Multiple mortality modeling in Poisson Lee-Carter framework

The academic literature in longevity field has recently focused on models for detecting multiple population trends (D'Amato et al., 2012b; Njenga and Sherris, 2011; Russolillo et al., 2011, etc.). In particular, increasing interest has been shown about "related" population dynamics or "parent" populations characterized by similar socioeconomic conditions and eventually also by geographical proximity. These studies suggest dependence across multiple populations and common long-run relationships between countries (for instance, see Lazar et al., 2009). In order to investigate cross-country longevity common trends, we adopt a multiple population approach. The algorithm we propose retains the parametric structure of the Lee-Carter model, extending the basic framework to include some cross-dependence in the error term. As far as time dependence is concerned, we allow for all idiosyncratic components (both in the common stochastic trend and in the error term) to follow a linear process, thus considering a highly flexible specification for the serial dependence structure of our data. We also relax the assumption of normality, which is typical of early studies on mortality (Lee and Carter, 1992) and on factor models (see e.g., the textbook by Anderson, 1984). The empirical results show that the multiple Lee-Carter approach works well in the presence of dependence

Sex-specific mortality forecasting for UK countries: a coherent approach

This paper introduces a gender specific model for the joint mortality projection of three countries (England and Wales combined, Scotland, and Northern Ireland) of the United Kingdom. The model, called 2-tier Augmented Common Factor model, extends the classical Lee and Carter [26] and Li and Lee [32] models, with a common time factor for the whole UK population, a sex specific period factor for males and females, and a specific time factor for each country within each gender. As death counts in each subpopulation are modelled directly, a Poisson framework is used. Our results show that the 2-tier ACF model improves the in-sample fitting compared to the use of independent LC models for each subpopulation or of independent Li and Lee models for each couple of genders within each country. Mortality projections also show that the 2-tier ACF model produces coherent forecasts for the two genders within each country and different countries within each gender, thus avoiding the divergence issues arising when independent projections are used. The 2-tier ACF is further extended to include a cohort term to take into account the faster improvements of the UK ‘golden generation’

IL-6 secretion in osteoarthritis patients is mediated by chondrocyte-synovial fibroblast cross-talk and is enhanced by obesity

Increasing evidence suggests that inflammation plays a central role in driving joint pathology in certain patients with osteoarthritis (OA). Since many patients with OA are obese and increased adiposity is associated with chronic inflammation, we investigated whether obese patients with hip OA exhibited differential pro-inflammatory cytokine signalling and peripheral and local lymphocyte populations, compared to normal weight hip OA patients. No differences in either peripheral blood or local lymphocyte populations were found between obese and normal-weight hip OA patients. However, synovial fibroblasts from obese OA patients were found to secrete greater amounts of the pro-inflammatory cytokine IL-6, compared to those from normal-weight patients (p < 0.05), which reflected the greater levels of IL-6 detected in the synovial fluid of the obese OA patients. Investigation into the inflammatory mechanism demonstrated that IL-6 secretion from synovial fibroblasts was induced by chondrocyte-derived IL-6. Furthermore, this IL-6 inflammatory response, mediated by chondrocyte-synovial fibroblast cross-talk, was enhanced by the obesity-related adipokine leptin. This study suggests that obesity enhances the cross-talk between chondrocytes and synovial fibroblasts via raised levels of the pro-inflammatory adipokine leptin, leading to greater production of IL-6 in OA patients

Computational framework for longevity risk management

Longevity risk threatens the financial stability of private and government sponsored defined benefit pension systems as well as social security schemes, in an environment already characterized by persistent low interest rates and heightened financial uncertainty. The mortality experience of countries in the industrialized world would suggest a substantial age-time interaction, with the two dominant trends affecting different age groups at different times. From a statistical point of view, this indicates a dependence structure. It is observed that mortality improvements are similar for individuals of contiguous ages (Wills and Sherris, Integrating financial and demographic longevity risk models: an Australian model for financial applications, Discussion Paper PI-0817, 2008). Moreover, considering the dataset by single ages, the correlations between the residuals for adjacent age groups tend to be high (as noted in Denton et al., J Population Econ 18:203-227, 2005). This suggests that there is value in exploring the dependence structure, also across time, in other words the inter-period correlation. In this research, we focus on the projections of mortality rates, contravening the most commonly encountered dependence property which is the "lack of dependence" (Denuit et al., Actuarial theory for dependent risks: measures. Orders and models, Wiley, New York, 2005). By taking into account the presence of dependence across age and time which leads to systematic over-estimation or under-estimation of uncertainty in the estimates (Liu and Braun, J Probability Stat, 813583:15, 2010), the paper analyzes a tailor-made bootstrap methodology for capturing the spatial dependence in deriving confidence intervals for mortality projection rates. We propose a method which leads to a prudent measure of longevity risk, avoiding the structural incompleteness of the ordinary simulation bootstrap methodology which involves the assumption of independence

Simultaneous resection of colorectal cancer and synchronous liver metastases: what determines the risk of unfavorable outcomes? An international multicenter retrospective cohort study

BACKGROUND: The use of a simultaneous resection (SIMR) in patients with synchronous colorectal liver metastases (sCRLM) has increased over the past decades. However, it remains unclear when a SIMR is beneficial and when it should be avoided. The aim of this retrospective cohort study was therefore to compare the outcomes of a SIMR for sCRLM in different settings, and to assess which factors are independently associated with unfavorable outcomes. METHODS: To perform this retrospective cohort study, patients with sCRLM undergoing SIMR (2004-2019) were extracted from an international multicenter database, and their outcomes were compared after stratification according to the type of liver and colorectal resection performed. Factors associated with unfavorable outcomes were identified through multivariable logistic regression. RESULTS: Overall, 766 patients were included, encompassing colorectal resections combined with a major liver resection (n=122), minor liver resection in the anterolateral (n=407), or posterosuperior segments ('Technically major', n=237). Minor and technically major resections, compared to major resections, were more often combined with a rectal resection (29.2 and 36.7 vs. 20.5%, respectively, both P=0.003) and performed fully laparoscopic (22.9 and 23.2 vs. 6.6%, respectively, both P = 0.003). Major and technically major resections, compared to minor resections, were more often associated with intraoperative transfusions (42.9 and 38.8 vs. 20%, respectively, both P = 0.003) and unfavorable incidents (9.6 and 9.8 vs. 3.3%, respectively, both P≤0.063). Major resections were associated, compared to minor and technically major resections, with a higher overall morbidity rate (64.8 vs. 50.4 and 49.4%, respectively, both P≤0.024) and a longer length of stay (12 vs. 10 days, both P≤0.042). American Society of Anesthesiologists grades ≥3 [adjusted odds ratio (aOR): 1.671, P=0.015] and undergoing a major liver resection (aOR: 1.788, P=0.047) were independently associated with an increased risk of severe morbidity, while undergoing a left-sided colectomy was associated with a decreased risk (aOR: 0.574, P=0.013). CONCLUSIONS: SIMR should primarily be reserved for sCRLM patients in whom a minor or technically major liver resection would suffice and those requiring a left-sided colectomy. These findings should be confirmed by randomized studies comparing SIMR with staged resections

The Role of Liver-Directed Surgery in Patients With Hepatic Metastasis From Primary Breast Cancer: a Multi-Institutional Analysis

BACKGROUND: Data on surgical management of breast liver metastasis are limited. We sought to determine the safety and long-term outcome of patients undergoing hepatic resection of breast cancer liver metastases (BCLM). METHODS: Using a multi-institutional, international database, 131 patients who underwent surgery for BCLM between 1980 and 2014 were identified. Clinicopathologic and outcome data were collected and analyzed. RESULTS: Median tumor size of the primary breast cancer was 2.5 cm (IQR: 2.0-3.2); 58 (59.8%) patients had primary tumor nodal metastasis. The median time from diagnosis of breast cancer to metastasectomy was 34 months (IQR: 16.8-61.3). The mean size of the largest liver lesion was 3.0 cm (2.0-5.0); half of patients (52.0%) had a solitary metastasis. An R0 resection was achieved in most cases (90.8%). Postoperative morbidity and mortality were 22.8% and 0%, respectively. Median and 3-year overall-survival was 53.4 months and 75.2%, respectively. On multivariable analysis, positive surgical margin (HR 3.57, 95% CI 1.40-9.16; p = 0.008) and diameter of the BCLM (HR 1.03, 95% CI 1.01-1.06; p = 0.002) remained associated with worse OS. DISCUSSION: In selected patients, resection of breast cancer liver metastases can be done safely and a subset of patients may derive a relatively long survival, especially from a margin negative resection.info:eu-repo/semantics/publishedVersio

Establecimiento del tamaño de raciones de consumo de frutas y hortalizas para su uso en guías alimentarias en el entorno español: propuesta del Comité Científico de la Asociación 5 al día

Introduction: Food servings are standard amounts of food stuffs or drinks to help dietetic advice to promote and preserve health. The aim is to establish the serving size of fruits and vegetables (FH) to be used in food based dietary guidelines (FBDG). Material and Methods: Methodology of the United States Department of Agriculture (USDA) was adapted to establish serving sizes for FBDG, along of the followed by the food exchange system. Data was collected from the FH portion sizes reported in nutritional surveys and common sizes available in the Spanish market, and they were adjusted to an easily recognisable quantities of food with equivalence on key nutrients: the compliance with public health goals for FH consumption was evaluated. Results: Portion sizes typically reported in Spanish nutrition surveys are scarce and not homogeneous, and no data published in scientific journals on portion sizes were available. The Spanish FBDG, in spite of showing a range of serving size for FH, do not assure that they are interchangeable nor specify the method to obtein them.The serving of vegetables was 139,44g (DS:+/- 21.98, CV:0.16), 137,68g (DS:+/- 49,61, CV:0,36) for fruits and 28.00g (DS:+/- 7,53, CV:0.27) for dried fruits. Conclusions: With the established servings, the recommendation of consuming "at least 5 servings of FH a day" would allow reaching the Public Health goals for FH established in 600g (net weight)/person/day. It is recommended that the Spanish Agency for Consumers, Food Safety and Nutrition (AECOSAN) uses this methodology to establish serving sizes for the rest of food groups that make up the FBDG for the Spanish population.Introducción: Las raciones de consumo son cantidades estándar de alimentos o bebidas sugeri-das para asesorar sobre la cantidad de alimento a consumir para preservar un estado de salud adecuado. El objetivo principal de este trabajo es establecer los tamaños de ración de consumo de frutas y hortalizas (FH) para uso en guías alimentarias.Material y Métodos: Se adaptó la metodología de la United States Department of Agriculture (USDA) para el establecimiento de los tamaños de ración de consumo para guías, y la del Sistema de Intercambios. Se recopilaron datos de porción reportados en encuestas y calibres comunes en el mercado, se ajustó a cantidades de alimento fácilmente reconocibles y con equivalencia de nutrientes clave y se evaluó el grado de cumplimiento de los objetivos de salud pública para el consumo de FH. Resultados: Los tamaños de porción típicamente reportados en encuestas españolas son escasos y poco homogéneos, y no se encontraron datos publicados en revistas científicas sobre los cali-bres. Las guías alimentarias españolas, a pesar de mostrar un rango de tamaño de ración para FH no aseguran que sean intercambiables ni especifican el método para llegar a las mismas. La ración de hortalizas obtenida ha sido de 139,44g (DS:±21,98; CV:0,16), de 137,68g (DS:±49,61; CV:0,36) para frutas y 28,00g (DS:±7,53; CV:0,27) para frutas desecadas. . Conclusiones: Con las raciones establecidas, el mensaje “consume al menos 5 raciones entre FH al día” permitiría alcanzar los objetivo de Salud Pública para FH establecidos en 600g (peso neto)/persona/día. Se recomienda a la Agencia Española de Consumo, Seguridad Alimentaria y Nutrición (AECOSAN) que use esta misma metodología para el establecimiento de raciones en el resto de grupos de alimentos que configuran la Guía Dietética Basada en Alimentos para la población española