Displaying publications 1 - 20 of 25 in total

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  1. Patel JJ, Hill A, Lee ZY, Heyland DK, Stoppe C
    Crit Care Med, 2022 Sep 01;50(9):1371-1379.
    PMID: 35853198 DOI: 10.1097/CCM.0000000000005602
    OBJECTIVES: Concise definitive review of how to read and critically appraise a systematic review.

    DATA SOURCES: None.

    STUDY SELECTION: Current literature describing the conduct, reporting, and appraisal of systematic reviews and meta-analyses.

    DATA EXTRACTION: Best practices for conducting, reporting, and appraising systematic review were summarized.

    DATA SYNTHESIS: A systematic review is a review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant original research, and to collect and analyze data from the studies that are included in the review. Critical appraisal methods address both the credibility (quality of conduct) and rate the confidence in the quality of summarized evidence from a systematic review. The A Measurement Tool to Assess Systematic Reviews-2 tool is a widely used practical tool to appraise the conduct of a systematic review. Confidence in estimates of effect is determined by assessing for risk of bias, inconsistency of results, imprecision, indirectness of evidence, and publication bias.

    CONCLUSIONS: Systematic reviews are transparent and reproducible summaries of research and conclusions drawn from them are only as credible and reliable as their development process and the studies which form the systematic review. Applying evidence from a systematic review to patient care considers whether the results can be directly applied, whether all important outcomes have been considered, and if the benefits are worth potential harms and costs.

  2. Beghi E, Ivashynka A, Logroscino G, de Oliveira FF, Fleisher JE, Dumitrascu OM, et al.
    J Neurol, 2023 Nov;270(11):5162-5170.
    PMID: 37682315 DOI: 10.1007/s00415-023-11981-y
    BACKGROUND: Neurological manifestations frequently occur in individuals with COVID-19, manifesting during the acute phase, persisting beyond the resolution of acute symptoms, and appearing days or weeks after the initial onset of COVID-19 symptoms. However, predicting the incidence, course, and outcome of these neurological manifestations at the individual patient level remains challenging. Biases in study design and limitations in data collection may contribute to the inconsistency and limited validity of the reported findings. Herein, we focused on critically appraising pitfalls and biases of prior reports and provide guidance for improving the quality and standardization of future research. Patients with COVID-19 exhibit diverse demographic features, sociocultural backgrounds, lifestyle habits, and comorbidities, all of which can influence the severity and progression of the infection and its impact on other organ systems. Overlooked or undocumented comorbidities and related treatments may contribute to neurological sequelae, which may not solely be attributable to COVID-19. It is crucial to consider the potential side effects of vaccines in relation to neurological manifestations.

    CONCLUSION: To investigate neurological manifestations of COVID-19, it is essential to employ valid and reliable diagnostic criteria and standard definitions of the factors of interest. Although population-based studies are lacking, well-defined inception cohorts, including hospitalized individuals, outpatients, and community residents, can serve as valuable compromises. These cohorts should be evaluated for the presence of common comorbidities, alongside documenting the primary non-neurological manifestations of the infectious disease. Lastly, patients with COVID-19 should be followed beyond the acute phase to assess the persistence, duration, and severity of neurological symptoms, signs, or diseases.

  3. Hussain Ismail AM, Solomon JA, Hansard M, Mareschal I
    Proc Biol Sci, 2019 Nov 06;286(1914):20191492.
    PMID: 31690239 DOI: 10.1098/rspb.2019.1492
    Ambiguous images are widely recognized as a valuable tool for probing human perception. Perceptual biases that arise when people make judgements about ambiguous images reveal their expectations about the environment. While perceptual biases in early visual processing have been well established, their existence in higher-level vision has been explored only for faces, which may be processed differently from other objects. Here we developed a new, highly versatile method of creating ambiguous hybrid images comprising two component objects belonging to distinct categories. We used these hybrids to measure perceptual biases in object classification and found that images of man-made (manufactured) objects dominated those of naturally occurring (non-man-made) ones in hybrids. This dominance generalized to a broad range of object categories, persisted when the horizontal and vertical elements that dominate man-made objects were removed and increased with the real-world size of the manufactured object. Our findings show for the first time that people have perceptual biases to see man-made objects and suggest that extended exposure to manufactured environments in our urban-living participants has changed the way that they see the world.
    Matched MeSH terms: Bias (Epidemiology)*
  4. Fauziah Maarof, Lim, Fong Peng, Noor Akma Ibrahim
    MyJurnal
    This paper investigates the confidence intervals of R2 MAD, the coefficient of determination based on
    median absolute deviation in the presence of outliers. Bootstrap bias-corrected accelerated (BCa)
    confidence intervals, known to have higher degree of correctness, are constructed for the mean and standard deviation of R2 MAD for samples generated from contaminated standard logistic distribution. The results indicate that by increasing the sample size and percentage of contaminants in the samples, and perturbing the location and scale of the distribution affect the lengths of the confidence intervals. The results obtained can also be used to verify the bound of R2 MAD.
  5. Qureshi N, Da Silva MLR, Abdul-Hamid H, Weng SF, Kai J, Leonardi-Bee J
    Cochrane Database Syst Rev, 2021 Oct 07;10(10):CD012985.
    PMID: 34617591 DOI: 10.1002/14651858.CD012985.pub2
    BACKGROUND: Familial hypercholesterolaemia is a common inherited condition that is associated with premature cardiovascular disease. The increased cardiovascular morbidity and mortality, resulting from high levels of cholesterol since birth, can be prevented by starting lipid-lowering therapy. However, the majority of patients in the UK and worldwide remain undiagnosed. Established diagnostic criteria in current clinical practice are the Simon-Broome and Dutch Lipid Clinical network criteria and patients are classified as having probable, possible or definite familial hypercholesterolaemia.

    OBJECTIVES: To assess the effectiveness of healthcare interventions strategies to systematically improve identification of familial hypercholesterolaemia in primary care and other community settings compared to usual care (incidental approaches to identify familial hypercholesterolaemia in primary care and other community settings).

    SEARCH METHODS: We searched the Cochrane Inborn Errors of Metabolism Trials Register. Date of last search: 13 September 2021. We also searched databases (Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, PubMed, Embase, CINAHL, Web of Science, and SCOPUS) as well as handsearching relevant conference proceedings, reference lists of included articles, and the grey literature. Date of last searches: 05 March 2020.  SELECTION CRITERIA: As per the Effective Practice and Organisation of Care (EPOC) Group guidelines, we planned to include randomised controlled trials (RCTs), cluster-RCTs and non-randomised studies of interventions (NRSI). Eligible NRSI were non-randomised controlled trials, prospective cohort studies, controlled before-and-after studies, and interrupted-time-series studies. We planned to selected studies with healthcare interventions strategies that aimed to systematically identify people with possible or definite clinical familial hypercholesterolaemia, in primary care and other community settings. These strategies would be compared with usual care or no intervention. We considered participants of any age from the general population who access primary care and other community settings.

    DATA COLLECTION AND ANALYSIS: Two authors planned to independently select studies according to the inclusion criteria, to extract data and assess for risk of bias and the certainty of the evidence (according to the GRADE criteria). We contacted corresponding study authors in order to obtain further information for all the studies considered in the review.

    MAIN RESULTS: No eligible RCTs or NRSIs were identified for inclusion, however, we excluded 28 studies.

    AUTHORS' CONCLUSIONS: Currently, there are no RCTs or controlled NRSI evidence to determine the most appropriate healthcare strategy to systematically identify possible or definite clinical familial hypercholesterolaemia in primary care or other community settings. Uncontrolled before-and-after studies were identified, but were not eligible for inclusion. Further studies assessing healthcare strategies of systematic identification of familial hypercholesterolaemia need to be conducted with diagnosis confirmed by genetic testing or validated through clinical phenotype (or both).

  6. Armijo-Olivo S, Mohamad N, Sobral de Oliveira-Souza AI, de Castro-Carletti EM, Ballenberger N, Fuentes J
    Am J Phys Med Rehabil, 2022 Sep 01;101(9):864-878.
    PMID: 35978455 DOI: 10.1097/PHM.0000000000001893
    Bias is a systematic error that can cause distorted results leading to incorrect conclusions. Intervention bias (i.e., contamination bias, cointervention bias, compliance bias, and performance bias) and detection bias are the most common biases in rehabilitation research. A better understanding of these biases is essential at all stages of research to enhance the quality of evidence in rehabilitation trials. Therefore, this narrative review aims to provide insights to the readers, clinicians, and researchers about contamination, cointervention, compliance, performance, and detection biases and ways of recognizing and mitigating them. The literature selected for this review was obtained mainly by compiling the information from several reviews looking at biases in rehabilitation. In addition, separate searches by biases and looking at reference lists of selected studies as well as using Scopus forward citation for relevant references were used.This review provides several strategies to guard against the impact of bias on study results. Clinicians, researchers, and other stakeholders are encouraged to apply these recommendations when designing and conducting rehabilitation trials.
  7. Lai NM, Ong JMJ, Chen KH, Chaiyakunapruk N, Ovelman C, Soll R
    Neonatology, 2019;116(2):123-131.
    PMID: 31108494 DOI: 10.1159/000497423
    BACKGROUND: The introduction of Neonatology as a subspecialty in 1960 has stimulated an enormous amount of neonatal research. A large proportion of neonatal randomized-controlled trials (RCTs) have been included in the Cochrane reviews, within which methodological quality or risk-of-bias (ROB) assessment is an integral feature.

    OBJECTIVES: We described the ROB profile of neonatal RCTs published since the 1950s.

    METHODS: We analyzed individual studies within the Cochrane Neonatal reviews published up to December 2016. We extracted the reviewers' judgments on the ROB domains including random sequence generation, allocation concealment, blinding, incomplete outcome data, and selective reporting. We evaluated blinding of personnel in trials in which blinding was considered feasible.

    RESULTS: We assessed 1980 RCTs published between 1952 and 2016 from 294 Cochrane Neonatal systematic reviews, with full ROB assessments performed in 848 trials (42.8%). Among the ROB domains, the highest proportion of trials (73%) were judged as satisfactory ("low risk") in handling incomplete outcome data, while fewest trials achieved blinding of outcome assessor (38.4%). In the last 6 decades, a progressive increase has been observed in the proportion of trials that were rated as low risk in random sequence generation, allocation concealment, and selective reporting. However, blinding was achieved in less than half of the trials with no clear improvement across decades (23-44% since the 1980s).

    CONCLUSIONS: Despite steady improvement in the overall quality of neonatal RCTs over the last 6 decades, blinding remained unsatisfactory in the majority of the trials.

    Matched MeSH terms: Bias (Epidemiology)*
  8. Mamikutty R, Aly AS, Marhazlinda J
    Int J Environ Res Public Health, 2021 Aug 15;18(16).
    PMID: 34444374 DOI: 10.3390/ijerph18168623
    In conducting a systematic review, assessing the risk of bias of the included studies is a vital step; thus, choosing the most pertinent risk of bias (ROB) tools is crucial. This paper determined the most appropriate ROB tools for assessing observational studies in a systematic review assessing the association between anthropometric measurements and dental caries among children. First, we determined the ROB tools used in previous reviews on a similar topic. Subsequently, we reviewed articles on ROB tools to identify the most recommended ROB tools for observational studies. Of the twelve ROB tools identified from the previous steps, three ROB tools that best fit the eight criteria of a good ROB tool were the Newcastle-Ottawa Scale (NOS) for cohort and case-control studies, and Agency for Healthcare Research and Quality (AHRQ) and the Effective Public Health Practice Project (EPHPP) for a cross-sectional study. We further assessed the inter-rater reliability for all three tools by analysing the percentage agreement, inter-class correlation coefficient (ICC) and kappa score. The overall percentage agreements and reliability scores of these tools ranged from good to excellent. Two ROB tools for the cross-sectional study were further evaluated qualitatively against nine of a tool's advantages and disadvantages. Finally, the AHRQ and NOS were selected as the most appropriate ROB tool to assess cross-sectional and cohort studies in the present review.
  9. Zhang Q, Lee K, Mansor Z, Ismail I, Guo Y, Xiao Q, et al.
    Heart Lung, 2024;63:51-64.
    PMID: 37774510 DOI: 10.1016/j.hrtlng.2023.09.007
    BACKGROUND: Despite the widespread adoption of the rapid response team (RRT) by many hospitals, questions remain regarding their effectiveness in improving several aspects of patient outcomes, such as hospital mortality, cardiopulmonary arrests, unplanned intensive care unit (ICU) admissions, and length of stay (LOS).

    OBJECTIVES: To conduct a systematic review to understand the rapid response team's (RRT) effect on patient outcomes.

    METHODS: A systematic search was conducted using PubMed, Cochrane, Embase, CINAHL, Web of Science, and two trial registers. The studies published up to May 6, 2022, from the inception date of the databases were included. Two researchers filtered the title, abstract and full text. The Version 2 of the Cochrane Risk of Bias tool and Bias in Non-Randomized Studies of Interventions (ROBINS-I) tool were used separately for randomized and non-randomized controlled trials for quality appraisal.

    RESULTS: Sixty-one eligible studies were identified, four randomized controlled trials(RCTs), four non-randomized controlled trials, six interrupted time-series(ITS) design , and 47 pretest-posttest studies. A total of 52 studies reported hospital mortality, 51 studies reported cardiopulmonary arrests, 18 studies reported unplanned ICU admissions and ten studies reported LOS.

    CONCLUSION: This systematic review found the variation in context and the type of RRT interventions restricts direct comparisons. The evidence for improving several aspects of patient outcomes was inconsistent, with most studies demonstrating that RRT positively impacts patient outcomes.

  10. Zaki R, Bulgiba A, Ismail NA
    Prev Med, 2013;57 Suppl:S80-2.
    PMID: 23313586 DOI: 10.1016/j.ypmed.2013.01.003
    The Bland-Altman method is the most popular method used to assess the agreement of medical instruments. The main concern about this method is the presence of proportional bias. The slope of the regression line fitted to the Bland-Altman plot should be tested to exclude proportional bias. The aim of this study was to determine whether the overestimation of bias in the Bland-Altman analysis is still present even when the proportional bias has been excluded.
    Matched MeSH terms: Bias (Epidemiology)*
  11. Montgomery MR, Richards T, Braun HI
    J Am Stat Assoc, 1986 Jun;81(394):297-309.
    PMID: 12155406
    This study examines the possibility that estimation of the effect of breast-feeding on infant survival is affected by selection bias, in that children who are healthier at birth may be more likely to be breast-fed. Data are from the 1976 Malaysian Family Life Survey. "Ordinary logit models for breast-feeding and survival are estimated, and the results suggest that selection is indeed present. For example, children of higher birth weight appear to be more likely to be breast-fed and likely to survive. In addition, weight at birth and the duration of breast-feeding appear to be linked." Using birth weight as an indicator for the child's health, the authors conclude that "the direct influence of breast-feeding on survival remains of overwhelming importance even after corrections for selection bias are made."
    Matched MeSH terms: Bias (Epidemiology)*
  12. Lombardo E
    Genus, 1983 Jan-Dec;39(1-4):167-73.
    PMID: 12266118
    "A tentative approximation of the expectation of life at 60-65 years, for populations with defective demographic statistics, is explored and expounded on the basis of a recent Horiuchi and [Coale] paper." The method is applied to data for El Salvador, Mexico, Puerto Rico, and Peninsular Malaysia, and it is shown that the method can be used on actual data, although it requires some drastic rounding off. (summary in ENG, FRE)
    Matched MeSH terms: Bias (Epidemiology)*
  13. Bhoo Pathy N, Uiterwaal CS, Taib NA, Verkooijen HM, Yip CH
    J Clin Epidemiol, 2012 May;65(5):568-71.
    PMID: 22269329 DOI: 10.1016/j.jclinepi.2011.09.013
    Many recent studies investigated the prognostic value of new biomarkers in breast cancer using data from cancer registries. Some of these studies were conducted using only patients for whom biomarker status was available (or tested). Using human epidermal growth factor receptor 2 (HER2) as an example, we determined whether testing for a recently introduced biomarker was associated with the outcome of women with breast cancer.
  14. Van Rostenberghe H, Ho JJ, Lim CH, Abd Hamid IJ
    Cochrane Database Syst Rev, 2020 07 01;7:CD012011.
    PMID: 32609375 DOI: 10.1002/14651858.CD012011.pub2
    BACKGROUND: Phototherapy is a well-established effective therapy for treating babies with significant neonatal jaundice. Studies have shown that increasing light intensity will increase its efficiency. A potentially inexpensive and easy way of increasing the intensity of light on the body of the infant may be to hang reflective materials from the sides of phototherapy units.

    OBJECTIVES: To assess the effects of reflective materials in combination with phototherapy compared with phototherapy alone for unconjugated hyperbilirubinaemia in neonates.

    SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 11), in the Cochrane Library; Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions(R); and the Cumulative Index of Nursing and Allied Health Literature (CINAHL), on 1 November 2019. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

    SELECTION CRITERIA: We included randomised and quasi-randomised controlled trials if the participants, who were term or preterm infants, received phototherapy with curtains made of reflective materials of any type in the treatment arm, and if those in the comparison arm received similar phototherapy without curtains or other intensified phototherapy, such as a double bank of lights.

    DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. We used the GRADE approach to assess the certainty of evidence.

    MAIN RESULTS: Of 15 studies identified, we included 12 (1288 babies) in the review - 11 comparing phototherapy with reflective materials and phototherapy alone, and one comparing a single phototherapy light bank with reflective materials with double phototherapy. All reflective materials consisted of curtains on three or four sides of the cot and were made of white plastic (five studies), white linen (two studies), or aluminium (three studies); materials were not specified in two studies. Only 11 studies (10 comparing reflective materials versus none and one comparing reflective curtains and a single bank of lights with a double (above and below) phototherapy unit) provided sufficient data to be included in the meta-analysis. Two excluded studies used the reflective materials in a way that did not meet our inclusion criteria, and we excluded one study because it compared four different phototherapy interventions not including reflective materials. The risk of bias of included studies was generally low, but all studies had high risk of performance bias due to lack of blinding of the intervention. Three studies (281 participants) reported a decline in serum bilirubin (SB) (μmol/L) at four to eight hours (mean difference (MD) -14.61, 95% confidence interval (CI) -19.80 to -9.42; I² = 57%; moderate-certainty evidence). Nine studies (893 participants) reported a decline in SB over 24 hours and showed a faster decline in SB in the intervention group, but heterogeneity (I² = 97%) was too substantial to permit a meaningful estimate of the actual effect size (very low-certainty evidence). Subgroup analysis by type of reflective material used did not explain the heterogeneity. Exchange transfusion was reported by two studies; both reported none in either group. Four studies (466 participants) reported the mean duration of phototherapy, and in each of these studies, it was reduced in the intervention group but there was substantial heterogeneity (I² = 88%), precluding meaningful meta-analysis of data. The only two studies that reported the mean duration of hospital stay in hours showed a meaningful reduction (MD -41.08, 95% CI -45.92 to -36.25; I² = 0; moderate-certainty evidence). No studies reported costs of the intervention, parental or medical staff satisfaction, breastfeeding outcomes, or neurodevelopmental follow-up. The only study that compared use of curtains with double phototherapy reported similar results for both groups. Studies that monitored adverse events did not report increased adverse events related to the use of curtains, including acute life-threatening events, but other rarer side effects could not be excluded.

    AUTHORS' CONCLUSIONS: Moderate-certainty evidence shows that the use of reflective curtains during phototherapy may result in greater decline in SB. Very low-certainty evidence suggests that the duration of phototherapy is reduced, and moderate-certainty evidence shows that the duration of hospital stay is also reduced. Available evidence does not show any increase in adverse events, but further studies are needed.

  15. Jahanfar S, Ho JJ, Jaafar SH, Abraha I, Noura M, Ross CR, et al.
    Cochrane Database Syst Rev, 2021 03 09;3:CD012553.
    PMID: 33686672 DOI: 10.1002/14651858.CD012553.pub2
    BACKGROUND: There is a need to standardize monitoring in obstetric research of twin pregnancies. Identification of birth weight discordance (BWD), defined as a difference in the birth weights of twins, is a well-documented phenomenon in twin pregnancies. Ultrasound for the diagnosis of BWD informs complex decision making including whether to intervene medically (via laser photo coagulation) or deliver the twins to avoid fetal morbidities or even death. The question is, how accurate is this measurement?

    OBJECTIVES: To determine the diagnostic accuracy (sensitivity and specificity) of ultrasound estimated fetal weight discordance (EFWD) of 20% and 25% using different estimated biometric ultrasound measurements compared with the actual BWD as the reference standard in twin pregnancies.

    SEARCH METHODS: The search for this review was performed on 15 March 2019. We searched CENTRAL, MEDLINE (Ovid), Embase (Ovid), seven other databases, conference proceedings, reference lists and contacted experts. There were no language or date restrictions applied to the electronic searches, and no methodological filters to maximize sensitivity.

    SELECTION CRITERIA: We selected cohort-type studies with delayed verification that evaluated the accuracy of biometric measurements at ultrasound scanning of twin pregnancies that had been proposed for the diagnosis of estimated BWD, compared to BWD measurements after birth as a reference standard. In addition, we only selected studies that considered twin pregnancies and applied a reference standard for EFWD for the target condition of BWD.

    DATA COLLECTION AND ANALYSIS: We screened all titles generated by electronic database searches. Two review authors independently assessed the abstracts of all potentially relevant studies. We assessed the identified full papers for eligibility, and extracted data to create 2 × 2 tables. Two review authors independently performed quality assessment using the QUADAS-2 tool. We excluded studies that did not report data in sufficient detail to construct 2 × 2 tables, and where this information was not available from the primary investigators. We assessed the certainty of the evidence using the GRADE approach.

    MAIN RESULTS: We included 39 eligible studies with a median study sample size of 140. In terms of risk of bias, there were many unclear statements regarding patient selection, index test and use of proper reference standard. Twenty-one studies (53%) were of methodological concern due to flow and timing. In terms of applicability, most studies were of low concern. Ultrasound for diagnosis of BWD in twin pregnancies at 20% cut-off Twenty-two studies provided data for a BWD of 20% and the summary estimate of sensitivity was 0.51 (95% CI 0.42 to 0.60), and the summary estimate of specificity was 0.91 (95% CI 0.89 to 0.93) (8005 twin pregnancies; very low-certainty evidence). Ultrasound for diagnosis of BWD in twin pregnancies at 25% cut-off Eighteen studies provided data using a BWD discordance of 25%. The summary estimate of sensitivity was 0.46 (95% CI 0.26 to 0.66), and the summary estimate of specificity was 0.93 (95% CI 0.89 to 0.96) (6471 twin pregnancies; very low-certainty evidence). Subgroup analyses were possible for both BWD of 20% and 25%. The diagnostic accuracy did not differ substantially between estimation by abdominal circumference and femur length but femur length had a trend towards higher sensitivity and specificity. Subgroup analyses were not possible by sex of twins, chorionicity or gestational age due to insufficient data.

    AUTHORS' CONCLUSIONS: Very low-certainty evidence suggests that EFWD identified by ultrasound has low sensitivity but good specificity in detecting BWD in twin pregnancies. There is uncertain diagnostic value of EFWD; this review suggests there is insufficient evidence to support this index as the sole measure for clinical decision making to evaluate the prognosis of twins with growth discordance. The diagnostic accuracy of other measures including amniotic fluid index and umbilical artery Doppler resistive indices in combination with ultrasound for clinical intervention requires evaluation. Future well-designed studies could also evaluate the impact of chorionicity, sex and gestational age in the diagnostic accuracy of ultrasound for EFWD.

  16. Niti M, Ng TP, Chiam PC, Kua EH
    J Clin Epidemiol, 2007 Apr;60(4):366-74.
    PMID: 17346611
    Item response bias (also called differential item functioning, DIF) in Instrumental Activities of Daily Living (IADL) occurs when members of different groups possessing the same disability level do not have the same probability of responding positively for a given item(s). This study aimed to identify the extent of DIF by gender, age, ethnicity, and dementia groups in IADL estimates in Asian (Chinese, Malays, and Indian) elderly subjects.
  17. Deurenberg-Yap M, Deurenberg P
    Food Nutr Bull, 2002 Sep;23(3 Suppl):34-7.
    PMID: 12362808
    Body fat percent (BF%) was measured in 108 adult Chinese, 76 Malays, and 107 Indians in Singapore by densitometry, deuterium oxide dilution (hydrometry), dual energy x-ray absorptiometry (DXA) and a chemical four-compartment model (BF%4c). The hydration of the fat-free mass (FFM) was calculated. Subjects ranged in age from 18 to 69 years and their body mass index ranged from 16 to 40 kg/m2. BF%4c for the various subgroups were: Chinese females (33.5 +/- 7.5%), Chinese males (24.4 +/- 6.1%), Malay females (37.8 +/- 6.3%), Malay males (26.0 +/- 7.6%), Indian females (38.2 +/- 7.0%) and Indian males (28.1 +/- 5.5%). Biases were found between BF%4c and BF% measured by 2-compartment models (hydrometry, densitometry, DXA), with systematic underestimation by DXA and densitometry. On a group level hydrometry had the lowest bias while DXA gave the highest bias. When validated against BF%4c, 2-compartment models were found to be unsuitable for accurate measures of body fat due to high biases at the individual level and the violation of assumptions of constant hydration of FFM and density FFM among the ethnic groups. On a group level the best 2-compartment model for measuring body fat was found to be hydrometry.
  18. Maniam T
    Asia Pac J Public Health, 1995;8(3):181-5.
    PMID: 10050186
    Suicide statistics are generally recognised to be unreliable. This study of the reported rates of suicide in West Malaysia between 1966-1990 shows that the mean crude suicide rate between 1966-1974 was 6.1 per 100,000, but had dropped drastically between 1975-1990 to a mean of 1.6 per 100,000. Three lines of evidence are presented to show that this reduction in the suicide rate is due to a systematic misclassification of medically certified suicides as deaths due to undetermined violent deaths (which refers to violent deaths not known to be accidentally or deliberately inflicted). Firstly, the large drop in reported suicide rates corresponds closely to an increase in the rate of deaths due to undetermined violent deaths. There is a highly positive negative correlation between the two rates (coefficient of correlation, r = -0.9). Secondly, the misclassification appears to be mainly a problem with the medically certified deaths which follow the ICD classification. The mean ratio of uncertified to certified suicides before 1975 was 0.8, but from 1975 onwards the mean was 3.1. This is in contrast to the corresponding ratio for deaths due to all accidents which has remained fairly constant throughout these years. Thirdly, the race and sex differences for the rates of undetermined violent deaths are identical to those of suicide. Taking the misclassification into account the corrected suicide rate for West Malaysia is estimated to be between 8-13 per 100,000 since 1982.
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