Inhibition of platelet aggregation by omega-3 polyunsaturated fatty acids is gender specific — redefining platelet response to fish oils

Existence of gender differences in cardiovascular disease (CVD) following long-chain omega-3 polyunsaturated fatty acid (LCn-3 PUFA) supplementation have suggested that sex hormones play a role in cardio-protection. The objective of this study was to determine gender specific responses in the efficacy of LCn-3 PUFA to inhibit platelet aggregation in vitro. Blood was analyzed for collagen-induced platelet aggregation following pre-incubation with LCn-3 PUFA in healthy adults (n=42). Eicosapentaenoic acid (EPA) was significantly more effective in reducing platelet aggregation compared with docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). When grouped by gender, this differential pattern was followed in males only. In females, DHA, DPA and EPA were all equally effective. Between group analyses (LCn-3 PUFA vs. gender) showed that both DHA and DPA were significantly less effective in males compared with females. EPA was equally effective in reducing platelet aggregation in both groups. These findings show that significant gender differences exist in platelet aggregation in response to various LCn-3 PUFA treatments.

Gender-specific inhibition of platelet aggregation following omega-3 fatty acid supplementation

Background and Aims : Increased platelet aggregation is a major risk factor for heart attacks, stroke and thrombosis. Long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA; eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA) reduce platelet aggregation; however studies in the published literature involving EPA and/or DHA supplementation have yielded equivocal results. Recent in vitro studies have demonstrated that inhibition of platelet aggregation by LCn-3PUFA is gender specific. We examined the acute effects of dietary supplementation with EPA or DHA rich oils on platelet aggregation in healthy male and females.

Methods and Results : A blinded placebo controlled trial involving 15 male and 15 female subjects. Platelet aggregation was measured at 0, 2, 5 and 24 h post-supplementation with a single dose of either a placebo or EPA or DHA rich oil capsules. The relationship between LCn-3PUFA and platelet activity at each time point was examined according to gender vs. treatment. EPA was significantly the most effective in reducing platelet aggregation in males at 2, 5 and 24 h post-supplementation (−11%, −10.6%, −20.5% respectively) whereas DHA was not effective relative to placebo. In contrast, in females, DHA significantly reduced platelet aggregation at 24 h (−13.7%) while EPA was not effective. An inverse relationship between testosterone levels and platelet aggregation following EPA supplementation was observed.

Conclusion : Interactions between sex hormones and omega-3 fatty acids exist to differentially reduce platelet aggregation. For healthy individuals, males may benefit more from EPA supplementation while females are more responsive to DHA.

Family relationship quality and early alcohol use : evidence for gender-specific risk processes

Objective: Family characteristics (relationship quality, parental behaviors, and attitudes relating to alcohol use) are known to influence alcohol use in the mid-teen years, and there is evidence that family characteristics have different influences on mid-teen girls versus boys. This study examined child gender differences in the association of family relationship quality, parental disapproval of children's alcohol use, and parental alcohol use with early adolescent alcohol use.

Method: Grade 6 and 8 students (modal age 11 and 13, respectively; N = 6,837; 52.6% female) were recruited from 231 schools across three Australian states. Hypotheses were tested using two-level ordinal logistic regression (individuals nested within schools). The main dependent measure was lifetime frequency of early adolescent alcohol consumption. Independent variables included mother's/father's alcohol use, closeness, conflict, and disapproval of adolescent alcohol use. Control variables included sensation seeking, peer alcohol use, and socioeconomic disadvantage.

Results: The key findings were that for the young age group (Grade 6), emotional closeness to the parent of the opposite sex was protective. Family conflict was associated with females' drinking in both age groups but not males' drinking.

Conclusions: There was evidence of gender differences in the epidemiology of family relationship quality and early alcohol use. Social developmental models may need revision to account for these child gender differences. Gender-specific family dynamics may be an important consideration for family-oriented prevention strategy.

Associations of the SREBP-1c gene polymorphism with gender-specific changes in serum lipids induced by a high-carbohydrate diet in healthy Chinese youth

We investigated the possible association between the sterol regulatory element-binding protein-1c gene (SREBP-1c) rs2297508 polymorphism and the changes in lipid profiles in a high-carbohydrate and low-fat (high-CHO/LF) diet in a Chinese population well characterized by a lower incidence of coronary heart disease and a diet featuring higher carbohydrate and lower fat. Fifty-six healthy youth (aged 22.89 ± 1.80 years) were given wash-out diets of 31% fat and 54% carbohydrate for 7 days, followed by the high-CHO/LF diet of 15% fat and 70% carbohydrate for 6 days, without total energy restriction. Fasting blood samples were collected. Serum variables of lipid and glucose metabolism after the wash-out and high-CHO/LF diets, as well as the rs2297508 polymorphism, were analyzed. Compared with the male subjects on the wash-out diet, significantly elevated levels of high-density lipoprotein cholesterol (HDL-C) and decreased levels of apolipoprotein B-100 were observed in the male carriers of the C allele after the high-CHO/LF diet. In the female subjects, significantly increased triacylglycerol levels, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) were found in the GG genotype after the high-CHO/LF diet. These results suggest that the C allele of the rs2297508 polymorphism is associated with a retardation of the increases in serum triacylglycerol, serum insulin, and HOMA-IR in females and with the elevated serum HDL-C in males after the high-CHO/LF diet.

Age- and gender-specific rate of fractures in Australia : a population-based study

There is little population-based data concerning fracture rates in Australia. We ascertained all fractures occurring during 2 years in adults aged 35 years and over residing within a defined region (population 218 000), representative of the Australian population. The major strength of this study is the comprehensive ascertainment of fractures, which was ensured by regular searches of the only two radiologic providers in the Geelong Osteoporosis Study region. Nevertheless, vertebral fractures are likely to be underestimated since our ascertainment relied on a clinical indication for a medical imaging procedure. Among those aged 35 – 55 years, the fracture rate (persons per 10 000/year) in men was about double the rate in women (65 vs 35). The fracture rate was almost 7 times higher in women over 60 years versus women less than 55 years of age. In contrast, the fracture rate in men over 60 years was only 50% higher than in men less than 55 years of age (72 vs 104). Fracture rates in women and men were highest at the hip (28 and 10 respectively), spine (21 and 7), distal forearm (Colles’) (18 and 4) and humerus (11 and 3), and were 3–4 times higher in women than men. These fractures accounted for 63% of all fractures in women and 32% in men. By contrast, the rate of lower leg and ankle fractures was less than 10 per 10 000 in both women and men and did not increase to the same extent with age. Hip fracture rates appear high, particularly among the older age strata, compared with retrospective ascertainment in other populations. In Australia, as in many other countries, there is an increasing longevity of the population. The number of women aged 90 years and over increased by 32% and the number of men of this age increased by 48% in the 5 years between the Australian national census of 1991 and 1996. Given stable fracture rates, the substantial health burden imposed by age-related fractures, particularly hip fractures, will continue to escalate in both women and men.

Gender specific age-related changes in bone density, muscle strength and functional performance in the elderly: a-10 year prospective population-based study

Background: 

Gender-specific barriers and facilitators to heart failure self-care: a mixed methods study

Sexual niche segregation and gender-specific individual specialisation in a highly dimorphic marine mammal

While sexual segregation is expected in highly dimorphic species, the local environment is a major factor driving the degree of resource partitioning within a population. Sexual and individual niche segregation was investigated in the Australian fur seal (Arctocephalus pusillus doriferus), which is a benthic foraging species restricted to the shallow continental shelf region of south-eastern Australia. Tracking data and the isotopic values of plasma, red blood cells and whiskers were combined to document spatial and dietary niche segregation throughout the year. Tracking data indicated that, in winter, males and females overlapped in their foraging habitat. All individuals stayed within central Bass Strait, relatively close (< 220 km) to the breeding colony. Accordingly, both genders exhibited similar plasma and red cell δ13C values. However, males exhibited greater δ13C intra-individual variation along the length of their whisker than females. This suggests that males exploited a greater diversity of foraging habitats throughout the year than their female counterparts, which are restricted in their foraging grounds by the need to regularly return to the breeding colony to suckle their pup. The degree of dietary sexual segregation was also surprisingly low, both sexes exhibiting a great overlap in their δ15N values. Yet, males displayed higher δ15N values than females, suggesting they fed upon a higher proportion of higher trophic level prey. Given that males and females exploit different resources (mainly foraging habitats), the degree of individual specialisation might differ between the sexes. Higher degrees of individual specialisation would be expected in males which exploit a greater range of resources. However, comparable levels of inter-individual variation in δ15N whisker values were found in the sampled males and females, and, surprisingly, all males exhibited similar seasonal and inter-annual variation in their δ13C whisker values, suggesting they all followed the same general dispersion pattern throughout the year.

The measurement of socio-economic status: investigation of gender-and age-specific indicators in Australia: national health survey 1995

Objective: To investigate thecorrelations between age- and gender-specificmeasures of socio-economic status versus healthstatus as measured by the SF-36.

Design: Population based study.

Participants: 38187 people aged between18 to 79 years who participated in the NationalHealth Survey in 1995.

Results: Factor analysis producedconsistent results that were interpreted interms of five conceptually meaningful domains(employment, housing, migration, family unitand education). The relative rank of thefactors differs between groups and in somecases factor composition requires items to beadded or deleted from the conceptual domains.

Conclusions: Age- and gender-specific SESscores based on these factors had strongerassociations with the physical and mentalcomponents of SF-36 than either an area basedindex or scores derived from males aged 40–44years. Overall the results supported thehypothesis that SES measures composed of socialand demographic items exhibit important age-and gender-specific differences which arerelevant for health.

Gender differences in beliefs about condom use among young, heterosexual Australian adults

Objective: To investigate gender differences in beliefs about condom use among young, sexually active, heterosexual Australian adults. Design: Cross-sectional survey of 1,113 adults aged 18–26 years. Setting: Higher education institutions across New South Wales and Victoria, Australia. Method: Participants were recruited during higher-education orientation activities and asked to complete an anonymous survey. The survey captured beliefs about condom use and demographic data. Results: Although males were more likely than females to agree that their partners endorsed the consistent use of condoms, they were less likely to agree that their friends would support consistent condom usage. Males were also more likely to believe that condoms reduce sexual pleasure and give the impression that they are sexually promiscuous. Conclusion: Normalizing the purchase of condoms, repositioning condoms as erotic stimuli, and creating a supportive peer environment using peer-to-peer communication tools may bring about more positive perceptions regarding consistent condom use. Gender-specific safe sex campaigns should also be developed to address the different pattern of condom beliefs held by males and females.

Bridging the gap: early warning, gender and the responsibility to protect

Women, Peace and Security (WPS) scholars and practitioners have expressed reservations about the Responsibility to Protect (R2P) principle because of its popular use as a synonym for armed humanitarian intervention. On the other hand, R2P’s early failure to engage with and advance WPS efforts such as United Nations Security Council (UNSC) resolution 1325 (2000) has seen the perpetuation of limited roles ascribed to women in implementing the R2P principle. As a result, there has been a knowledge and practice gap between the R2P and WPS agendas, despite the fact that their advocates share common goals in relation to the prevention of atrocities and protection of populations. In this article we propose to examine just one of the potential avenues for aligning the WPS agenda and R2P principle in a way that is beneficial to both and strengthens the pursuit of a shared goal – prevention. We argue that the development and inclusion of gender-specific indicators – particularly economic, social and political discriminatory practices against women – has the potential to improve the capacity of early warning frameworks to forecast future mass atrocities.

Social factors and obesity: an investigation of the role of health behaviours

OBJECTIVES: This study evaluated a behavioural model of the relation between social factors and obesity, in which differences in body mass index (BMI) across sociodemographic groups were hypothesized to be attributable to social group differences in health behaviours affecting energy expenditure (physical activity, diet and alcohol consumption and weight control).

METHODS: A total of 8667 adults who participated in the 1995 Australian National Health and Nutrition Surveys provided data on a range of health factors including objectively measured height and weight, health behaviours, and social factors including family status, employment status, housing situation and migration status.

RESULTS: Social factors remained significant predictors of BMI after controlling for all health behaviours. Neither social factors alone, nor health behaviours alone, adequately explained the variance in BMI. Gender-specific interactions were found between social factors and individual health behaviours.

CONCLUSIONS: These results suggest that social factors moderate the relation between BMI and weight-related behaviours, and that the mechanisms underlying sociodemographic group differences in obesity may vary among men and women. Additional factors are likely to act in conjunction with current health behaviours to explain variation in obesity prevalence across sociodemographic groups.

Overweight and obesity prevalence in children based on 6- or 12- month IOTF cut-points: does interval size matter?

The International Obesity Taskforce (IOTF) recommends using age- and gender-specific body mass index (BMI) cut-points for defining the prevalence of overweight and obesity in children. These are given in both 6- and 12-month age intervals. Since the BMI-for-age curves are nonlinear, a degree of bias will be introduced when age intervals are wide. We aimed to quantify this bias in prevalence estimates in 2178 Australian children aged 4-12 years using 12- versus 6-month age intervals. Using the 12-month interval, the prevalence of overweight and obesity was underestimated by 1.4% compared to the 6-month interval estimates; however, this was age-dependent. It overestimated prevalence for 4-year olds, but underestimated it for older ages by up to 2.6%. Overweight prevalence was generally affected more than obesity prevalence. The use of different age intervals for IOTF cut-points introduces a small but systematic bias in prevalence estimates of overweight and obesity.

A prospective study of extreme weight change behaviors among adolescent boys and girls.

This study examined changes in extreme weight change attitudes and behaviors (exercise dependence, food supplements, drive for thinness, bulimia) among adolescent boys and girls over a 16 month period. It also investigated the impact of body mass index, puberty, body image, depression and positive affect on these attitudes and behaviors 16 months later. The participants were 847 young adolescents (411 boys, 436 girls). Participants completed questionnaires evaluating the above variables on three occasions, eight months apart. Girls obtained higher scores on exercise dependence, drive for thinness and bulimia. Changes in depression and body image importance were the strongest predictors of changes in these extreme attitudes and behaviors among boys; changes in depression, body dissatisfaction and body image importance were the strongest predictors for girls. The need for gender specific educational and intervention programs for adolescents are discussed.