Papers by Antonio Ponce de Leon
International Journal of Behavioral Nutrition and Physical Activity, 2011
Background: Although social support has been observed to exert a beneficial influence on leisure-... more Background: Although social support has been observed to exert a beneficial influence on leisure-time physical activity (LTPA), multidimensional approaches examining social support and prospective evidence of its importance are scarce. The purpose of this study was to investigate how four dimensions of social support affect LTPA engagement, maintenance, type, and time spent by adults during a two-year follow-up. Methods: This paper reports on a longitudinal study of 3,253 non-faculty public employees at a university in Rio de Janeiro (the Pró-Saúde study). LTPA was evaluated using a dichotomous question with a two-week reference period, and further questions concerning LTPA type (individual or group) and time spent on the activity. Social support was measured by the Medical Outcomes Study Social Support Scale (MOS-SSS). To assess the association between social support and LTPA, two different statistical models were used: binary and multinomial logistic regression models for dichotomous and polytomous outcomes, respectively. Models were adjusted separately for those who began LTPA in the middle of the follow up (engagement group) and for those who had maintained LTPA since the beginning of the follow up (maintenance group). Results: After adjusting for confounders, statistically significant associations (p < 0.05) between dimensions of social support and group LTPA were found in the engagement group. Also, the emotional/information dimension was associated with time spent on LTPA (OR = 2.01; 95% CI 1.2-3.9). In the maintenance group, material support was associated with group LTPA (OR = 1.80; 95% CI; 1.1-3.1) and the positive social interaction dimension was associated with time spent on LTPA (OR = 1.65; 95% CI; 1.1-2.7). Conclusions: All dimensions of social support influenced LTPA type or the time spent on the activity. However, our findings suggest that social support is more important in engagement than in maintenance. This finding is important, because it suggests that maintenance of LTPA must be associated with other factors beyond the individual's level of social support, such as a suitable environment and social/health policies directed towards the practice of LTPA.
Implementation Science, 2010
BACKGROUND: The gap between evidence-based guidelines for clinical care and their use in medical ... more BACKGROUND: The gap between evidence-based guidelines for clinical care and their use in medical settings is well recognized and widespread. Only a few implementation studies of psychiatric guidelines have been carried out, and there is a lack of studies on their long-term effects. The aim of this study was to measure compliance to clinical guidelines for treatment of patients with
Neste trabalhoé proposta a extensão do modelo em espaço de estados Poisson-gama, proposto por Har... more Neste trabalhoé proposta a extensão do modelo em espaço de estados Poisson-gama, proposto por Harvey e Fernandes [1], para uma formulação mais geral na qual o preditor linear das covariáveisé substituÃdo por um preditor aditivo de funções suaves destas covariáveis. A famÃlia de funções utilizadaé a das splines cúbicas naturais . Este suavizador tem propriedades matemáticas que são atrativas para a análise estatÃstica de dados e para diagnósticos de adequação do modelo.
Journal of Injury and Violence Research, 2014
Childhood sexual abuse (CSA) is a substantial global health and human rights problem and conseque... more Childhood sexual abuse (CSA) is a substantial global health and human rights problem and consequently a growing concern in sub-Saharan Africa. We examined the association between individual and community-level socioeconomic status (SES) and the likelihood of reporting CSA. We applied multiple multilevel logistic regression analysis on Demographic and Health Survey data for 6,351 female adolescents between the ages of 15 and 18 years from six countries in sub-Saharan Africa, between 2006 and 2008. About 70% of the reported cases of CSA were between 14 and 17 years. Zambia had the highest proportion of reported cases of CSA (5.8%). At the individual and community level, we found that there was no association between CSA and socioeconomic position. This study provides evidence that the likelihood of reporting CSA cut across all individual SES as well as all community socioeconomic strata. We found no evidence of socioeconomic differentials in adolescents&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; experience of CSA, suggesting that adolescents from the six countries studied experienced CSA regardless of their individual- and community-level socioeconomic position. However, we found some evidence of geographical clustering, adolescents in the same community are subject to common contextual influences. Further studies are needed to explore possible effects of countries&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; political, social, economic, legal, and cultural impact on childhood sexual abuse.
BMC Public Health, 2008
Area-based studies of childhood injuries strongly suggest that neighborhood sociodemographic and ... more Area-based studies of childhood injuries strongly suggest that neighborhood sociodemographic and economic circumstances impact on various -though not all -types of injuries. The primary aim of this study was to investigate the stability over time of the association between area characteristics and childhood injuries of various causes.
Revista De Saude Publica, 2008
OBJETIVO: Avaliar a relação entre poluição do ar e efeitos respiratórios agudos em crianças.
Revista de Salud Pública, 2009
Objective Evaluating the association between TB and AIDS and estimating the determinant effects a... more Objective Evaluating the association between TB and AIDS and estimating the determinant effects and factors for TB incidence rates in Brazilian metropolitan regions from 2001 to 2003. Methods A Poisson longitudinal multilevel model was fitted to the annual TB case number by municipality and year, including the population as an offset variable, and AIDS incidence by metropolitan region, percentage low-income households, demographic density and TB cure rate by municipality and Brazilian geographic area as independent variables. Results All variables were found to be significantly associated with tuberculosis (except for cure rate %): low income, demographic density, AIDS and Brazilian area. Interaction between AIDS and low income was significant and modified the effect of AIDS on TB incidence. Empty model and full model variance reduction percentages from first to third levels were 40.2 %, 42.2 % and 77.3 %, respectively. Conclusions AIDS has become an impressive morbidity factor due to tuberculosis; this has not been found in previous studies in Brazil. The interaction between income and AIDS and the metropolitan regions' important contribution towards tuberculosis distribution were heterogeneously manifest amongst large Brazilian areas.
PLoS Neglected Tropical Diseases, 2011
Background: This study aimed to evaluate the risk factors associated with developing leprosy amon... more Background: This study aimed to evaluate the risk factors associated with developing leprosy among the contacts of newlydiagnosed leprosy patients.
Archives of Environmental Health: An International Journal, 1999
There are concerns about the possible short-term effects of outdoor air pollution on health in th... more There are concerns about the possible short-term effects of outdoor air pollution on health in the United Kingdom. In a study conducted during the time period between 1987 and 1992, investigators determined that ozone had small, but significant effects on emergency respiratory admissions. In the current study, the authors investigated associations between emergency admissions and outdoor air pollution for the time period from 1992 to 1994, inclusive, and compared the results with those obtained in the earlier study. The authors also examined particulate matter less than 10 microm in diameter (PM10) and carbon monoxide in the current study. Appropriate confounding factors, such as seasonal patterns, temperature, and humidity, were controlled for, and the authors used Poisson regression to estimate the association between daily emergency admissions for respiratory and cardiovascular diseases and ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, particles measured as Black Smoke, and PM10. Significant positive associations were found between emergency hospital admissions for respiratory disease and PM10 and sulfur dioxide, but such an association did not exist for ozone. The results were not significantly different from earlier results from London and were comparable with those determined in North America and Europe. Cardiovascular disease was associated with carbon monoxide and Black Smoke, but weaker associations existed with the other pollutants studied.
BMJ, 1996
To investigate whether outdoor air pollution levels in London influence daily mortality. Poisson ... more To investigate whether outdoor air pollution levels in London influence daily mortality. Poisson regression analysis of daily counts of deaths, with adjustment for effects of secular trend, seasonal and other cyclical factors, day of the week, holidays, influenza epidemic, temperature, humidity, and autocorrelation, from April 1987 to March 1992. Pollution variables were particles (black smoke), sulphur dioxide, ozone, and nitrogen dioxide, lagged 0-3 days. Greater London. Relative risk of death from all causes (excluding accidents), respiratory disease, and cardiovascular disease. Ozone levels (same day) were associated with a significant increase in all cause, cardiovascular, and respiratory mortality; the effects were greater in the warm seasons (April to September) and were independent of the effects of other pollutants. In the warm season an increase of the eight hour ozone concentration from the 10th to the 90th centile of the seasonal change (7-36 ppb) was associated with an increase of 3.5% (95% confidence interval 1.7 to 5.3), 3.6% (1.04 to 6.1), and 5.4% (0.4 to 10.7) in all cause, cardiovascular, and respiratory mortality respectively. Black smoke concentrations on the previous day were significantly associated with all cause mortality, and this effect was also greater in the warm season and was independent of the effects of other pollutants. For black smoke an increase from the 10th to 90th centile in the warm season (7-19 microg/m3) was associated with an increase of 2.5% (0.9 to 4.1) in all cause mortality. Significant but smaller and less consistent effects were also observed for nitrogen dioxide and sulphur dioxide. Daily variations in air pollution within the range currently occurring in London may have an adverse effect on daily mortality.
European Respiratory Journal, 1999
Many epidemiological studies have shown positive short-term associations between health and curre... more Many epidemiological studies have shown positive short-term associations between health and current levels of outdoor air pollution. The aim of this study was to investigate the association between air pollution and the number of visits to accident and emergency (A&E) departments in London for respiratory complaints. A&E visits include the less severe cases of acute respiratory disease and are unrestricted by bed availability.
Journal of Epidemiology & Community Health, 1996
Study objective -To review the issues and methodologies in epidemiologic time series studies of d... more Study objective -To review the issues and methodologies in epidemiologic time series studies of daily counts of mortality and hospital admissions and imustrate some of the methodologies. Design -This is a review paper with an example drawn from hospital admissions of the elderly in Cleveland, Ohio, USA.
Thorax, 1995
In December 1991 London experienced a unique air pollution episode during which concentrations of... more In December 1991 London experienced a unique air pollution episode during which concentrations of nitrogen dioxide rose to record levels, associated with moderate increases in black smoke. The aim of this study was to investigate whether this episode was associated with adverse health effects and whether any such effects could be attributed to air pollution. The numbers of deaths and hospital admissions occurring in Greater London during the week of the episode were compared with those predicted using data from the week before the episode and from equivalent periods from the previous four years. Relative risks (RR) (episode week versus predicted) for adverse health events were estimated using log linear modelling and these were compared with estimates from control areas which had similar cold weather but without increased air pollution. In all age groups mortality was increased for all causes (excluding accidents) (relative risk = 1.10) and cardiovascular diseases (1.14); non-significant increases were observed for all respiratory diseases (1.22), obstructive lung diseases (1.23), and respiratory infections (1.23). In the elderly (65 + years) the relative risk of hospital admission was increased for all respiratory diseases (1.19) and for obstructive lung diseases (1.43), and a non-significant increase was observed for ischaemic heart disease (1.04). In children (0-14 years) there was no increase in admissions for all respiratory diseases and only a small non-significant increase for asthma. When compared with control areas the relative risks became non-significant but remained increased. The air pollution episode was associated with an increase in mortality and morbidity which was unlikely to be explained by the prevailing weather, a coincidental respiratory epidemic, or psychological factors due to publicity. Air pollution is a plausible explanation but the relative roles of nitrogen dioxide and particulates cannot be distinguished.
Thorax, 1998
A study was undertaken to investigate the relationship between daily hospital admissions for asth... more A study was undertaken to investigate the relationship between daily hospital admissions for asthma and air pollution in London in 1987-92 and the possible confounding and modifying effects of airborne pollen. For all ages together and the age groups 0-14, 15-64 and 65+ years, Poisson regression was used to estimate the relative risk of daily asthma admissions associated with changes in ozone, sulphur dioxide, nitrogen dioxide and particles (black smoke), controlling for time trends, seasonal factors, calendar effects, influenza epidemics, temperature, humidity, and autocorrelation. Independent effects of individual pollutants and interactions with aeroallergens were explored using two pollutant models and models including pollen counts (grass, oak and birch). In all-year analyses ozone was significantly associated with admissions in the 15-64 age group (10 ppb eight hour ozone, 3.93% increase), nitrogen dioxide in the 0-14 and 65+ age groups (10 ppb 24 hour nitrogen dioxide, 1.25% and 2.96%, respectively), sulphur dioxide in the 0-14 age group (10 micrograms/m3 24 hour sulphur dioxide, 1.64%), and black smoke in the 65% age group (10 micrograms/m3 black smoke, 5.60%). Significant seasonal differences were observed for ozone in the 0-14 and 15-64 age groups, and in the 0-14 age group there were negative associations with ozone in the cool season. In general, cumulative lags of up to three days tended to show stronger and more significant effects than single day lags. In two-pollutant models these associations were most robust for ozone and least for nitrogen dioxide. There was no evidence that the associations with air pollutants were due to confounding by any of the pollens, and little evidence of an interaction between pollens and pollution except for synergism of sulphur dioxide and grass pollen in children (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). Ozone, sulphur dioxide, nitrogen dioxide, and particles were all found to have significant associations with daily hospital admissions for asthma, but there was a lack of consistency across the age groups in the specific pollutant. These associations were not explained by confounding by airborne pollens nor was there convincing evidence that the effects of air pollutants and airborne pollens interact in causing hospital admissions for asthma.
Oral Diseases, 2007
To assess the prevalence of persistent oral malodour in a general population in Rio de Janeiro an... more To assess the prevalence of persistent oral malodour in a general population in Rio de Janeiro and to find out whether sex and age are risk factors for this condition. This was a cross-sectional survey in which university students (informants) were interviewed regarding the prevalence of persistent oral malodour in their households. To estimate the effects of sex and age logistic regression models with and without random effects for the informant were applied. The prevalence of persistent oral malodour was 15% (95% confidence interval: 11-19). The risk of persistent malodour was nearly three times higher in men than in women, regardless of age. The risk was slightly more than three times higher in people over 20 years of age compared with those aged 20 years or under, controlling for sex. Oral malodour is common in Rio de Janeiro, more prevalent in men and in those over 20 years of age, in both sexes. CLINICAL RELEVANCE OF THE FINDINGS: Freedom from disabling oral malodour is an outcome indicator of social well-being. Health professionals in general, and dentists in particular, should be trained to appropriately manage and treat people who suffer from persistent oral malodour.
The European Journal of Public Health, 2008
Background: Multiple control areas and time-series analyses have been recommended for effect eval... more Background: Multiple control areas and time-series analyses have been recommended for effect evaluations of community-based health promotion. Large fluctuations, maybe due to chance, among the areas and over the years might obscure the intervention effect. Methods: A quasi-experimental timeseries analysis with several control areas was performed as an effect evaluation of a community-based elderly safety promotion program. The program was implemented during 1995-99 in a community in the Stockholm Metropolitan area (population +65 years: 5500; number of first hip fractures in 1995: 60). Four control areas were selected based on similar hip fracture-related characteristics as the intervention community, complemented with two larger control areas. The time series covered 6 years pre-intervention (1990-95) and 6 years post-intervention (1996)(1997)(1998)(1999)(2000)(2001). The study population was divided into two age groups and gender, resulting in 28 panels. The first hip fracture incidence was obtained from the Swedish national in-patient register. Results: The time series revealed no discernible pattern, and conventional analyses showed no conclusive results. A multivariate analysis, examining the time trends by employing the intra-annual and intra-panel variance, revealed the underlying trends in hip fracture rates. Comparisons between predicted numbers of hip fractures in the intervention and control areas was enabled, which resulted in 14 less hip fractures in the intervention community than expected from the control communities. If one extreme value was altered, the result changed considerably. Conclusion: Effect evaluations of community-based health promotion programs using time-series from small communities might give faulty results, if statistical modelling is not employed.
This paper deals with the application of optimal design theory in a typical experiment in economi... more This paper deals with the application of optimal design theory in a typical experiment in economics. It describes general principles for conducting efficient experiments for model discrimination and illustrates the benefits of the techniques by an empirical comparison. Copyright 1996 by Royal Economic Society.
Journal of Epidemiology & Community Health, 1996
To investigate whether air pollution levels in London have short term effects on hospital admissi... more To investigate whether air pollution levels in London have short term effects on hospital admissions for respiratory disease. Poisson regression analysis of daily counts of hospital admissions, adjusting for effects of trend, seasonal and other cyclical factors, day of the week, holidays, influenza epidemic, temperature, humidity, and autocorrelation. Pollution variables were particulates (black smoke: BS), sulphur dioxide (SO2), ozone (O3), and nitrogen dioxide (NO2), lagged 0-3 days. All immediate admissions for respiratory disease (ICD 460-519) to hospitals in London health districts in the five years April 1987 to February 1992 for all ages and the 0-14, 15-64, and 65+ age groups. O3 (lagged one day) was significantly associated with an increase in daily admissions among all age groups, except the 0-14 group, and this effect was stronger in the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;warm&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; season (April-September). In this season, the relative risks of admission associated with an increase in 8 hour O3 levels of 29 ppb (10th to 90th centile) were 1.0483 (95% CI 1.0246, 1.0726), 1.0294 (0.9930,1.0672), 1.0751 (1.0354,1.1163), and 1.0616 (1.0243,1.1003) for all ages and age groups 0-14, 15-64, and 65+ respectively. Very few significant associations were observed with the other pollutants, though these tended to be positive. Controlling for other pollutants made little difference to the O3 coefficients. There was evidence of a threshold at about 40-60 ppb O3 (maximum hourly or maximum 8 hour). O3 levels in London have a small but significant effect on hospital admissions for respiratory disease at all ages. The possible role of aerollergen as a confounding factor needs to be examined. Unlike other cities where similar effects have been reported, little or no effect of particulates was observed in London.
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Papers by Antonio Ponce de Leon