Trends in lung cancer incidence in Spain (1990-2019): insights from Global Burden of Diseases data.

BACKGROUND: This study examines lung cancer incidence in Spain (1990-2019) through age-period-cohort (A-P-C) analysis and Global Burden of Diseases (GBD) data, unravelling the complex interplay of age, period, and birth cohort in shaping these trends. METHODS: Utilizing GBD and Spanish population data, the study calculates age-standardized incidence rates (ASIRs) and employs Joinpoint analysis to identify significant trends. A-P-C analysis dissects the individual effects of age, calendar period, and birth cohort on incidence patterns. RESULTS: Between 1990 and 2019, almost 738,000 cases of lung cancer were diagnosed in Spain, with an average annual increase of 1.7%. The ASIR of lung cancer in Spain from 1990 to 2019 showed a sustained upward trend in women (Average Annual Per cent Change: 2.5%, P < 0.05), reaching 23.3 cases per 100,000 in 2019, whilst men experienced a significant decrease in incidence rates (AAPC: -0.6%, P < 0.05), falling to 108.9 in 2019. The male-to-female incidence ratio decreased from 12.2 in 1992 to 4.9 in 2019. Joinpoint analysis identified distinct periods for both sexes, with men showing stability, decline and then a significant decrease, whereas women showed an initial increase followed by a decrease. The longitudinal age curves showed a consistently higher incidence risk in men, peaking in the 80-84 age group. Male cohorts since the 1920s showed a decreasing relative risk, whereas women showed fluctuations in risk over time. CONCLUSION: Lung cancer rates are falling in Spain, especially amongst men, due to lower smoking rates. The gender gap is closing, but prevention targeted at women is needed. Tighter tobacco control and research into other risk factors are essential. Understanding the long-term effects of smoking and early exposure is key to better prevention and treatment in Spain.

Epidemiological trends and age-period-cohort effects on cardiovascular diseases burden attributable to ambient air pollution across BRICS.

Long-term exposure to ambient air pollution raises the risk of deaths and morbidity worldwide. From 1990 to 2019, we observed the epidemiological trends and age-period-cohort effects on the cardiovascular diseases (CVD) burden attributable to ambient air pollution across Brazil, Russia, India, China, and South Africa (BRICS). The number of CVD deaths related to ambient particulate matter (PM) pollution increased nearly fivefold in China [5.0% (95% CI 4.7, 5.2)] and India [5.7% (95% CI 5.1, 6.3)] during the study period. The age-standardized CVD deaths and disability-adjusted life years (DALYs) due to ambient PM pollution significantly increased in India and China but decreased in Brazil and Russia. Due to air pollution, the relative risk (RR) of premature CVD mortality (< 70 years) was higher in Russia [RR 12.6 (95% CI 8.7, 17.30)] and India [RR 9.2 (95% CI 7.6, 11.20)]. A higher period risk (2015-2019) for CVD deaths was found in India [RR 1.4 (95% CI 1.4, 1.4)] followed by South Africa [RR 1.3 (95% CI 1.3, 1.3)]. Across the BRICS countries, the RR of CVD mortality markedly decreased from the old birth cohort to young birth cohorts. In conclusion, China and India showed an increasing trend of CVD mortality and morbidity due to ambient PM pollution and higher risk of premature CVD deaths were observed in Russia and India.

Age-period-cohort effects on incidence trends of childhood leukemia from four population-based cancer registries in Colombia.

BACKGROUND: Childhood leukemia (CL) is the most prevalent form of pediatric cancer on a global scale. However, there is a limited understanding of the dynamics of CL incidence in South America, with a specific knowledge gap in Colombia. This study aimed to identify trends in CL incidence and to analyze the effects of age, period, and birth cohort on the risk of leukemia incidence in this population. METHODS: Information on all newly diagnosed leukemia cases (in general and by subtype) among residents aged 0-18 years and living in the serving areas of population-based cancer registries of Cali (2008-2017), Bucaramanga (2000-2017), Manizales (2003-2017), and Pasto (1998-2018). Estimated annual percent changes (EAPC) in incidence over time and potential changes in the slope of these EAPCs were calculated using joinpoint regression models. The effects of age, period, and cohort in CL incidence trends were evaluated using age-period-cohort models addressing the identifiability issue through the application of double differences. RESULTS: A total of 966 childhood leukemia cases were identified. The average standardized incidence rate (ASIR) of leukemia was calculated and expressed per 100,000 person-years - observing ASIR of 4.46 in Cali, 7.27 in Bucaramanga, 3.89 in Manizales and 4.06 in Pasto. Concerning CL trends there were no statistically significant changes in EAPC throughout the different periods, however, when analyzed by leukemia subtype, statistically significant changes were observed in the EAPC for both ALL and AML. Analysis of age-period-cohort models revealed that age-related factors significantly underpin the incidence trends of childhood leukemia in these four Colombian cities. CONCLUSIONS: This study offers valuable insights into the incidence trends of childhood leukemia in four major Colombian cities. The analysis revealed stable overall CL incidence rates across varying periods, predominantly influenced by age-related factors and the absence of cohort and period effects. This information is useful for surveillance and planning purposes for CL diagnosis and treatment in Colombia.

Myelodysplastic syndromes mortality in Spain: a comprehensive age-period-cohort and joinpoint analysis.

OBJECTIVE: The present study aims to assess the mortality trends in myelodysplastic syndromes (MDS) in Spain from 1980 to 2021. METHODS: Deaths and mid-year population data were collected from the National Institute of Statistics. We estimated age-standardised mortality rates (ASMRs) per 100,000 person-years for all ages and ages 35-64. Joinpoint regression identified significant changes in mortality trends. The independent effects of age, period and birth cohort on MDS mortality were also examined. RESULTS: MDS-related deaths gradually increased from 36 in 1980 to 1118 in 2021, with an overall increase of 6.6% in age-standardised mortality rates (ASMRs) for both men and women. Joinpoint analysis identified four periods for both men and women: 1980-1987 (stable rates), 1987-1990 (sharp increase), 1990-1999 (slower increase) and 1999-2021 (stable rates). ASMRs (35-64 years) increased by 2.5% over the study period, with a turning point identified in 1996 when rates decreased. Mortality from MDS increases with age and is higher in men. The cohort's relative risk increased until the mid-1950s and then stabilised, whilst the period relative risk increased between 1982 and 1996 and then stabilised. CONCLUSION: The results of this study indicate a progressive increase in MDS-related deaths in Spain between 1980 and 2021. Notably, this increase was more pronounced in men than in women. Analysis of birth cohort trends revealed shifts in MDS risk, characterised by an increase until the mid-twentieth century, followed by a stabilisation. Using joinpoint analysis, four distinct periods were identified, shedding light on the changing patterns of mortality over time. These findings help to shape future research directions and inform public health strategies. They also provide optimism for advances in MDS treatment and potential reductions in mortality.

Does a Reduction in Receiving Assistance With Daily Activities Among Older Adults in Mexico Indicate An Increase in Unmet Needs or a Decrease in Needs for Care?

OBJECTIVES: The percentage of older adults in Mexico with difficulty completing activities of daily living (ADL) who receive assistance from family appears to be decreasing. We compared 2 birth cohorts of older adults in Mexico to investigate whether this trend reflects an increase in unmet caregiving needs or a decrease in the need for care. METHODS: We selected Mexican Health and Aging Study participants aged 60-76 in 2001 (n = 4,805) and 2018 (n = 6,494). ADL tasks were dressing, walking, bathing, getting in and out of bed, and toileting. Participants who reported difficulty with an ADL were asked if anyone helped them with the task. Logistic regression was used to estimate adjusted odds ratios (aOR) for cohort differences in ≥1 ADL limitations and help with ≥1 ADL. We used a decomposition analysis to identify participant characteristics that mediated cohort differences in receiving help with ≥1 ADL. RESULTS: The 2018 cohort had higher odds for ≥1 ADL limitations (aOR = 1.85, 95% CI = 1.60-2.14) but lower odds for help with ≥1 ADL (aOR = 0.66, 95% CI = 0.49-0.89). Among participants with ADL disability, the 2018 cohort had fewer living children and a lower prevalence of probable dementia. The lower number of living children and lower prevalence of probable dementia explained 9.34% and 43.7% of the cohort effect on receiving help with ≥1 ADL, respectively. DISCUSSION: The declining percentage of older adults in Mexico with ADL disability receiving assistance may not reflect increasing unmet needs. However, the increased prevalence of ADL disability will increase the number of older adults needing informal care.

Analysis of age, period, and birth cohort effects on suicide mortality in Brazil and the five major geographic regions.

OBJECTIVE: Estimate the effects of age, period, and birth cohort on suicide mortality in Brazil by major geographic region in the overall population and by sex. METHODS: This was a time trend ecological study. National and regional suicide mortality data from 1981 to 2020 were analyzed for the overall population and by sex. Age, period, and cohort effects were calculated with a Poisson regression model using estimable functions with the Epi package of the R statistical program, version 4.2.1. RESULTS: There were 272,716 suicides in individuals ranging from 20 to 79 years old. In the overall population, the age model-adjusted suicide mortality rates showed an upward pattern for Brazil. The most recent cohort showed the highest associated risk, 1.67 (95%CI 1.63; 1.71), while for the reference period, it was the highest risk among all the periods. CONCLUSIONS: Suicide mortality rates have shown an upward trend with advancing age in both men and women in the Brazilian population. However, the behavior of the period effect and cohort depends on the population analyzed and regional distribution.

Inequalities in Temporal Effects on Cervical Cancer Mortality in States in Different Geographic Regions of Brazil: An Ecological Study.

Cervical cancer is a public health issue with high disease burden and mortality in Brazil. The objectives of the present study were, firstly, to analyze age, period, and cohort effects on cervical cancer mortality in women 20 years old or older from 1980 to 2019 in the North, South, and Southeast Regions of Brazil; and secondly, to evaluate whether the implementation of a national screening program and the expansion of access to public health services impacted the examined period and reduced the risk of death compared with previous years and among younger cohorts. The effects were estimated by applying Poisson regression models with estimable functions. The highest mortality rate per 100,000 women was found in Amazonas (24.13), and the lowest in São Paulo (10.56). A positive gradient was obtained for death rates as women's age increased. The states in the most developed regions (South and Southeast) showed a reduction in the risk of death in the period that followed the implementation of the screening program and in the cohort from the 1960s onwards. The North Region showed a decreased risk of death only in Amapá (2000-2004) and Tocantins (1995-2004; 2010-2019). The findings indicate that health inequities remain in Brazil and suggest that the health system has limitations in terms of decreasing mortality associated with this type of cancer in regions of lower socioeconomic development.

Social Engagement and Cognitive Function of Older Adults in Mexico and the United States: How Universal Is the Interdependence in Couples?

OBJECTIVES: Increased social engagement in older adults has been linked to positive cognitive outcomes; however, it is unclear if the social engagement of husbands and wives influences their own cognition as well as each other's cognition. Moreover, it is unknown if any such patterns persist in different country contexts. METHODS: Data from the 2001 Mexican Health and Aging Study (MHAS) and the 2000 Health and Retirement Study (HRS) were combined, and comparable samples of married couples without cognitive impairment at baseline were drawn. Follow-up cognition data was obtained from the 2012 MHAS and the 2012 HRS. Structural equation models (SEM) were used to test the actor-partner interdependence model with moderating effect of country on the association of social engagement with cognition. RESULTS: Significant actor effects were observed for wives in both countries. Actor effects for husbands were observed in the United States only. In Mexico, a significant partner effect was observed where wives' social engagement benefited their own cognition as well as their husbands', but not vice versa. Partner effects were not observed in the United States. No moderation effects of country were observed. DISCUSSION: Our results suggest asymmetric patterns of actor-partner interdependence in Mexico, which may be reflective of the more traditional social role of women, and codependence within the couple. On the other hand, our results for the United States, where each spouse had significant actor effects but no partner effects, may suggest more independence within the couple.

Impact of a pollution breach at a coke oven factory on asthma control in nearby vulnerable adults.

BACKGROUND: Previous studies have related sulfur dioxide (SO2) exposure to asthma exacerbations. We utilized the University of Pittsburgh Asthma Institute registry to study associations of asthma exacerbations between 2 geographically distinct populations of adults with asthma. OBJECTIVE: Our objective was to examine whether asthma symptoms worsened following a significant fire event that destroyed pollution control equipment at the largest coke works in the United States. METHODS: Two groups of patients with asthma, namely, those residing within 10 miles of the coke works fire (the proximal group [n = 39]) and those residing beyond that range (the control group [n = 44]), were geocoded by residential address. Concentrations of ambient air SO2 were generated by using local University of Pittsburgh Asthma Institute registry air monitoring data. Factory emissions were also evaluated. Data from a patient historical acute exposure survey and in-person follow-up data were evaluated. Inferential statistics were used to compare the groups. RESULTS: In the immediate postfire period (6-8 weeks), the level of emissions of SO2 from the factory emissions increased to 25 times more than the typical level. Following the pollution control breach, the proximal cohort self-reported an increase in medication use (risk ratio = 1.76; 95% CI = 1.1-2.8; P < .01) and more exacerbations. In a small subset of the follow-up cohort of those who completed the acute exposure survey only, asthma control metrics improved. CONCLUSIONS: Real-world exposure to a marked increase in ambient levels of SO2 from a pollution control breach was associated with worsened asthma control in patients proximal to the event, with the worsened control improving following repair of the controls. Improved spatial resolution of air pollutant measurements would enable better examination of exposures and subsequent health impacts.

Association between the handgrip strength and the isokinetic muscle function of the elbow and the knee in asymptomatic adults.

BACKGROUND: The handgrip strength is a practical, valid, reliable, low-cost tool that presents strong correlations with several health conditions. However, handgrip strength may be inaccurate to prospectively predict the variability of muscular function since the decrease in muscular strength over the years varies according to a muscular group or between upper and lower limbs. Our hypothesis is that the handgrip strength cannot explain the variance of muscle function prospectively. PURPOSE: The aim of this study was to evaluate the cross-sectional and prospective association between handgrip strength and isokinetic muscle function of the knee and elbow in 780 asymptomatic adults. METHODS: In a sample of 780 adults, we obtained handgrip strength and elbow and knee muscle function (for both flexion and extension at 60°/s and 300°/s) using, respectively, a hydraulic dynamometer and an isokinetic dynamometer. In a cross-sectional analysis, we analyzed the data obtained from baseline assessment. Then, we calculated the absolute change as a result of the variation data between the baseline and the 1-year follow-up assessment of each participant. The correlations were analyzed using Pearson or Spearman coefficients. We used multivariate models to investigate the association between handgrip strength and isokinetic muscle function. RESULTS AND DISCUSSION: The cross-sectional correlations were significantly moderate-to-strong (r = 0.41-0.71, p < 0.01), but became weak-to-moderate (r = 0.26-0.34, p < 0.01) prospectively. In the cross-sectional analysis, the handgrip strength was selected as a strong predictor for isokinetic variables (∆R 2 = 0.171-0.583, p < 0.05) as expected. Although handgrip strength was also selected as a significant predictor in prospective analysis, it explained only a little variance in isokinetic muscle function of the knee (∆R 2 = 0.7-0.117, p < 0.05). Regarding the predictive models for the elbow, handgrip strength was not selected prospectively. CONCLUSION: The 1-year absolute change of the handgrip strength cannot explain the variance of the isokinetic muscle function. Thus, specific measures are required for assessing muscle function in epidemiological studies.

The changing landscape of religious affiliation in Brazil between 1980 and 2010: age, period, and cohort perspectives / /Um estudo sobre a filiação religiosa no Brasil entre 1980 e 2010: efeitos de idade, período e coorte / /El cambio de panorama de las afiliaciones religiosas en Brasil entre 1980 y 2010: perspectivas de edad, período y cohorte

There has been a remarkable decline in the number of Catholics in Brazil over the last few decades, a fact that is attributed to the growth of Pentecostal churches and to an increase in the number of people with no religious affiliation. We analyzed the age, period, and cohort effects associated with religious affiliation in Brazil from 1980 to 2010, applying the Hierarchical Age-Period-Cohort and Cross-Classified Random Effects Model. We observed that age effects were significant but low for Catholics and Pentecostals, and were substantial for those with no religious affiliation, with a negative relationship. For these first two religious affiliations, period effects were of greater magnitude with clear trends: negative for Catholics and positive for Pentecostals. Cohort effects were significant for all three affiliations, but magnitudes were lower than the other two effects. We also verified that the likelihood of being a Pentecostal decreased with formal education, and the opposite occurred for persons with no religious affiliation. These effects, however, were smaller for younger cohorts, possibly due to the reduced social selectivity of recent students pursuing higher education and the increase in overall levels of education...

Houve uma marcante redução no número relativo de católicos no Brasil nas últimas décadas, fato que é associado, principalmente, ao crescimento das igrejas pentecostais e neopentecostais, bem como ao aumento no número de pessoas sem filiação religiosa. Foram analisados os efeitos de idade, período e coorte associados à filiação religiosa no Brasil entre 1980 e 2010, com o uso do modelo idade-período-coorte hierárquico e modelos de efeitos randômicos com classificação-cruzada. Observaram-se efeitos de idade significativos, mas de pequena magnitude para católicos e pentecostais, e efeitos substanciais para aqueles sem filiação religiosa, sendo essa com uma relação negativa. Para as duas primeiras afiliações, os efeitos de período eram de maior magnitude e com tendências claras: negativa para católicos e positiva para pentecostais. Os efeitos de coorte foram significativos para as três afiliações, mas as magnitudes foram menores do que para dos dois outros efeitos. Também verificou-se que a propensão em ser pentecostal diminui com o nível de educação, sendo que o contrário ocorre para pessoas sem religião. Entretanto, esses efeitos são menos marcantes para coortes mais jovens, possivelmente por causa da natureza menos seletiva da educação superior atualmente no Brasil e do aumento generalizado dos níveis de educação...

Ha ocurrido una notable reducción en el número de católicos en Brasil en las últimas décadas, un hecho que se atribuye al crecimiento de las iglesias pentecostales y un aumento del número de personas sin afiliación religiosa. Analizamos los efectos de edad, período y cohortes asociadas a las afiliaciones religiosas en Brasil desde 1980 hasta 2010, aplicando modelos Jerárquico de Edad-Período-Cohorte y de Efecto Aleatorio de Clasificación Cruzada. Observamos que los efectos de edad fueron significativos pero de baja magnitud para católicos y pentecostales, mientras fueron sustanciales para aquellos sin afiliación religiosa, con una relación negativa. Para las dos primeras afiliaciones religiosas, los efectos de período fueron de mayor magnitud y presentaron tendencias claras: negativas para los católicos y positivas para los pentecostales. Los efectos de cohorte fueron significativos para todas las tres afiliaciones, pero las magnitudes fueron menores que los otros dos efectos. También verificamos que la propensión a ser pentecostal se reduce con la educación formal, y lo opuesto ocurrió con las personas sin afiliación religiosa. Sin embargo, tales efectos fueron menores para cohortes más jóvenes, posiblemente debido a la reducción de la selectividad social de estudiantes recientes en búsqueda de una educación más alta y al aumento general en todos los niveles de educación...

Breast cancer mortality in mexico: an age-period-cohort analysis / Mortalidad por cáncer de mama en méxico: un análisis de edad-periodo-cohorte

OBJECTIVE: To assess the age, period and cohort effects on breast cancer (BC) mortality in Mexico. MATERIAL AND METHODS: Age, period and cohort curvature trends for BC mortality were estimated through the Poisson Regression model proposed by Holford. RESULTS: Nationally, BC death rates have leveled off since 1995 in most age groups. BC mortality trends are mainly determined by birth cohort and age effects in Mexico. Women born between 1940 and 1955 show the highest rate of increase in BC mortality. Women born afterwards still show an increasing trend but at a much lower rate. Mammography and adjuvant therapy have had a limited impact on mortality. Potential reasons for observed patterns are discussed. An increase in BC mortality in Mexico is expected in the following decades. CONCLUSIONS: Mammography screening programs and timely access to effective treatment should be a national priority to reverse the expected increasing BC mortality trend.

OBJETIVO: Evaluar efectos de edad-periodo-cohorte en la mortalidad por cáncer de mama (CaMa) en México. MATERIAL Y MÉTODOS: Las tendencias de los efectos de edad-periodo-cohorte fueron estimados mediante un modelo de regresión de Poisson propuesto por Holford. RESULTADOS: Las tasas de mortalidad por CaMa se han estabilizado en la mayoría de los grupos de edad desde 1995 y están determinadas principalmente por efectos de cohorte y edad. Las mujeres nacidas entre 1940 y 1955 muestran los mayores aumentos en la mortalidad en comparación con las nacidas después de este período. La mamografía y la terapia adyuvante han tenido un impacto limitado sobre la mortalidad. Se discuten posibles explicaciones de las tendencias observadas. En las siguientes décadas se espera continúe aumentando la mortalidad por CaMa. CONCLUSIONES: El acceso a mamografía y a tratamiento oportuno y efectivo debieran ser una prioridad para revertir la tendencia creciente esperada de la mortalidad por CM.

Como avaliar criticamente estudos de coorte em terapia intensiva? / How to critically assess intensive care cohort studies?

JUSTIFICATIVA E OBJETIVOS: Estudos de coorte são úteis na identificação de fatores de risco e prognósticos, no acompanhamento da história natural de certas doenças e no estudo do impacto de intervenções diagnósticas e terapêuticas. O objetivo deste estudo foi subsidiar o leitor na avaliação crítica de artigos que lançaram mão deste tipo de delineamento de pesquisa. CONTEÚDO: Na avaliação dos estudos de coorte, é crítico observar a existência de vieses de seleção e informação, a continuidade do seguimento dos sujeitos de pesquisa, o controle dos fatores de confusão, a importância dos resultados e sua aplicabilidade na prática clínica. CONCLUSÕES: O conhecimento dos fatores que afetam a qualidade dos estudos de coorte permite ao intensivista selecionar as melhores evidências para auxílio na tomada de decisões clínicas.

BACKGROUND AND OBJECTIVES: Cohort studies are useful to identify risk and prognostic factors, assess disease natural history and verify the impact of diagnostic or therapeutic interventions. This article aims to guide readers on how to critically assess papers using a cohort research design. CONTENTS: For a critical appraisal of cohort studies, one must observe: the existence of selection and information bias, the continuity of the follow-up, the control of confounding variables, the significance of the results and its applicability in clinical practice. CONCLUSIONS: Knowledge of factors which affect the quality of cohort studies allows intensive care professionals to select the best available evidence to guide the decision making process.

Vaccine-associated paralytic poliomyelitis: a retrospective cohort study of acute flaccid paralyses in Brazil.

BACKGROUND: At the present time, in Brazil and other countries in the Americas, the only cases of paralytic poliomyelitis due to poliovirus are caused by vaccine strains. The recognition of possible determinants of vaccine-associated paralytic poliomyelitis (VAPP) by public health surveillance and immunization programmes is relevant to inform the debate on criteria for case definition and vaccination strategies. METHODS: A retrospective cohort study based on the cases of acute flaccid paralysis (AFP) reported to the Ministry of Health (MoH) was designed, with the objective of studying cases of VAPP in Brazil between 1989 and 1995. Clinical, laboratory and epidemiological data from 3656 acute flaccid paralysis (AFP) cases, 30 of them diagnosed as VAPP, were analysed. RESULTS: An 8.88 risk ratio of VAPP (95% CI : 4.37-18.03) was found when comparing individuals who received oral poliovirus vaccine (OPV) between 4 and 40 days before the onset of paralysis and individuals who did not receive the vaccine within this period. A risk of 1 case/2.39 million first doses and 1 case/13.03 million OPV doses administered was estimated for the general population. CONCLUSIONS: Cases of AFP who received OPV between 4 and 40 days before the onset of paralysis and had fever, a prodrome of gastrointestinal symptoms, history of first dose of OPV, isolation of vaccine poliovirus type 2, and young age deserve careful investigation, since they are at increased risk for the condition studied.

Pregnancy rates among Chilean women who had non-surgical sterilization with quinacrine pellets between 1977 and 1989.

We describe cumulative pregnancy probabilities among women who underwent quinacrine pellet sterilization in Chile between 1977 and 1989 (N = 1492). We interviewed the women or relatives in 1991-93 and 1994-96, and reviewed hospital records. Mean follow-up was 9.6 years (median 9 years). We recorded 120 pregnancies, including 40 that went to term or near-term. There were nine adverse outcomes in eight infants: one fetal death at 18 weeks gestation; three infants born prematurely; one stillbirth (placental infarct); and four infants with birth defects. There was no clustering of any particular kind of birth defect. For two insertions, the 10-year cumulative pregnancy probability was 8.9 (95% confidence interval 3. 7, 14.1). For 3 insertions, the 10-year rate was 7.0 (4.4, 9.5). For women who were under 35 years at insertion, the 10-year rate was 10. 7 (7.4, 14.1). For women who were 35 or older at insertion, the 10-year rate was 3.1 (0.6, 5.7). The pregnancy rate varied little for 2 vs. three insertions, but the rate did vary significantly by age, with women who received quinacrine at 35 years or older 0.3 (0. 2, 0.5) times as likely to become pregnant as younger women. The 10-year cumulative ectopic pregnancy probabilities for women with two and three insertions of quinacrine were 0.9 (<0.1, 2.6) and 0.5 (<0.1, 1.2), respectively. Pregnancy rates after quinacrine insertion are higher than after surgical sterilization, but ectopic pregnancy rates appear similar.

Effects of Cryptosporidium parvum infection in Peruvian children: growth faltering and subsequent catch-up growth.

The authors conducted a 2-year (1989-1991) community-based longitudinal study in a shantytown in Lima, Peru, to examine the effect of Cryptosporidium parvum infection on child growth during the year following the onset of infection. A cohort of children, aged 0-3 months at recruitment, was followed monthly for anthropometrics, weekly for stool samples, and daily for diarrheal status. Data from 185 children in the cohort permitted a comparison of growth in C. parvum-infected and noninfected children. The analyses fitted smooth, flexible curves with a linear random-effects model to estimate growth differences between C. parvum-infected and noninfected children. Children infected with C. parvum experienced growth faltering, both in weight and in height, for several months after the onset of infection, followed by a period of catch-up growth. Younger children took longer to catch up in weight than did older children. Catch-up growth, however, did not occur in children infected between ages 0 and 5 months. These children did not catch up in height, and one year after infection they exhibited an average deficit of 0.95 cm (95% confidence interval (CI) 0.38-1.53) relative to noninfected children of similar age. Stunted children who became infected also did not catch up in either weight or height, and one year after infection they exhibited a height deficit of 1.05 cm (95% CI 0.46-1.66) relative to noninfected, stunted children of similar age. These results indicate that Cryptosporidium parvum has a lasting adverse effect on linear (height) growth, especially when acquired during infancy and when children are stunted before they become infected.

PIP: A 2-year (1989-91) community-based study conducted in a shantytown in Lima, Peru, used regression splines to assess the effect of Cryptosporidium parvum infection on child growth during the year following the onset of infection. The 185 children 0-3 months of age at enrollment who comprised the study cohort underwent daily monitoring of diarrheal status, weekly stool analysis, and monthly anthropometric measurements. 88 children (48%) became infected with C. parvum during the study period. A linear random effects model was used to model differences in temporal growth patterns between C. parvum-infected and noninfected children. Children infected with C. parvum demonstrated growth faltering, both in weight and height, for several months after the onset of infection, followed by a period of catch-up growth. Younger age at infection intensified the effect of C. parvum infection on growth. In children infected between 0 and 5 months of age, catch-up weight gain was complete 6 months later but, 12 months after infection, these children exhibited an average height deficit of 0.95 cm relative to uninfected children the same age. Stunting also increased the magnitude and duration of the effect of C. parvum infection on growth. 12 months after infection onset, stunted children demonstrated a 1.05 cm height deficit relative to their noninfected, nonstunted age counterparts. These findings indicate that cryptosporidiosis has an adverse effect on child growth, especially when infection is acquired during infancy. C. parvum-related intestinal damage and malabsorption are presumed to be the mechanisms associated with growth retardation.

Direct and indirect estimates of HIV-1 incidence in a high-prevalence population.

While the worldwide AIDS epidemic continues to expand, directly measured incidence data are difficult to obtain. Methods to reliably estimate human immunodeficiency virus type 1 (HIV-1) incidence from more easily available data are particularly relevant in those parts of the world where prevalence is rising in heterosexually exposed populations. The authors set out to estimate HIV-1 incidence in a population of heterosexual sexually transmitted disease clinic attendees in Trinidad who had a known high prevalence of HIV-1 subtype B. Over the period 1987-1995, HIV-1 incidence estimates from serial cross-sectional studies of HIV-1 prevalence, passive follow-up of clinic recidivists, modeling of early markers of HIV-1 infection (p24 antigen screening), and a cohort study of seronegative genital ulcer disease cases were compared. Measuring incidence density in the genital ulcer disease cases directly gave the highest estimate, 6.9% per annum. Screening for the detection of early HIV-1 markers yielded an incidence of 5.0% per annum, while estimating incidence from serial cross-sectional prevalence data and clinic recidivists gave estimates of 3.5% and 4.5% per annum, respectively. These results were found to be internally consistent. Indirect estimates of incidence based on prevalence data can give accurate surrogates of true incidence. Within limitations, even crude measures of incidence are robust enough for health planning and evaluation purposes. For planning vaccine efficacy trials, consistent conservative estimates may be used to evaluate populations before targeting them for cohort studies.

PIP: HIV incidence data, necessary for the planning and evaluation of national AIDS control programs, are difficult to obtain directly. In this study, HIV-1 incidence in Trinidad was estimated in a population known to be at high risk: heterosexuals attending a sexually transmitted disease clinic in Port of Spain in 1987-95. HIV incidence estimates were obtained from serial cross-sectional studies of HIV-1 prevalence (n = 3625), passive follow-up of clinic recidivists (n = 98), modeling of early markers of HIV-1 infection (p24 antigen screening) (n = 12,154), and a cohort study of seronegative genital ulcer disease cases (n = 196). Measuring incidence density in genital ulcer disease cases directly gave the highest estimate: 6.9% per year. Screening for the detection of early HIV-1 markers yielded an incidence of 5.0% per year, while estimating incidence from serial cross-sectional prevalence data and clinic recidivists provided estimates of 3.5% and 4.5%, respectively. Although these estimates come from groups within the clinic population with differential HIV-1 risk, they were internally consistent. These findings suggest that indirect estimates of incidence based on prevalence data can provide accurate surrogates of true HIV incidence and may be used to target suitable populations for cohort studies.

Length and ponderal index at birth: associations with mortality, hospitalizations, development and post-natal growth in Brazilian infants.

BACKGROUND: Low birthweight infants suffer greater mortality and neonatal morbidity, grow less well in infancy and show poorer psycho-motor development. However, this simple categorization may obscure important differences in aetiology and prognosis between infants born stunted, thin, or both. METHODS: In 1993, all births in Pelotas, Brazil, were enrolled into a prospective study of health and development in infancy. Of 5249 live births, 5160 had length and weight measures at birth, and were classified into tertiles of length and ponderal index. All deaths and hospitalizations were monitored, and suspected developmental delay and attained growth at 12 months were assessed on a subsample of 1364 infants. Logistic regression was used to control for gestational age and socioeconomic status. RESULTS: There was no association between birth length and ponderal index tertiles. After adjusting for gestational age, infants in the lower tertiles of both length and ponderal index presented a 3.8-times higher risk of mortality from day 8 to day 365, and a 2.5-times higher risk of hospitalization compared to infants with greater birth lengths and/or ponderal indices. Suspected developmental delay was associated with length and, less strongly, with ponderal index, but there was no synergism between the two. Infants in the middle and upper tertiles of ponderal index at birth became thinner. CONCLUSIONS: Birth length was strongly associated with development at 12 months, but only infants born both short and thin were at increased risk of mortality and hospitalizations. The combination of the two measures provides a useful classification of the anthropometric status of the newborn.

PIP: A prospective study of all 5249 live births in Pelotas, Brazil, in 1993 examined interactions between health and development in infancy. The 5160 infants who had length and weight measurements taken at birth were classified into tertiles of length-for-age Z score and ponderal index--a measure of soft tissue growth. There was no association between these two measures. After adjustments for gestational age, infants in the lower tertiles of both length and ponderal index had a 3.8 times greater risk of mortality from day 8 to 365 and a 2.5 times higher risk of hospitalization than infants in the high tertile. However, infants born short but not thin, or thin but not short, were not at increased risk of either mortality or hospitalization. Suspected developmental delay at 12 months was associated with shorter stature at birth and, less strongly, with a lower ponderal index, but there was no synergism between the two measures. Infants in the middle and upper tertiles of ponderal index at birth became markedly thinner in the first year of life, while length changes were less strongly associated with initial status. Overall, these findings suggest that the combination of length and ponderal index at birth may provide a functionally relevant means of classifying the newborn's anthropometric status since the two measures are relatively independent of each other at the level of the individual and appear to affect different aspects of the infant's subsequent health and development.

Using logistic regression to describe the length of breastfeeding: a study in Guadalajara, Mexico.

This study seeks, through a logistic regression model, to describe the pattern of breastfeeding duration in Guadalajara, Mexico, during 1993. A multistage random sample of children under 1 year of age (n = 1036) was studied; observational data regarding breastfeeding duration, obtained through a "status quo" procedure, were compared with prevalence rates obtained from the logistic regression model. Modeling the duration of breastfeeding during the first year of life rather than only analyzing observational data helps researchers to understand this process in a dynamic and quantitative way. For example, uncommon indicators of breastfeeding were derived from the model. These indicators are impossible to obtain from observational data. The prevalence curve estimated through the logistic model was adequately fitted to observed data: there were no significant differences between the number or distribution of breastfed infants observed and those predicted by the model. Moreover, the model revealed that less than 40% of the children were breastfed in the fourth month of life; the median age for weaning was 39.3 days; 55% of the potential breastfeeding in the first 4 months did not occur; and the greatest abandonment of breastfeeding in the first 4 months was observed in the first 60 days. Thus, logistic regression seems a suitable option to construct a population-based model that describes breastfeeding duration during the first year of life. The indicators derived from the model offer health care providers valuable information for developing programs that promote breastfeeding.

PIP: This study describes the pattern of breast-feeding duration in Guadalajara, Mexico, in 1993, using a logistic regression model. A multistage random sample of children under 1 year of age (n = 1036) was studied; observational data regarding breast-feeding duration, obtained through a "status quo" procedure, were compared with prevalence rates obtained from the logistic regression model. Modeling the duration of breast-feeding during the first year of life rather than only analyzing observational data helps researchers to understand this process in a dynamic and quantitative way. For example, uncommon indicators of breast-feeding were derived from the model. These indicators are impossible to obtain from observational data. The prevalence curve estimated through the logistic model was adequately fitted to observe data: there were no significant differences between the number or distribution of breast-fed infants observed and those predicted by the model. Moreover, the model revealed that less than 40% of the children were breast-fed in the fourth month of life. The median age for weaning was 39.3 days and about 55% of potential breast-feeding in the first 4 months did not occur. Lastly, the highest abandonment of breast-feeding in the first 4 months was observed in the first 60 days. Thus, logistic regression seems a suitable option to construct a population-based model that describes breast-feeding duration during the first year of life.

Return of fertility after discontinuation of the once-a-month injectable contraceptive Cyclofem.

The objective of this study was to evaluate the return of fertility in women who used Cyclofem as a contraceptive method during the introductory studies conducted in Brazil, Chile, Colombia, and Peru. From these four cohorts, 101 women were eligible for the study. Thirty-one were not included in the study either because they refused to be interviewed, had initiated another contraceptive method the month after discontinuation, or were unable to be contacted. A total of 70 women were included in the study. Our results showed that the return to fertility rate after the discontinuation of Cyclofem was 1.4 per 100 women at the end of the first month and reached 82.9 at one year. More than 50% were pregnant at 6 months. Fifty-one (94.4%) pregnancies ended in a live birth, two were spontaneous first trimester abortions, and one was a hydatidiform mole. Return of fertility was not related to the woman's age at the time of discontinuation, her weight, or the number of Cyclofem injections. In conclusion, fertility is restored by 1 month following Cyclofem discontinuation. Users and potential users should be counseled regarding the rapid return of fertility after discontinuing this method of contraception.

PIP: Cyclofem, a monthly injectable contraceptive containing 5 mg estradiol cypionate and 25 mg medroxyprogesterone acetate, has been registered in several Latin American countries; however, the return to fertility after method discontinuation has not been investigated. To address this issue, 70 women were followed who had participated in introductory studies in Brazil, Chile, Colombia, and Peru during 1992-94 and who then discontinued injectable use to achieve pregnancy. The mean number of Cyclofem injections was 7.1 (range, 1-19). The fertility rate was 1.4 at the end of the first month after Cyclofem discontinuation, 52.9 after 6 months, and 82.9 at 12 months. 55 pregnancies (94.8%) ended in live-term births, with no congenital malformations; there were 2 spontaneous abortions in the first trimester. The number of months required to become pregnant was not significantly associated with maternal age, body weight, number of injections, or country site. The return to fertility for this method is comparable to that following discontinuation of copper IUDs, barrier methods, and oral contraceptives. Since information on return to fertility is essential to informed choice, these findings should be incorporated into educational and counseling materials for providers and potential acceptors of this new contraceptive method.