morningness-Eveningness Questionnaire (MEQ) is the most frequently used to assess individual chronotype. The distribution of MEQ scores is likely to be biased by several fact, ors, such as gender, age, genetic background, latitude, and social habits. The objective of the present study was to determine the effect of different social synchronizers on the sleep/wake cycle of persons with different chronotypes. Volunteers were selected from a total of 1232 UFPR undergraduate students who completed the MEQ. Thirty-two subjects completed the study, including 8 morning types, 8 evening types and 16 intermediate types. Sleep schedules were recorded by actigraphy for 1 week on two occasions: during the school term and during vacation. Sleep onset and offset times, sleep duration, and mid-sleep time for each chronotype group were compared by the Mann-Whitney U-test separately for school term and vacation. School term and vacation data were compared by the Wilcoxon matched-pair test. Morning types showed earlier sleep times and longer sleep duration compared with evening types (23:00 +/- 44 and 508.9 +/- 50.27 vs 01:08 +/- 61.95 and 456.44 +/- 59.08, for the weekdays during vacation). During vacation, the subjects showed later sleep times, except for the morning types, who did not exhibit differences for sleep onset times. The results support the idea that social schedules have an impact on the expression of circadian rhythmicity but this impact depends on the individual chronotype.


Chronobiology International | 2004

Sleep Patterns of Day-Working, Evening High-Schooled Adolescents of São Paulo, Brazil

Liliane Reis Teixeira; Frida Marina Fischer; Miriam Mendonça Morato de Andrade; Fernando Mazzili Louzada; Roberta Nagai

Children who grow up in developing countries of the world must work to help financially support their families, and they must also attend school. We investigated the impact of work on the sleep of working vs. nonworking high school students. Twenty-seven São Paulo, Brazil, public high school students (eight male and eight female working students plus six nonworking female and five nonworking male students) 14–18 yrs of age who attended school Monday–Friday between 19:00 to 22:30 h participated. A comprehensive questionnaire about work and living conditions, health status, and diseases and their symptoms was also answered. The activity level and rest pattern (sleep at night and napping during the day) were continuously assessed by wrist actigraphy (Ambulatory Monitoring, USA). The main variables were analyzed by a two-factor ANOVA with application of the Tukey HSD test for multiple comparisons, and the length of sleep during weekdays vs. weekends was compared by Student t-test. Working students went to sleep earlier weekends [F(1,23) = 6.1; p = 0.02] and woke up earlier work days than nonworking students [F(1,23) = 17.3; p = 0.001]. The length of nighttime sleep during weekdays was shorter among all the working [F(1,23) = 16.7; p < 0.001] than all the nonworking students. The sleep duration of boys was shorter than of girls during weekends [F(1,23) = 10.8; p < 0.001]. During weekdays, the duration of napping by working and nonworking male students was shorter than nonworking female students. During weekdays, working girls took the shortest naps [F(1,23) = 5.6; p = 0.03]. The most commonly reported sleep complaint during weekdays was difficulty waking up in the morning [F(1,23) = 6.5; p = 0.02]. During weekdays, the self-perceived sleep quality of working students was worse than nonworking students [F(1,23) = 6.2; p = 0.02]. The findings of this study show that work has negative effects on the sleep of adolescents, with the possible build-up of a chronic sleep debt with potential consequent impact on quality of life and school learning.


Brazilian Journal of Medical and Biological Research | 2014

Chronotype ontogeny related to gender

Leandro Lourenção Duarte; Luiz Menna-Barreto; M.A.L. Miguel; Fernando Mazzili Louzada; John Fontenele Araújo; Marilene Farias Alam; Roberta Areas; Mario Pedrazzoli

Chronotype is an established concept designed to identify distinct phase relationships between the expression of circadian rhythms and external synchronizers in humans. Although it has been widely accepted that chronotype is subjected to ontogenetic modulation, there is no consensus on the interaction between age and gender. This study aimed to determine the relationship between age- and gender-related changes in the morningness-eveningness character in a large sample of people. A total of 14,650 volunteers were asked to complete the Brazilian version of the Horne and Östberg chronotype questionnaire. The data demonstrated that, on average, women were more morning-oriented than men until the age of 30 and there were no significant differences between men and women from 30 to 45 years of age. In contrast to the situation observed until the age of 30, women older than 45 years were more evening-oriented than men. These results suggest that the ontogenetic development of the circadian timekeeping system is more plastic in men, as represented by the larger amplitude of chronotype changes throughout their aging process. The phase delay of adolescence and phase advance of the elderly seem to be phenomena that are more markedly present in men than in women. Thus, our data, for the first time, provide support that sharply opposes the view that there is a single path toward morningness as a function of age, regardless of gender.


Genetics and Molecular Biology | 2010

Interactions of polymorphisms in different clock genes associated with circadian phenotypes in humans.

Mario Pedrazzoli; Rodrigo Secolin; Luiz Otávio Bastos Esteves; Danyella Silva Pereira; Bruna Del Vechio Koike; Fernando Mazzili Louzada; Iscia Lopes-Cendes; Sergio Tufik

Several studies have shown that mutations and polymorphisms in clock genes are associated with abnormal circadian parameters in humans and also with more subtle non-pathological phenotypes like chronotypes. However, there have been conflicting results, and none of these studies analyzed the combined effects of more than one clock gene. Up to date, association studies in humans have focused on the analysis of only one clock gene per study. Since these genes encode proteins that physically interact with each other, combinations of polymorphisms in different clock genes could have a synergistic or an inhibitory effect upon circadian phenotypes. In the present study, we analyzed the combined effects of four polymorphisms in four clock genes (Per2, Per3, Clock and Bmal1) in people with extreme diurnal preferences (morning or evening). We found that a specific combination of polymorphisms in these genes is more frequent in people who have a morning preference for activity and there is a different combination in individuals with an evening preference for activity. Taken together, these results show that it is possible to detect clock gene interactions associated with human circadian phenotypes and bring an innovative idea of building a clock gene variation map that may be applied to human circadian biology.


Scientific Reports | 2017

Latitudinal cline of chronotype

Mario André Leocadio-Miguel; Fernando Mazzili Louzada; Leandro Lourenção Duarte; Roberta Areas; Marilene Farias Alam; Marcelo Ventura Freire; John Fontenele-Araujo; Luiz Menna-Barreto; Mario Pedrazzoli

The rotation of the Earth around its own axis and around the sun determines the characteristics of the light/dark cycle, the most stable and ancient 24 h temporal cue for all organisms. Due to the tilt in the earth’s axis in relation to the plane of the earth’s orbit around the sun, sunlight reaches the Earth differentially depending on the latitude. The timing of circadian rhythms varies among individuals of a given population and biological and environmental factors underlie this variability. In the present study, we tested the hypothesis that latitude is associated to the regulation of circadian rhythm in humans. We have studied chronotype profiles across latitudinal cline from around 0° to 32° South in Brazil in a sample of 12,884 volunteers living in the same time zone. The analysis of the results revealed that humans are sensitive to the different sunlight signals tied to differences in latitude, resulting in a morning to evening latitudinal cline of chronotypes towards higher latitudes.


Sleep | 2005

Association of the Length Polymorphism in the Human Per3 Gene with the Delayed Sleep-Phase Syndrome: Does Latitude Have an Influence Upon It?

Danyella Silva Pereira; Sergio Tufik; Fernando Mazzili Louzada; Ana Amélia Benedito-Silva; Alberto Remesar Lopez; Lemos Na; Anna Ligia Korczak; D'Almeida; Mario Pedrazzoli


Behavior Genetics | 2007

The G619A Aa-nat Gene Polymorphism does not Contribute to Sleep Time Variation in the Brazilian Population

Danyella Silva Pereira; Mario Pedrazzoli; Bruna Del Vechio Koike; Fernando Mazzili Louzada; Ana Amélia Benedito-Silva; Alberto Remesar Lopez; Sergio Tufik

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Anna Ligia Korczak

Federal University of Paraná

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Danyella Silva Pereira

Federal University of São Paulo

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Sergio Tufik

Federal University of São Paulo

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Alberto Remesar Lopez

Federal University of São Paulo

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Bruna Del Vechio Koike

Federal University of São Paulo

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