BDNF, metabolic risk factors, and resistance training in middle-aged individuals

Introduction and Purpose: Brain-derived neurotrophic factor (BDNF) and physical inactivity contribute to the development of the metabolic syndrome (MetS). There appears to be an association between BDNF and risk factors for MetS, and the effects of resistance training (RT) on BDNF and metabolic risk in middle-aged individuals with high and low numbers of metabolic risk factors (HiMF and LoMF, respectively) are unclear and are the focus of this research.

Methods: Forty-nine men (N = 25) and women (N = 24) aged 50.9 ± 6.2 yr were randomized to four groups, HiMF training (HiMFT), HiMF control (HiMFC), LoMF training (LoMFT), and LoMF control (LoMFC). Before and after 10 wk of RT, participants underwent tests for muscle strength and anthropometry, and a fasting blood sample was taken. Data were analyzed using Spearman correlations and repeated-measures ANOVA.

Results: BDNF was positively correlated with plasma triglycerides, glucose, HbA1C, and insulin resistance. BDNF was elevated in HiMF compared with LoMF (904.9 ± 270.6 vs 709.6 ± 239.8 respectively, P = 0.01). Training increased muscle strength and lean body mass but had no effect on BDNF levels or any examined risk factors.

Conclusion: BDNF levels correlated with risk factors for MetS and were elevated in individuals with HiMF. RT had no effect on BDNF levels or other risk factors for MetS. As RT has an effect on muscle strength and lean body mass, it should be added to other nonpharmacological interventions for middle-aged individuals with HiMF such as aerobic and/or diet.

Five-year change in cardiovascular risk factors according to education level : the Australian diabetes, obesity and lifestyle (AusDiab) study

Background: Lower socioeconomic status (SES) is strongly associated with a higher prevalence of major cardiovascular risk factors, but few studies have examined changes in these risk factors over time according to SES. We aimed to determine whether SES is a predictor of the change in cardiovascular risk factor levels in a contemporary Australian adult cohort

Methods: Participants in the population-based AusDiab study aged 25+ years who attended both baseline and 5-year follow-up examinations (n=5 954) were categorised according to their level of education at baseline. Cardiovascular risk factor data at both time points were ascertained through questionnaire and physical measurement. Analysis was stratified by gender.

Results: The mean levels of systolic blood pressure, total cholesterol and the prevalence of smoking decreased between the two time points across all educational categories. Increases were also seen in mean BMI and the prevalence of diabetes. For blood pressure, the smallest decrease was seen among men with lower education (age-adjusted difference from higher education 2.8 mmHg, 95% CI 1.0 to 4.6). For total cholesterol, the decrease was greatest among women with lower education (age-adjusted difference from higher education 0.11 mmol/l, 95% CI 0.19 to 0.02). Among those "not at risk" at baseline for each risk factor, women with lower education were more likely than those with higher education to progress to being "at risk" for BMI (age-adjusted odds ratio 1.60, 95% CI 1.09 to 2.35).

Conclusion: Educational gradients narrowed for total cholesterol in women, but widened for systolic blood pressure in men and remained static for other risk factors. Lower education was also associated with an earlier onset of overweight or obesity in women. Given current socioeconomic gradients in risk factors levels, these findings suggest that social inequalities in CVD will persist and may even widen in the future.

Television viewing habits associated with obesity risk factors: a survey of Melbourne schoolchildren.

Objectives: To examine whether children’s television viewing may be a useful indicator of risk of obesity-promoting versus healthy eating behaviours, low-level physical activity (PA) and overweight or obesity among children of primary school entry and exit ages. Design: Cross-sectional study, stratified by area-level socioeconomic status. Participants and setting: 1560 children (613 aged 5–6 years [50% boys], and 947 aged 10–12 years [46% boys]) from 24 primary schools in Melbourne, Australia, randomly selected proportionate to school size between 1 November 2002 and 30 December 2003 . Main outcome measures: Parents’ reports of the time their child spends watching television, their participation in organised physical activities (PA), and their food intake; each child’s measured height and weight and their PA levels as assessed by accelerometry for one week. Results: After adjusting for the age and sex of child, the parents’ level of education, clustering by school, and all other health behaviour variables, children who watched television for > 2 h/day were significantly more likely than children who watched television for ≤ 2 h/day to: to have one or more serves/day of high energy drinks (adjusted odds ratio [AOR], 2.31; 95% CI, 1.61–3.32), and to have one or more serves/day of savoury snacks (AOR, 1.50; 95% CI, 1.04–2.17). They were also less likely to have two or more serves/day of fruit (AOR, 0.58; 95% CI, 0.46–0.74), or to participate in any organised PA (AOR, 0.52; 95% CI, 0.34–0.80). Conclusions: Health practitioners in the primary care setting may find that asking whether a child watches television for more than 2 hours daily can be a useful indicator of a child’s risk of poor diet and low physical activity level.

Pressure injury: an exploration of the relationship between risk factors and interface pressure

Pressure injuries are a serious risk for patients admitted to hospital and are thought to result from a number of forces operating on skin tissue (pressure, shear and friction). Most research on interface pressure (IP) has taken place using healthy volunteers or mannequins. Little is currently known about the relationship between pressure injury risk and IP for hospital patients. This relationship was investigated with a sample of 121 adult hospital patients. Pressure injury risk was evaluated using the Waterlow Risk Assessment Tool (WRAT) and IP was measured at the sacrum using a Tekscan ClinSeatTM IP sensor mat. Other factors considered were body mass index (BMI), blood pressure, reason for hospital admission, comorbidities and admission route to hospital. Patients were classified according to WRAT categories (‘low risk’, ‘at risk’, ‘high risk’, ‘very high risk’) and then remained still on a standard hospital mattress for 10 minutes while IP was measured. Participants in the ‘low risk’ group were significantly younger than all other groups (p<0.001) and there were some group differences in BMI. IP readings were compared between the ‘low risk’ group and all of the participants at greater risk. The ‘low risk’ group had significantly lower IP at the sacrum on a standard hospital mattress than those at greater risk (p=0.002). Those at greater risk tended to have IP readings at the low end of the compromised IP range. This study is significant because it describes a new, clinically relevant methodology and presents findings that challenge clinician assumptions about the relationships between pressure injury risk assessment and IP.

Impact of an empowerment-based parent education program on the reduction of youth suicide risk factors

Purpose: To evaluate the impact of parent education groups on youth suicide risk factors. The potential for informal transmission of intervention impacts within school communities was assessed.

Methods: Parent education groups were offered to volunteers from 14 high schools that were closely matched to 14 comparison schools. The professionally led groups aimed to empower parents to assist one another to improve communication skills and relationships with adolescents. Australian 8th-grade students (aged 14 years) responded to classroom surveys repeated at baseline and after 3 months. Logistic regression was used to test for intervention impacts on adolescent substance use, deliquency, self-harm behavior, and depression. There were no differences between the intervention (n = 305) and comparison (n = 272) samples at baseline on the measures of depression, health behavior, or family relationships.

Results: Students in the intervention schools demonstrated increased maternal care (adjusted odds ratio [AOR] 1.9), reductions in conflict with parents (AOR .5), reduced substance use (AOR .5 to .6), and less delinquency (AOR .2). Parent education group participants were more likely to be sole parents and their children reported higher rates of substance use at baseline. Intervention impacts revealed a dose-response with the largest impacts associated with directly participating parents, but significant impacts were also evident for others in the intervention schools. Where best friend dyads were identified, the best friend’s positive family relationships reduced subsequent substance use among respondents. This and other social contagion processes were posited to explain the transfer of positive impacts beyond the minority of directly participating families.

Conclusions: A whole-school parent education intervention demonstrated promising impacts on a range of risk behaviors and protective factors relevant to youth self-harm and suicide.

Effects of gamma-tocopherol supplementation on thrombotic risk factors

Objective: The antioxidant activity of vitamin E is derived primarily from alpha-tocopherol (α-T) and gammatocopherol (γ-T). Results of epidemiological studies have demonstrated an inverse relationship between vitamin E intake and coronary disease. However, the results of clinical trials using α-T are equivocal. We determined the effect of 5 weeks of 100 mg/d or 200 mg/d γ-T supplementation on thrombotic markers such as platelet reactivity, lipid profile and the inflammation marker C-reactive protein (CRP). Methods and results: Fourteen healthy subjects consumed 100 mg/day while 13 consumed 200 mg/d of γ-T and 12 received placebo (soybean capsules with less than 5 mg/d γ-T) in a double-blinded parallel study design. Fasting pre and post dose blood samples were analysed. Blood γ-T concentrations increased significantly (p<0.05) relative to dose during the intervention period. Both groups receiving active ingredients showed significantly lower platelet activation after supplementation (p<0.05). Subjects consuming 100 mg/d γ-T had significantly decreased LDL cholesterol, platelet aggregation and mean platelet volume (MPV) (p<0.05). Little effect of γ-T was observed on other parameters. Conclusions: These data suggest that γ-T  supplementation may have a permissive role in decreasing the risk of
thrombotic events by improving lipid profile and reducing platelet activity.

Family risk factors for cannabis use: a population-based survey of Australian secondary school students

The objective of this study was to investigate relationships between adolescent cannabis use and indices of parent - child attachment, family functioning and parent attitudes to drugs and delinquency. A total of 2848 year 9 and 2363 year 11 students participated in the Victorian Adolescent Health and Well-Being Survey (1999). The study was a school-based random sample of 535 metropolitan and rural, government and non-government secondary schools throughout Victoria, Australia. Cannabis use was defined as 'any' and 'weekly' use in the last 30 days. Multivariate logistic regression was used to identify independent associations between cannabis use and parent - child attachment, family functioning and parent attitudes to drugs and delinquency. Cannabis use in year 9 was associated with permissive parent attitudes to drugs and delinquency (any use: adjusted odds ratio (OR) = 8.1; weekly use: adjusted OR = 7.6), and was particularly sensitive to small changes in the quality of the parent - child relationship with risk increasing threefold for those describing their attachment as 'good' compared with 'very good' (any use: adjusted OR = 2.8, weekly use adjusted OR = 2.9). A similar, but more moderate pattern association was evident in year 11. After adjusting for other family and background factors, poor family functioning showed minimal association with level of cannabis use at both year levels. Results suggest that intervention efforts might sensibly target strengthening parent - children relationships and promoting less permissive parent attitudes to drug use.

Environmental risk factors of young onset Parkinson`s disease: a case-control study

While the cause of Parkinson's disease (PD) remains unknown, recent evidence suggests certain environmental factors, such as well water drinking, herbicides and pesticides exposure, and neurotoxins, may trigger the chain of oxidative reactions culminating in the death of dopaminergic neurons in substantia nigra to cause parkinsonism. Most studies to date focused on PD with old age onset. However, there is a peculiar group of parkinsonian patients, the young onset Parkinson's disease (YOPD), in whom the age of onset is before 40. It is intriguing to know whether earlier exposure to the putative neurotoxin(s) may contribute to the earlier onset. We therefore conducted this case-control study in which 60 PD patients, 30 YOPD patients and the same number of age- and sex-matched young controls were included. Using logistic regression, we found well water drinking and head injury were risk factors for the development of YOPD. When YOPD patients were compared with PD, we found head injury and exercise were the significant predictors. Keeping all other variables constant, head injury was a risk factor and exercise appeared to be a protective factor. We conclude early exposure to well water drinking and head trauma may trigger and expedite the appearance of parkinsonian features, but such acceleration may be prevented through regular exercise.

Prevalence of and risk factors for erectile dysfunction in Hong Kong diabetic patients

Aim To estimate the prevalence of erectile dysfunction (ED) in Chinese diabetic men and to identify its risk factors, we carried out a cross-sectional survey of 500 Chinese diabetic men attending a community hospital diabetic clinic in Hong Kong.
Methods Patients were interviewed and asked to report on their experience of ED as defined in the National Institutes of Health Consensus Conference 1993. Diabetic complications and patient clinical data were obtained from patients' medical records.
Results Of the 486 patients studied, the prevalence of ED was 63.6% (95% confidence interval 59.3–67.9%). The prevalence of ED increased with age, from 33.3% to 73.8% for diabetic men aged between 21 and 80 years (P = 0.001). Severity of ED also increased with age. Among diabetic men with ED, there was no report of complete ED for diabetic men aged 40 years and below, whereas the proportion of patients with complete ED increased from 7.4% to 71.1% between the ages of 41 and 80 years. ED occurred early in the course of the disease, with a prevalence increasing from 56.0% in men with diabetes mellitus (DM) for < 5 years to 72.0% in those with DM for > 20 years (P = 0.038). Duration of DM was also associated with severity; the proportion of patients with complete ED increased from 30.8% for those with DM for < 5 years to 72.2% for those with DM for ≥ 20 years (P < 0.001). Using logistic regression analysis, DM duration, diabetic complications including retinopathy, abnormal albuminuria and sensory neuropathy, and higher level of education were associated with a higher risk of ED. By polychotomous logistic regression, age was the only factor found to be associated with the severity of ED, after adjusting for other variables.
Conclusions Chinese diabetic patients have a prevalence of self-reported ED that appears to be higher than that of Western populations. This may be due to cultural differences and the association of abnormal albuminuria and hypertension.

Markers and risk factors for HCV, HBV and HIV in a network of injecting drug users in Melbourne

Background and aims: Current injecting drug users (IDU) in major street drug markets within greater Melbourne were recruited to a longitudinal study on blood borne viruses. Here we investigated risk factors for hepatitis C virus (HCV), hepatitis B virus (HBV) and HIV infection in these IDU at the time of their recruitment.

Methods : Three hundred and eighty-two IDU completed detailed questionnaires on their drug use and risk behaviours, and provided blood samples for serology testing. These data were analysed using univariate and multivariate techniques.

Results : The overall prevalence of exposure to HCV, HBV and HIV was estimated at 70%, 34% and <1%, respectively. Independent predictors of HCV exposure were history of imprisonment (RR 1.34, 95% CI 1.19–1.52), use of someone else's needle or syringe (RR 1.23, 95% CI 1.07–1.42), >7.6 years length of time injecting (RR 1.21, 95% CI 1.07–1.37), and originating from Vietnam (RR 1.12, 95% CI 1.07–1.18). Independent predictors of HBV exposure were HCV exposure (RR 2.15, 95% CI 1.35–3.43), >7.6 years length of time injecting (RR 1.57, 95% CI 1.17–2.13) and originating from outside Australia (RR 1.60, 95% CI 1.22–2.10). Neither prison- nor community-applied tattoos predicted HCV or HBV exposure. Up to 31% of IDU who injected for 1 year or less were HCV antibody positive, as were 53% of those who injected for 2 years or less.

Conclusions : Ongoing engagement with young IDU, through the provision of harm reduction education and resources, is critical if we are to address blood borne viral infections and other health and social harms associated with injecting drug use.

Hepatitis C virus infection in South Australian prisoners : seroprevalence, seroconversion, and risk factors

Objectives : To determine entry antibody seroprevalence and seroconversion to hepatitis C virus (HCV) and associated risk factors in newly incarcerated prisoners.

Methods : Males and females entering South Australian prisons completed risk factor surveys and were offered HCV-antibody testing. Participants completed additional surveys and, if HCV-negative at last test, underwent further antibody tests at 3-monthly intervals for up to 15 months. Data were analyzed using univariate and multivariate techniques.

Results : HCV seroprevalence among 662 prison entrants was estimated at 42%. Previous injecting history was highly prevalent at entry (64%) and both community and prison injecting independently predicted entry HCV status. Tattooing was not an important risk factor. While community exposure could not be ruled out, three seroconversions were noted in 148 initially HCV-seronegative individuals occurring in a median 121 days – 4.6 per 100 person-years. Prison injecting was infrequently reported, but HCV-seropositive participants were significantly more likely to commence IDU in prison than seronegative participants (p = 0.035).

Conclusions : Entry HCV seroprevalence in South Australian prisoners is extremely high and may have contributed to a ‘ceiling effect’, minimizing the observable seroconversion rate. Greater frequency of injecting among those already infected with HCV represents a significant threat to other prisoners and prison staff.

Risk factors for female sexual dysfunction in the general population : exploring factors associated with low sexual function and sexual distress

Introduction. No previous population-based studies have used validated instruments to measure female sexual dysfunction (FSD) in Australian women across a broad age range.
Aim. To estimate prevalence and explore factors associated with the  components of FSD.
Main Outcome Measures. Sexual Function Questionnaire measured low sexual function. Female Sexual Distress Scale measured sexual distress.
Methods. Multivariate analysis of postal survey data from a random sample of 356 women aged 20–70 years.
Results. Low desire was more likely to occur in women in relationships for 20–29 years (odds ratio 3.7, 95% confidence intervals 1.1–12.8) and less likely in women reporting greater satisfaction with their partner as a lover (0.3, 0.1–0.9) or who placed greater importance on sex (0.1, 0.03–0.3). Low genital arousal was more likely among women who were perimenopausal (4.4, 1.2–15.7), postmenopausal (5.3, 1.6–17.7), or depressed (2.5, 1.1–5.3), and was less likely in women taking hormone therapy (0.2, 0.04–0.7), more educated (0.5, 0.3–0.96), in their 30s (0.2, 0.1–0.7) or 40s (0.2, 0.1–0.7), or placed greater importance on sex (0.2, 0.05–0.5). Low orgasmic function was less likely in women who were in their 30s (0.3, 0.1–0.8) or who placed greater importance on sex (0.3, 0.1–0.7). Sexual distress was positively associated with depression (3.1, 1.2–7.8) and was inversely associated with better communication of sexual needs (0.2, 0.05–0.5). Results were adjusted for other covariates including age, psychological, socioeconomic, physiological, and relationship factors.
Conclusions. Relationship factors were more important to low desire than age or menopause, whereas physiological and psychological factors were more important to low genital arousal and low orgasmic function than relationship factors. Sexual distress was associated with both psychological and relationship factors.

Effects of dietary constituents on coronary heart disease risk factors

Coronary Heart Disease (CHD) is a major cause of death in Western countries. Mediterranean and Asian populations have a lower risk of death from CHD compared to Westernised population, as do vegetarian versus omnivorous populations. Dietary constituents of traditional diets consumed by these populations are thought to influence both the classical risk factors for CHD, and the more recently identified risk factors, such as oxidative modification of low density lipoprotein (LDL), LDL particle size, arterial compliance and haemostatic factors. The aim of this thesis was to examine the effects of several food components, particularly soybean and monounsaturated fat (MUFA), on CHD risk factors through 3 carefully controlled dietary interventions, and a cross-sectional study. A randomised crossover dietary intervention study was conducted in 42 healthy males to investigate the effect on CHD risk factors of replacing lean meat with tofu, a soybean product regularly consumed by Asian populations, while controlling all other dietary factors. The tofu diet resulted in significantly lower total cholesterol and triacylglycerol levels compared to the lean meat diet, and LDL particles that were more resistant to in vitro oxidative modification. However, insulin, fibrinogen, factor VII, and lipoprotein (a) were not significantly different on the 2 diets. A postprandial study was subsequently conducted to investigate any acute effects of a tofu test meal on the oxidative modification of LDL in 16 male subjects. There was no significant difference between the susceptibility of LDL to oxidative modification before and after the tofu meal. Twenty eight healthy subjects completed a separate randomised crossover dietary intervention comparing a high MUFA fat diet, using an Australian high oleic sunflower oil, with a low fat, high carbohydrate diet on CHD risk factors. The high MUFA oil diet significantly increased high density lipoprotein cholesterol compared to the low fat diet as well as producing LDL that were more resistant to oxidative modification. Neither the size of the LDL particle nor arterial compliance were significantly different on the 2 diets. Twelve matched pairs of vegetations and omnivores were also studies to compare the habitual diet of a low and higher risk population group, to compare their risk factors and identify dietary constituents that may explain the differences. The vegetarians consumed less saturated fat (SFA) and dietary cholesterol while consuming more polyunsaturated fat, dietary fibre and vitamin E compared to omnivores. The vegetarians had lower total cholesterol, LDL cholesterol and triacylglycerol levels compared to the omnivores and had LDL particles that were more resistant to in vitro oxidation. These findings contribute to our knowledge about the dietary constituents that can alter some CHD risk factors in healthy subjects, and which could reduce the risk of developing CHD. Investigations in high risk groups might reveal even more benefits.

Adolescent and pre-conception risk factors for perinatal depression

Women who experienced psychiatric disorder during adolescence reported a 5̃-fold increased risk for depressive symptoms during pregnancy and during the postnatal period. A number of other adolescent and pre-conception risk factors, such as persistent stress and hormonal volatility, were also found to be implicated in the development of perinatal depression. Four case studies of children with profound and pervasive attachment-related disturbances are presented in the portfolio in order to highlight the shortcomings of the current diagnostic criteria for reactive attachment disorder in infancy or early childhood.