Browse publications by year: 2016

  1. Damanhuri H, Abdul Rahim N, Nasri W, Tan J, Makpol S, Wan Ngah W
    Sains Malaysiana, 2016;45:1363-1370.
    Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by deterioration of the brain functions
    that result in impairment of memory, cognition and behavioural functions. Oxidative stress is well known to be one of the
    causative factors for AD. Thus this disease is potentially modulated by natural antioxidants such as vitamin E. The aim
    of this study was to evaluate the effect of tocotrienol-rich fraction (TRF) supplementation on antioxidant enzymes and
    DNA damage using APPswe/PS1dE9 transgenic mouse model of AD. Animals were supplemented with TRF (200 mg/kg)
    or alpha-tocopherol (αT) (200 mg/kg) for six months starting from nine months old. We found that superoxide dismutase
    (SOD) activity in AD mouse was decreased by supplementation of TRF and αT as compared with AD control mouse with no
    significant differences in glutathione peroxidise (GPx) activity in all groups. TRF supplementation significantly increased
    catalase (CAT) activity. The level of DNA damage of AD mouse shows significant decrease with supplementation of TRF
    and αT. In conclusion, TRF was able to modulate antioxidant enzymes activity and decreased the level of DNA damage
    of AD transgenic mouse model.
  2. Eshkoor SA, Tengku Aizan Hamid, Chan YM
    Sains Malaysiana, 2016;45:1357-1361.
    The improvement of health care support has greatly extended the average life expectancy over the last 50 years, which
    has increased the rate of cognitive decline consequently. The avoidance of risk factors such as toxins, stress and somatic
    diseases can be protective against the reduction of cognitive function in the elderly. This study aimed to determine the
    effects of socio-demographic factors, constipation and renal failure on cognitive status among 2322 samples who were
    the non-institutionalized Malaysian elderly. The multiple logistic regression analysis was applied to estimate the risk of
    such factors on cognitive decline in subjects. Approximately, 77.54% of samples experienced cognitive impairment. The
    results showed that advanced age (odds ratio (OR) = 1.03), Malay ethnic (OR = 2.15), constipation (OR = 3.31) and renal
    failure (OR= 4.42), significantly increased the risk of cognitive impairment in subjects (p<0.05). In addition, education
    (OR = 0.38) significantly reduced the risk. However, we concluded that age, Malay ethnic, constipation and renal failure
    increased the risk of cognitive impairment in subjects but education reduced the risk.
    MeSH terms: Aged; Cognition; Constipation; Demography; Humans; Life Expectancy; Malaysia; Risk Factors; Logistic Models; Odds Ratio; Renal Insufficiency
  3. Ng TP
    Sains Malaysiana, 2016;45:1351-1355.
    Dementia poses a major global burden of care to society and health systems in ageing populations. The majority (over 60%) of persons with dementia in the world are found in Asia and developing countries with rapid rates of population ageing. Improving and maintaining the cognitive health of older persons is vital to national strategies for dementia prevention. Increasing numbers of population-based ageing cohort studies in the past decade have provided a better understanding of the factors that contribute to cognitive function and decline in old age. The roles of major demographic, psychosocial, lifestyle, behavioral and cardiovascular risk factors contributing to cognitive health were discussed using examples from the Singapore Longitudinal Ageing Studies. They include socio-demographic factors, particularly education and marital status, leisure time activity such as physical activity, social engagement and mental activities, psychological factors such as depression, cardiovascular and metabolic risk factors: obesity, diabetes, hypertension and dyslipidemia, and the metabolic syndrome, under-nutrition, low albumin, low hemoglobin, nutritional factors such as blood folate, B12 and homocysteine, omega-3 poly-unsaturated fatty acids, tea drinking and curcumin-rich turmeric in curry meals. These factors are found to be associated variously with cognitive functions (memory and learning, language, visuospatial, attention and information processing speed), rates of cognitive impairment and cognitive decline, or increased risk of developing MCI and progression to dementia.
    MeSH terms: Aging; Albumins; Asia; Attention; Cardiovascular Diseases; Cognition; Curcumin; Dementia; Demography; Depression; Developing Countries; Diabetes Mellitus; Folic Acid; Hemoglobins; Homocysteine; Hypertension; Language; Leisure Activities; Life Style; Longitudinal Studies; Memory; Obesity; Risk Factors; Singapore; Tea; Cohort Studies; Exercise; Fatty Acids, Omega-3; Marital Status; Curcuma; Malnutrition; Dyslipidemias
  4. Normaz Wana Ismail, Siti Wardah Abd Rahman, Tengku Aizan Tengku Abdul Hamid, Rusmawati Said
    Sains Malaysiana, 2016;45:1345-1350.
    The purpose of this study was to examine the impact of aging on economic growth. The study used dynamic growth model and employed Autoregressive Distributed Lag (ARDL) approach for the period of 1980 to 2011. Three proxies for aging are used namely fertility rate, life expectancy and old dependency ratio. However, only fertility rate is detected to have a long run cointegration. The major finding of this study showed that a reduction of fertility rate lead to higher economic growth. This implied that even though Malaysia will face aging society by 2020, the economic growth is still stable and can increase by investing more on human capital.
    MeSH terms: Birth Rate; Dependency (Psychology); Employment; Humans; Investments; Life Expectancy; Malaysia; Economic Development
  5. Normah Che Din, Suzana Shahar, Baitil Husna Zulkifli, Rosdinom Razali, Chyn AV, Azhadi Omar
    Sains Malaysiana, 2016;45:1337-1343.
    The goal of this study was to examine the reliability and validity of the Bahasa Malaysia version of the Montreal cognitive assessment (MoCA-BM) and to determine its optimal cut-off score among older adults with mild cognitive impairment (MCI), after adjustments for age, gender, levels of education, physical functioning and depressive symptoms. A total of 2237 community dwelling older adults aged 60 years and above were randomly selected for the study, excluding those with MMSE score below 14. Instruments administered were the MoCA-BM, the Malay Mini-Mental State Examination (MMMSE), the Rey Auditory Verbal Learning Test (RAVLT), the Digit Span and the Digit Symbol subtests of the Wechsler Adult Intelligence Scale (WAIS), activities of daily living (ADL) and the Geriatric Depression Scale (GDS). MCI were determined using the Petersen’s 2014 criteria as the gold standard. SPSS version 22 was used for reliability and validity analysis and optimal cut-off score detection. Cronbach’s α of the MoCA-BM was 0.691 and concurrent validity was high between MoCA-BM and MMMSE scores (r=0.741). Optimal cut-off point for MoCA-BM to detect MCI among older adults in Malaysia was 17/18, with sensitivity of 68.2% and specificity of 61.3%. Using this cut-off, 38.9% of participants were detected to be at risk of MCI. In conclusion, MoCA-BM is a reliable and valid screening instrument for MCI among Malaysian elderly community. The newly derived optimal cut-off for MCI is much lower than the original MoCA with modest ability to discriminate between normal and MCI older adults in the community.
  6. Hasnah Haron, Tasneem Shaari, Chan BK
    Sains Malaysiana, 2016;45:1329-1335.
    Soy-based products are one of famous raw ingredients used in the preparation of Asian cuisines. These soy-based products are good source of isoflavones. This study was carried out to observe the effects of different cooking methods on isoflavone content in soy-based products. A total of eight Malaysian dishes prepared using soy-based products with different cooking methods was selected as samples for this study. Daidzein and genestein contents in raw and cooked soy-based products were both quantified using high performance liquid chromatography (HPLC). The results showed that dishes containing tempe as ingredients had significantly higher (p<0.05) amount of isoflavone content, in both raw and cooked forms, as compared to those prepared from other types of soy-based products when based on dry and wet. In conclusion, the isoflavone content was significantly reduced (p<0.05) in some cooked soy-based products (tempe (TSS and ML), fu jook (ML) and firm tofu (FTC)) based on dry weight as compared with the raw ones. However, the correlations between isoflavone content with cooking methods, durations and temperatures were not significant (p>0.05) in this study.
    MeSH terms: Chromatography, High Pressure Liquid; Cooking; Isoflavones; Lidocaine; Prilocaine; Temperature; Genistein; Soy Foods
  7. Khaw HW, Hasnah Haron, Chan BK
    Sains Malaysiana, 2016;45:1319-1327.
    There is an increasing trend of fruit juice consumption due to increasing reported health benefits of antioxidant content present in fruit juices. The aim of this study was to compare the total phenolic contents (TPC) and antioxidant activities of fresh fruit juices, commercial 100% fruit juices and fruit drinks. Seven types of freshly blended fruit juices and their commercial counterparts were selected. Folin-Ciocalteu method was used to determine the total phenolic content, whilst ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were performed to evaluate the antioxidant activities of fruit juices. The TPC contents of fresh fruit juices, commercial 100% fruit juices and fruit drinks were at the ranges of 13.38-80.40, 21.65-130.39 and 3.32-45.10 mg GAE/100 mL, respectively. Both fresh guava juice and commercial guava drinks have exhibited the highest antioxidant activities in DPPH assay (205.71-770.12 μmol TE/100 mL) and FRAP assay (320.80-843.13 μmol TE/100 mL). Pomegranate juices demonstrated the highest antioxidant activities among commercial 100% fruit juices with DPPH and FRAP values of 2705.01 and 2953.85 μmol TE/100 mL, respectively. Fruits drinks group had the lowest TPC and antioxidant activities for all types of fruits. TPC was significantly correlated (p<0.05) to FRAP (r=0.954) and DPPH (r=0.908) assays. In conclusion, the TPC and antioxidant activities of commercial 100% fruit juices and fresh juices were comparable as no significantly difference (p>0.05) was found between these two groups. Commercial fruit drinks in this study were not good source of antioxidants. These findings provide some useful information especially for ageing population in choosing healthy fruit juice or drinks for their health maintenance purposes.
  8. Alia Hamad, Mani V, Ramasamy K, Lim SM, Abu Bakar Abdul Majeed
    Sains Malaysiana, 2016;45:1299-1310.
    The continued progression of neurodegeneration may result in dementia. The present study compared the neuroprotective
    activities between soybean and tempeh extracts in rats. The extracts were administered orally at 10, 20 and 40 mg/kg for
    15 days. Radial arm maze and elevated plus maze served as exteroceptive behavioural models for memory measuring.
    Brain cholinergic activities (acetylcholine and acetylcholinesterase) and neuroinflammatory related cytokines interleukin
    1β and interleukin-10 were also tested. Soybean and tempeh extracts significantly improved memory, but overall 40 mg/
    kg tempeh showed better improvement (p<0.05). The tempeh extracts at 20 and 40 mg/kg exhibited a significant (p<0.05)
    increase and decrease in the level of acetylcholine and acetylcholinesterase activities, respectively. Tempeh extract (40
    mg/kg) resulted in greater reduction (p<0.05) of inflammation than soybean extract. Altogether, tempeh extract may be
    beneficial in the management and prevention of dementia and Alzheimer’s disease.
  9. Mohamad Fakri E, Lim S, Musa N, Hazizul Hasan M, Adam A, Ramasamy K
    Sains Malaysiana, 2016;45:1289-1297.
    This study examined lactic acid bacteria (LAB)-fermented soymilk for their ability in hydrolyzing glucosides to aglycones
    and corresponding antioxidant capacity and memory enhancing effect. Twelve LAB isolated from Malaysian fermented food
    and milk products were incubated in commercially available soymilk for 48 h. Generally, soymilk supported LAB growth
    and significantly increased (p<0.05) conversion to bioactive aglycone by 2.1-6.5 fold when compared to unfermented
    soymilk. Lactobacillus fermentum LAB 9- fermented soymilk, in particular, was presented with increased total phenolic
    content (+10%) as opposed to unfermented soymilk. Lactobacilli (LAB 10-12)- and pediococci (LAB 5)-fermented soymilk
    elicited maximal DPPH radical-scavenging activity. LAB 1, 7, 8, 9 and 12 exhibited significantly higher (p<0.05) ferrous
    ion chelating activity when compared to control. Interestingly, LAB 9 had significantly improved memory deficit (p<0.05)
    in LPS-challenged mice. LAB-enriched nutritional value of soymilk could be useful against oxidative stress and memory
    MeSH terms: Animals; Antioxidants; Fermentation; Glucosides; Lactobacillus; Memory Disorders; Milk; Nutritive Value; Pediococcus; Oxidative Stress; Soy Milk; Mice; Lactobacillus fermentum; Lactobacillales
  10. Al-Sharabi A, Sarah Yasmin Tajuddin, Au Diya Fatihah Wan Saffiey, Syazana Jasman, Alwi H, Jumali M, et al.
    Sains Malaysiana, 2016;45:1959-1968.
    Kesan penambahan PbO dengan saiz 10 hingga 30 nm terhadap kekondukisan lebihan YBa2Cu3O7-δ telah dikaji. Kekonduksian lebihan ialah fluktuasi kekonduksian elektrik disebabkan oleh interaksi pasangan Cooper dengan elektron biasa berhampiran suhu genting, Tc. Sampel dengan komposisi permulaan YBa2Cu3O7-δ(PbO)x untuk x = 0.00- 0.45 peratus berat (% bt.) telah disediakan melalui tindak balas keadaan pepejal. Analisis fluktuasi dan kekonduksian lebihan menggunakan teori Aslamazov-Larkin (AL) untuk menentukan dimensi kekonduksian l telah dijalankan. Teori Lawrence-Donaich (LD) pula digunakan untuk menentukan panjang koheren ξc(0), gandingan Josephson J dan anisotropi γ = (ξab(0)/ξc(0)). Suhu genting mula adalah tertinggi (Tc mula = 94 K) untuk sampel x = 0.35. Analisis kekonduksian menunjukkan PbO menyebabkan peralihan kekonduksian daripada 2 dimensi ke 3 dimensi dengan suhu peralihan, T2D–3D tertinggi bagi sampel x = 0.20 (120 K). Model Lawrence-Donaich menunjukkan panjang koheren ξc(0) adalah terpanjang dan anisotropi terendah bagi sampel x = 0.25. Sampel ini juga menunjukkan gandingan Josephson tertinggi, J = 0.296. Dua kesan yang mungkin berlaku akibat penambahan PbO ialah pembentukan bahan bukan superkonduktor dalam sampel dan peningkatan hubungan antara butiran yang meningkatkan sifat-sifat kesuperkonduksian.
  11. Afifah-radiah Fauzi, Mariati Abdul Rahman, Saliana A. Aziz, Norashikin Hamzah, Badiah Baharin, Norzana Abdul Ghafar
    Sains Malaysiana, 2016;45:1923-1930.
    Periodontitis adalah penyakit kronik yang melibatkan kehilangan tulang dan inflamasi pada tisu periodontium. Interleukin-6 (IL-6) dan Tumor Necrosis Factor-α (TNF-α) merupakan penanda pro-inflamasi yang penting yang terlibat dalam periodontitis. Sebanyak 20 ekor tikus Sprague-Dawley dibahagikan kepada empat kumpulan iaitu: Kumpulan kawalan dengan salin normal (CS); kumpulan kawalan dengan madu Gelam 3 g/mL (CH); kumpulan ujian periodontitis dengan salin normal (TS); dan kumpulan ujian periodontitis dengan madu Gelam 3 g/mL (TH). Benang bersaiz 4/0 diikat pada molar pertama gigi tikus sebelah kiri bagi tujuan rangsangan penyakit periodontitis. Madu Gelam diberi secara paksa oral selama 15 hari. Selepas 15 hari, sampel plasma dan tisu dianalisis menggunakan kaedah Elisa dan pewarnaan histologi. Kehilangan tulang alveolar pada kumpulan TS adalah paling tinggi berbanding dengan kumpulan kawalan, CS dan CH namun, tiada perbezaan yang signifikan berbanding dengan kumpulan TH. Berdasarkan ujian imunohistokimia, ekspresi IL-6 dan TNF-α pada tisu periodontium adalah tinggi secara signifikan pada kumpulan TS berbanding dengan kumpulan lain. Namun, tiada perubahan aras IL-6 dan TNF-α yang signifikan pada plasma ke semua tikus kajian.
  12. Nabilah Afiqah Mohd Radzuan, Abu Bakar Sulong, Somalu MR
    Sains Malaysiana, 2016;45:1931-1921.
    Proses penyemperitan merupakan salah satu proses pra-pencampuran yang dapat membantu meningkatkan tahap serakan
    bahan pengalir dalam komposit polimer pengalir (CPC). Tahap keberaliran elektrik dilihat tidak begitu memuaskan
    walaupun telah melalui proses serakan melalui pengacuan mekanik. Kajian ini dijalankan bagi mengoptimumkan
    proses penyemperitan bahan gentian karbon terkisar (MCF) dan polipropilena (PP) iaitu suhu penyemperitan dan halaju
    putaran melalui kaedah reka bentuk eksperimen (Taguchi). Susunan orthogonal Taguchi L9 digunakan bagi menentukan
    aras yang paling optimum serta menjalankan analisis varian bagi memperoleh nilai keberaliran elektrik yang paling
    baik. Pengoptimuman parameter pada suhu penyemperitan 210ºC hingga 250ºC dan halaju putaran 50 hingga 90 rpm
    menggunakan komposisi bahan sebanyak 80 % bt. MCF dan 20 % bt. PP dengan tahap keberaliran elektrik meningkat
    pada tahap maksimum 3.67 S/cm. Pengoptimuman parameter ini menunjukkan bahawa reka bentuk eksperimen yang
    terhasil mampu menghasilkan nilai keberaliran elektrik yang tinggi serta mempunyai sifat mekanik yang baik.
  13. Mohamad Hanif Kamal Roslan, Che Aziz Ali, Kamal Roslan Mohamed
    Sains Malaysiana, 2016;45:1897-1904.
    Batuan Formasi Singa yang terdiri daripada batu lumpur dominan, berselang lapis dengan batu lodak, batu pasir dan
    juga sedikit unit konglomerat tertabur secara meluas di kepulauan Langkawi. Formasi Singa boleh dibahagikan kepada
    sepuluh fasies sedimen dan empat sekutuan fasies. Keputusan kajian menunjukkan Formasi Singa telah terendap di
    lautan cetek, iaitu di sub-sekitaran luar pesisir, transisi, muka pesisir serta dalam alur. Lautan cetek Lembangan Singa
    dipengaruhi oleh iklim sejuk kerana terdapat sedimen asalan glasier, iaitu fasies batu lumpur berpebel. Kertas kerja ini
    akan menjelas dan membincangkan segala aspek sedimentologi formasi batuan ini.
    MeSH terms: Animals; Tetrahydroisoquinolines; Gastropoda
  14. Mohd. Suhaimi Ahmad, Muhammad Ridwan Fahmi, Mustaqqim Abdul Rahim, Naimah Ibrahim
    Sains Malaysiana, 2016;45:1857-1867.
    Suatu kajian untuk menilai kesan gabungan aktiviti guna tanah dan perubahan musim terhadap kualiti sumber air telah dijalankan di Terusan Utara, Kedah. Kajian ini dijalankan di lima stesen terpilih selama 12 bulan berdasarkan Indeks Kualiti Air (WQI) dan Piawaian Interim Kualiti Air Kebangsaan (INWQS). Kajian mendapati kualiti air di Terusan Utara berada pada Kelas III dan berlaku peningkatan kualiti air dari hulu ke hilir. Hampir semua stesen berpotensi sebagai punca pencemaran berdasarkan aktiviti guna tanah terutamanya di Pelubang, Jitra serta Tunjang. Kajian menunjukkan terdapat perbezaan yang signifikan ketika perubahan musim pada DO, TSS serta BOD, namun tidak pada ammonia, pH dan COD. Secara amnya, kombinasi aktiviti guna tanah dan perubahan musim boleh mempengaruhi atau memberi kesan terhadap kualiti sumber air. Oleh itu, tindakan segera perlu dilakukan untuk mengawal punca pencemaran bagi memastikan kualiti sumber air di Terusan Utara kekal terpelihara.
    MeSH terms: Ammonia; Animals; Hydrocarbons, Chlorinated; Tetrahydroisoquinolines; Bivalvia
  15. Shidqiyyah Abdul-Hamid, Norliza Muhammad, Isa Naina Mohamed
    Sains Malaysiana, 2016;45(12):1815-1822.
    Postmenopausal osteoporosis is one of the main health problems in aging women. It was due to several factors including oxidative stress, which can be controlled through intake of antioxidants from food sources. Virgin coconut oil (VCO) is one of the natural product rich in antioxidants and has been proven to protect osteoporotic bone. This study was conducted to gain in-depth understanding on virgin coconut oil’s activity on osteoporosis at molecular level. Thirty two female Sprague-Dawley rats were divided into four groups, namely Sham operated group, ovariectomized control group (Ovx+Ctrl), ovariectomized with VCO treatment (Ovx+VCO), and ovariectomized with estrogen treatment (Ovx+E). All treatments were administered orally for ten weeks. Bone samples were obtained to examine changes on expression of superoxide dismutase (SOD), glutathione peroxidase (GPX), osteocalcin and runt-related transcription factor 2 (Runx2) genes. The results indicated that rats receiving VCO treatment had experienced significant increments in SOD, GPX and osteocalcin gene expressions compared to the ovariectomized control group, besides the gene expressions of Runx2 which also showed an increment pattern. In conclusion, VCO helps to protect bone in osteoporotic rat model by increasing the expressions of antioxidant genes and genes which increase the osteoblast acitivities.
    Keywords: Osteoporosis; ovariectomized rat model; postmenopausal; virgin coconut oil
    MeSH terms: Animals; Estrogens; Femur; Malaysia; Osteoporosis; Rats, Sprague-Dawley
  16. Shafiq M, Alamgir, Atif M
    Sains Malaysiana, 2016;45:1773-1777.
    Countless statistical tools are available to extract information from data. Life time modeling is considered as one of
    the most prominent fields of statistics, which is evident from the developments made in this field in the last few decades.
    Almost every statistic for life time analysis is based on precise life time observations, however, life time is not a precise
    measurement but more or less fuzzy. Therefore, in addition to classical statistical tools, fuzzy number approaches to
    describe life time data are more suitable. In order to incorporate fuzziness of the observations, fuzzy estimators for the
    three parameter lognormal distribution were suggested. The proposed estimators cover stochastic variation as well as
    fuzziness of the observations.
    MeSH terms: Biometry; Statistical Distributions; Life
  17. Abdur Razzaque Mughal, Zakiyah Zain, Nazrina Aziz
    Sains Malaysiana, 2016;45:1763-1772.
    In this study, group acceptance sampling plan (GASP) proposed by Aslam et al. (2011) is redesigned where the lifetime of
    test items are following Pareto distribution of 2nd kind. The optimal plan parameters are found by considering various
    pre-determined designed parameters. The plan parameters were obtained using the optimization solution and it also
    concludes that the proposed plan is more efficient than the existing plan as it requires minimum sample size.
    MeSH terms: Radiotherapy Planning, Computer-Assisted; Sample Size; Radiotherapy, Intensity-Modulated
  18. Ser G, Keskin S, Can Yilmaz M
    Sains Malaysiana, 2016;45:1755-1761.
    Multiple imputation method is a widely used method in missing data analysis. The method consists of a three-stage
    process including imputation, analyzing and pooling. The number of imputations to be selected in the imputation step
    in the first stage is important. Hence, this study aimed to examine the performance of multiple imputation method at
    different numbers of imputations. Monotone missing data pattern was created in the study by deleting approximately 24%
    of the observations from the continuous result variable with complete data. At the first stage of the multiple imputation
    method, monotone regression imputation at different numbers of imputations (m=3, 5, 10 and 50) was performed. In the
    second stage, parameter estimations and their standard errors were obtained by applying general linear model to each
    of the complete data sets obtained. In the final stage, the obtained results were pooled and the effect of the numbers of
    imputations on parameter estimations and their standard errors were evaluated on the basis of these results. In conclusion,
    efficiency of parameter estimations at the number of imputation m=50 was determined as about 99%. Hence, at the
    determined missing observation rate, increase was determined in efficiency and performance of the multiple imputation
    method as the number of imputations increased.
    MeSH terms: Data Interpretation, Statistical; Models, Statistical; Linear Models
  19. Fudziah Ismail, Kasim Hussain, Norazak Senu
    Sains Malaysiana, 2016;45:1747-1754.
    In this article, the general form of Runge-Kutta method for directly solving a special fourth- order ordinary differential
    equations denoted as RKFD method is given. The order conditions up to order seven are derived, based on the order
    conditions, we construct a new explicit four-stage sixth-order RKFD method denoted as RKFD6 method. Zero-stability of
    the method is proven. Comparisons are made using the existing Runge–Kutta methods after the problems are reduced
    to a system of first order ordinary differential equations. Numerical results are presented to illustrate the efficiency and
    competency of the new method.
  20. Nor Azah Samat, Syafiqah Husna Mohd Imam Ma’arof
    Sains Malaysiana, 2016;45:1741-1745.
    Disease frequency is used to measure the situation of the disease with reference to the population size and time period
    which is in a fractional form. The lower part of the fraction, known as denominator is the important part as it was used
    to calculate a rate or ratio. Since the disease frequency is based on a ratio estimator, the results are highly dependent
    upon the value of denominator. Therefore, the main aim of this paper was to propose a new method in calculating the
    denominator for the relative risk equation with the application to chikungunya disease data from Malaysia. The new
    method of calculating the denominator of the relative risk equation includes the use of discrete time-space stochastic
    SIR-SI (susceptible-infective-recovered for human population and susceptible-infective for vector population) disease
    transmission model instead of the total disease counts. The results of the analysis showed that the estimation of expected
    disease counts based on total posterior means can overcome the problem of expected counts estimation based on the total
    number of disease especially when there is no observed disease count in certain regions. The proposed new approach to
    calculate the denominator for the relative risk equation is suitable for the case of rare disease in which it offers a better
    method of expected disease counts estimation.
    MeSH terms: Animals; Disease Susceptibility; Disease Vectors; Humans; Malaysia; Paper; Population Density; Risk; Rare Diseases; Chikungunya Fever
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