Displaying all 12 publications

  1. Leong YH, Gan CY, Majid MI
    Arch Environ Contam Toxicol, 2014 Jul;67(1):21-8.
    PMID: 24651928 DOI: 10.1007/s00244-014-0019-5
    A total of 127 and 177 seafood samples from Malaysia were analyzed for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs), respectively. The World Health Organization-toxic-equivalency quotients (WHO-TEQ) of PCDD/Fs varied from 0.13 to 1.03 pg TEQ g(-1), whereas dl-PCBs ranged from 0.33 to 1.32 pg TEQ g(-1). Based on food-consumption data from the global environment monitoring system-food contamination monitoring and assessment programme, calculated dietary exposures to PCDD/Fs and dl-PCBs from seafood for the general population in Malaysia were 0.042 and 0.098 pg TEQ kg(-1) body weight day(-1), respectively. These estimations were quite different from the values calculated using the Malaysian food-consumption statistics (average of 0.313 and 0.676 pg TEQ kg(-1) body weight day(-1) for PCDD/Fs and PCBs, respectively). However, both of the dietary exposure estimations were lower than the tolerable daily intake recommended by WHO. Thus, it is suggested that seafood from Malaysia does not pose a notable risk to the health of the average consumer.
  2. Leong YH, Latiff AA, Ahmad NI, Rosma A
    Mycotoxin Res, 2012 May;28(2):79-87.
    PMID: 23606045 DOI: 10.1007/s12550-012-0129-8
    Aflatoxins are highly toxic secondary fungal metabolites mainly produced by Aspergillus flavus and A. parasiticus. Human exposure to aflatoxins may result directly from ingestion of contaminated foods, or indirectly from consumption of foods from animals previously exposed to aflatoxins in feeds. This paper focuses on exposure measurement of aflatoxins and aflatoxin metabolites in various human body fluids. Research on different metabolites present in blood, urine, breast milk, and other human fluids or tissues including their detection techniques is reviewed. The association between dietary intake of aflatoxins and biomarker measurement is also highlighted. Finally, aspects related to the differences between aflatoxin determination in food versus the biomarker approach are discussed.
  3. Leong YH, Rosma A, Latiff AA, Ahmad NI
    Mycotoxin Res, 2011 Aug;27(3):207-14.
    PMID: 23605801 DOI: 10.1007/s12550-011-0097-4
    Aflatoxin B1 (AFB1) was detected in 57% of the nuts and nut products marketed in Penang, Malaysia using the liquid chromatography tandem mass spectrometry. The contamination levels ranged from 0.40 to 222 μg/kg and 17 out of 128 samples (13.3%) contained AFB1 above the European Commission permitted level (2 μg/kg). Estimated dietary exposure of AFB1 in nuts and nut products were 0.36 ng per kg body weight and day and 8.89 ng per kg body weight and day, representing the low and high-level of exposure, respectively. Dose-response modelling resulted in benchmark dose lower confidence limit (BMDL10) values of 0.305 ng per kg body weight and day, with the best fitted from the log-logistic model. The derived margin of exposure (MoE) values ranged from 34 to 847 suggested that AFB1 would be of public health concern and might reasonably be considered as a high priority for risk management actions.
  4. Leong YH, Rosma A, Latiff AA, Izzah AN
    Int J Hyg Environ Health, 2012 Apr;215(3):368-72.
    PMID: 22230243 DOI: 10.1016/j.ijheh.2011.12.005
    Aflatoxins are one of the major risk factors in the multi-factorial etiology of human hepatocellular carcinoma. Therefore, the information on aflatoxins exposure is very important in the intervention planning in order to reduce the dietary intake of aflatoxins, especially among the children. This study investigated the relationship between aflatoxin B(1) (AFB(1)) lysine adduct levers in serum and socio-demographic factors and dietary intake of aflatoxins from nuts and nut products in Penang, Malaysia. A cross-sectional field study was conducted in five districts of Penang. A survey on socio-demographic characteristics was administered to 364 healthy adults from the three main ethnic groups (Malay, Chinese and Indian). A total of 170 blood samples were successfully collected and tested for the level of AFB(1)-lysine adduct. 97% of the samples contained AFB(1)-lysine adduct above the detection limit of 0.4 pg/mg albumin and ranged from 0.20 to 23.16 pg/mg albumin (mean±standard deviation=7.67±4.54 pg/mg albumin; median=7.12 pg/mg albumin). There was no significant association between AFB(1)-lysine adduct levels with gender, district, education level, household number and occupation when these socio-demographic characteristics were examined according to high or low levels of AFB(1)-lysine. However, participants in the age group of 31-50 years were 3.08 times more likely to have high AFB(1) levels compared to those aged between 18 and 30 years (P=0.026). Significant difference (P=0.000) was found among different ethnic groups. Chinese and Indian participants were 3.05 and 2.35 times more likely to have high AFB(1) levels than Malay. The result of AFB(1)-lysine adduct suggested that Penang adult population is likely to be exposed to AFB(1) but at a level of less than that needed to cause direct acute illness or death.
  5. Leong YH, Gan CY, Tan MA, Majid MI
    Malays J Med Sci, 2014 Mar;21(2):63-7.
    PMID: 24876809 MyJurnal
    Newborn screening (NBS) program is an important tool for the early diagnosis and preventive treatment of life-long impairments. NBS is one of the strategies recommended by the World Health Organization to promote the primary prevention of congenital anomalies and the health of children with these conditions. However, NBS initiation and implementation in developing countries, especially South-East Asian and North African regions, are slow and challenging. Expanded NBS is not mandatory and has not yet been incorporated into the public healthcare system in our country. Limited funding, manpower shortages, inadequate support services, low public awareness, and uncertain commitment from healthcare practitioners are the main challenges in establishing this program at the national level. Involvement and support from policy makers are very important to the success of the program and the benefit of the entire population.
  6. Leong YH, Azmi NI, Majid MIA, Wen S
    PMID: 34014804 DOI: 10.1080/19440049.2021.1922758
    An average 50 ml breast milk samples were collected from 21 lactating primiparous mothers (range 25 to 45 years, mean 33 years), 4-8 weeks after delivery in Penang Island, Malaysia. The geometric mean concentration of the most toxic congeners, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) was 0.14 pg WHO2005-TEQ g-1 zlipid. The most abundant congeners of PCDD/Fs were octachlorodibenzo-p-dioxin (OCDD) (5.9-75.4%), followed by 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (1,2,3,4,6,7,8-HpCDD) (1.1-30.7%). The geometric mean level of total dioxins and dl-PCBs was 2.2 pg WHO2005-TEQ g-1 lipid, significantly lower than those in developed countries or highly contaminated areas. The total dioxins and dl-PCBs in pg WHO2005-TEQ levels in breast milk were significantly correlated with years of residence at potential contaminated site. The average daily intake of 11.8 pg WHO2005-TEQ kg-1 body weight was estimated for a breastfed infant at 6 months of age. This demonstrates the exposure risk to infants, especially from Penang region, to these pollutants from human milk intake are potentially high during the lactation period.
  7. Leong YH, Chiang PN, Jaafar HJ, Gan CY, Majid MI
    PMID: 24392728 DOI: 10.1080/19440049.2014.880519
    A total of 126 food samples, categorised into three groups (seafood and seafood products, meat and meat products, as well as milk and dairy products) from Malaysia were analysed for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The concentration of PCDD/Fs that ranged from 0.16 to 0.25 pg WHO05-TEQ g(-1) fw was found in these samples. According to the food consumption data from the Global Environment Monitoring System (GEMS) of the World Health Organization (WHO), the dietary exposures to PCDD/F from seafood and seafood products, meat and meat products, as well as milk and dairy products for the general population in Malaysia were 0.064, 0.183 and 0.736 pg WHO05-TEQ kg(-1) bw day(-1), respectively. However, the exposure was higher in seafood and seafood products (0.415 pg WHO05-TEQ kg(-1) bw day(-1)) and meat and meat products (0.317 pg WHO05-TEQ kg(-1) bw day(-1)) when the data were estimated using the Malaysian food consumption statistics. The lower exposure was observed in dairy products with an estimation of 0.365 pg WHO05-TEQ kg(-1) bw day(-1). Overall, these dietary exposure estimates were much lower than the tolerable daily intake (TDI) as recommended by WHO. Thus, it is suggested that the dietary exposure to PCDD/F does not represent a risk for human health in Malaysia.
  8. Leong YH, Ariff AM, Khan HRM, Rani NAA, Majid MIA
    J Forensic Leg Med, 2018 May;56:16-20.
    PMID: 29525581 DOI: 10.1016/j.jflm.2018.03.007
    This study analyses the incidences and patterns of paraquat poisoning from calls received at the Malaysia National Poison Centre (NPC) since 2004 following the ban of the herbicide (2004-2006) and subsequent restriction up to year 2015. Related reported cases to the centre over twelve years (2004-2015) were retrieved and studied in respect to socio-demographic characteristics, mode and type of poisonings, exposure routes and location of incident. Ages of poisoned victims range from 10 months old to 98 years with males being intoxicated more frequently than females (ratio male to female = 2.7). The age group mainly involved in the poisoning was 20-39 years. The most common mode was intentional (62.8%) followed by unintentional (36.9%). Among the 1232 reported cases, suicidal poisoning was the highest (57.2%); accidental poisoning (30.8%) and occupational poisoning (3.3%). The findings showed an upward trend of suicidal poisoning over the years, clearly emphasizing the need for more stringent and effective enforcement to ensure the safe use of paraquat.
  9. Nik Azmi NNA, Tan TC, Ang MY, Leong YH
    PMID: 36602442 DOI: 10.1080/19440049.2022.2163054
    The presence of 3-monochloropropanediol esters (3-MCPDE), 2-monochloropropanediol esters (2-MCPDE) and glycidyl esters (GE) in infant formula products has raised serious concerns. They incorporate vegetable oils, particularly palm-based oils, which are well-known to contain large amounts of these process contaminants. An analysis was conducted on infant formula samples (n = 16) obtained from the Malaysian market to determine the levels of 3-MCPDE, 2-MCPDE and GE using gas chromatography-mass spectrometry (GC-MS). The method was validated, with a limit of quantification (LOQ) on instrument of 0.10 µg/g for all analytes. The median concentrations of 3-MCPDE, 2-MCPDE and GE in infant formula in this study were 0.008 µg/g, 0.003 µg/g and 0.002 µg/g respectively. The estimated dietary intakes calculated from consumption of infant formula show higher exposures to infants within the age group of 0 to 5 months, highest for GE (1.61 µg/kg bw/day), followed by 3-MCPDE (0.68 µg/kg bw/day) and 2-MCPDE (0.41 µg/kg bw/day) compared to the age group of 6 to 12 months. Only one sample, relating to GE exposure is a potential risk for both age groups with MOE value below 25,000.
  10. Sam IC, Wong LP, Rampal S, Leong YH, Pang CF, Tai YT, et al.
    J Adolesc Health, 2009 Jun;44(6):610-2.
    PMID: 19465327 DOI: 10.1016/j.jadohealth.2008.11.014
    Acceptability rates of human papillomavirus (HPV) vaccination by 362 Malaysian mothers were 65.7% and 55.8% for daughters and sons, respectively. Younger mothers, and those who knew someone with cancer, were more willing to vaccinate their daughters. If the vaccine was routine and cost free, acceptability rate was 97.8%.
  11. Leong YH, Isa ASM, Mohamed Mahmood M, Moey CEJ, Utar Z, Soon YI, et al.
    Regul Toxicol Pharmacol, 2018 Jun;95:280-288.
    PMID: 29567329 DOI: 10.1016/j.yrtph.2018.03.011
    This study aimed to investigate the oral acute and subacute toxicity of Poly [3-hydroxybutyrate-co-4-hydroxybutyrate], P(3HB-co-4HB) in the form of nanoparticles in Sprague-Dawley rats. Acute oral administration of P(3HB-co-4HB) nanoparticles was performed as a single dose up to 2000 mg/kg in six female rats for 14 days. Subacute toxicity study via oral administration for 28 days at doses of 0 (control), 500, 1000 and 2000 mg/kg in rats (10 rats in each group, female:male = 1:1) was conducted. The estimated lethal dose (LD50) of P(3HB-co-4HB) nanoparticles was >2000 mg/kg. No mortality, unusual changes in behaviour, adverse clinical signs, abnormal changes in body weights or food consumption were observed on all animals treated with P(3HB-co-4HB) nanoparticles during 14 days of the acute toxicity study. In the subacute test, there was no mortality and toxicologically significant changes in clinical signs, body weights, food consumption, hematology, clinical biochemistry, urinalysis, macroscopic findings, organ weights as well as histopathological examination were observed.
  12. Kamaruzaman NA, Leong YH, Jaafar MH, Mohamed Khan HR, Abdul Rani NA, Razali MF, et al.
    BMJ Open, 2020 06 01;10(6):e036048.
    PMID: 32487578 DOI: 10.1136/bmjopen-2019-036048
    OBJECTIVE: Pesticide poisoning is a global health problem, and its progressive deterioration is a major cause of concern. The objective of this study is to assess epidemiological characteristics and identify risk factors of pesticide poisoning in Malaysia.

    SETTING: Pesticide poisoning database of Malaysia National Poison Centre (NPC) from 2006 to 2015.

    PARTICIPANTS: Telephone enquiries regarding pesticide poisoning were made by healthcare professionals. Information received by the NPC was entered into a retrievable database of standardised Poison Case Report Form, as adapted from the World Health Organization (WHO).

    OUTCOMES: The outcome of the study is to provide an overview of national epidemiological profile of pesticide poisoning. High-risk groups of people and their circumstances were also identified to ensure that appropriate measures are strategised.

    RESULTS: Within the study period, a total of 11 087 pesticide poisoning cases were recorded. Sixty per cent of these cases were intentional in nature and most were found among male individuals (57%) of the Indian race (36.4%) aged between 20 and 29 years (25.5%), which occurred at home (90%) through the route of ingestion (94%). The highest number of poisoning was due to herbicides (44%) followed by agricultural insecticides (34%), rodenticides (9.9%), household insecticides (9.5%) and fungicides (0.5%). In addition, 93.6% of intentional pesticide poisoning cases were caused by suicide attempts. The results of this study show that there was an increasing trend in pesticide poisoning incidents over the 10-year duration. This indicates that pesticide poisoning is a prevalent public health problem in Malaysia, resulting in an average incidence rate of 3.8 per 100 000 population.

    CONCLUSIONS: Deliberate pesticide ingestion as a method of suicide has become a disturbing trend among Malaysians. Therefore, regulation of highly hazardous pesticides must be enforced to ensure controlled and limited access to these chemicals by the public.

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