On the economic analysis of response to preventive measures

There are many circumstances in which the effectiveness of preventive measures depends to a large extent on the compliance of the patient in changing his or her behavior or lifestyle. It is shown how economic techniques can be used (i) to describe the rationale of individuals and predict their behavior (Section 2); and (ii) to assess preventive measures that, by requiring a change of conduct, imply "costs" to the individual due to a decline in the quality of life (Appendix). Cigarette smoking and coronary heart disease are used as an illustration. While the analysis of Section 2 uses graphical techniques, a simple textbook-type of lifetime utility model with a mathematical emphasis is used in the Appendix. It is also shown that techniques often used to assess health care programs such as the QALYs (Quality-Adjusted Life Years) are inappropriate to the evaluation of preventive programs aiming at behavioral changes. Finally, topics that call for further research are indicated.

Blood lipid associations in 18 year-old men

The association of cigarette smoking, physical activity at work, and social class with total cholesterol and with high and low density lipoprotein cholesterol were examined in a random sample of 238 males, of 18 years of age, of Rosario, Argerntina. The mean (mg/dl) total serum cholesterol of the whole sample was 174.7, the high density lipoprotein cholesterol 52.8, and the low density lipoprotein cholesterol 121.5. Black tobacco consumers, evenly distributed by social class, had higher levels of total and low density lipoprotein cholesterol. Total cholesterol was higher in the high social class, differently from what smokers' distribution by social class, would lead one to expect. While a highly negative association was found between social class and physical activity at work, there were no significant diferences in lipoprotein levels between manual and non-manual workers. It is possible that the nutritional differences by social class still prevail over the smoking habit in their influence on the lipoprotein levels in these subjects.

Lifestyle factors influence in the frequency in buccal micronucleus

Genomic damage is probably the most important fundamental cause of development and degenerative disease. It is also well established that genomic damage is produced by environmental exposure to genotoxins, medical procedures (e.g. radiation and chemicals), micronutrient deficiency (e.g. folate), lifestyle factors (e.g. alcohol, smoking, drugs and stress), and genetic factors such as inherited defects in DNA metabolism and/or repair. Tobacco smoke has been associated to a higher risk of development of cancer, especially in the oral cavity, larynx and lungs, as these are places of direct contact with many carcinogenic tobacco’s compounds. Alcohol is definitely a recognized agent that influence cells in a genotoxic form, been citied as a strong agent with potential in the development of carcinogenic lesions. Epidemiological evidence points to a strong synergistic effect between cigarette smoking and alcohol consumption in the induction of cancers in the oral cavity. Approximately 90% of human cancers originate from epithelial cells. Therefore, it could be argued that oral epithelial cells represent a preferred target site for early genotoxic events induced by carcinogenic agents entering the body via inhalation and ingestion. The MN assay in buccal cells was also used to study cancerous and precancerous lesions and to monitor the effects of a number of chemopreventive agents.

Effects of the interaction of tobacco smoke and alcohol consumption on buccal micronucleus in workers exposed occupationally to formaldehyde

Occupational exposure to formaldehyde (FA) has been shown to induce nasopharyngeal cancer and has been classified as carcinogenic to humans (group 1) on the basis of sufficient evidence in humans. Tobacco smoke has been associated to a higher risk of development of cancer, especially in the oral cavity, larynx and lungs, as these are places of direct contact with many carcinogenic tobacco’s compounds. Alcohol is a recognized agent that influence cells in a genotoxic form, been citied as a strong agent with potential in the development of carcinogenic lesions. Epidemiological evidence points to a strong synergistic effect between cigarette smoking and alcohol consumption in the induction of cancers in the oral cavity. Approximately 90% of human cancers originate from epithelial cells. Therefore, it could be argued that oral epithelial cells represent a preferred target site for early genotoxic events induced by carcinogenic agents entering the body via inhalation and ingestion. The MN assay in buccal cells was also used to study cancerous and precancerous lesions and to monitor the effects of a number of chemopreventive agents.

Perfil lipídico em estudantes do ensino superior: caracterização numa população de jovens

O perfil lipídico é condicionado por diversos fatores, entre os quais os estilos de vida, a prática de exercício físico e os hábitos alimentares. Com o presente estudo pretende‑se avaliar o perfil lipídico numa população de jovens e estudar a sua associação com o índice de massa corporal, com os estilos de vida e os hábitos alimentares. Com um estudo exploratório descritivo, transversal, foi determinado o perfil lipídico de 97 estudantes, voluntários, do ensino superior, com idades compreendidas entre os 18 e os 25 anos. O perfil lipídico foi determinado pelo doseamento do colesterol total e frações (HDL e LDL) e triglicéridos. Foi identificado o índice de massa corporal e hábitos e estilos de vida, recolhidos pela aplicação de um questionário validado. No presente estudo não se observou alteração significativa do perfil lipídico, do IMC nem com o total do score alimentar. Não se encontraram associações entre as alterações lipídicas e o género, sendo que, nos estudantes com hábitos tabágicos, a fração HDL se encontrava mais baixa. O baixo score alimentar não se encontra associado ao perfil lipídico, o mesmo não se verificando em relação à prática de exercício físico. Verificou‑se um perfil lipídico alterado em 44,4% dos participantes, média de colesterol de 198,04mg/dl, triglicéridos de 82,58mg/dl, que são valores elevados para esta faixa etária. Os resultados deste estudo indicam que esta população deve monitorizar os fatores de risco de modo a prevenir patologia do foro cardio e cerebrovascular. ABSTRACT - The lipid profile is conditioned by several factors including the styles of life, physical exercise and eating habits. The present study is to evaluate the lipid profile in a population of students in higher education, and study their association with body mass index, with the lifestyles and eating habits. A descriptive exploratory study, transversal, we determined the lipid profile of 97 students, volunteers, higher education, aged 18 to 25 years. The lipid profile was determined by assay of total cholesterol and fractions (HDL and LDL) and triglycerides. It identified the body mass index and habits and lifestyles, collected by applying a validated questionnaire. In the present study, no significant change in lipid profile, BMI, nor with the total food score. No associations were found between lipid disorders and gender, and smoking habits in the students with the HDL fraction was lower. The low food score is not associated with lipid profile, the same was not observed in relation to physical exercise. There is an altered lipid profile in 44.4% of participants, average 198.04mg/dl cholesterol, triglycerides 82.58mg/dl, which are high values for this age group. The results of this study indicate that this population is to monitor the risk factors to prevent cardiovascular and cerebrovascular diseases.

Occupational exposure to environmental tobacco smoke in hospitality venues: are genetic- or proteomics-based biomarkers predictive of respiratory diseases?

Environmental tobacco smoke (ETS) is recognized as an occupational hazard in the hospitality industry. Although Portuguese legislation banned smoking in most indoor public spaces, it is still allowed in some restaurants/bars, representing a potential risk to the workers’ health, particularly for chronic respiratory diseases. The aims of this work were to characterize biomarkers of early genetic effects and to disclose proteomic signatures associated to occupational exposure to ETS and with potential to predict respiratory diseases development. A detailed lifestyle survey and clinical evaluation (including spirometry) were performed in 81 workers from Lisbon restaurants. ETS exposure was assessed through the level of PM 2.5 in indoor air and the urinary level of cotinine. The plasma samples were immunodepleted and analysed by 2D-SDSPAGE followed by in-gel digestion and LC-MS/MS. DNA lesions and chromosome damage were analysed innlymphocytes and in exfoliated buccal cells from 19 cigarette smokers, 29 involuntary smokers, and 33 non-smokers not exposed to tobacco smoke. Also, the DNA repair capacity was evaluated using an ex vivo challenge comet assay with an alkylating agent (EMS). All workers were considered healthy and recorded normal lung function. Interestingly, following 2D-DIGE-MS (MALDI-TOF/TOF), 61 plasma proteins were found differentially expressed in ETS-exposed subjects, including 38 involved in metabolism, acute-phase respiratory inflammation, and immune or vascular functions. On the other hand, the involuntary smokers showed neither an increased level of DNA/chromosome damage on lymphocytes nor an increased number of micronuclei in buccal cells, when compared to non-exposed non-smokers. Noteworthy, lymphocytes challenge with EMS resulted in a significantly lower level of DNA breaks in ETS-exposed as compared to non-exposed workers (P<0.0001) suggestive of an adaptive response elicited by the previous exposure to low levels of ETS. Overall, changes in proteome may be promising early biomarkers of exposure to ETS. Likewise, alterations of the DNA repair competence observed upon ETS exposure deserves to be further understood. Work supported by Fundação Calouste Gulbenkian, ACSS and FCT/Polyannual Funding Program.

The Bambuí health and ageing study (BHAS): methodological approach and preliminary results of a population-based cohort study of the elderly in Brazil

OBJECTIVE: A cohort study has been designed to identify predictors of adverse health events in the elderly. The methodology of the study and preliminary descriptive results are presented. METHODS: The study population comprises all residents of Bambuí (Minas Gerais, Brazil), aged 60 or more years (n=1.742). From these, 92.2% were interviewed and 85.9% underwent clinical examination, consisting of haematological and biochemical tests, serology for Trypanosoma cruzi, anthropometric and blood pressure measures and electrocardiogram. Aliquots of serum, plasma and DNA were stored for future investigations. The baseline interview included sociodemographic characteristics, self-referred health condition and history of selected diseases, medication use, health service use, source of medical care, physical activities, smoking, drinking and eating habits, reproductive history, physical functioning, life events, social support and mental health. Individuals are being followed up annually. RESULTS: The following characteristics predominated among participants: women (60,0%), married (48.9%) or widowed (35.4%), people living in households with up to 2 residents (73.8%), heads of family (76.7%), people with monthly income between 1.00 and 2.99 Brazilian minimum wages (62.0%) and people with up to 4 years of schooling (89.1%). The median age was 68 years. Among the cohort members, only 1.7% were lost in the first follow-up. CONCLUSIONS: In general, the characteristics of the study population were very similar to those from other epidemiological studies of the elderly based on large Brazilian cities. The small number of losses to follow-up indicates that the choice of Bambuí was adequate, assuring the feasibility of a long term cohort study.

Food frequency consumption and lipoproteins serum levels in the population of an urban area, Brazil

OBJECTIVE: To identify the association between food group consumption frequency and serum lipoprotein levels among adults. METHODS: The observations were made during a cross-sectional survey of a representative sample of men and women over 20 years old living in Cotia county, S. Paulo, Brazil. Data on food frequency consumption, serum lipids, and other covariates were available for 1,045 adults. Multivariate analyses adjusted by age, gender, body mass index, waist-to-hip ratio, educational level, family income, physical activity, smoking, and alcohol consumption were performed. RESULTS: Consumption of processed meat, chicken, red meat, eggs and dairy foods were each positively and significantly correlated with LDL-C, whereas the intake of vegetables and fruits showed an inverse correlation. Daily consumption of processed meat, chicken, red meat, eggs, and dairy foods were associated with 16.6 mg/dl, 14.5 mg/dl, 11.1 mg/dl, 5.8 mg/dl, and 4.6 mg/dl increase in blood LDL-C, respectively. Increases of daily consumption of fruit and vegetables were associated with 5.2 mg/dl and 5.5 mg/dl decreases in LDL-C, respectively. Alcohol beverage consumption showed a significant positive correlation with HDL-C. CONCLUSIONS: Dietary habits in the study population seem to contribute substantially to the variation in blood LDL and HDL concentrations. Substantially CHD risk reduction could be achieved with dietary changes.

Risk factors for the increasing trend in low birth weight among live births born by vaginal delivery, Brazil

OBJECTIVE: To identify risk factors for low birth weight (LBW) among live births by vaginal delivery and to determine if the disappearance of the association between LBW and socioeconomic factors was due to confounding by cesarean section. METHODS: Data were obtained from two population-based cohorts of singleton live births in Ribeirão Preto, Southeastern Brazil. The first one comprised 4,698 newborns from June 1978 to May 1979 and the second included 1,399 infants born from May to August 1994. The risks for LBW were tested in a logistic model, including the interaction of the year of survey and all independent variables under analysis. RESULTS: The incidence of LBW among vaginal deliveries increased from 7.8% in 1978--79 to 10% in 1994. The risk was higher for: female or preterm infants; newborns of non-cohabiting mothers; newborns whose mothers had fewer prenatal visits or few years of education; first-born infants; and those who had smoking mothers. The interaction of the year of survey with gestational age indicated that the risk of LBW among preterm infants fell from 17.75 to 8.71 in 15 years. The mean birth weight decreased more significantly among newborns from qualified families, who also had the highest increase in preterm birth and non-cohabitation. CONCLUSIONS: LBW among vaginal deliveries increased mainly due to a rise in the proportion of preterm births and non-cohabiting mothers. The association between cesarean section and LBW tended to cover up socioeconomic differences in the likelihood of LBW. When vaginal deliveries were analyzed independently, these socioeconomic differences come up again.

Hospital visitors as controls in case-control studies

OBJECTIVE: Selecting controls is one of the most difficult tasks in the design of case-control studies. Hospital controls may be inadequate and random controls drawn from the base population may be unavailable. The aim was to assess the use of hospital visitors as controls in a case-control study on the association of organochlorinated compounds and other risk factors for breast cancer conducted in the main hospital of the "Instituto Nacional de Câncer" -- INCA (National Cancer Institute) in Rio de Janeiro (Brazil). METHODS: The study included 177 incident cases and 377 controls recruited among female visitors. Three different models of control group composition were compared: Model 1, with all selected visitors; Model 2, excluding women visiting relatives with breast cancer; and Model 3, excluding all women visiting relatives with any type of cancer. Odds ratios (OR) and 95% confidence intervals were calculated to test the associations. RESULTS: Age-adjusted OR for breast cancer associated with risk factors other than family history of cancer, except smoking and breast size, were similar in the three models. Regarding family history of all cancers, except for breast cancer, there was a decreased risk in Models 1 and 2, while in Model 3 there was an increased risk, but not statistically significant. Family history of breast cancer was a risk factor in Models 2 and 3, but no association was found in Model 1. In multivariate analysis a significant risk of breast cancer was found when there was a family history of breast cancer in Models 2 and 3 but not in Model 1. CONCLUSIONS: These results indicate that while investigating risk factors unrelated to family history of cancer, the use of hospital visitors as controls may be a valid and feasible alternative.

Reproductive outcomes in an area adjacent to a petrochemical plant in southern Brazil

OBJECTIVE: To evaluate possible adverse reproductive outcomes in an area adjacent to a petrochemical plant in southern Brazil. METHODS: A review of 17,113 birth records of the main hospital of the municipality of Montenegro, southern Brazil, from 1983 to 1998 was carried out. Three groups of cases were selected: (1) newborns with major congenital malformations; (2) newborns with low birth weight (<2,500 g); and (3) stillborns (>500 g). A control was assigned to each case. Controls were the first newborns weighing > or = 2,500 g without malformations and of case-matching sex. Mother's residence during pregnancy was used as an exposure parameter. Statistical analyses were performed using Chi-square test or Fisher test, odds ratio, 0.05 significance level, and 95% confidence interval. RESULTS: For unadjusted analysis, it was found a correlation between low birth weight and geographical proximity of mother's residence to the petrochemical plant (OR = 1.66; 95% CI = 1.01--2.72) or residence on the way of preferential wind direction (OR = 1.62; 95% CI = 1.03--2.56). When other covariates were added in the conditional logistic regression (maternal smoking habits, chronic disease and age), there was no association. CONCLUSIONS: Despite final results were negative, low birth weight could be a good parameter of environmental contamination and should be closely monitored in the studied area.

Caracterização dos estilos de vida dos sem-abrigo da cidade do Porto

O fenómeno dos sem-abrigo está em constante crescimento nos centros urbanos, na cidade no Porto o mesmo acontece, sendo esta uma realidade ainda pouco conhecida. Têm sido realizados alguns estudos sobre esta problemática, no entanto poucos incidem sobre a população portuguesa, pouco se sabe sobre como vivem estes indivíduos e sobre o que define o seu estilo de vida. Os estilos de vida têm vindo a ser uma área de crescente interesse para estudo, visto que afecta a nossa saúde e a longo prazo tem influência nos padrões de morbilidade e mortalidade. Com este estudo procurou-se caracterizar os sem-abrigo da cidade do Porto e os comportamentos que tipificam o seu estilo de vida, bem como verificar se existem variáveis dos estilos de vida que se encontram correlacionadas com a presença de sintomatologia psicopatológica. Para este efeito, foi realizado um inquérito por questionário a 30 pessoas que vivem na condição de sem-abrigo na cidade do Porto, através da administração de um questionário de estilos de vida e da Brief Psychiatric Rating Scale (BPRS). Concluímos que os sem-abrigo se caracterizam por ser do sexo masculino, solteiros de nacionalidade portuguesa e baixa escolaridade. Constatamos que a maioria apresenta comportamentos pouco saudáveis como fumar e não praticar exercício físico, contudo têm cuidado com a higiene pessoal, apresentam uma boa higiene do sono e manifestam poucos comportamentos sexuais de risco. Verificamos que a ansiedade se encontra correlacionada negativamente com o stress, higiene do sono, insight e alimentação. As perturbações somáticas mostraram uma correlação com a higiene do sono, o humor depressivo com a higiene do sono e insight, o retraimento emocional com a socialização e falta de cooperação com a socialização, sendo todas estas correlações negativas. Encontramos ainda uma correlação positiva entre a lentificação e o consumo de substâncias e uma correlação negativa entre a lentificação e higiene do sono. Considerando os resultados obtidos pensamos ser fundamental prosseguir com estudos de investigação nesta área, para que de futuro as intervenções junto desta população consigam dar uma melhor resposta ao seu estado de saúde.

Hippuric acid in urine: reference values

OBJECTIVE: To establish reference values for hippuric acid (HA) excreted in the urine, and to evaluate the impact of age, gender, alcohol, and tobacco, on these levels in a population nonexposed to toluene. METHODS: Reference values for hippuric acid in urine were determined in 115 toluene nonexposed healthy volunteers, from Alfenas city, Southeastern Brazil. A questionnaire was applied to each volunteer and data on occupational and personal habits were collected. Biochemical and hematological analyses were used to confirm the volunteers' good health condition. Reference values were expressed in g HA/g urine creatinine, as mean ± standard deviation (x ± SD), median, 95% confidence interval (95%CI), 95th percentile, and upper reference value (URV, mean +2 SD). RESULTS: Reference values of hippuric acid in urine were: mean ± standard deviation =0.18±0.10; median =0.15; 95% confidence interval =0.16±0.20; 95th percentile = 0.36 and upper reference value (URV, mean +2 SD) =0.38. Statistically significant differences in urinary HA (Wilcoxon - Mann/Whitney, p<0.05) were observed for different genders and age groups. Alcohol ingestion and smoking habit did not significantly affect the results. CONCLUSIONS: The reference values of hippuric acid in urine can be used in biomonitoring programs of workers occupationally exposed to toluene, especially in the southern region of the state of Minas Gerais. Age and gender may affect the HA reference values.

Infant mortality and low birth weight in cities of Northeastern and Southeastern Brazil

OBJECTIVE: To compare estimates of low birth weight (LBW), preterm birth, small for gestational age (SGA), and infant mortality in two birth cohorts in Brazil. METHODS: The two cohorts were performed during the 1990s, in São Luís, located in a less developed area in Northeastern Brazil, and Ribeirão Preto, situated in a more developed region in Southeastern Brazil. Data from one-third of all live births in Ribeirão Preto in 1994 were collected (2,839 single deliveries). In São Luís, systematic sampling of deliveries stratified by maternity hospital was performed from 1997 to 1998 (2,439 single deliveries). The chi-squared (for categories and trends) and Student t tests were used in the statistical analyses. RESULTS: The LBW rate was lower in São Luís, thus presenting an epidemiological paradox. The preterm birth rates were similar, although expected to be higher in Ribeirão Preto because of the direct relationship between preterm birth and LBW. Dissociation between LBW and infant mortality was observed, since São Luís showed a lower LBW rate and higher infant mortality, while the opposite occurred in Ribeirão Preto. CONCLUSIONS: Higher prevalence of maternal smoking and better access to and quality of perinatal care, thereby leading to earlier medical interventions (cesarean section and induced preterm births) that resulted in more low weight live births than stillbirths in Ribeirão Preto, may explain these paradoxes. The ecological dissociation observed between LBW and infant mortality indicates that the LBW rate should no longer be systematically considered as an indicator of social development.

Infant mortality: comparison between two birth cohorts from Southeast and Northeast, Brazil

OBJECTIVE: To obtain population estimates and profile risk factors for infant mortality in two birth cohorts and compare them among cities of different regions in Brazil. METHODS: In Ribeirão Preto, southeast Brazil, infant mortality was determined in a third of hospital live births (2,846 singleton deliveries) in 1994. In São Luís, northeast Brazil, data were obtained using systematic sampling of births stratified by maternity unit (2,443 singleton deliveries) in 1997-1998. Mothers answered standardized questionnaires shortly after delivery and information on infant deaths was retrieved from hospitals, registries and the States Health Secretarys' Office. The relative risk (RR) was estimated by Poisson regression. RESULTS: In São Luís, the infant mortality rate was 26.6/1,000 live births, the neonatal mortality rate was 18.4/1,000 and the post-neonatal mortality rate was 8.2/1,000, all higher than those observed in Ribeirão Preto (16.9, 10.9 and 6.0 per 1,000, respectively). Adjusted analysis revealed that previous stillbirths (RR=3.67 vs 4.13) and maternal age <18 years (RR=2.62 vs 2.59) were risk factors for infant mortality in the two cities. Inadequate prenatal care (RR=2.00) and male sex (RR=1.79) were risk factors in São Luís only, and a dwelling with 5 or more residents was a protective factor (RR=0.53). In Ribeirão Preto, maternal smoking was associated with infant mortality (RR=2.64). CONCLUSIONS: In addition to socioeconomic inequalities, differences in access to and quality of medical care between cities had an impact on infant mortality rates.