Michelle Louise Gatton

The existing literature predominantly focuses on clinical conditions related to gambling, with evidence suggesting the co-occurrence of gambling disorders, major depressive disorders, and personality disorders. This study aimed to broaden our understanding beyond clinical conditions by investigating the impact of different gambling activity groups on mental wellbeing. These activity groups were identified using latent class analysis, which enabled a person-centered approach to examine the types and the number of gambling activities as well as expenditure levels, as a single latent variable. Based on the Household, Income and Labour Dynamics in Australia (HILDA) Survey, our findings suggested that gambling activity groups were associated with reduced mental wellbeing through problem gambling symptoms. Among respondents with the same levels of problem gambling symptoms and age, men who engaged in multiple gambling activities with high spending tended to have better mental wellbeing than those primarily gambling on lotteries. In contrast, women's mental wellbeing did not differ across gambling activity groups. This study clarifies the roles of problem gambling symptoms and gambling activity groups in reduced mental wellbeing. Gambling activity groups featuring multiple activities, high spending, and electronic gaming machines (EGMs) were related to problem gambling symptoms. This study shifts the focus from examining how gambling influences specific mental health conditions or symptoms to exploring its impact on overall mental wellbeing. The empirical evidence supports the expansion of targeted, evidence-based strategies beyond treatments to preventive measures that promote mental wellbeing.

Background: Radical cure of Plasmodium vivax infections is key to the control of vivax malaria. However, the standard doses of 8-aminoquinoline drugs used for radical cure can cause severe haemolysis in G6PD-deficient patients. The availability of near-patient G6PD tests could increase use of primaquine (PQ), however direct evidence of the impacts that G6PD testing has on downstream patient outcomes, such as haemolysis and recurrence is lacking. Methodology/Principle findings: A linked-evidence model was created to investigate changes in the number of severe haemolysis events and P. vivax recurrences within 6 months of treatment when qualitative G6PD testing was used to guide PQ treatment (0.25mg/kg/day for 14 days and 0.5mg/kg/day for 7 days), compared to prescribing 14-day PQ with no G6PD testing. In the model patients identified as G6PD-deficient received 8-week PQ (0.75mg/kg/week). The model was used to simulate scenarios with 1%, 5% and 10% prevalence of G6PD-deficiency (G6PDd) in theoretical populations of 10,000 male and female P. vivax patients and initially assumed 100% adherence to the prescribed PQ regiment. Results illustrate that G6PD testing to guide the 14-day PQ regiment reduced severe haemolysis by 21–80% and increased recurrences by 3–6%, compared to applying the 14-day PQ regiment without G6PD testing. Results for the 7-day PQ regiment informed by G6PD testing were mixed, dependent on G6PDd prevalence and sex. When adherence to the PQ regiments was less than perfect the model predicted reductions in the number of recurrences at all prevalence levels, provided adherence to 7-day PQ was 5–10% higher than adherence to the 14-day regiment. Conclusions/Significance: Introduction of G6PD testing to guide PQ treatment reduces severe haemolysis events for the 14-day regiment, and the 7-day regiment in higher G6PDd prevalence settings, compared to use of 14-day PQ without G6PD testing when all patients adhere to the prescribed PQ treatment. At a population level, there were increases in recurrences, but this could be resolved when the 7-day regiment was used and had superior adherence compared to the 14-day regiment.

Background: Due to the relatively low numbers of households in high income countries experiencing food insecurity most studies conflate the levels of severity, which masks between- and within-country differences. This study aims to describe the characteristics of individuals living in high income countries who were moderately or severely food insecure and investigates temporal trends in prevalence. It assesses these characteristics in comparison to those who were food secure. Methods: This is a secondary analysis of data collected by the FAO Voices of the Hungry between 2014–2018. The data were collected during the annual Gallup World Polls of nationally representative samples using the Food Insecurity Experience Scale. Data from 34 highly developed, wealthy countries were analysed. The age, gender, income, education, area of residence and household structure of individuals experiencing moderate/severe food insecurity (FI), and severe FI, were compared using ANOVA, Welch’s F, Pearson’s Chi-square, and Linear-by-Linear Association, dependent on the variable of interest. Hierarchical cluster analysis was used to group countries according to their prevalence of moderate/severe FI, and severe FI. Results: Overall, 6.5% of the weighted sample were moderately/severely food insecure (M-SFI), while 1.6% were severely food insecure. M-SFI individuals were present in all 34 countries, in all years and across all education levels and income quintiles. The proportion of individuals experiencing moderate/severe FI varied between years and countries. Fifteen countries showed a significant downward temporal trend in prevalence of moderate/severe FI (p < 0.001), while three countries demonstrated an increasing temporal trend driven by increasing prevalence in those aged 65 years or less (p < 0.001). Comparing individuals experiencing moderate versus severe FI showed over-representation of males, single adult households and lower household income in the severe FI group. Conclusions: Individuals across all income, education and age categories living in high income countries are experiencing moderate/severe food insecurity, but with higher prevalence in those experiencing more disadvantage. Over the study period some countries experienced escalating while others demonstrated decreasing moderate/severe FI trends. This comparison of countries with similar economic and human development indices highlights an opportunity to investigate subtle variations in social, economic and education policy that could have profound impacts on food insecurity.

Healthy, diverse diets are vital for life. In low/middle-income countries, however, the focus is more on food quantity rather than diet quality. This study assessed household diet diversity (HDD) in the Vietnamese Mekong Delta and its associations with household food insecurity (HFI) and household food availability (HFA) controlling for socioeconomic factors. Primary food-preparers in 552 randomly selected households in two rural provinces were interviewed about socioeconomic factors, HDD, HFI, and HFA. More than 80% of households predominantly consumed energy-dense foods, whereas less than 20% consumed nutrient-dense foods. Lower HDD was associated with HFI, lower HFA, for the Khmer ethnic minority, and low livelihood capitals (landlessness, low expenditure, debt) and low utensil scores. The study highlighted the need to provide improved food and nutrition policies that increase availability and access to diverse and healthy foods as well as reduce poverty and increase incomes for at-risk rural and ethnic minority groups.

Household food security in Vietnam remains tenuous. We surveyed 552 households to investigate household food insecurity (HFI) in rural districts in the Vietnamese Mekong Delta. HFI prevalence was 34.4% and 48.4% in the last month and last year, respectively. Khmer households were twice as likely to experience HFI compared to their Kinh counterparts. The primary factors associated with HFI were weak livelihood assets including lower natural, financial, and human assets (being landless, low incomes), physical and social assets (poor market access, social networks), lower kitchen utensil scores, belonging to a minority and experiencing financial, agricultural, and extreme weather shocks.

Malaria rapid diagnostic tests (RDTs) are dominated by products which use histidine-rich protein 2 (HRP2) to detect Plasmodium falciparum. The emergence of parasites lacking the pfhrp2 gene can lead to high rates of false-negative results amongst these RDTs. One solution to restore the ability to correctly diagnose falciparum malaria is to switch to an RDT which is not solely reliant on HRP2. This study used an agent-based stochastic simulation model to investigate the impact on prevalence and transmission caused by switching the type of RDT used once false-negative rates reached pre-defined thresholds within the treatment-seeking symptomatic population. The results show that low transmission settings were the first to reach the false-negative switch threshold, and that lower thresholds were typically associated with better long-term outcomes. Changing the diagnostic RDT away from a HRP2-only RDT is predicted to restore the ability to correctly diagnose symptomatic malaria infections, but often did not lead to the extinction of HRP2-negative parasites from the population which continued to circulate in low density infections, or return to the parasite prevalence and transmission levels seen prior to the introduction of the HRP2-negative parasite. In contrast, failure to move away from HRP2-only RDTs leads to near fixation of these parasites in the population, and the inability to correctly diagnose symptomatic cases. Overall, these results suggest pfhrp2-deleted parasites are likely to become a significant component of P. falciparum parasite populations, and that long-term strategies are needed for diagnosis and surveillance which do not rely solely on HRP2.

Background: Malaria rapid diagnostic tests (RDTs) have greatly improved access to diagnosis in endemic countries. Most RDTs detect Plasmodium falciparum histidine-rich protein 2 (HRP2), but their sensitivity is seriously threatened by the emergence of pfhrp2-deleted parasites. RDTs detecting P. falciparum or pan-lactate dehydrogenase (Pf- or pan-LDH) provide alternatives. The objective of this study was to systematically assess the performance of malaria RDTs against well-characterized pfhrp2-deleted P. falciparum parasites. Methods: Thirty-two RDTs were tested against 100 wild-type clinical isolates (200 parasites/µL), and 40 samples from 10 culture-adapted and clinical isolates of pfhrp2-deleted parasites. Wild-type and pfhrp2-deleted parasites had comparable Pf-LDH concentrations. Pf-LDH-detecting RDTs were also tested against 18 clinical isolates at higher density (2,000 parasites/µL) lacking both pfhrp2 and pfhrp3. Results: RDT positivity against pfhrp2-deleted parasites was highest (> 94%) for the two pan-LDH-only RDTs. The positivity rate for the nine Pf-LDH-detecting RDTs varied widely, with similar median positivity between double-deleted (pfhrp2/3 negative; 63.9%) and single-deleted (pfhrp2-negative/pfhrp3-positive; 59.1%) parasites, both lower than against wild-type P. falciparum (93.8%). Median positivity for HRP2-detecting RDTs against 22 single-deleted parasites was 69.9 and 35.2% for HRP2-only and HRP2-combination RDTs, respectively, compared to 96.0 and 92.5% for wild-type parasites. Eight of nine Pf-LDH RDTs detected all clinical, double-deleted samples at 2,000 parasites/µL. Conclusions: The pan-LDH-only RDTs evaluated performed well. Performance of Pf-LDH-detecting RDTs against wild-type P. falciparum does not necessarily predict performance against pfhrp2-deleted parasites. Furthermore, many, but not all HRP2-based RDTs, detect pfhrp2-negative/pfhrp3-positive samples, with implications for the HRP2-based RDT screening approach for detection and surveillance of HRP2-negative parasites.