Gender differences in the association of perceived social support and social network with self-rated health status among older adults: a population-based study in Brazil

BACKGROUND: Older adults are more likely to live alone, because they may have been predeceased by their spouse and friends. Social interaction could also be reduced in this age group due by limited mobility caused by chronic conditions. Therefore, aging is frequently accompanied by reduced social support, which might affect health status. Little is known about the role of gender in the relationship between social support and health in older adults. Hence, the present study tests the hypothesis that gender differences exist in the relationship between perceived social support, social network, and self-rated health (SRH) among older adults. METHODS: A cross-sectional study using two-stage probabilistic sampling recruited 3,649 individuals aged 60 years and above. Data were collected during the national influenza vaccination campaign in Rio de Janeiro, Brazil, in 2006. Individual interviews collected information on SRH, perceived social support, social network, and other covariates. Multivariate logistic regression analyses using nested models were conducted separately for males and females. Independent variables were organised into six blocks: (1) perceived social support and social network, (2) age group, (3) socioeconomic characteristics, (4) health-related behaviours, (5) use of health care services, (6) functional status measures and somatic health problems. RESULTS: Older men who did not participate in group activities were more likely to report poor SRH compared to those who did, (OR = 1.63; 95% CI = 1.16–2.30). Low perceived social support predicted the probability of poor SRH in women (OR = 1.64; 95% CI = 1.16–2.34). Poor SRH was associated with low age, low income, not working, poor functional capacity, and depression in both men and women. More somatic health problems were associated with poor SRH in women. CONCLUSIONS: The association between social interactions and SRH varies between genders. Low social network involvement is associated with poor SRH in older men, whereas low perceived social support is associated with poor SRH in older women. The hypothesis that the relationship of perceived social support and social networks to SRH differs according to gender has been confirmed

Effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture Efeito da suplementação com ácido linoléico conjugado sobre a atividade da lípase lipoprotéica em cultura de adipócitos 3T3-L1

Supplementation with conjugated linoleic acid may reduce fat body mass and increase lean body mass in various species. Some studies have demonstrated that conjugated linoleic acid reduces body fat, in part, by inhibiting the activity of lipoprotein lipase in adipocytes. The objective of this work was to study the effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture. 3T3-L1 adipocytes received linoleic acid (group C) or conjugated linoleic acid (group AE, supplemented with AdvantEdge® CLA, and group CO, supplemented with CLA One®) in concentrations of 1 mmol/L. Heparin-releasable lipoprotein lipase activity was analyzed by means of a 3T3-L1 adipocyte culture. After 7 days, heparin-releasable lipoprotein lipase activity was lower in the groups AE and CO supplemented with conjugated linoleic acid. These results suggest that one of the mechanisms by which CLA is capable of reducing body fat is by reducing lipoprotein lipase activity.<br>A suplementação com ácido linoléico conjugado pode reduzir a gordura corporal e aumentar a massa magra em diferentes espécies. Alguns estudos têm demonstrado que o ácido linoléico conjugado reduz a gordura corporal, por meio da inibição da atividade de lípase lipoprotéica em adipócitos. O objetivo deste estudo foi avaliar o efeito da suplementação com uma mistura de isômeros do ácido linoléico conjugado sobre a atividade da lípase lipoprotéica em cultura de adipócitos 3T3-L1. Os adipócitos 3T3-L1 receberam ácido linoléico (grupo controle) ou ácido linoléico conjugado (grupo AE, suplementado com AdvantEdge® CLA, e grupo CO, suplementado com CLA One®) na concentração de 1 mmol/L. A atividade de lípase lipoprotéica livre de heparina foi analisada pela média da cultura de adipócitos. Após 7 dias, a atividade da lípase lipoprotéica livre de heparina mostrou menores valores nos grupos AE e CO, suplementados com ácido linoléico conjugado. Estes resultados sugerem que um dos mecanismos pelo qual o ácido linoléico conjugado seja capaz de reduzir a gordura corporal é a partir da redução da atividade da lípase lipoprotéica

Suplementação com ácido linoléico conjugado: estabilidade oxidativa dos suplementos e correlações com conteúdo dos lípides totais hepáticos e indicadores da oxidação dos lípides biológicos de ratos Wistar Conjugated linoleic acid supplementation: oxidative stability of supplements and correlations with total hepatic lipid contents and biological lipid oxidation indicators in Wistar rats

OBJETIVO:O objetivo do trabalho foi avaliar a estabilidade oxidativa de misturas comerciais de ácido linoléico conjugado e buscar possível correlação entre a suplementação e o conteúdo total de lípides hepáticos, e também de alguns indicadores da oxidação lipídica em ratos. MÉTODOS:Um ensaio biológico com 30 ratos divididos em três grupos (n=10) caracterizando os grupos controle e suplementados com as misturas comerciais AdvantEdge® e One® foi realizado. A concentração administrada foi de 2% em relação ao consumo de dieta e os animais foram suplementados durante 42 dias. O conteúdo total de lípides do fígado foi determinado e a morfologia do órgão foi examinada por meio de microscopia ótica. Índice de peróxido e malondialdeído foram determinados para avaliar a estabilidade oxidativa dos suplementos in vitro. Índice de peróxido, malondialdeído, 8-iso-PGF2&#945; isoprostana e catalase foram determinados como indicadores da oxidação dos lípides biológicos. RESULTADOS: Os resultados demonstraram baixa estabilidade das misturas comerciais à oxidação in vitro. As associações entre o consumo de ácido linoléico conjugado e malondialdeído (r=-0,7914, p<0,0001) e catalase (r=-0,5991, p=0,008) foram moderadas, negativas e significantes, demonstrando que o ácido linoléico conjugado reduziu a oxidação lipídica in vivo. O conteúdo dos lípides totais hepáticos não aumentou (22,42%, DP=1,40%) e a morfologia do órgão permaneceu íntegra. CONCLUSÃO:Embora esse protocolo de suplementação com ácido linoléico conjugado tenha reduzido a oxidação lipídica, há que considerar a tendência para o aumento de 8-iso-PGF2&#945; isoprostana e de peróxidos como perspectiva de continuidade das pesquisas sobre a reinvestigação do efeito antioxidante do ácido linoléico conjugado.<br>OBJECTIVE:The claimed action of conjugated linoleic acid as an antioxidant is unexpected and unclear, in view of its chemical structure - a conjugated diene, i.e., a fatty acid in its initial stage of autoxidation. Indeed, it can be speculated that it could act as a pro-oxidant, increasing oxidative stress in biological systems, nevertheless it has carbon-carbon bonds in the trans configuration. The objective of the present work was to evaluate the oxidative stability of commercial mixtures, and to investigate a possible correlation between conjugated linoleic acid supplementation and total hepatic lipid content, as well as some lipid oxidation indicators in rats. METHODS:A biological assay was done with thirty rats divided into three groups (n=10) characterized as control and supplemented with the commercial mixtures AdvantEdge® and One®. The mixtures were administered in the concentration of 2% of the total diet consumption, and animals were supplemented for 42 days. The total liver lipid content was determined, and the morphology of the organ was examined by optical microscopy. Peroxide and malondialdehyde indexes were determined in vitro in order to evaluate the oxidative stability of the supplements. Peroxide, malondialdehyde and 8-iso-PGF2&#945; isoprostane and catalase were determined as biological lipid oxidation indicators. RESULTS:Results indicated a low in vitro oxidation stability of commercial mixtures. Associations between conjugated linoleic acid consumption and malondialdehyde (r=-0.7914, p<0.0001), and catalase (r=-0.5991, p=0.008) were moderate, negative and significant, demonstrating that conjugated linoleic acid reduced in vivo lipid oxidation. Total hepatic lipid content did not increase (22.42%, (SD=1.40%), and the organ remained morphologically undamaged. CONCLUSION:However, even though this CLA supplementation protocol did reduce lipid oxidation, a tendency was observed to an increase of 8-iso-PGF2 alpha isoprostane and peroxides induced by conjugated linoleic acid. Further research may be needed to verify its antioxidant effect