Association between glycemic index and glycemic load and the risk of incident coronary heart disease among whites and African Americans with and without type 2 diabetes: The Atherosclerosis Risk in Communities study

Several studies have examined the association between high glycemic index (GI) and glycemic load (GL) diets and the risk for coronary heart disease (CHD). However, most of these studies were conducted primarily on white populations. The primary aim of this study was to examine whether high GI and GL diets are associated with increased risk for developing CHD in whites and African Americans, non-diabetics and diabetics, and within stratifications of body mass index (BMI) and hypertension (HTN). Baseline and 17-year follow-up data from ARIC (Atherosclerosis Risk in Communities) study was used. The study population (13,051) consisted of 74% whites, 26% African Americans, 89% non-diabetics, 11% diabetics, 43% male, 57% female aged 44 to 66 years at baseline. Data from the ARIC food frequency questionnaire at baseline were analyzed to provide GI and GL indices for each subject. Increases of 25 and 30 units for GI and GL respectively were used to describe relationships on incident CHD risk. Adjusted hazard ratios for propensity score with 95% confidence intervals (CI) were used to assess associations. During 17 years of follow-up (1987 to 2004), 1,683 cases of CHD was recorded. Glycemic index was associated with 2.12 fold (95% CI: 1.05, 4.30) increased incident CHD risk for all African Americans and GL was associated with 1.14 fold (95% CI: 1.04, 1.25) increased CHD risk for all whites. In addition, GL was also an important CHD risk factor for white non-diabetics (HR=1.59; 95% CI: 1.33, 1.90). Furthermore, within stratum of BMI 23.0 to 29.9 in non-diabetics, GI was associated with an increased hazard ratio of 11.99 (95% CI: 2.31, 62.18) for CHD in African Americans, and GL was associated with 1.23 fold (1.08, 1.39) increased CHD risk in whites. Body mass index modified the effect of GI and GL on CHD risk in all whites and white non-diabetics. For HTN, both systolic blood pressure and diastolic blood pressure modified the effect on GI and GL on CHD risk in all whites and African Americans, white and African American non-diabetics, and white diabetics. Further studies should examine other factors that could influence the effects of GI and GL on CHD risk, including dietary factors, physical activity, and diet-gene interactions. ^

The relationship between body image and physical activity in African American women

High rates of overweight and obesity in African American women have been attributed, in part, to poor health habits, such as physical inactivity, and cultural influences on body image perceptions. The purpose of this study was to determine the relationship among body mass index (BMI=kg/m2), body image perception (perceived and desired) and physical activity, both self-reported and objectively measured. Anthropometric measures of BMI and Pulvers' culturally relevant body image, physical activity and demographic data were collected from 249 African American women in Houston. Women ( M = 44.8 yrs, SD = 9.5) were educated (53% college graduates) and were overweight (M = 35.0 kg/m2, SD = 9.2). Less than half of women perceived their weight correctly regardless of their actual weight (p < 0.001). Nearly three-fourths (73.9%) of women who were normal weight desired to be obese, and only 39.4% of women desired to be normal weight, regardless of actual or perceived weight. Women in all weight classes (normal, overweight and obese) varied in objective measures of physical activity (F(2,112) = 4.424, p = .014). Regression analyses showed objectively measured physical activity was significantly associated with BMI ( Beta = -2.45, p < .01) and self-reported walking was significantly associated with perceived BMI (Beta = -.156, p = .017). Results suggest African American women who are smaller want to be larger and African American women who are larger want to be smaller, revealing dichotomous distortion in body images. Low rates of physical activity may be a factor. Research is needed to increase physical activity levels in African American women, leading to improved satisfaction with normal weight as desirable for health and beauty. Supported by NCI (NIH) 1R01CA109403. ^

Body mass index trajectories and predictors among 3rd to 12th graders using growth curve mixture modeling the Child and Adolescent Trial for Cardiovascular Health (CATCH) study

This dissertation examined body mass index (BMI) growth trajectories and the effects of gender, ethnicity, dietary intake, and physical activity (PA) on BMI growth trajectories among 3rd to 12th graders (9-18 years of age). Growth curve model analysis was performed using data from The Child and Adolescent Trial for Cardiovascular Health (CATCH) study. The study population included 2909 students who were followed up from grades 3-12. The main outcome was BMI at grades 3, 4, 5, 8, and 12. ^ The results revealed that BMI growth differed across two distinct developmental periods of childhood and adolescence. Rate of BMI growth was faster in middle childhood (9-11 years old or 3rd - 5th grades) than in adolescence (11-18 years old or 5th - 12th grades). Students with higher BMI at 3rd grade (baseline) had faster rates of BMI growth. Three groups of students with distinct BMI growth trajectories were identified: high, average, and low. ^ Black and Hispanic children were more likely to be in the groups with higher baseline BMI and faster rates of BMI growth over time. The effects of gender or ethnicity on BMI growth differed across the three groups. The effects of ethnicity on BMI growth were weakened as the children aged. The effects of gender on BMI growth were attenuated in the groups with a large proportion of black and Hispanic children, i.e., “high” or “average” BMI trajectory group. After controlling for gender, ethnicity, and age at baseline, in the “high BMI trajectory”, rate of yearly BMI growth in middle childhood increased 0.102 for every 500 Kcals increase (p=0.049). No significant effects of percentage of energy from total fat and saturated fat on BMI growth were found. Baseline BMI increased 0.041 for every 30 minutes increased in moderate-to-vigorous PA (MVPA) in the “low BMI trajectory”, while Baseline BMI decreased 0.345 for every 30 minutes increased in vigorous PA (VPA) in the “high BMI trajectory”. ^ Childhood overweight and obesity interventions should start at the earliest possible ages, prior to 3rd grade and continue through grade school. Interventions should focus on all children, but specifically black and Hispanic children, who are more likely to be highest at-risk. Promoting VPA earlier in childhood is important for preventing overweight and obesity among children and adolescents. Interventions should target total energy intake, rather than only percentage of energy from total fat or saturated fat. ^

Proliferation index in ductal carcinoma in situ of the breast: Relation to estrogen, progesterone and HER2/neu receptors

Background. Ductal carcinoma in situ (DCIS) is the most prevalent precursor to invasive breast cancer (IBC), the second leading cause of death in women in the United States. The three most important prognostic markers for IBC are Estrogen receptor (ER), Progesterone receptor (PR) and HER2/neu. The four groups (IBC) defined as (1) ER and/or PR positive and HER2/neu negative, (2) ER and/or PR positive and HER2/neu positive (3) ER and/or PR negative and HER2/neu positive and (4) negative for all three of these receptors (Triple negative). However, they have not been well studied in DCIS. This is an exploratory study with a primary objective to examine the prevalence of ER, PR, and HER2/neu in DCIS, to explore if the defined groups of IBC occur in DCIS and to consider the biological relationship between these four groups and the proliferative activity of the tumor. A secondary goal of this study is to examine the relationship between grade and proliferative activity. Methods. Using immunohistochemistry, I have measured Ki-67, ER, PR and HER2/neu positivity for a series of cases of DCIS. Results. 20 ER and/or PR positive and HER2/neu negative (50%) with average PI of 0.05, 7 ER and/or PR positive and HER2/neu positive (17.5%) with average PI of 0.14, 10 ER and/or PR negative and HER2/neu positive (25%) with average PI of 0.18, and three triple negative (7.5%) with average PI of 0.18. ER and/or PR positive and HER2/neu positive group has the highest PI (p<0.001). Further, the ER and/or PR positive and HER2/neu positive group show a linear relationship between PI and average ER/PR positivity (R=0.6). PI increases with higher grades. Conclusion. PI appears to depend upon the average fraction of positive ER/PR tumor cells, possibly with a synergistic dependence when HER2/neu is positive. If ER/PR is negative, then both HER2/neu positive and the triple negative cases appear to cluster around an average PI that is higher than the average PI in HER2/neu negative ER/PR positive negative cases. In the triple negative tumors there must be another driver of proliferation.^

GMZ27 is a new organic arsenic derivative with anti-leukemic activity, via the induction of reactive oxygen species through NADPH oxidase and mitochondrial pathway that lead to leukemia cell apoptosis

Arsenic trioxide (ATO) is an inorganic arsenic derivative that is very effective against relapsed acute promyelocytic leukemia. It is being investigated as therapy for other cancers, but the risk/benefit ratio is questionable due to significant side effects. In contrast, organic arsenic derivatives (OAD) are known to be much less toxic than ATO. Based on high activity, we selected GMZ27 (dipropil-s-glycerol arsenic) for further study and have confirmed its potent activity against human acute leukemia cell lines. This anti-leukemic activity is significantly higher than that of ATO. Both in vivo and in vitro tests have shown that GMZ27 is significantly less toxic to normal bone marrow mononuclear cells and normal mice. Therefore, further study of the biological activity of GMZ27 was undertaken. ^ GMZ27, in contrast to ATO, can only marginally induce maturation of leukemic cells. GMZ27 has no effect on cell cycle. The anti-leukemic activity of GMZ27 against acute myeolocytic leukemia cells is not dependent upon degradation of PML-RARα fusion protein. GMZ27 causes dissipation of mitochondrial transmembrane potential, cleavage of caspase 9, caspase 3 activation. Further studies indicated that GMZ27 induces intracellular reactive oxygen species (ROS) production, and modification of intracellular ROS levels had profound effect on its potential to inhibit proliferation of leukemic cells. Therefore ROS production plays a major role in the anti-leukemic activity of GMZ27. ^ To identify how GMZ27 induces ROS, our studies focused on mitochondria and NADPH oxidase. The results indicated that the source of ROS generation induced by GMZ27 is dose dependent. At the low dose (0.3 uM) GMZ27 induces NADPH oxidase activity that leads to late ROS production, while at the high dose (2.0 uM) mitochondria function is disrupted and early ROS production is induced leading to dramatic cell apoptosis. Therefore, late, ROS production can be detected in mitochondria are depleted Rho-0 cells. Our work not only delineates a major biologic pathway for the anti-leukemic activity of GMZ27, but also discusses possible ways of enhancing the effect by the co-application of NADPH oxidase activator. Further study of this interaction may lead to achieving better therapeutic index.^

Objective assessment of the built environment and its relationship to physical activity and obesity

The role of physical activity in the promotion of individual and population health has been well documented in research and policy publications. Significant research activities have produced compelling evidence for the support of the positive association between physical activity and improved health. Despite the knowledge about these public health benefits of physical activity, over half of US adults do not engage in physical activity at levels consistent with public health recommendations. Just as physical inactivity is of significant public health concern in the US, the prevalence of obesity (and its attendant co-morbidities) is also increasing among US adults.^ Research suggests racial and ethnic disparities relevant to physical inactivity and obesity in the US. Various studies have shown more favorable outcomes among non-Hispanic whites when compared to other minority groups as far as physical activity and obesity are concerned. The health disparity issue is especially important because Mexican-Americans who are the fastest growing segment of the US population are disproportionately affected by physical inactivity and obesity by a significant margin (when compared to non-Hispanic whites), so addressing the physical inactivity and obesity issues in this group is of significant public health concern. ^ Although the evidence for health benefits of physical activity is substantial, various research questions remain on the potential motivators for engaging in physical activity. One area of emerging interest is the potential role that the built environment may play in facilitating or inhibiting physical activity.^ In this study, based on an ongoing research project of the Department of Epidemiology at the University of Texas M. D. Anderson Cancer Center, we examined the built environment, measured objectively through the use of geographical information systems (GIS), and its association with physical activity and obesity among a cohort of Mexican- Americans living in Harris County, Texas. The overall study hypothesis was that residing in dense and highly connected neighborhoods with mixed land-use is associated with residents’ increased participation in physical activity and lowered prevalence of obesity. We completed the following specific aims: (1) to generate a land-use profile of the study area and create a “walkability index” measure for each block group within the study area; (2) to compare the level of engagement in physical activity between study participants that reside in high walkability index block groups and those from low walkability block groups; (3) to compare the prevalence of obesity between study participants that reside in high walkability index block groups and those from low walkability block groups. ^ We successfully created the walkability index as a form of objective measure of the built environment for portions of Harris County, Texas. We used a variety of spatial and non-spatial dataset to generate the so called walkability index. We are not aware of previous scholastic work of this kind (construction of walkability index) in the Houston area. Our findings from the assessment of relationships among walkability index, physical activity and obesity suggest the following, that: (1) that attempts to convert people to being walkers through health promotion activities may be much easier in high-walkability neighborhoods, and very hard in low-walkability neighborhoods. Therefore, health promotion activities to get people to be active may require supportive environment, walkable in this case, and may not succeed otherwise; and (2) Overall, among individuals with less education, those in the high walkability index areas may be less obese (extreme) than those in the low walkability area. To the extent that this association can be substantiated, we – public health practitioners, urban designers, and policy experts – we may need to start thinking about ways to “retrofit” existing urban forms to conform to more walkable neighborhoods. Also, in this population especially, there may be the need to focus special attention on those with lower educational attainment.^

Photosynthetic activity buffers ocean acidification in seagrass meadows

Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5-12 m) seagrass (Posidonia oceanica) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (omega Ar)) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and range pHNBS and max and range omega Ar. In June, vertical mixing (as Turbulent Kinetic Energy) influenced max and min omega Ar, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. Max and range omega Ar within the meadow showed a positive trend with the calcium carbonate load of the leaves, pointing to a possible link between structural parameters, omega Ar and carbonate deposition.

Motivating Young Students to Start a Career in Nuclear: The Basic Course of Science and Nuclear Technology, An Educational Activity of Spanish Young Generation in Nuclear (JÓVENES NUCLEARES)

The main objective of this course, conducted by Jóvenes Nucleares (Spanish Young Generation in Nuclear, JJNN), a non-profit organization that depends on the Spanish Nuclear Society (SNE) is to pass on basic knowledge about Science and Nuclear Technology to the general public, mostly students and introduce them to its most relevant points. The purposes of this course are to provide general information, to answer the most common questions about Nuclear Energy and to motivate the young students to start a career in nuclear. Therefore, it is directed mainly to high school and university students, but also to general people that wants to learn about the key issues of such an important matter in our society. Anybody could attend the course, as no specific scientific education is required. The course is done at least once a year, during the Annual Meeting of the Spanish Nuclear Society, which takes place in a different Spanish city each time. The course is done also to whichever university or institution that asks for it to JJNN, with the only limit of the presenter´s availability. The course is divided into the following chapters: Physical nuclear and radiation principles, Nuclear power plants, Nuclear safety, Nuclear fuel, Radioactive waste, Decommission of nuclear facilities, Future nuclear power plants, Other uses of nuclear technology, Nuclear energy, climate change and sustainable development. The course is divided into 15 minutes lessons on the above topics, imparted by young professionals, experts in the field that belongs either to the Spanish Young Generation in Nuclear, either to companies and institutions related with nuclear energy. At the end of the course, a 200 pages book with the contents of the course is handed to every member of the audience. This book is also distributed in other course editions at high schools and universities in order to promote the scientific dissemination of the Nuclear Technology. As an extra motivation, JJNN delivers a course certificate to the assistants. At the end of the last edition course, in Santiago de Compostela, the assistants were asked to provide a feedback about it. Some really interesting lessons were learned, that will be very useful to improve next editions of the course. As a general conclusion of the courses it can be said that many of the students that have assisted to the course have increased their motivation in the nuclear field, and hopefully it will help the young talents to choose the nuclear field to develop their careers

Proposal of a dynamic performance index to analyze driving pattern effect on car emissions

The contributions of driver behaviour as well as surrounding infrastructure are decisive on pollutant emissions from vehicles in real traffic situations. This article deals with the preliminary study of the interaction between the dynamic variables recorded in a vehicle (driving pattern) and pollutant emissions produced over a given urban route. It has been established a “dynamic performance index”-DPI, which is calculated from some driving pattern parameters, which in turn depends on traffic congestion level and route characteristics, in order to determine whether the driving has been aggressive, normal or calm. Two passenger cars instrumented with a portable activity measurement system -to record dynamic variables- and on-board emission measurement equipment have been used. This study has shown that smooth driving patterns can reduce up to 80% NOX emissions and up to 20% of fuel in the same route

Effects of dietary restriction combined with different exercise programs or physical activity recommendations on blood lipids in overweight adults

Background and aim: Many exercise studies, although generally showing the beneficial effects of supervised aerobic, resistance or combined exercise on blood lipids, have sometimes reached equivocal conclusions. The aim of this study is to evaluate the impact of different programs that combined exercise and dietary restriction on blood lipids versus a clinical practice intervention for weight loss, in overweight adults. Methods: For this study 66 subjects participated in a supervised 22 weeks training program, composed of three sessions per week and they were randomized in three groups: strength training (S; n = 19), endurance training (E; n = 25), a combination of E and S (SE; n = 22). Eighteen subjects served as physical activity group (PA) that followed a clinical intervention consisted of physical activity recommendations. All groups followed the same dietary treatment, and blood samples were obtained for lipids measurements, at the beginning and end of the study. Results: Lipid profile improved in all groups. No significant differences for baseline and post-training values were observed between groups. In general, SE and PA decreased low-density lipoprotein cholesterol (LDL-C) values (p menor que 0.01). S decreased triglyceride levels (p menor que 0.01) and E, SE, and PA decreased total cholesterol levels (p menor que 0.05, p menor que 0.01 and p menor que 0.01, respectively). Conclusions: These results suggest that an intervention program of supervised exercise combined with diet restriction did not achieved further improvements in blood lipid profile than diet restriction and physical activity recommendations, in overweight adults. (Clinical Trials gov number: NCT01116856).

Influencia del ejercicio físico desarrollado durante el embarazo en la respuesta cardiaca fetal = Influence of a physical activity program performed during pregnancy on fetal heart response

INTRODUCCIÓN: El riesgo de padecer enfermedades cardiovasculares y los índices de obesidad infantil han ido en aumento durante los últimos años empobreciendo la salud de la población. La Teoría de Barker relaciona el estado de salud de la madre con el desarrollo fetal, asociando a un deficiente estado físico y hábitos de vida negativos de la mujer embarazada con el aumento del riesgo de padecer cardiopatías en la infancia y adolescencia, así como predisponer al recién nacido a padecer sobrepeso y/u obesidad en su vida posterior. Por otro lado los estudios efectuados sobre ejercicio físico durante el embarazo reportan beneficios para salud materna y fetal. Uno de los parámetros más utilizados para comprobar la salud fetal es su frecuencia cardiaca, mediante la que se comprueba el buen desarrollo del sistema nervioso autónomo. Si se observa este parámetro en presencia de ejercicio materno podría encontrarse una respuesta crónica del corazón fetal al ejercicio materno como consecuencia de una adaptación y mejora en el funcionamiento del sistema nervioso autónomo del feto. De esta forma podría mejorar su salud cardiovascular intrauterina, lo que podría mantenerse en su vida posterior descendiendo el riesgo de padecer enfermedades cardiovasculares en la edad adulta. OBJETIVOS: Conocer la influencia de un programa de ejercicio físico supervisado en la frecuencia cardiaca fetal (FCF) en reposo y después del ejercicio materno en relación con gestantes sedentarias mediante la realización de un protocolo específico. Conocer la influencia de un programa de ejercicio físico en el desarrollo del sistema nervioso autónomo fetal, relacionado con el tiempo de recuperación de la FCF. MATERIAL Y MÉTODO: Se diseñó un ensayo clínico aleatorizado multicéntrico en el que participaron 81 gestantes (GC=38, GE=43). El estudio fue aprobado por el comité ético de los hospitales que participaron en el estudio. Todas las gestantes fueron informadas y firmaron un consentimiento para su participación en el estudio. Las participantes del GE recibieron una intervención basada en un programa de ejercicio físico desarrollado durante la gestación (12-36 semanas de gestación) con una frecuencia de tres veces por semana. Todas las gestantes realizaron un protocolo de medida de la FCF entre las semanas 34-36 de gestación. Dicho protocolo consistía en dos test llevados a cabo caminando a diferentes intensidades (40% y 60% de la frecuencia cardiaca de reserva). De este protocolo se obtuvieron las principales variables de estudio: FCF en reposo, FCF posejercicio al 40 y al 60% de intensidad, tiempo de recuperación de la frecuencia cardiaca fetal en ambos esfuerzos. El material utilizado para la realización del protocolo fue un monitor de frecuencia cardiaca para controlar la frecuencia cardiaca de la gestante y un monitor fetal inalámbrico (telemetría fetal) para registrar el latido fetal durante todo el protocolo. RESULTADOS: No se encontraron diferencias estadísticamente significativas en la FCF en reposo entre grupos (GE=140,88 lat/min vs GC= 141,95 lat/min; p>,05). Se encontraron diferencias estadísticamente significativas en el tiempo de recuperación de la FCF entre los fetos de ambos grupos (GE=135,65 s vs GC=426,11 s esfuerzo al 40%; p<,001); (GE=180,26 s vs GC=565,61 s esfuerzo al 60%; p<,001). Se encontraron diferencias estadísticamente significativas en la FCF posejercicio al 40% (GE=139,93 lat/min vs GC=147,87 lat/min; p<,01). No se encontraron diferencias estadísticamente significativas en la FCF posejercicio al 60% (GE=143,74 lat/min vs GC=148,08 lat/min; p>,05). CONLUSIÓN: El programa de ejercicio físico desarrollado durante la gestación influyó sobre el corazón fetal de los fetos de las gestantes del GE en relación con el tiempo de recuperación de la FCF. Los resultados muestran un posible mejor funcionamiento del sistema nervioso autónomo en fetos de gestantes activas durante el embarazo. ABSTRACT INTRODUCTION: The risk to suffer cardiovascular diseases and childhood obesity index has grown in the last years worsening the health around the population. Barker´s Theory related maternal health with fetal development establishing an association between a poorly physical state and an unhealthy lifestyle in the pregnant woman with the risk to suffer heart disease during childhood and adolescence, childhood overweight and/or obese is related to maternal lifestyle. By the other way researches carried out about physical exercise and pregnancy show benefits in maternal and fetal health. One of the most studied parameters to check fetal health is its heart rate, correct fetal autonomic nervous system development and work is also corroborated by fetal heart rate. Looking at this parameter during maternal exercise a chronic response of fetal heart could be found due to an adaptation and improvement in the working of the autonomic nervous system. Therefore its cardiovascular health could be enhanced during its intrauterine life and maybe it could be maintained in its posterior life descending the risk to suffer cardiovascular diseases in adult life. OBJECTIVES: To know the influence of a supervised physical activity program in the fetal heart rate (FHR) at rest, FHR after maternal exercise related to sedentary pregnant women by a FHR assessment protocol. To know the influence of a physical activity program in the development of the autonomic nervous system related to FHR recovery time. MATERIAL AND METHOD: A multicentric randomized clinical trial was design in which 81 pregnant women participated (CG=38, EG=43). The study was approved by the ethics committee of all of the hospitals participating in the study. All of the participants signed an informed consent for their participation in the study. EG participants received an intervention based on a physical activity program carried out during gestation (12-36 gestation weeks) with a three days a week frequency. All of the participants were tested between 34-36 weeks of gestation by a specific FHR assessment protocol. The mentioned protocol consisted in two test performed walking and at a two different intensities (40% and 60% of the reserve heart rate). From this protocol we obtained the main research variables: FHR at rest, FHR post-exercise at 40% and 60% intensity, and FHR recovery time at both walking test. The material used to perform the protocol were a FH monitor to check maternal HR and a wireless fetal monitor (Telemetry) to register fetal beats during the whole protocol. RESULTS: There were no statistical differences in FHR at rest between groups (EG=140,88 beats/min vs CG= 141,95 beats/min; p>,05). There were statistical differences in FHR recovery time in both walking tests between groups (EG=135,65 s vs CG=426,11 s test at 40% intensity; p<,001); (EG=180,26 s vs CG=565,61 s test at 60% intensity; p<,001). Statistical differences were found in FHR post-exercise at 40% intensity between groups (EG=139,93 beats/min vs CG=147,87 beats/min; p<,01). No statistical differences were found in FHR at rest post-exercise at 60% intensity between groups (EG=143,74 beats/min vs CG=148,08 beats/min; p>,05). CONCLUSIONS: The physical activity program performed during gestation had an influence in fetal heart of the fetus from mother in the EG related to FHR recovery time. These results show a possible enhancement on autonomic nervous system working in fetus from active mothers during gestation.

Quality cost in bus operations based on activity-based costing

The study of service quality and its implication for transport contracts has several approaches in research and practical applications, where the main emphasis is the consideration of quality from the user's point of view, thus obtaining a customer satisfaction index as a measurement of the overall quality with no further implications for service providers. The main aim of this paper is to estimate the real economic impact of improving quality attributes for a bus operator. An application of the activity-based costing methodology is developed for a bus contract in Madrid, using quality data from surveys together with economic and performance information, and focusing on headway as a quality variable. Results show the consistency and practicality of this methodology, overcoming simplifications from traditional procedures. This method is a powerful tool in quality-based contracting as well as for effective investment in transport quality under poverty funding constraints