Search

Background: Functional capacity is recognized as a central factor for health in old age and not all studies that seek to clarify the role of social relationships in functional capacity are conclusive. The subject has only been studied in a limited way in Latin America, a region that is aging prematurely, with evidence primarily from developed countries, which have experienced a more gradual aging of their population. This longitudinal study aimed to determine how aspects of social relationships impact the functionality of older Chileans. Methodology: We conducted a cohort study of 2,265 people aged 60 years or older who lived in the community and resided in Greater Santiago, Chile. Five aspects of social relationships were considered at baseline (participation in groups, clubs, or organizations; number of people in the household; participation in recreational activities; perception of material support, help or advice, and marital status), from which a cluster analysis by conglomerate was performed and used as the exposure of interest. Functional limitation (FL) was the dependent variable, classified as a limitation in at least 1 basic activity of daily living or 1 instrumental activity or 2 advanced activities. The control variables considered were: sex, age, educational level, multimorbidity, depression and years of follow-up. Survival analyses using a Cox proportional hazard regression and multilevel logistic regressions (person level and follow-up wave level) were performed. Results: The identified clusters were four: "without social participation and does not live alone"; "without a partner and without social participation"; "no perception of support and no social participation"; "with participation, partner and perception of support". Social relationship clusters predicted FL incidence and FL reporting during follow-up. Being in the clusters "without social participation and does not live alone" and "without partner and without social participation" were risk factors for incident FL and report of FL during follow-up, compared to being in the reference cluster "with participation, partner and perception of support. Conclusions: In summary, our study showed that participating in social organizations, not living alone and having a partner are protective factors for presenting and developing functional limitation in old age for community-living Chileans in an urban area. [ABSTRACT FROM AUTHOR]

Background: The leading cause of death in older people is cardiovascular diseases. Several studies have found that neck circumference (NC) is a simple anthropometric marker associated with adiposity. The aim of this study is to estimate and validate NC cut-off points as adiposity markers and analyze their association with cardiovascular and chronic metabolic diseases in older people. Methods: A cross-sectional study in 358 non-disabled, community-dwelling older people (71.7 ± 3.9 years) living in Santiago de Chile and participating in the HTSMayor study was conducted. Measurements of body composition and cardiovascular risks were evaluated. Receiver operating characteristic (ROC) curves and multiple logistic regression models were used to evaluate the association of NC with cardiovascular and chronic metabolic diseases. NC cut-off points were obtained to predict obesity, abdominal obesity, and adiposity. Results: The best performance values of neck circumference relative to obesity and adiposity were obtained with respect to abdominal obesity (40.6 cm in men and 34.2 cm in women). Higher NC values were associated with a higher area under the curve (AUC) for men and women (men: AUC = 0.84; women: AUC = 0.86). NC was significantly associated with a higher risk for diabetes mellitus (OR = 1.95), hypertension (OR = 2.42), acute myocardial infarction (OR = 4.36), and comorbidities (OR = 2.01), and a lower risk for sarcopenia (OR = 0.35). Conclusions: This study shows that NC is a useful tool for detecting abdominal obesity, obesity, and adiposity in older people and that a higher NC increases the risk of chronic diseases. [ABSTRACT FROM AUTHOR]

A novel symmetric cryptosystem of the substitution permutation network type is presented for image encryption in 14 rounds. An algorithm is developed to generate 15 keys to encrypt images where each key is the image size. These keys are calculated using an elliptic curve with a constant zero value. The proposed curve is non-singular, non-supersingular, nor trace one. Chaos is employed to find a generating element in a cyclic subgroup and it is produced using the logistic map equation. In addition, a 16 × 16 substitution box is constructed using both chaos and an algorithm that defines a bijective function. The following tools are used in order to measure the degree of randomness of the encrypted figures: entropy, correlation, the discrete Fourier transform and a goodness-of-fit test with the chi-square distribution. Furthermore, an image size variable permutation is applied in the first round, and its inverse in the fourteenth.