Guilherme Loureiro Werneck

An Empirical Comparison of Respondent-driven Sampling, Time Location Sampling, and Snowball Sampling for Behavioral Surveillance in Men Who Have Sex with Men, Fortaleza, Brazil

Obtaining samples of populations at risk for HIV challenges surveillance, prevention planning, and evaluation. Methods used include snowball sampling, time location sampling (TLS), and respondent-driven sampling (RDS). Few studies have made side-by-side comparisons to assess their relative advantages. We compared snowball, TLS, and RDS surveys of men who have sex with men (MSM) in Forteleza, Brazil, with a focus on the socio-economic status (SES) and risk behaviors of the samples to each other, to known AIDS cases and to the general population. RDS produced a sample with wider inclusion of lower SES than snowball sampling or TLS—a finding of health significance given the majority of AIDS cases reported among MSM in the state were low SES. RDS also achieved the sample size faster and at lower cost. For reasons of inclusion and cost-efficiency, RDS is the sampling methodology of choice for HIV surveillance of MSM in Fortaleza.

Validade de constructo de escala de apoio social do Medical Outcomes Study adaptada para o português no Estudo Pró-Saúde

This paper evaluates the construct validity of the Medical Outcomes Studys social support scale adapted to Portuguese, when utilized in a cohort study among non-faculty civil servants at a university in Rio de Janeiro, Brazil (Pró-Saúde Study). Baseline data were obtained in 1999, when 4,030 participants (92.0% of those eligible) completed a multidimensional self-administered questionnaire at the workplace. From the original scales five social support dimensions, factor analysis of the data extracted only three dimensions: positive social interaction/affective support; emotional/information support; and material support. We estimated associations between social support dimensions and socio-demographic, health, and well being-related characteristics. We confirmed the hypotheses that less isolated individuals, those with better self-rated health, those who reported more participation in group activities, and those with no evidence of common mental disorders reported better perception of social support. In conclusion, we found good evidence for a high construct validity of this scale, supporting its use in future analyses in the Pró-Saúde Study and in similar population groups.

Gender and leisure-time physical activity.

This article discusses the relationship between gender and the social construction of the body, specifically focusing on physical exercise during leisure time. The Pró-Saúde Project is a prospective study consisting of 4,030 employees of a university in Rio de Janeiro, in which we analyzed the answers on leisure-time physical activity (LTPA) by 3,740 participants. The results show a prevalence of males in LTPA. Age, schooling, and per capita family income were directly associated with exercise among women, as compared to per capita family among men. Men were more frequently involved in group sports and physical activities that required more strength than women, including football, tennis, volleyball, martial arts, jogging, and weight lifting. Women performed more individual physical activities and those demanding less strength, like walking, dance, gymnastics, and hydrogym. The results suggest that LTPA is a domain of daily life that is organized according to certain conventions, amongst which gender-related conceptions concerning the ideal body, where men and women display distinct behaviors in relation to physical exercise.

Multilevel modelling of the incidence of visceral leishmaniasis in Teresina, Brazil

Epidemics of visceral leishmaniasis (VL) in major Brazilian cities are new phenomena since 1980. As determinants of transmission in urban settings probably operate at different geographic scales, and information is not available for each scale, a multilevel approach was used to examine the effect of canine infection and environmental and socio-economic factors on the spatial variability of incidence rates of VL in the city of Teresina. Details on an outbreak of greater than 1200 cases of VL in Teresina during 1993-1996 were available at two hierarchical levels: census tracts (socio-economic characteristics, incidence rates of human VL) and districts, which encompass census tracts (prevalence of canine infection). Remotely sensed data obtained by satellite generated environmental information at both levels. Data from census tracts and districts were analysed simultaneously by multilevel modelling. Poor socio-economic conditions and increased vegetation were associated with a high incidence of human VL. Increasing prevalence of canine infection also predicted a high incidence of human VL, as did high prevalence of canine infection before and during the epidemic. Poor socio-economic conditions had an amplifying effect on the association between canine infection and the incidence of human VL. Focusing interventions on areas with characteristics identified by multilevel analysis could be a cost-effective strategy for controlling VL. Because risk factors for infectious diseases operate simultaneously at several levels and ecological data usually are available at different geographical scales, multilevel modelling is a valuable tool for epidemiological investigation of disease transmission.

The relationship between smoking and age at the menopause: A systematic review

CONTEXT AND OBJECTIVE Increasing life expectancy has made it ever more important to study the factors that influence the age at the menopause, given that when it is reached outside of the normal range, it is associated with increased risk of osteoporosis and cardiovascular diseases, among other conditions. Among the factors studied in relation to early menopause, smoking is prominent. Destruction of the ovarian follicles is one of the mechanisms postulated for this effect. The aim of this study was to review and describe the associations between age at the menopause and the habit of smoking, its duration and its intensity. METHOD A systematic review of the literature indexed in the MEDLINE and LILACS databases was conducted, without restriction on publication date. After initially identifying 1325 articles and preselecting 161 articles for consideration of their complete texts, 96 articles reporting on the results from 109 studies were selected for analysis. RESULTS A great majority of the studies reported an association between the habit of smoking and early menopause, but there was no clear evidence that the duration of smoking and quantity of cigarettes smoked had any association with age at the natural menopause. CONCLUSION Additional studies are needed, preferably of prospective nature and with a large number of women, in order to deepen the knowledge of the effects of various aspects of smoking on age at the menopause. Experimental studies on animals may also contribute towards clarifying the physiopathological mechanisms through which smoking influences age at the menopause.

Prognostic Factors for Death from Visceral Leishmaniasis in Teresina, Brazil

Abstract.Background: A possible strategy to reduce fatality rates of visceral leishmaniasis is to identify prognostic factors that can be easily assessed and used as an aid to clinical decision-making. Patients and Methods: A case-control study was developed in Teresina, Brazil, in which cases were patients who died during treatment (n = 12) and controls (n = 78) comprised a random sample of patients who were alive when treatment was finished. Results: Variables significantly associated with death were severe anemia, fever for more than 60 days, diarrhea and jaundice. The prognostic system had a sensitivity of 85.7% and a specificity of 92.5%. Conclusion: The prognostic model developed in this study had satisfactory performance and might be useful in developing countries, since it is simple and inexpensive. However, it is still preliminary and needs to be improved and validated using larger and more recent samples.

The association between socio-demographic factors and leisure-time physical activity in the Pró-Saúde Study

This study evaluated the relationship between socio-demographic variables and leisure-time physical activity (LTPA). A baseline survey questionnaire was completed by 4,030 employees. LPTA was assessed as engagement in physical activities during the previous two weeks. The metabolic cost of LTPA was calculated based on frequency and amount of time participating in physical activities, assigning weekly metabolic equivalents (METs) to each activity. Odds ratios (OR) to express the relationship between socio-demographic factors and LTPA were estimated from multinomial regression models. The questions used to evaluate LTPA presented moderate reproducibility, with kappa correlation coefficients ranging from 0.45 to 0.88. Prevalence of LTPA was higher among men (52.2% men; 40.8% women). For both men and women, higher educational level and higher income were both associated with engaging in LPTA, this relationship being stronger for the highest tercile of METs as compared to physical inactivity. Men were more engaged in LTPA, and there was a strong association between LTPA and socio-demographic variables for both genders.

The urban spread of visceral leishmaniasis: clues from spatial analysis.

Background. The pattern of spread of visceral leishmaniasis in Brazilian cities is poorly understood. Methods. We used geographic information systems and spatial statistics to evaluate the distribution of 1061 cases of visceral leishmaniasis in Teresina, Brazil, in 1993 through 1996. Results. A locally weighted (LOESS) regression model, which was fit as a smoothed function of spatial coordinates, demonstrated large-scale variation, with high incidence rates in peripheral neighborhoods that bordered forest land and pastures. Moran’s I indicated small-scale variation and clustering up to 300 m, roughly the flight range of the sand fly vector. Conclusions. Spatial analytical techniques can identify high-risk areas for targeting control interventions.

Associação entre fatores contextuais e auto-avaliação de saúde: uma revisão sistemática de estudos multinível

The influence of residential characteristics on self-rated health has received little research attention, especially in Brazil. This study summarizes the available evidence on the association between contextual factors and self-rated health, using a systematic review of articles published from January 1995 to August 2005. We searched for the terms neighbourhood or neighborhood, ecological, contextual, environment, and community, combined with self-rated health, self-reported health, and multilevel or hierarchical in digital bases. Most of the 18 reviewed studies analyzed socioeconomic indicators, while some investigated psychosocial variables and a few included physical environmental indicators. Spatial units of reference varied from census tracts to States. Differences among scales of contextual analysis and several indicators, with different categories, were identified. The associations corroborate the hypothesis that neighborhood context influences self-rated health, beyond the effect of individual factors. Physical and psychosocial neighborhood characteristics are important contextual factors in the determination of self-rated health. Worse socioeconomic neighborhood conditions have a negative effect on health, thereby increasing the odds of worse self-rated health.

Geographic spread of visceral leishmaniasis in Brazil

Cad. Saúde Pública, Rio de Janeiro, 26(4):644-645, abr, 2010 Visceral leishmaniasis (VL) affects 65 countries, with an estimated incidence of 500 thousand new cases and 59 thousand deaths per year. In Brazil, the disease is caused by the protozoan Leishmania infantum chagasi, transmitted by sandflies from genus Lutzomyia, with dogs as the principal source of infection in urban areas. VL is a serious disease with few treatment options, and even with adequate treatment the case fatality rate is some 5%. Historically, VL has been considered a rural endemic, but since the 1980s the disease has undergone gradual urbanization. The first major urban epidemic in the country was in Teresina, Piaui State. Epidemics occurred later in Natal (Rio Grande do Norte) and São Luís (Maranhão), and the disease subsequently spread to other regions of the country. Autochthonous cases were recently described for the first time in the southernmost State of Rio Grande do Sul. The epidemiological panorama leaves no doubt as to the severity of the situation and the unchecked geographic spread of VL. From 1980 to 2008, more than 70 thousand cases of VL were reported in Brazil, with 3,800 deaths. The mean number of cases reported per year increased from 1,601 (1985-1989) to 3,630 (2000-2004), leveling off since then. In the 1990s, only 10% of cases occurred outside the Northeast Region, but in 2007 the proportion reached 50% of cases. From 2006 to 2008, autochthonous transmission of VL was reported in more than 1,200 municipalities (counties) in 21 States. VL is a neglected disease that affects neglected populations. Poverty, migration, unplanned urban settlement, environmental destruction, precarious sanitation and housing, and malnutrition are some of its numerous determinants. The World Health Organization recognizes the lack of sufficient means for its elimination, despite initiatives on the Indian subcontinent, where the disease is transmitted from person to person by vector bites. In this case, treatment of cases may help decrease transmission. However, in Brazil, where the disease is zoonotic, treatment of human cases plays an essentially curative role. The National Program for the Control of Visceral Leishmaniasis bases its strategy on the detection and treatment of human cases, control of domestic reservoirs, and vector control. Still, after years of investment, these measures have proven insufficient to prevent spread of the disease. The introduction of VL in Brazilian cities represents a different epidemiological reality from the historical situation and requires new strategies by VL surveillance and control systems. Visceral leishmaniasis raises many challenges, but the emphasis should be on scientific and technological development and health innovation. More research is needed for the development of new drugs, treatment regimens, and clinical management protocols. Studies on the effectiveness of control measures should be backed by solid methodologies; it is necessary to invest in integrated tactics for structured intervention according to the different transmission scenarios, preferably targeting the areas at highest risk. The production and validation of new diagnostic tests should be highlighted. Studies for effective vaccines to protect individuals and decrease transmission should be prioritized. Research should also be encouraged to solve operational barriers to the implementation of preventive measures. There is still a huge lack of knowledge on VL. However, besides scientific production itself, a broad social commitment is needed to prevent VL from taking a definitive foothold as one more serious health problem in Brazil’s daily urban reality. Geographic spread of visceral leishmaniasis in Brazil EDITORIAL