Prevalence of smoking and incidence of initiation in the Latin American adult population: the PLATINO study

Background

The PLATINO project was launched in 2002 in order to study the prevalence of chronic obstructive pulmonary disease (COPD) in Latin America. Because smoking is the main risk factor for COPD, detailed data on it were obtained. The aim of this paper was to evaluate the prevalence of smoking and incidence of initiation among middle-aged and older adults (40 years or older). Special emphasis was given to the association between smoking and schooling.

Methods

PLATINO is a multicenter study comprising five cross-sectional population-based surveys of approximately 1,000 individuals per site in Sao Paulo (Brazil), Santiago (Chile), Mexico City (Mexico), Montevideo (Uruguay) and Caracas (Venezuela). The outcome variable was smoking status (never, former or current). Current smokers were those who reported to smoke within the previous 30 days. Former smokers were those who reported to quit smoking more than 30 days before the survey. Using information on year of birth and age of smoking onset and quitting, a retrospective cohort analysis was carried out. Smoking prevalence at each period was defined as the number of subjects who started to smoke during the period plus those who were already smokers at the beginning of the period, divided by the total number of subjects. Incidence of smoking initiation was calculated as the number of subjects who started to smoke during the period divided by the number of non-smokers at its beginning. The independent variables included were sex, age and schooling.

Results

Non-response rates ranged from 11.1% to 26.8%. The prevalence of smoking ranged from 23.9% (95%CI 21.3; 26.6) in Sao Paulo to 38.5% (95%CI 35.7; 41.2) in Santiago. Males and middle-aged adults were more likely to smoke in all sites. After adjustment for age, schooling was not associated with smoking. Using retrospective cohort analysis, it was possible to detect that the highest prevalence of smoking is found between 20–29 years, while the highest incidence is found between 10–19 years. Age of smoking onset tended to decline over time among females.

Conclusion

The prevalence of smoking varied considerably across sites, but was lower among countries with national anti-smoking campaigns.

Frequency of self-reported COPD exacerbation and airflow obstruction in five Latin American cities: the Proyecto Latinoamericano de Investigacion en Obstruccion Pulmonar (PLATINO) study

BACKGROUND

Recurrent exacerbations are common in COPD patients. Limited information exists regarding exacerbation frequency in COPD patients from epidemiologic studies. We examined the frequency of self-reported exacerbations and the factors influencing exacerbation frequency among COPD patients in a population-based study conducted in Latin America.

METHODS

We used a post-bronchodilator FEV(1)/FVC ratio of < 0.70 to define COPD. Exacerbation was self-reported and defined by symptoms (deterioration of breathing symptoms that affected usual daily activities or caused missed work).

RESULTS

Spirometry was performed in 5,314 subjects. There were 759 subjects with airflow limitation; of these, 18.2% reported ever having had an exacerbation, 7.9% reported having an exacerbation, and 6.2% reported having an exacerbation requiring at least a doctor visit within the past year. The proportion of individuals with an exacerbation significantly increased by Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages, from 4.2% in stage 1 to 28.9% in stages 3 and 4. The self-reported exacerbation rate was 0.58 exacerbations per year. The rate of exacerbations requiring at least a doctor visit and length of stay in hospital due to exacerbations also increased as COPD severity progressed. The factors associated with having an exacerbation in the past year were dyspnea, prior asthma diagnosis, receiving any respiratory therapy, and disease severity of GOLD stages 3 and 4.

CONCLUSIONS

The proportion of individuals with airflow limitation and self-reported exacerbation increases as the disease severity progresses. Dyspnea, prior asthma diagnosis, receiving any respiratory therapy, and more severe obstruction were significantly associated with having an exacerbation in the past year.

[Influence of obesity on health care costs and absenteeism among employees of a mining company]

BACKGROUND

The health associated costs of obesity can represent between 2% and 9% of the total health costs of a given country.

AIM

To assess the impact of obesity on health care costs and absenteeism in a cohort of mine workers.

PATIENTS AND METHODS

Prospective study of 4.673 men, employees of a mining company, aged 49 +/- 7 years that were followed for 24 +/- 11 months. Total health care cost and days of sick leave were recordedfor each individual. The association between obesity and these variables was analyzed by logistic regression adjusting for co-morbidities, age and other variables.

RESULTS

Mean annual health care costs for obese workers were 17% higher (p <0.001) compared to workers with normal weight and 58% higher (p <0.001) for workers with severe and morbid obesity. Mean annual days of sick leave increased by 25%o in the obese (p =0.002) and by 57%o in subjects with severe and morbid obesity (p <0.001). For health care costs the most significant predictors were: presence of diabetes mellitus (Odds ratio (OR) 6.21, 95%o confidence intervals (95% CI) 4.9 to 7.9), hypertension (OR 3-99; 95% CI3-4 to 4.6) and severe and morbid obesity (OR 2.55, 95%o CI 1.9 to 3-4). For absenteeism the most significant predictors were: presence of diabetes mellitus (OR 1.58, 95%> CI 1.2 to 2.0), hypertension (OR 1,34, 95%> CI 1.2 to 1.6) and severe and morbid obesity (OR 1.50, 95%o CI 1.1 to 2.1).

CONCLUSIONS

Obesity increases significantly health care costs and absenteeism.

Prevalence of sleep related symptoms in four Latin American cities

STUDY OBJECTIVES

to estimate the prevalence of the most common sleep related symptoms (SRS) in the metropolitan areas of Mexico City, Montevideo (Uruguay), Santiago (Chile), and Caracas (Venezuela).

METHODS

The study consisted of a multistage cluster sampling of adults aged > or = 40 years living in metropolitan areas. All participants completed a questionnaire on sleep related symptoms. Simplified respiratory polygraphy during sleep was conducted on 188 subjects from Mexico City. Obstructive sleep apnea syndrome was defined as Epworth Sleepiness Scale score > or = 11 and respiratory disturbance index (RDI) > or = 15 events/h; a cut-off of 15 was chosen because of its high sensitivity and specificity in association with the portable monitor used in the study.

RESULTS

The study included 4,533 subjects (1,062 in Mexico City, 941 in Montevideo, 1,173 in Santiago, and 1,357 in Caracas). Snoring was reported by 60.2% (95% CI 58.8% to 61.6%), excessive daytime sleepiness by 16.4% (15.3% to 17.5%), observed apneas by 12.3% (11.4% to 13.3%), insomnia by 34.7% (33.3% to 36%), sedative use by 15.1% (14.1% to 16.2%), daytime napping by 29.2% (27.7% to 30.6%), and a combination of snoring, sleepiness, and observed apneas by 3.4% (2.9% to 4%). Men had a higher frequency of snoring and daytime napping, whereas women reported more insomnia and sedative use. Prevalence of OSAS varied from 2.9% among subjects who denied snoring, excessive daytime sleepiness, and observed apneas, to 23.5% among those reporting these 3 symptoms.

CONCLUSIONS

A high prevalence of sleep related symptoms and undiagnosed obstructive sleep apnea in Latin America was observed.

[Treatment of chronic obstructive pulmonary disease in 5 Latin American cities: the PLATINO study]

OBJECTIVE

PLATINO project is a population-based study designed to determine the prevalence of chronic obstructive pulmonary disease (COPD) in São Paulo, Brazil; Mexico City, Mexico; Montevideo, Uruguay; Santiago de Chile, Chile; and Caracas, Venezuela. The objective of this portion of PLATINO was to describe preventive and pharmacological treatment of COPD patients and factors associated with such treatment.

PATIENTS AND METHODS

Eligible subjects completed a questionnaire and underwent postbronchodilator spirometry.

RESULTS

Of the total of 5529 individuals who answered items referring to treatment, 758 had COPD (ratio of postbronchodilator forced expiratory volume in 1 second to forced vital capacity of <0.7), and 86 of them had been previously diagnosed by a physician. Among all COPD patients, only half of smokers or former smokers had been advised to quit and 24.7% had received some type of respiratory medication. Only 13.5% had used inhaled corticosteroids, and those were the patients with the most severe disease. In the group of patients who had a previous medical diagnosis of COPD, 69% of the smokers or former smokers had been advised to quit by a physician and 75.6% had received respiratory medication in the preceding year: 43% reported having used inhaled medication and 36% had used bronchodilators. Rates of vaccination against influenza and the use of mucolytic drugs and inhalers varied from one health care facility to another. All drug prescriptions were based on previous spirometry.

CONCLUSIONS

Spirometry emerged not only as a diagnostic tool, but also as a factor associated with treatment, against a background of uneven use of available health care resources in these 5 Latin American cities.

Worldwide burden of COPD in high- and low-income countries. Part II. Burden of chronic obstructive lung disease in Latin America: the PLATINO study

SETTING

Five Latin American cities: São Paulo, Brazil; Mexico City, Mexico; Montevideo, Uruguay; Santiago, Chile; Caracas, Venezuela.

OBJECTIVE

To describe the burden of chronic obstructive pulmonary disease (COPD) in Latin America.

DESIGN

This is a multicentre study. Post-bronchodilator spirometry was used and the main outcome measure was FEV(1)/FVC < 0.7 (fixed ratio criterion). Global Obstructive Lung Disease (GOLD) stages were also analysed.

RESULTS

The combined population aged > or =40 years in the five countries included in the study was approximately 85.3 million. Of these, it was estimated that 12.2 million have airflow obstruction, which corresponds to our prevalence estimate of 14.3%. The proportion of subjects in Stages II-IV of the GOLD classification was 5.6%. Risk factors presenting the highest aetiological fractions for COPD were age, current smoking, indoor exposure to coal and exposure to dust in the workplace. Smoking, the modifiable factor with the strongest aetiological fraction for COPD, affects 29.2% of adults aged > or =40 years in these cities, corresponding to approximately 25 million smokers in this age group.

CONCLUSION

Prevention of smoking and exposure to pollutants, such as coal and dust, are the interventions most likely to succeed against COPD in Latin America. The information obtained by a collaborative study has been vast and encouraging for other similar studies.

Use of respiratory medication in five Latin American cities: The PLATINO study

BACKGROUND

There is scanty information regarding respiratory medication prescription pattern in Latin America. We examined the use of bronchodilators and corticosteroids in a population-based study conducted in five Latin American cities.

METHODS

Medication use was derived from questions regarding the use of medication "to help breathing" within the previous 12 months, type of medicine, and frequency of use. To minimize the possibility of overdiagnosis, we used postbronchodilator FEV(1)/FVC<0.70 plus FEV(1)<80% as the definition of obstruction.

RESULTS

Interviews were completed in 5571 subjects from 6711 eligible individuals, and spirometry was performed in 5314 subjects. There were 360 (6.5%) treated subjects and 5211 not treated. Treated subjects were more likely to be older, women, unemployed, have higher tobacco consumption, higher body mass index, higher FEV(1) reversibility and airway obstruction. They were also more likely to report prior spirometry, prior diagnosis of COPD, asthma or tuberculosis, and more respiratory symptoms. Over half of treated subjects had neither obstruction nor FEV(1) reversibility, and approximately 30% reported no prior diagnosis of asthma or COPD. Prior respiratory diagnoses and wheezing were more strongly associated with treatment than objective measures of airway obstruction.

CONCLUSIONS

The use of bronchodilators and/or corticosteroids is common in the general population aged 40 years or older, with over one-half of treated subjects using them without being obstructed.

Chronic obstructive pulmonary disease and body mass index in five Latin America cities: the PLATINO study

BACKGROUND

The body mass index (BMI) is a prognostic factor for chronic obstructive pulmonary disease (COPD). Despite its importance, little information is available regarding BMI alteration in COPD from a population-based study. We examined characteristics by BMI categories in the total and COPD populations in five Latin-American cities, and explored the factors influencing BMI in COPD.

METHODS

COPD was defined as a postbronchodilator forced expiratory volume in the first second/forced vital capacity (FEV(1)/FVC) <0.70. BMI was categorized as underweight (< 20 kg/m(2)), normal weight (20-24.9 kg/m(2)), overweight (25.0-29.9 kg/m(2)), and obese (> or = 30.0 kg/m(2)).

RESULTS

Interviews were completed in 5571 subjects from 6711 eligible individuals, and spirometry was performed in 5314 subjects. There were 759 subjects with COPD and 4555 without COPD. Compared with the non-COPD group, there was a higher proportion of COPD subjects in the underweight and normal weight categories, and a lower proportion in the obese category. Over one-half COPD subjects had BMI over 25 kg/m(2). No differences in BMI strata among countries were found in COPD subjects. Factors associated with lower BMI in males with COPD were aging, current smoking, and global initiative for chronic obstructive lung disease (GOLD) stages III-IV, whereas wheeze and residing in Santiago and Montevideo were associated with higher BMI. In females with COPD, current smoking, lower education, and GOLD stages II-IV were associated with lower BMI, while dyspnea and wheeze were associated with higher BMI.

CONCLUSIONS

BMI alterations are common in COPD with no significant differences among countries. Current smoking, age, GOLD stages, education level, residing in Santiago and Montevideo, dyspnea and wheeze were independently associated with BMI in COPD.

Tuberculosis and airflow obstruction: evidence from the PLATINO study in Latin America

The aim of the present study was to evaluate the association between history of tuberculosis and airflow obstruction. A population-based, multicentre study was carried out and included 5,571 subjects aged > or =40 yrs living in one of five Latin American metropolitan areas: Sao Paulo (Brazil); Montevideo (Uruguay); Mexico City (Mexico); Santiago (Chile); and Caracas (Venezuela). Subjects performed pre- and post-bronchodilator spirometry and were asked whether they had ever been diagnosed with tuberculosis by a physician. The overall prevalence of airflow obstruction (forced expiratory volume in one second/forced vital capacity post-bronchodilator <0.7) was 30.7% among those with a history of tuberculosis, compared with 13.9% among those without a history. Males with a medical history of tuberculosis were 4.1 times more likely to present airflow obstruction than those without such a diagnosis. This remained unchanged after adjustment for confounding by age, sex, schooling, ethnicity, smoking, exposure to dust and smoke, respiratory morbidity in childhood and current morbidity. Among females, the unadjusted and adjusted odds ratios were 2.3 and 1.7, respectively. In conclusion, history of tuberculosis is associated with airflow obstruction in Latin American middle-aged and older adults.

Impact of bronchodilator use on the prevalence of COPD in population-based samples

The aim of this study was to describe the impact of using bronchodilators on the prevalence of Chronic Obstructive Pulmonary Disease in a population-based survey (Platino study). A cluster sampling of subjects 40 years of age or older, representative of the metropolitan areas of 5 Latin American cities (Sao Paulo, Mexico, Montevideo, Santiago and Caracas) was chosen. Spirometry according to ATS standards was done before and after inhalation of 200 micrograms of salbutamol in 5183 subjects. Prevalences of airflow obstruction were estimated using different criteria, in tests done before and after bronchodilator use, and with reference values for pre- or post-bronchodilator use. Bronchodilator testing reduced the overall prevalence of FEV(1)/FVC% < 0.70 from 21.7% to 14% (35%). In the group with FEV(1)/FVC < 0.70 after bronchodilator use, 21% were asymptomatic from the respiratory point of view, and lacked significant adverse exposures. Subjects below the 5th percentile for FEV(1)/FVC and FEV(1)/FEV(6) were fewer than those with FEV(1)/FVC < 0.70, especially among the elderly. More subjects are below the 5th percentile of FEV(1)/FVC and FEV(1)/FEV(6) using reference values for tests after bronchodilator use than using the reference values determined without bronchodilator testing. Testing after bronchodilator use reduces the prevalence of airflow obstruction from 32 to 39% depending on the definition used. In addition, the subjects who were still obstructed after bronchodilator use were the ones who showed more respiratory symptoms and exposure to tobacco and other smokes and dusts, than subjects with reversible obstruction, suggesting an increased specificity for COPD.

[Spirometric reference values in 5 large Latin American cities for subjects aged 40 years or over]

OBJECTIVE

In clinical practice, spirometry is a extremely useful test that requires strict quality control, an appropriate strategy for interpretation, and reliable reference values. The aim of this study was to report spirometric reference values for 5 cities in Latin America.

PATIENTS AND METHODS

From data for 5315 subjects who had undergone spirometry in the PLATINO study in Caracas, Mexico City, Santiago, São Paulo, and Montevideo, we selected information for 906 (17%) individuals aged between 40 years and 90 years to provide reference values. The chosen subjects had never smoked, were asymptomatic, had not been diagnosed with lung disease, and were not obese. Multiple regression models were constructed with the following spirometric parameters: forced expiratory volume in 1 second (FEV1) and in 6 seconds (FEV6), peak expiratory flow, forced vital capacity (FVC), FEV1/FEV6, FEV1/FVC, and forced midexpiratory flow rate. Height, sex, and age were also included in the model.

RESULTS

Average values for the subjects studied were similar to those for the white North American population and the Mexican-American population of the third National Health and Nutrition Examination Survey, but exceeded those of the black population of the same survey by 20%.

CONCLUSIONS

The proposed reference values are an improvement on those currently available for Latin America because the participants were chosen by population sampling methods and standardized up-to-date methodology was used.

Comminuted talar neck fractures: a mechanical comparison of fixation techniques

OBJECTIVE

To compare the mechanical performance of 3 fixation techniques for comminuted talar neck fractures.

DESIGN

In vitro biomechanical study.

SETTING

Bioengineering research laboratory.

PARTICIPANTS

Thirty previously frozen human cadaveric tali were osteotomized across the talar neck. A wedge of bone 2 cm long and extending 50% of the medial to lateral and superior to inferior dimension of the talus was removed to create an unstable, comminuted fracture.

INTERVENTION

The specimens were randomized to one of 3 fixation groups. The first group was fixed with 3 anterior-to-posterior screws. The second group was fixed with 2 cannulated screws inserted from posterior to anterior. The third group was fixed with 1 screw from anterior to posterior and a medially applied blade plate. Specimens were embedded in acrylic cement and mounted on an Instron mechanical testing machine. Loading was applied in the dorsal-medial direction to failure.

MAIN OUTCOME MEASURES

For each specimen, the load-displacement curve, yield point, and 3 mm displacement point were recorded in response to controlled dorsal-medial loading to failure. Stiffness was calculated as the linear portion of the slope of the load (kN) versus displacement (mm) curve. Statistical analysis of the data was conducted using analysis of variance.

RESULTS

The mean yield point of each of the fixation techniques tested exceeded 1.4 kN. No statistically significant difference was found between the fixation methods, even when variations in age and sex were considered.

CONCLUSIONS

The mean yield point of the fixation techniques tested exceeds the theoretical stress across the talar neck during active motion. Anterior plate fixation provided equivalent stability to posterior screw fixation.

Diagnostic Labeling of COPD in Five Latin American Cities

BACKGROUND

COPD is a major worldwide problem with a rising prevalence. Despite its importance, there is a lack of information regarding underdiagnosis and misdiagnosis of COPD in different countries. As part of the Proyecto Latinoamericano de Investigación en Obstrucción Pulmonar study, we examined the relationship between prior diagnostic label and airway obstruction in the metropolitan areas of five Latin American cities (São Paulo, Santiago, Mexico City, Montevideo, and Caracas).

METHODS

A two-stage sampling strategy was used in each of the five areas to obtain probability samples of adults aged >or= 40 years. Participants completed a questionnaire that included questions on prior diagnoses, and prebronchodilator and postbronchodilator spirometry. A study diagnosis of COPD was based on airway obstruction, defined as a postbronchodilator FEV(1)/FVC < 0.70.

RESULTS

Valid spirometry and prior diagnosis information was obtained for 5,303 participants; 758 subjects had a study diagnosis of COPD, of which 672 cases (88.7%) had not been previously diagnosed. The prevalence of undiagnosed COPD was 12.7%, ranging from 6.9% in Mexico City to 18.2% in Montevideo. Among 237 subjects with a prior COPD diagnosis, only 86 subjects (36.3%) had postbronchodilator FEV(1)/FVC < 0.7, while 151 subjects (63.7%) had normal spirometric values. In the same group of 237 subjects, only 34% reported ever undergoing spirometry prior to our study.

CONCLUSIONS

Inaccurate diagnostic labeling of COPD represents an important health problem in Latin America. One possible explanation is the low rate of spirometry for COPD diagnosis.

The long-term stability of portable spirometers used in a multinational study of the prevalence of chronic obstructive pulmonary disease

BACKGROUND

We report the performance of an ultrasound-based portable spirometer (EasyOne) used in a population-based survey of the prevalence of chronic obstructive pulmonary disease, conducted in 5 Latin American cities: São Paulo, Brazil; México City, México; Montevideo, Uruguay; Santiago, Chile; and Caracas, Venezuela (the Latin American COPD Prevalence Study [PLATINO]).

METHODS

During the survey period (which ranged from 3 months to 6 months in the various locations) we collected daily calibration data from the 70 EasyOne spirometers used in the 5 survey cities. The calibrations were conducted with a 3-L syringe, and the calibration data were stored in the spirometer's database.

RESULTS

Ninety-seven percent of the calibration volumes were within +/- 64 mL (2.1%) of the 3-L calibration signal. Excluding data from the first city studied (São Paulo), where one calibration syringe had to be replaced, 98% of the calibration checks were within +/- 50 mL (1.7%). The measured volume was affected only minimally by the syringe's peak flow or emptying time.

CONCLUSION

In these 70 EasyOne spirometers neither calibration nor linearity changed during the study. Such calibration stability is a valuable feature in spirometry surveys and in the clinical setting.

[Epidemiological transition: the other side of the coin]

The model of epidemiological transition proposed by Omram explains the changes in disease patterns in communities. In societies with a high level of development this model has been complemented with the study of the post transition process. In this context, the emergence of allergic diseases, asthma and subsequently, of autoimmune diseases, has reached worrisome proportions in some countries, and no model can explain these changes. The hygiene theory supported by Strachan gives a reasonable explanation to this phenomenon. It postulates that the reduction of early exposure to biological agents, along with an improvement of sanitation conditions, immunizations and medical therapies, causes an asymmetrical immunological response, favoring the expression of Th2 response. The hygiene theory does not fully explain by itself what is happening in developed countries and it is not universally accepted. Chile is experiencing an epidemiological transition from a high burden of infectious diseases to a growing prevalence of non communicable diseases. In a previous similar setting in developed countries, there is some evidence to suspect that asthma, allergic and autoimmune diseases are becoming part of the epidemiological situation of Chile.

[Microsatellite marker AGAT of the mineralocorticoid receptor gene is associated with plasma renin activity in patients with essential hypertension]

BACKGROUND

Hypertensive states could result from constitutive activation of mineralorticoid receptor (MR) that generates salt retention and blood pressure elevation. Moreover, microsatellite regions can be associated to the regulation of the gene expression, producing subtle pathologies.

AIM

To determine the influence of microsatellite marker AGAT of the mineralocorticoid receptor gene in the plasma renin activity (PRA) and serum aldosterone (SA) levels of essential hypertensives (HT).

PATIENTS AND METHODS

We studied 292 HT patients and 57 normotensive (NT) controls. Blood samples were collected for PRA, SA and DNA isolation. Subjects were genotyped according to the length of the tetranucleotide AGAT repeat using polymerase chain reaction and polyacrylamide gel electrophoresis. Based on the normal distribution, we considered 13 to 15 repeats as a habitual (H) length and less than 13 or more than 15 repeats, as non-habitual (non-H).

RESULTS

We detected 8 different lengths in the AGAT repeat (allele) in both groups, ranging from 9-17 repeats, where the allele 11 was not detected in either hypertensive or normotensive groups. The allelic distribution was different in both groups (c2 =37.57, 4GL, p <0.001). In hypertensive patients, the H group showed higher PRA levels (median (Q1-Q3)) than the non-H group: 1.3 (0-7-3.5) vs 1.0 (0.5-2.3) ng/mL*h, p <0.05. The SA levels did not show differences between both groups, but the SA*PRA product was higher in the H group than the no-H group: 9.3 (3.0-24.6) vs 6.5 (2.5-14.6) p <0.05. In normotensive patients, no differences were observed in PRA, SA and SA*PRA between both groups.

CONCLUSION

These results show association between the length of the AGAT repeat with the PRA in HT, suggesting a plausible role in the control of the MR gene expression, and secondarily in the regulation of blood pressure.

Chronic obstructive pulmonary disease in five Latin American cities (the PLATINO study): a prevalence study

BACKGROUND

Both the prevalence and mortality attributable to chronic obstructive pulmonary disease (COPD) seem to be increasing in low-income and middle-income countries, but few data are available. The aim of the PLATINO study, launched in 2002, was to describe the epidemiology of COPD in five major Latin American cities: São Paulo (Brazil), Santiago (Chile), Mexico City (Mexico), Montevideo (Uruguay), and Caracas (Venezuela).

METHODS

A two-stage sampling strategy was used in the five areas to obtain probability samples of adults aged 40 years or older. These individuals were invited to answer a questionnaire and undergo anthropometry, followed by prebronchodilator and postbronchodilator spirometry. We defined COPD as a ratio less than 0.7 of postbronchodilator forced expiratory volume in the first second over forced vital capacity.

FINDINGS

Complete information, including spirometry, was obtained from 963 people in São Paulo, 1173 in Santiago, 1000 in Mexico City, 885 in Montevideo, and 1294 in Caracas. Crude rates of COPD ranged from 7.8% (78 of 1000; 95% CI 5.9-9.7) in Mexico City to 19.7% (174 of 885; 17.2-22.2) in Montevideo. After adjustment for key risk factors, the prevalence of COPD in Mexico City remained significantly lower than that in other cities.

INTERPRETATION

These results suggest that COPD is a greater health problem in Latin America than previously realised. Altitude may explain part of the difference in prevalence. Given the high rates of tobacco use in the region, increasing public awareness of the burden of COPD is important.

[Smoking habit in school age children, in Chile]

BACKGROUND

In Chile, there is no information about the prevalence of smoking among basic and high school students.

AIM

To study the prevalence of smoking among school age population. MATERAL AND METHODS: A cross sectional survey was conducted during 2001, assessing tobacco use and smoking habit in a representative sample of 15,119 randomly selected students.

RESULTS

Sixty four percent of students had smoked at least once in their lifetime. Eighteen percent of students smoked daily and 15%, occasionally. The figures for women were higher (19 and 18% respectively). The mean age for the first contact with smoking was 12.3 years and, for starting the smoking habit, 13.2 years. Smokers increased the amount of cigarettes during weekends. Higher prevalence rates of smoking were observed in students from the Southern region of the country and of lower socioeconomic levels. From the 3rd grade on, there is an increased risk of having contact with tobacco and smoking for the first time and from 6th grade on, this risk becomes permanent. The adjusted Odds Ratio to be a smoker is significantly higher when the mother is a current or irregular smoker (OR 1.9 95 CI; 1.7-2.0).

CONCLUSIONS

High smoking prevalence rates were detected in this survey, mainly in women. The risk for smoking starts early during school life. Therefore, health promotion programs must include elementary and high school students.

[Development of an instrument to assess the severity of community acquired pneumonia among hospitalized patients]

BACKGROUND

Community acquired pneumonia (CAP) severity assessment is crucial.

AIM

To develop a practical clinical severity assessment model for stratifying immunocompetent adult patients hospitalized with CAP into different management groups.

PATIENTS AND METHODS

During a 24 months period, 455 adult patients (250 male, mean age 69 +/- 19 years old) were evaluated. All the relevant clinical information recorded and they were followed during hospital stay until discharge or death. Mortality until 30 days after admission was determined.

RESULTS

The mean hospital length of stay was 9.9 +/- 9.4 days and 76% had an underlying disease. In hospital mortality was 7.6% and 10.1% at 30 days follow up. Admission prognostic factors associated with high mortality at 30 days follow up were: advanced age, presence of comorbidity, suspicion of aspiration, duration of symptoms < or = 2 days, altered mental status, absence of cough, fever and cbills, low blood pressure, tachypnea, hypoxemia and multilobar radiographic pulmonary infiltrates. A clinical prognostic index derived from a logistic regression analysis including five independent variables associated with mortality (confuson, comorbidity, low systolic blood pressure, temperature < 37.5 degrees C and respiratory rate > 20/min), enabled patients to be stratified according to increasing risk of mortality: class 1: 0.9%, class 2: 4.9%, class 3: 14.2%, and class 4: 35.6%.

CONCLUSION

A simple clinical severity assessment tool based on confusion, comorbidity, blood pressure, temperature and respiratory rate could be used to stratify patients with CAP into different risk class categories and management groups.

Cambios recientes en la mortalidad por cáncer de próstata en Chile: estudio de tendencias en el período 1955-2001

BACKGROUND

By the year 2000, prostate cancer became the second leading cause of cancer death in Chilean men of all ages and is the leading cause of cancer deaths in men of eighty years of age or older.

AIM

To analyze the trends in mortality rates from prostate cancer in Chile in a fifty years series, estimating the rate of increase of such rates and their changes in time.

MATERIAL AND METHODS

A trend analysis for age standardized mortality rates was performed, using join point regression analysis, which allows estimation of the annual percent change of rates and to find significant changes in such trend.

RESULTS

Age standardized mortality rates in Chile reached their peak value in 1996, becoming apparently stable from then on. Crude rates have had a steady increase during the whole period. The trends analysis identified three different periods in the growth of the age standardized rates: a first one of slot increase in rates between 1955 and 1981 (0.9% annual increase), a second one of more aggressive growth starting in 1981 (2.6% annual increase), and a third period starting in 1996, in which rates slowly decline at an annual rate of 1%.

CONCLUSIONS

The tendency of prostate cancer seen in Chile resembles that of industrialized countries, with an increase in its age standardized death rates that suffers a downturn by the end of the past decade. Besides early detection techniques, a substantial part of the reduction in mortality from prostate cancer could be explained by therapeutic improvements.

Risk factors for recurrent wheezing following acute bronchiolitis: a 12-month follow-up

The objective of this study was to identify wheezing recurrences and related risk factors in two groups of infants with bronchiolitis: respiratory syncytial virus (RSV)+ and RSV- as determined by RSV enzyme immunoassay. A 1-year prospective cohort study was conducted with infants younger than 2 years old. Follow-up was made monthly, by a clinical visit and/or by telephone, checking the number of wheezing episodes per month and possible related risk factors. There were 96 subjects enrolled, of whom 77 reached complete follow-up: 36 were RSV+ (46.8%), and 41 were RSV- (53.2%). In the RSV+ group, there were 17 males (47%), vs. RSV- with 30 males (73%) (P < 0.05); 22 RSV+ (61%) were admitted to hospital, vs.14 RSV- (34%) (P < 0.05). Mean age was not significantly different in both groups. The mean number of recurrences was 3.36 episodes/infant/year in the RSV+ and 2.34 in the RSV- group (P = 0.06). Crude relative risk (RR) for a new recurrence of an obstructive episode was 1.33 (95% CI, 0.99-1.79). After adjustment for several potential confounders, the RR was 1.41 (95% CI, 1.03-1.93). Hospitalization stay was longer in the RSV+ than the RSV- group (P < 0.05). In the RSV+ group, patients who had been hospitalized showed more recurrences (4.18) than those with outpatient treatment (2.07) (P < 0.05); this difference did not exist in the RSV- group. The related risk factors for recurrent wheeze in the RSV- group were male gender, number of siblings, and daycare attendance (P < 0.05). In the RSV+ group, the risk of recurrent wheeze was only increased by admission to hospital during the acute bronchiolitis episode (P < 0.05). We speculate that there may be a higher rate of increased airway reactivity and/or preexisting diminished lung function in RSV+ infants requiring hospitalization for their initial illness. In conclusion, RSV-proven bronchiolitis, particularly in those infants who are hospitalized, is associated with a higher recurrence of wheezing episodes in the subsequent 12 months. Other factors appear to account for recurrent wheeze in the RSV- group.

[Bronchial asthma and atopic diseases as an emerging problem in public health: new etiological hypothesis. The experience of developed societies]

Developed countries report increasing trends in the prevalence of asthma and atopic diseases over the last 40 years. This change cannot be attributed to artefactual effects. Emerging from these information, new approaches have been generated to explore these novel findings. Among the most important new factors to be explored, scientific research is pointing out to variables related with physical environment, socio-economic and genetic background, anthropometry at birth, nutritional status, diet, exercise and hormonal profile. Changes in the epidemiology of asthma and atopic conditions in developed countries were also preceded by increases in the prevalence of chronic diseases and their risk factors. Chile does not have information about time trends on these diseases, but several studies are reporting a high prevalence of asthma among adults. Conversely, results from the collaborative ISAAC study carried out in children, have shown a relative low prevalence of asthma in Chilean children. An increasing trend in chronic diseases and their risk factors has been reported in Chile, suggesting an epidemiological pattern similar to that experienced by industrialised countries, when the prevalence of asthma and atopic began to increase. This article review current information about etiological research emphasising the need to develop local research on asthma and atopic diseases taking into account our epidemiological situation.

Cellular immune response of intracecally inoculated Mongolian gerbils with Entamoeba histolytica trophozoites

We analyzed the local and systemic cellular immune response in mongolian gerbils inoculated with Entamoeba histolytica. Two groups were intracecally inoculated with E. histolytica trophozoites and two groups were used as controls. A inoculated groups and a control groups were sacrificed on days 10 and 30 post inoculation (p.i), the spleen and mesenteric lymph nodes (MLNs) lymphocytes (Ly) were isolated and incubated in vitro with 2 different amebic antigens. The proliferative Ly response of inoculated groups was greater than the Ly mitogenic response seen in control groups, at day 10 p.i. as well as day 30 p.i. (alpha = 0.05). Ly response of MLNs was greater in comparison to those of the spleen (alpha = 0.05). In other four groups, intradermal reactions with a antigen were used to demonstrated delayed hypersensitivity in gerbils after being inoculated with E. histolytica trophozoites. The percentage of volume increase of the plantar pad swelling were measured. Groups inoculated presented greater increases (alpha = 0.05) than groups controls. The evidence presented herein demonstrates that the presence of E. histolytica trophozoites in cecum induced a local and systemic cellular immune response.

[Gastric cancer and cerebrovascular diseases. A natural history with common elements? Analysis of the salt theory in Chile (1955-1994)]

BACKGROUND

In the last forty years, a sustained reduction in the gastric cancer and cerebrovascular disease mortality has been recorded. Joossens has postulated that sodium intake has an influence in the natural history of both diseases.

AIM

To analyze the mortality caused by both diseases in Chile.

MATERIAL AND METHODS

The mortality of people aged 35 to 64 years old, due to gastric cancer and cerebrovascular diseases in the period 1955-1994, was analyzed. An analysis according to regions, using temporal series and correlation techniques was performed.

RESULTS

In the studied period, the mortality due to gastric cancer decreased by 71.6% in men and by 79.5% in women. Mortality due to cerebrovascular diseases decreased by 56.9% in men and by 63.9% in women. There was a correlation coefficient of +0.91 between the mortality due to both diseases. Cerebrovascular disease mortality appears as a predictor of gastric cancer mortality in temporal series analysis.

CONCLUSIONS

Joossens theories are supported by the present data. Prospective studies should be designed to confirm the hypothesis.

[Respiratory symptoms and cough reflex in populations exposed to different degrees of environmental pollution]

BACKGROUND

Santiago is a city with a high degree of environmental pollution caused by particulate matter and ozone, producing adverse effects in the respiratory system.

AIM

To compare respiratory symptoms and cough reflex in adults from Santiago and from a rural area with low levels of environmental pollution.

SUBJECTS AND METHODS

One hundred twenty six non-smoker adults from Santiago and 116 from a rural area with low levels of pollution answered a respiratory symptom questionnaire. Of these 101 subjects from Santiago and 116 from the rural area inhaled doubling concentrations of capsaicin from 0.5 to 500 microM or until five coughs were elicited. The lowest concentration eliciting 2 or more coughs (CD2) or 5 or more coughs (CD5) was recorded. Levels of environmental particulate matter were also recorded in both locations.

RESULTS

Levels of particulate matter were 102 +/- 41 and 64 +/- 24 micrograms/m3 in Santiago and the rural area respectively. People from Santiago had higher rates of throat clearing, cough and phlegm. CD2 geometric mean and confidence limits in Santiago and the rural area were 6.9 (5.2-7.4) and 2.8 (2.7-2.9) respectively (p < 0.001). No differences in CD5 were observed between both locations. Multivariate analysis disclosed the variable location (city) as the only independent predictor of respiratory symptoms.

CONCLUSIONS

The increased CD2 found in Santiago suggests that the higher rates of respiratory symptoms related to air pollution can be associated to a decreased sensitivity of the cough reflex.

Late motor deficits of Chilean manganese miners: a blinded control study

High-level chronic manganese (Mn) exposure produces dystonic rigidity and proximal tremor. The late effects of asymptomatic exposure are uncertain. To evaluate hand movements of asymptomatic Chilean miners, we utilized a manual tremormeter (EAP) and a digitizing tablet (MOVEMAP). In Andacollo, Chile, we examined 59 individuals aged > 50 years (mean age, 64.4 years). Twenty-seven exposed miners had heavy Mn dust exposure in Mn mines for more than 5 years (mean duration, 20.25 years), ending at least 5 years previously. Thirty-two control miners had never worked in Mn mines or had short-term Mn employment. Tests of resting tremor (EAP Tremormeter, MOVEMAP Steady paradigm), action tremor (MOVEMAP Square paradigm), and repetitive hand movements (EAP Tapping Test and Orthokinesimeter) differentiated performance of exposed miners from that of controls. Chronic asymptomatic Mn exposure results in detectable late-life abnormalities of movement.

[Hip fracture: a case-control study in the metropolitan region I]

BACKGROUND

Hip fracture is a preventable cause of disability among elderly people

AIM

To study factors associated to hip fractures in Chile.

PATIENTS AND METHODS

Patients admitted to seven public hospitals in Chile, with hip fracture not due to major accidents, were considered as cases. To each, at least one age and sex matched hospitalized control, without or neoplastic diseases, was assigned. All patients were subjected to an inquiry, using an instrument devised by the WHO.

RESULTS

Two hundred sixty eight cases and 501 controls were studied. Cases and controls has similar educational and labor histories. The right hip was fractures in 47% of cases and the left in the rest. Compared with controls, cases had a higher body mass index, loss of height during life, rate of hysterectomy, incidence of smoking and a lower consumption of diary products. Cases had higher risk of falls inside their homes and controls outside.

CONCLUSIONS

The obtained information may contribute to the development of preventive measures and reduce the public health impact of hip fracture.

[Frequency of lumbar spine osteopenia in an asymptomatic postmenopausal Chilean population]

The aim of this study was to assess lumbar spine bone density in a group of chilean postmenopausal females and to estimate the frequency of vertebral osteopenia in the national urban female population. A clinical assessment and lumbar spine bone density measurement were performed to 171 healthy women over 40 years of age and not receiving medications that modify bone turnover. Calcium ingestion was recalled in 77 of these. Fifty women (29.2%) had osteopenia, defined as a bone density of less than 0.92 g/cm2. Extrapolating this figure to the national urban population, an osteopenia frequency of 21.7% was estimated. Body mass index was 25.5 +/- 3.8 and 57% of the sample was overweight. Calcium ingestion was 740.3 +/- 331.7. These two parameters did not correlative with bone density. Women with osteopenia were older and had a longer postmenopausal lapse than those with normal bone density. The completion of further clinical an epidemiological studies is recommended to know the real magnitude of osteoporosis in Chile.

Development of a program of behavior modification directed to the rehabilitation of drug-dependent patients: treatment and follow-up of 223 cases

The study reports treatment and follow-up of compulsive drug-consuming patients (mainly of coca paste). The program used was based on a behavioral cognitive and instructional model. The traditional functional analysis was modified to include the therapeutical work in seven behavioral areas: (1) drug use; (2) behavior during free time; (3) behavior at work; (4) social behavior; (5) self- and environmental management behaviors; (6) problem solving and decision-making behaviors; (7) recognition, evaluation, and modification of irrational beliefs. For each area objectives, therapeutical procedures, control and evaluation methods, and termination criteria were determined. Patients engaged in a multiple activity program and received individual and group therapy. Out of 223 male patients, 130 were discharged (that is, they fulfilled all the conditions stated by the program) and 93 patients abandoned treatment. For evaluation purposes a test was used to determine the accomplishment of the behavioral objectives. Follow-up interviews after 6 to 72 months showed that although 24 patients relapsed to drug use, 106 (81.48%) of the patients who had finished the program restrained from using drugs and obtained high scores in all seven behavioral areas.

[Gallbladder cancer mortality in Chile and its relation to cholecystectomy rates. An analysis of the last decade]

Extrahepatic biliary tract cancer (mainly gallbladder cancer) mortality rates have increased from 7.84 x 100.000 to 9.6 x 100.000 in Chile during the last decade. The most significant risk factor for gallbladder cancer is gallstone disease. However, no apparent changes in the prevalence of gallstone disease has occurred during this period. In contrast, cholecystectomy rates have consistently decreased during the decade. The aim of this study was to correlate extrahepatic biliary tract cancer mortality and cholecystectomy rates of previous years during the last decade in our country. The best correlation coefficient between both variables was obtained when mortality was correlated with cholecystectomy rates two years prior to the mortality rate (r = -0.92). This finding is consistent with the hypothesis that changes in the number of cholecystectomies performed in a specific geographic area would reciprocally change gallbladder cancer mortality rate. It was estimated that increasing cholecystectomies by 12,500 per year would decrease at mortality rate from this cancer by approximately 1.0 x 100.000 two years in Chile.