Displaying publications 1 - 20 of 38 in total

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  1. Yovich JL, Mariappen U, Hinchliffe PM, Dhaliwal SS, Keane KN
    Reprod Biol, 2020 Sep;20(3):424-432.
    PMID: 32389607 DOI: 10.1016/j.repbio.2020.03.008
    This observational study examines the outcomes of pregnancies arising in women referred for infertility, where those who experienced threatened miscarriage were treated with medroxyprogesterone acetate (MPA) tablets. The 14-year study period covers comprehensive real-time data entries into the validated electronic database including details of the infertility management, pregnancy outcomes and any foetal anomalies among the infants, each being tracked and recorded. Of 4057 clinical pregnancies, 1343 received MPA for threatened miscarriage; 934 (69.6 %) of which continued to livebirths. These were compared with the remaining 2714 clinical pregnancies without threatened miscarriage or MPA and which resulted in 2075 (76.5 %) livebirths. There were 134 developmental abnormalities recorded among the 3009 livebirths of which 78 (2.6 %) were categorised appropriate for the Western Australian Developmental Abnormalities Register; WARDA. These comprised 55 in the MPA group, 36 of which were categorised as serious (being 2.7 % of clinical pregnancies and 3.9 % of births). In the group without MPA, there were 79 abnormalities, of which 42 were categorised as serious (being 1.7 % of clinical pregnancies and 2.2 % of births). Specifically, there were no cases of androgenisation noted among the female infants. The abnormality rates were low overall and well within the annual WARDA ranges. We cautiously suggest that oral MPA can be considered for studies throughout pregnancy including the early first trimester to assess a potential role in reducing miscarriage, as well as advanced pregnancies to evaluate a potential role in reducing stillbirths and preterm delivery.
  2. Yong HS, Cheong WH, Chiang GL, Dhaliwal SS, Loong KP, Sarjan R
    Comp. Biochem. Physiol., B, 1983;76(3):611-3.
    PMID: 6641178
    Three taxa of the malaria mosquito Anopheles balabacensis complex representing three geographical regions (Thailand, Peninsular Malaysia and Sabah) in Southeast Asia, were analysed for genetic variation at 15 gene-enzyme systems. The Sabah taxon was monomorphic for all the 15 gene-enzyme systems. Only two gene-enzyme systems (esterase and glucose phosphate isomerase) were variable in the Thailand and Peninsular Malaysia taxa. The average heterozygosity or gene diversity was 0.007 for the Thailand taxon and 0.028 for the Peninsular Malaysia (Perlis) taxon. There were no unique gene-enzyme markers in the three taxa studied. The average values of genetic identities (0.933-0.997) and genetic distances (0.003-0.069) indicate that these three taxa are of subspecific status.
  3. Yong HS, Yao L, Dhaliwal SS, Cheong WH, Chiang GL
    Comp. Biochem. Physiol., B, 1983;75(1):43-5.
    PMID: 6406135
    1. A total of 8 samples from three natural populations and a laboratory strain of Aedes albopictus were analysed for glycerol-3-phosphate dehydrogenase phenotypes by means of horizontal starch-gel electrophoresis. 2. The electrophoretic phenotypes were governed by three codominant Gpd alleles. 3. There was low variability, with the heterozygosity in the variable samples ranging from 0.02 to 0.12. 4. The commonest allele in all the population samples was GpdB which encoded an electrophoretic band with intermediate mobility. 5. There was no temporal or spatial variation.
  4. Yong HS, Chan KL, Dhaliwal SS, Cheong WH, Mak JW, Chiang GL
    PMID: 6108615
  5. Yong HS, Dhaliwal SS, Cheong WH, Chiagng GL
    Comp. Biochem. Physiol., B, 1982;73(2):265-7.
    PMID: 7172625
    1. Three natural populations and a laboratory strain of Aedes albopictus were analysed for glucose phosphate isomerase by means of horizontal starch-gel electrophoresis. 2. The electrophoretic phenotypes were governed by five codominant Gpi alleles. 3. The commonest allele in all the four population samples was GpiC which encoded an electrophoretic band with intermediate mobility. 4. The distributions of GPI phenotypes were in accordance with Hardy-Weinberg expectations. 5. The four population samples could be differentiated by the presence of a unique Gpi allele or the absence of a particular Gpi allele.
  6. Yong HS, Chan KL, Dhaliwal SS, Cheong WH, Chiang GL, Mak JW
    Theor Appl Genet, 1981 Nov;59(6):345-8.
    PMID: 24276567 DOI: 10.1007/BF00276447
    Glucose phosphate isomerase (E.C. 5.3.1.9) and phosphoglucomutase (E.C. 2.7.5.1) were found to be polymorphic in a laboratory colony of Aedes albopictus. The glucose phosphate isomerase locus is represented by two alleles resulting in three genotypes, while the phosphoglucomutase locus is represented by at least five alleles giving rise to a total of 15 genotypes. The inheritance of these two enzymes is of the Mendelian type with codominant alleles. Present data indicate that these genes are not linked.Of 105 mosquitoes analysed for these two gene-enzyme systems, the frequencies for glucose phosphate isomerase alleles are Gpi (S)=0.68 and Gpi (F)=0.32, while the frequencies for phosphoglucomutase alleles are Pgm (A)=0.16, Pgm (B)=0.11, Pgm (C)=0.19, Pgm (D)=0.30 and Pgm (F)= 0.24. The frequencies of the three glucose phosphate isomerase genotypes are in accord with Hardy-Weinberg expectations (X 1 (2) =2.74). Similarly, the frequencies of the 15 phosphoglucomutase genotypes probably do not differ significantly from Hardy-Weinberg expectations (X 10 (2) = 18.45).
  7. Yong HS, Cheong WH, Mak JW, Chiang GL, Chan KL, Dhaliwal SS
    Biochem Genet, 1980 Oct;18(9-10):939-45.
    PMID: 7225086
    The genetics of glucosephosphate isomerase (E.C. 5.3.1.9) in two strains (Malaysian and Taiwan) of Aedes togoi is reported. Three electrophoretic phenotypes were presented in both sexes. The zymogram patterns were identical in both strains of A. togoi. The phenotypes were governed by a pair of codominant alleles. The allele frequency of the slow-moving band was 0.63 in the Malaysian strain adn was 0,86 and 0.82 in F161 and F169 generations, respectively, of the Taiwan strain. The sample studied was in good accord with Hardy-Weinberg expectation.
  8. Yip MY, Dhaliwal SS, Yong HS
    Hum. Hered., 1979;29(1):5-9.
    PMID: 761922
    Four red cell enzyme systems were studied in Malaysian mothers and their newborn belonging to three racial groups, the Malays, Indians and Chinese. No significant heterogeneity was observed in the distribution of phosphoglucomutase (PGM1), adenosine deaminase (ADA), 6-phosphogluconate dehydrogenase (6PGD) and acid phosphatase (AP) phenotypes between mothers and their newborn of the three groups. Pooled mother and child acid phosphatase data show a significant heterogeneity between the Malays and Chinese, and between the Malays and Indians. This is comparable to previous studies conducted. For the placental phosphoglucomutase (PGM3) system, a significant heterogeneity was observed between the Chinese and Malays only. No significant heterogeneity was detected in the distribution of PGM1, ADA and 6PGD phenotypes among Malays, Chinese and Indians.
  9. Yip MY, Yong HS, Dhaliwal SS
    Med J Malaysia, 1978 Jun;32(4):316-20.
    PMID: 732631
  10. Yadav M, Shah FH, Dhaliwal SS
    PMID: 751216
    Serum immunoglobulin G, A, M, D and E levels were determined in the forest-dwelling Orang Asli of age group 8 to 64 years. The levels are higher than observed for urban Malaysians and comparable to levels reported for populations residing in the tropics. There was no significant difference in serum levels of all the immunoglobulins studied in both sexes. The elevated serum immunoglobulins levels are discussed in terms of the nature of the immune defence developed in the Orang Asli to contend with the many parasites prevalent in their environment.
  11. Wong MTJ, Dhaliwal SS, Balakrishnan V, Nordin F, Norazmi MN, Tye GJ
    PMID: 36674401 DOI: 10.3390/ijerph20021647
    (1) Background: The assessment of vaccine effectiveness against the Omicron variant is vital in the fight against COVID-19, but research on booster vaccine efficacy using nationwide data was lacking at the time of writing. This study investigates the effectiveness of booster doses on the Omicron wave in Malaysia against COVID-19 infections and deaths; (2) Methods: This study uses nationally representative data on COVID-19 from 1 January to 31 March 2022, when the Omicron variant was predominant in Malaysia. Daily new infections, deaths, ICU utilization and Rt values were compared. A screening method was used to predict the vaccine effectiveness against COVID-19 infections, whereas logistic regression was used to estimate vaccine effectiveness against COVID-19-related deaths, with efficacy comparison between AZD1222, BNT162b2 and CoronaVac; (3) Results: Malaysia's Omicron wave started at the end of January 2022, peaking on 5 March 2022. At the time of writing, statistics for daily new deaths, ICU utilization, and effective reproductive values (Rt) were showing a downtrend. Boosted vaccination is 95.4% (95% CI: 95.4, 95.4) effective in curbing COVID-19 infection, compared to non-boosted vaccination, which is 87.2% (95% CI: 87.2, 87.2). For symptomatic infection, boosted vaccination is 97.4% (95% CI: 97.4, 97.4) effective, and a non-boosted vaccination is 90.9% (95% CI: 90.9, 90.9). Against COVID-19-related death, boosted vaccination yields a vaccine effectiveness (VE) of 91.7 (95% CI: 90.6, 92.7) and full vaccination yields a VE of 65.7% (95% CI: 61.9, 69.1). Looking into the different vaccines as boosters, AZD1222 is 95.2% (CI 95%: 92.7, 96.8) effective, BNT162b2 is 91.8% (CI 95%: 90.7, 92.8) effective and CoronaVac is 88.8% (CI 95%: 84.9, 91.7) effective against COVID-19 deaths. (4) Conclusions: Boosters are effective in increasing protection against COVID-19, including the Omicron variant. Given that the VE observed was lower, CoronaVac recipients are encouraged to take boosters due to its lower VE.
  12. Whitton C, Ramos-García C, Kirkpatrick SI, Healy JD, Dhaliwal SS, Boushey CJ, et al.
    Adv Nutr, 2022 Dec 22;13(6):2620-2665.
    PMID: 36041186 DOI: 10.1093/advances/nmac085
    Error in self-reported food and beverage intake affects the accuracy of dietary intake data. Systematically synthesizing available data on contributors to error within and between food groups has not been conducted but may help inform error mitigation strategies. In this review we aimed to systematically identify, quantify, and compare contributors to error in estimated intake of foods and beverages, based on short-term self-report dietary assessment instruments, such as 24-h dietary recalls and dietary records. Seven research databases were searched for studies including self-reported dietary assessment and a comparator measure of observed intake (e.g., direct observation or controlled feeding studies) in healthy adults up until December 2021. Two reviewers independently screened and extracted data from included studies, recording quantitative data on omissions, intrusions, misclassifications, and/or portion misestimations. Risk of bias was assessed using the QualSyst tool. A narrative synthesis focused on patterns of error within and between food groups. Of 2328 articles identified, 29 met inclusion criteria and were included, corresponding to 2964 participants across 15 countries. Most frequently reported contributors to error were omissions and portion size misestimations of food/beverage items. Although few consistent patterns were seen in omission of consumed items, beverages were omitted less frequently (0-32% of the time), whereas vegetables (2-85%) and condiments (1-80%) were omitted more frequently than other items. Both under- and overestimation of portion size was seen for most single food/beverage items within study samples and most food groups. Studies considered and reported error in different ways, impeding the interpretation of how error contributors interact to impact overall misestimation. We recommend that future studies report 1) all error contributors for each food/beverage item evaluated (i.e., omission, intrusion, misclassification, and portion misestimation), and 2) measures of variation of the error. The protocol of this review was registered in PROSPERO as CRD42020202752 (https://www.crd.york.ac.uk/prospero/).
  13. Whitton C, Healy JD, Collins CE, Mullan B, Rollo ME, Dhaliwal SS, et al.
    JMIR Res Protoc, 2021 Dec 16;10(12):e32891.
    PMID: 34924357 DOI: 10.2196/32891
    BACKGROUND: The assessment of dietary intake underpins population nutrition surveillance and nutritional epidemiology and is essential to inform effective public health policies and programs. Technological advances in dietary assessment that use images and automated methods have the potential to improve accuracy, respondent burden, and cost; however, they need to be evaluated to inform large-scale use.

    OBJECTIVE: The aim of this study is to compare the accuracy, acceptability, and cost-effectiveness of 3 technology-assisted 24-hour dietary recall (24HR) methods relative to observed intake across 3 meals.

    METHODS: Using a controlled feeding study design, 24HR data collected using 3 methods will be obtained for comparison with observed intake. A total of 150 healthy adults, aged 18 to 70 years, will be recruited and will complete web-based demographic and psychosocial questionnaires and cognitive tests. Participants will attend a university study center on 3 separate days to consume breakfast, lunch, and dinner, with unobtrusive documentation of the foods and beverages consumed and their amounts. Following each feeding day, participants will complete a 24HR process using 1 of 3 methods: the Automated Self-Administered Dietary Assessment Tool, Intake24, or the Image-Assisted mobile Food Record 24-Hour Recall. The sequence of the 3 methods will be randomized, with each participant exposed to each method approximately 1 week apart. Acceptability and the preferred 24HR method will be assessed using a questionnaire. Estimates of energy, nutrient, and food group intake and portion sizes from each 24HR method will be compared with the observed intake for each day. Linear mixed models will be used, with 24HR method and method order as fixed effects, to assess differences in the 24HR methods. Reporting bias will be assessed by examining the ratios of reported 24HR intake to observed intake. Food and beverage omission and intrusion rates will be calculated, and differences by 24HR method will be assessed using chi-square tests. Psychosocial, demographic, and cognitive factors associated with energy misestimation will be evaluated using chi-square tests and multivariable logistic regression. The financial costs, time costs, and cost-effectiveness of each 24HR method will be assessed and compared using repeated measures analysis of variance tests.

    RESULTS: Participant recruitment commenced in March 2021 and is planned to be completed by the end of 2021.

    CONCLUSIONS: This protocol outlines the methodology of a study that will evaluate the accuracy, acceptability, and cost-effectiveness of 3 technology-enabled dietary assessment methods. This will inform the selection of dietary assessment methods in future studies on nutrition surveillance and epidemiology.

    TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12621000209897; https://tinyurl.com/2p9fpf2s.

    INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/32891.

  14. Whitton C, Healy JD, Dhaliwal SS, Shoneye C, Harray AJ, Mullan BA, et al.
    Br J Nutr, 2022 May 19;129(4):1-39.
    PMID: 35587722 DOI: 10.1017/S0007114522001532
    Improving dietary reporting among people living with obesity is challenging as many factors influence reporting accuracy. Reactive reporting may occur in response to dietary recording but little is known about how image-based methods influence this process. Using a 4-day image-based mobile food record (mFRTM), this study aimed to identify demographic and psychosocial correlates of measurement error and reactivity bias, among adults with BMI 25-40kg/m2. Participants (n=155, aged 18-65y) completed psychosocial questionnaires, and kept a 4-day mFRTM. Energy expenditure (EE) was estimated using ≥4 days of hip-worn accelerometer data, and energy intake (EI) was measured using mFRTM. Energy intake: energy expenditure ratios were calculated, and participants in the highest tertile were considered to have Plausible Intakes. Negative changes in EI according to regression slopes indicated Reactive Reporting. Mean EI was 72% (SD=21) of estimated EE. Among participants with Plausible Intakes, mean EI was 96% (SD=13) of estimated EE. Higher BMI (OR 0.81, 95%CI 0.72-0.92) and greater need for social approval (OR 0.31, 95% CI 0.10-0.96), were associated with lower likelihood of Plausible Intakes. Estimated EI decreased by 3% per day of recording (IQR -14%,6%) among all participants. The EI of Reactive Reporters (n=52) decreased by 17%/day (IQR -23%,-13%). A history of weight loss (>10kg) (OR 3.4, 95% CI 1.5-7.8), and higher percentage of daily energy from protein (OR 1.1, 95%CI 1.0-1.2) were associated with greater odds of Reactive Reporting. Identification of reactivity to measurement, as well as Plausible Intakes, is recommended in community-dwelling studies to highlight and address sources of bias.
  15. Whitton C, Collins CE, Mullan BA, Rollo ME, Dhaliwal SS, Norman R, et al.
    Am J Clin Nutr, 2024 May 04.
    PMID: 38710447 DOI: 10.1016/j.ajcnut.2024.04.030
    BACKGROUND: Technology-assisted 24-hour dietary recalls (24HR) have been widely adopted in population nutrition surveillance. Evaluations of 24HR inform improvements but direct comparisons of 24HR methods for accuracy in reference to a measure of true intake are rarely undertaken in a single study population.

    OBJECTIVE: To compare the accuracy of energy and nutrient intake estimation of four technology-assisted dietary assessment methods relative to true intake across breakfast, lunch, and dinner.

    METHODS: In a controlled feeding study with a crossover design, 152 participants (55% women; mean age 32y (SD 11); mean BMI 26 kg/m2 (SD 5)) were randomized to one of three separate feeding days to consume breakfast, lunch, and dinner, with unobtrusive weighing of foods and beverages consumed. Participants undertook a 24HR the following day (Automated Self-Administered Dietary Assessment Tool-Australia© (ASA24); Intake24-Australia©; mobile Food Record™ - Trained Analyst (mFR-TA); or Image-Assisted Interviewer-Administered 24-hour recall (IA-24HR)). When assigned to IA-24HR, participants referred to images captured of their meals using the mobile Food Record™ app. True and estimated energy and nutrient intakes were compared, and differences among methods were assessed using linear mixed models.

    RESULTS: The mean difference between true and estimated energy intake as a percentage of true intake was 5.4% (95% CI 0.6, 10.2) using ASA24, 1.7% (95% CI -2.9, 6.3) using Intake24, 1.3% (95% CI -1.1, 3.8) using mFR-TA, and 15.0% (95% CI 11.6, 18.3) using IA-24HR. The variances of estimated and true energy intakes were statistically significantly different for all methods (P<0.01), apart from Intake 24 (P=0.1). Differential accuracy in nutrient estimation was present among the methods.

    CONCLUSIONS: Under controlled conditions, Intake24, ASA24, and mFR-TA estimated average energy and nutrient intakes with reasonable validity, but intake distributions were estimated accurately by Intake24 only (energy and protein). This study may inform considerations regarding instruments of choice in future population surveillance.

    TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry Number ACTRN12621000209897; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=381165&isReview=true.

  16. White BK, Burns SK, Giglia RC, Dhaliwal SS, Scott JA
    PMID: 35565015 DOI: 10.3390/ijerph19095626
    Participant engagement is an important consideration in mHealth interventions and there are no standardised measurements available to guide researchers. This paper describes the engagement index customised for the Milk Man app, a mobile app designed to engage fathers with breastfeeding and parenting information. Participants were recruited from maternity hospitals in Perth, Western Australia. An engagement index with scores ranging from 0 to 100 was calculated. Kaplan Meier survival analysis was used to determine difference in duration of exclusive breastfeeding, and Pearson's chi square analysis was conducted to investigate the association of engagement level with demographic characteristics and exclusive breastfeeding at 6 weeks. While overall, partners of participants who installed Milk Man were less likely to have ceased exclusive breastfeeding at any time point from birth to six weeks postpartum, this result was modest and of borderline significance (log rank test p = 0.052; Breslow p = 0.046; Tarone-Ware p = 0.049). The mean engagement score was 29.7% (range 1-80%), median 27.6%. Engagement level had no impact on duration of exclusive breastfeeding and demographic factors were not associated with engagement level. This research demonstrates a range of metrics that can be used to quantify participant engagement. However, more research is needed to identify ways of measuring effective engagement.
  17. Tartaglia J, Jancey J, Scott JA, Dhaliwal SS, Begley A
    Health Promot J Austr, 2024 Apr;35(2):263-275.
    PMID: 37160723 DOI: 10.1002/hpja.742
    ISSUE ADDRESSED: Lifelong eating behaviours are established in childhood. Improving parents' food literacy skills is essential, as parents play a fundamental role in establishing their children's healthy eating behaviours and preferences for nutritious food. This paper describes the development and evaluation of an innovative program that combines food literacy with positive parent feeding practices, targeting parents in disadvantaged areas of Western Australia.

    METHODS: The Food Sensations® for Parents five-week program was delivered to participants from community-based parenting organisations during 2020 and 2021. Formative research and a pre-post evaluation design were adopted.

    RESULTS: Pre- and post-evaluation data were collected from 224 participants (96% female). There was a statistically significant improvement in the mean score for 13 food literacy behaviours, 10 positive parenting feeding practices and a mean increase in parents' daily vegetable intake of 1/3 serve. Participants reported significantly greater net improvements in food literacy behaviours than feeding practices, the largest being the Use a nutrition information panel to make food choices (33.1%). Multivariate logistic regression analyses found English as a first language, being older than 35, and from a higher Socio-Economic Index for Areas resulted in a higher likelihood of positive changes in behaviours and practices.

    CONCLUSIONS: The findings indicate that the program is effective in improving the frequency of use of food literacy behaviours, positive parenting feeding practices and increasing vegetable consumption. SO WHAT?: Analysing improvements in food literacy behaviours and feeding practices provides clarity on what change can be expected with a five-week parent program.

  18. Sansom K, Reynolds A, McVeigh J, Mazzotti DR, Dhaliwal SS, Maddison K, et al.
    Sleep Adv, 2023;4(1):zpad028.
    PMID: 37485312 DOI: 10.1093/sleepadvances/zpad028
    Comparisons of actigraphy findings between studies are challenging given differences between brand-specific algorithms. This issue may be minimized by using open-source algorithms. However, the accuracy of actigraphy-derived sleep parameters processed in open-source software needs to be assessed against polysomnography (PSG). Middle-aged adults from the Raine Study (n = 835; F 58%; Age 56.7 ± 5.6 years) completed one night of in-laboratory PSG and concurrent actigraphy (GT3X+ ActiGraph). Actigraphic measures of total sleep time (TST) were analyzed and processed using the open-source R-package GENEActiv and GENEA data in R (GGIR) with and without a sleep diary and additionally processed using proprietary software, ActiLife, for comparison. Bias and agreement (intraclass correlation coefficient) between actigraphy and PSG were examined. Common PSG and sleep health variables associated with the discrepancy between actigraphy, and PSG TST were examined using linear regression. Actigraphy, assessed in GGIR, with and without a sleep diary overestimated PSG TST by (mean ± SD) 31.0 ± 50.0 and 26.4 ± 69.0 minutes, respectively. This overestimation was greater (46.8 ± 50.4 minutes) when actigraphy was analyzed in ActiLife. Agreement between actigraphy and PSG TST was poor (ICC = 0.27-0.44) across all three methods of actigraphy analysis. Longer sleep onset latency and longer wakefulness after sleep onset were associated with overestimation of PSG TST. Open-source processing of actigraphy in a middle-aged community population, agreed poorly with PSG and, on average, overestimated TST. TST overestimation increased with increasing wakefulness overnight. Processing of actigraphy without a diary in GGIR was comparable to when a sleep diary was used and comparable to actigraphy processed with proprietary algorithms in ActiLife.
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