Interventions in sports settings to reduce risky alcohol consumption and alcohol-related harm: a systematic review

Background: Elevated levels of risky alcohol consumption and alcohol-related harm have been reported for sportspeople and supporters compared to non-sporting populations. Limited systematic reviews have been conducted to assess the effect of interventions targeting such behaviours. Methods: A review was undertaken to determine if interventions implemented in sports settings decreased alcohol consumption and related harms. Studies were included that implemented interventions within sports settings; measured alcohol consumption or alcohol-related injury or violence and were either randomised controlled trials, staggered enrolment trials, stepped-wedged trials, quasi-randomised trials, quasi-experimental trials or natural experiments. Studies without a parallel comparison group were excluded. Studies from both published and grey literature were included. Two authors independently screened potential studies against the eligibility criteria, and two authors independently extracted data from included studies and assessed risk of bias. The results of included studies were synthesised narratively. Results: The title and abstract of 6382 papers and the full text of 45 of these papers were screened for eligibility. Three studies met the inclusion criteria for the review. One of the included studies was a randomised controlled trial (RCT) of a cognitive-behavioural intervention with athletes within an Olympic training facility in the USA. The study reported a significant change in alcohol use between pre-test and follow-up between intervention and control groups. The other two studies were RCTs in community sports clubs in Ireland and Australia. The Australian study found a significant intervention effect for both risky alcohol consumption at sports clubs and overall risk of alcohol-related harm. The Irish study found no significant intervention effect. Conclusions: A limited number of studies have been conducted to assess the effect of interventions implemented in sports settings on alcohol consumption and related harms. While two of the three studies found significant intervention effects, it is difficult to determine the extent to which such effects are generalisable. Further controlled trials are required in this setting. Systematic review registration: PROSPERO CRD4201400173

The role of zinc in chronic disease

Research Doctorate - Doctor of Philosophy (PhD)This thesis by publication is composed of a background, rationale & aims, brief literature review, four papers, and a final chapter providing conclusions. All but one of the papers relates to prospectively investigating the role of dietary zinc in chronic disease, which has been examined inadequately in the literature. At this stage of the thesis, three of the four papers have been accepted for publication in peer-reviewed journals. The final paper has been currently submitted to a peer-reviewed journal that is internationally recognised. Chapter 1 outlines the background, structure of the thesis and describes the rationale and aims of the research. Chapter 2 provides a summary of the general literature on the current understanding of the role of zinc in normal human physiology and chronic disease in particular. This chapter does not review literature specific to each health outcome investigated, which is presented and discussed in each of the chapters dealing with these health outcomes. Chapter 3 (Paper 1), "Is Serum Zinc Associated with Pancreatic Beta Cell Function and Insulin Sensitivity in Pre-Diabetic and Normal Individuals? Findings from the Hunter Community Study" reports the association between serum zinc concentration and Homeostasis Model Assessment (HOMA) parameters cross-sectionally in a random sample of 452 older community-dwelling men and women in Newcastle, NSW, Australia. HOMA parameters were found to be significantly different between normoglycaemic and prediabetes groups (p<0.001). In adjusted linear regression, higher serum zinc concentration was associated with increased insulin sensitivity (p = 0.01) in the prediabetic group and a significant association between smoking and worse insulin activity was also observed. This paper has been published in PLOS ONE. Chapter 4 (Paper 2), "Is dietary zinc protective for type 2 diabetes? Results from the Australian longitudinal study on women's health," reports the longitudinal association of dietary zinc with incident type 2 diabetes in 8921 women, aged 50-55 years at baseline over 6-years of follow-up. 333 incident cases of type 2 diabetes were identified at the end of follow-up and after adjustment for dietary and non-dietary factors, the highest quintile of dietary zinc intake had almost half the odds of developing type 2 diabetes (OR = 0.50, 95% C.I. 0.32-0.77) compared with the lowest quintile. Similar findings were observed for the zinc/iron ratio; the highest quintile had half the odds of developing type 2 diabetes (OR = 0.50, 95% C.I. 0.30-0.83) after adjustment of covariates, This paper has been published in BMC Endocrine Disorders. Chapter 5 (Paper 3), "Dietary zinc is associated with a lower incidence of depression: Findings from two Australian cohorts" reports the longitudinal association of dietary zinc with incident depression in two large Australian cohort aged 50 and above over 6-years of follow-up. Both studies showed that low dietary zinc intake is associated with a greater incidence of depression in both men and women, after adjusting for potential cofounders. Compared to those with the lowest zinc intake, those with the highest zinc intake had significantly lower odds of developing depression with a reduction of about 30-50%. This paper has been published in Journal of Affective Disorders. Chapter 6 (Paper 4), "Prospective Study of Dietary Zinc Intake and Risk of Cardiovascular Disease in Women," reports the longitudinal association of dietary zinc and cardiovascular disease (CVD) over 6-years of follow-up in a cohort of women aged 50-55 years at baseline. The study showed that risk of CVD increases with increased intake of dietary zinc. Compared to those in the lowest quintile of zinc intake those with in the highest quintile of zinc intake had significantly higher odds of developing CVD (OR = 1.67, 95% CI 1.08, 2.62) at the end of the follow-up. The same finding was also observed between energy-adjusted zinc to iron ration and risk of developing CVD. This has been submitted to the 'Nutrition, Metabolism & Cardiovascular Diseases' Journal in July 2014. Conclusions (Chapter 7). This program of research provided formative assessment of the potential role of dietary zinc in the following chronic diseases: Type 2 diabetes, depression and cardiovascular diseases. Given that this thesis studies were carried out in an Australian population, additional prospective cohort studies in other populations are needed to support the causal relationship between dietary zinc and these health outcomes. Hence, research that employs a longitudinal design, and rigorous randomized controlled trials aimed at determining the efficacy of zinc in the prevention of chronic disease are needed. Furthermore, studies looking into the precise role and mechanisms for the effects of zinc compared to other essential nutrients from diet are needed to establish and reinforce the importance of dietary zinc in this chronic disease and other diseased state

Is serum zinc associated with pancreatic beta cell function and insulin sensitivity in pre-diabetic and normal individuals? Findings from the Hunter Community Study.

AIM: To determine if there is a difference in serum zinc concentration between normoglycaemic, pre-diabetic and type-2 diabetic groups and if this is associated with pancreatic beta cell function and insulin sensitivity in the former 2 groups. METHOD: Cross sectional study of a random sample of older community-dwelling men and women in Newcastle, New South Wales, Australia. Beta cell function, insulin sensitivity and insulin resistance were calculated for normoglycaemic and prediabetes participants using the Homeostasis Model Assessment (HOMA-2) calculator. RESULT: A total of 452 participants were recruited for this study. Approximately 33% (N = 149) had diabetes, 33% (N = 151) had prediabetes and 34% (N = 152) were normoglycaemic. Homeostasis Model Assessment (HOMA) parameters were found to be significantly different between normoglycaemic and prediabetes groups (p<0.001). In adjusted linear regression, higher serum zinc concentration was associated with increased insulin sensitivity (p = 0.01) in the prediabetic group. There was also a significant association between smoking and worse insulin sensitivity. CONCLUSION: Higher serum zinc concentration is associated with increased insulin sensitivity. Longitudinal studies are required to determine if low serum zinc concentration plays a role in progression from pre-diabetes to diabetes

Prospective Study of Dietary Zinc Intake and Risk of Cardiovascular Disease in Women

Several animal and human studies have shown that zinc is associated with cellular damage and cardiac dysfunction. This study aims to investigate dietary zinc and the zinc-iron ratio, as predictors of incident cardiovascular disease (CVD) in a large longitudinal study of mid-age Australian women (aged 50–61 years). Data was self-reported and validated food frequency questionnaires were used to assess dietary intake. Energy-adjusted zinc was ranked using quintiles and predictors of incident CVD were examined using stepwise logistic regression. After six years of follow-up, 320 incident CVD cases were established. A positive association between dietary zinc intake, zinc-iron ratio and risk of CVD was observed even after adjusting for potential dietary and non-dietary confounders. Compared to those with the lowest quintile of zinc, those in the highest quintile (Odds Ratio (OR) = 1.67, 95% Confidence Interval (CI) = 1.08–2.62) and zinc-iron ratio (OR = 1.72, 95% CI = 1.05–2.81) had almost twice the odds of developing CVD (p trend = 0.007). This study shows that high dietary zinc intake and zinc-iron ratio is associated with a greater incidence of CVD in women. Further studies are required detailing the source of zinc and iron in diet and their precise roles when compared to other essential nutrients

Baseline characteristics by participants fasting blood glucose status.

<p>Baseline characteristics by participants fasting blood glucose status.</p

Adjusted linear regression analysis for HOMA parameters in pre-diabetic participants.

<p>CI: Confidence Interval.</p

Prevalence of and associations with excessive daytime sleepiness in an Australian older population

The aim of this research is to estimate the prevalence of excessive daytime sleepiness in an older population and associations with sociodemographic, health, and lifestyle factors using a cross-sectional, population-based study. Participants were men (1560) and women (1759), aged 55 to 85 years, enrolled in the Hunter Community Study, a longitudinal study of aging. Measurements were self-reported questionnaires, biochemical measures, and clinical measures. Of the 3319 participants, 3053 participants completed the Epworth Sleepiness Scale questionnaire. The prevalence of excessive daytime sleepiness was 15.3% overall and this was higher in males. In adjusted multivariate analysis, gender, working full time, body mass index, high-density and low-density lipoprotein cholesterol, Center for Epidemiologic Studies-Depression scale score, and Kessler psychological distress score were associated with excessive daytime sleepiness. Given the high prevalence of excessive daytime sleepiness observed in this study, further investigation and/or interventions to reduce adverse health outcomes, especially in males is warranted

Is serum zinc level associated with prediabetes and diabetes?: A cross-sectional study from Bangladesh

Aims: To determine serum zinc level and other relevant biological markers in normal, prediabetic and diabetic individuals and their association with Homeostasis Model Assessment (HOMA) parameters. Methods: This cross-sectional study was conducted between March and December 2009. Any patient aged ≥30 years attending the medicine outpatient department of a medical university hospital in Dhaka, Bangladesh and who had a blood glucose level ordered by a physician was eligible to participate. Results: A total of 280 participants were analysed. On fasting blood sugar results, 51% were normal, 13% had prediabetes and 36% had diabetes. Mean serum zinc level was lowest in prediabetic compared to normal and diabetic participants (mean differences were approximately 65 ppb/L and 33 ppb/L, respectively). In multiple linear regression, serum zinc level was found to be significantly lower in prediabetes than in those with normoglycemia. Beta cell function was significantly lower in prediabetes than normal participants. Adjusted linear regression for HOMA parameters did not show a statistically significant association between serum zinc level, beta cell function (P = 0.07) and insulin resistance (P = 0.08). Low serum zinc accentuated the increase in insulin resistance seen with increasing BMI. Conclusion: Participants with prediabetes have lower zinc levels than controls and zinc is significantly associated with beta cell function and insulin resistance. Further longitudinal population based studies are warranted and controlled trials would be valuable for establishing whether zinc supplementation in prediabetes could be a useful strategy in preventing progression to Type 2 diabetes

Adjusted linear regression analysis for HOMA parameters with serum zinc as continuous value in prediabetic participants (N = 35).

†<p>CI: Confidence Interval.</p

Adjusted linear regression analysis for HOMA parameters with serum zinc as category in normal participants (N = 142).

*<p>Coeff: Coefficient,</p>*<p>CI: Confidence Interval.</p