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Fulltext Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead

Goodson WH, Lowe L, Carpenter DO, Gilbertson M, Manaf Ali A, Lopez de Cerain Salsamendi A, et al.

Carcinogenesis, 2015 Jun;36 Suppl 1:S254-96.
PMID: 26106142 DOI: 10.1093/carcin/bgv039

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology.

Matched MeSH terms: Environmental Exposure/adverse effects*
Deoxyribonucleic acid (DNA) methylation in children exposed to air pollution: a possible mechanism underlying respiratory health effects development

Suhaimi NF, Jalaludin J, Abu Bakar S

Rev Environ Health, 2021 Mar 26;36(1):77-93.
PMID: 32857724 DOI: 10.1515/reveh-2020-0065

Air pollution is a substantial environmental threat to children and acts as acute and chronic disease risk factors alike. Several studies have previously evaluated epigenetic modifications concerning its exposure across various life stages. However, findings on epigenetic modifications as the consequences of air pollution during childhood are rather minimal. This review evaluated highly relevant studies in the field to analyze the existing literature regarding exposure to air pollution, with a focus on epigenetic alterations during childhood and their connections with respiratory health effects. The search was conducted using readily available electronic databases (PubMed and ScienceDirect) to screen for children's studies on epigenetic mechanisms following either pre- or post-natal exposure to air pollutants. Studies relevant enough and matched the predetermined criteria were chosen to be reviewed. Non-English articles and studies that did not report both air monitoring and epigenetic outcomes in the same article were excluded. The review found that epigenetic changes have been linked with exposure to air pollutants during early life with evidence and reports of how they may deregulate the epigenome balance, thus inducing disease progression in the future. Epigenetic studies evolve as a promising new approach in deciphering the underlying impacts of air pollution on deoxyribonucleic acid (DNA) due to links established between some of these epigenetic mechanisms and illnesses.

Matched MeSH terms: Environmental Exposure/adverse effects*
Toxicity of single-walled carbon nanotubes

Ong LC, Chung FF, Tan YF, Leong CO

Arch Toxicol, 2016 Jan;90(1):103-18.
PMID: 25273022 DOI: 10.1007/s00204-014-1376-6

Carbon nanotubes (CNTs) are an important class of nanomaterials, which have numerous novel properties that make them useful in technology and industry. Generally, there are two types of CNTs: single-walled nanotubes (SWNTs) and multi-walled nanotubes. SWNTs, in particular, possess unique electrical, mechanical, and thermal properties, allowing for a wide range of applications in various fields, including the electronic, computer, aerospace, and biomedical industries. However, the use of SWNTs has come under scrutiny, not only due to their peculiar nanotoxicological profile, but also due to the forecasted increase in SWNT production in the near future. As such, the risk of human exposure is likely to be increased substantially. Yet, our understanding of the toxicological risk of SWNTs in human biology remains limited. This review seeks to examine representative data on the nanotoxicity of SWNTs by first considering how SWNTs are absorbed, distributed, accumulated and excreted in a biological system, and how SWNTs induce organ-specific toxicity in the body. The contradictory findings of numerous studies with regards to the potential hazards of SWNT exposure are discussed in this review. The possible mechanisms and molecular pathways associated with SWNT nanotoxicity in target organs and specific cell types are presented. We hope that this review will stimulate further research into the fundamental aspects of CNTs, especially the biological interactions which arise due to the unique intrinsic characteristics of CNTs.

Matched MeSH terms: Environmental Exposure/adverse effects
Fulltext Effect of Air Pollution and Hospital Admission: A Systematic Review

Ab Manan N, Noor Aizuddin A, Hod R

Ann Glob Health, 2018 11 05;84(4):670-678.
PMID: 30779516 DOI: 10.29024/aogh.2376

IntroductionMany epidemiological studies have demonstrated associations between air pollution levels and human health in terms of hospital admissions. The aim of this paper is to gather evidence concerning air pollution effects on the risk of hospital admission. We hypothesised that increase in: particulate matter (PM), ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), and sulphur dioxide (SO2) levels would be associated with the increasing trend of hospital admission.MethodsA systematic review of literature was carried out. Literature search was done in Sage, Ovid Medline, Science Direct, Wiley and ProQuest from 2010 to 2016 using keywords "hospital admission and air pollution". Studies of any relevant design were included if they presented original data, included at least one analysis where hospital admission was the specific outcome, and one or more of the following exposures were investigated: PM, O3, CO, NO2 and SO2.ResultsA total of 175 potential studies were identified by the search. Twenty two studies qualified for the review. Air pollution was noted to have an excessive risk of 3.46 (95%CI, 1.67, 5.27) of total hospital admissions. Cardiovascular admission was noted to have an increased risk of hospitalization for PM2.5 of 1.5 to 2.0; PM10 (1.007 to 2.7); NO2 (1.04 to 1.17) and SO2 (1.007). For respiratory admission, PM2.5 can caused an increased risk of hospitalization by 1.1 to 1.8; PM10 (1.007 to 1.13); NO2 (1.08 to 1.94) and SO2 (1.02). While O3 have minimal effect on COPD and stroke, CO does not influence in the effect of these hospitalization.ConclusionThe exposure to air pollutants confers an increased risk of admission of several disease. Our findings call for greater awareness of environmental protection and the implementation of effective measures to improve the quality of air, which may reduce the risks of adverse effects on the population's health.

Matched MeSH terms: Environmental Exposure/adverse effects*
Fulltext Parental health risk perceptions and preventive measures related to Children's second-hand cigarette smoke exposure in Malaysia

Junus S, Chew CC, Sugunan P, Meor-Aziz NF, Zainal NA, Hassan HM, et al.

BMC Public Health, 2021 10 15;21(1):1860.
PMID: 34654405 DOI: 10.1186/s12889-021-11825-2

BACKGROUND: Secondhand smoke (SHS) exposure can affect physical development in children. An understanding of parental risk perception of SHS could guide efforts to develop measures for prevention of SHS exposure among children. This study aimed to assess parental risk perceptions of SHS and action taken by parents to minimise SHS exposure in their children.
METHODS: This cross-sectional nationwide study conducted in 2018 recruited convenience sample of 289 parents with children up to age 12 at public areas. Parents were asked to rate the risk level from 1 (no risk) to 5 (extremely high risk) by looking at photographs of an adult smoking in the presence of a child in 8 different situations. The implementation of smoking restriction rules was assessed. Mean scores were calculated with higher scores representing higher risk perception of SHS to child's health. Linear regression analysis was used to determine factors associated with the level of parental risk perception of SHS exposure to their children's health.
RESULTS: A total of 246 parents responded. Their mean age was 35 years (SD 6.4). The majority were mothers (75.6%), Malays (72.0%) and had tertiary education level (82.5%), and non-smoker (87.1%). The mean age of respondents' youngest child was 3 years (SD 3.1). The risk perception level was high [mean scores: 4.11 (SD: 0.82)]. Most parents implemented household (65.0%) and car (68.3%) smoking restriction rules. Lower levels of risk perception were observed among participants who were current smokers (p

Matched MeSH terms: Environmental Exposure/adverse effects
The impact of traffic-related air pollution on lung function status and respiratory symptoms among children in Klang Valley, Malaysia

Suhaimi NF, Jalaludin J, Mohd Juhari MA

Int J Environ Health Res, 2022 Mar;32(3):535-546.
PMID: 32579034 DOI: 10.1080/09603123.2020.1784397

Increasing the range of vehicles on traffic roads in the urban area has led to traffic-related air pollution (TRAP) and is currently becoming the main concern for health, especially among children. The study aimed to determine associations between TRAP and respiratory health, also to identify the main factors that influenced them. A cross-sectional comparative study was carried out among children in high and low traffic areas. Air quality monitoring was conducted in six primary schools. A set of standardized questionnaires was distributed to obtain respondents' exposure history and respiratory health symptoms, while spirometry test was carried out to determine the lung function status. There were associations between TRAP and abnormality of FEV1% among children. NO2 was the main predictor that influenced both chest tightness and abnormality of FEV1%. Children exposed to a high level of traffic-related air pollution have an increased risk of respiratory symptoms and abnormality of lung function.

Matched MeSH terms: Environmental Exposure/adverse effects
Fulltext Metabolic reprogramming and dysregulated metabolism: cause, consequence and/or enabler of environmental carcinogenesis?

Robey RB, Weisz J, Kuemmerle NB, Salzberg AC, Berg A, Brown DG, et al.

Carcinogenesis, 2015 Jun;36 Suppl 1(Suppl 1):S203-31.
PMID: 26106140 DOI: 10.1093/carcin/bgv037

Environmental contributions to cancer development are widely accepted, but only a fraction of all pertinent exposures have probably been identified. Traditional toxicological approaches to the problem have largely focused on the effects of individual agents at singular endpoints. As such, they have incompletely addressed both the pro-carcinogenic contributions of environmentally relevant low-dose chemical mixtures and the fact that exposures can influence multiple cancer-associated endpoints over varying timescales. Of these endpoints, dysregulated metabolism is one of the most common and recognizable features of cancer, but its specific roles in exposure-associated cancer development remain poorly understood. Most studies have focused on discrete aspects of cancer metabolism and have incompletely considered both its dynamic integrated nature and the complex controlling influences of substrate availability, external trophic signals and environmental conditions. Emerging high throughput approaches to environmental risk assessment also do not directly address the metabolic causes or consequences of changes in gene expression. As such, there is a compelling need to establish common or complementary frameworks for further exploration that experimentally and conceptually consider the gestalt of cancer metabolism and its causal relationships to both carcinogenesis and the development of other cancer hallmarks. A literature review to identify environmentally relevant exposures unambiguously linked to both cancer development and dysregulated metabolism suggests major gaps in our understanding of exposure-associated carcinogenesis and metabolic reprogramming. Although limited evidence exists to support primary causal roles for metabolism in carcinogenesis, the universality of altered cancer metabolism underscores its fundamental biological importance, and multiple pleiomorphic, even dichotomous, roles for metabolism in promoting, antagonizing or otherwise enabling the development and selection of cancer are suggested.

Matched MeSH terms: Environmental Exposure/adverse effects*
Fulltext Disruptive chemicals, senescence and immortality

Carnero A, Blanco-Aparicio C, Kondoh H, Lleonart ME, Martinez-Leal JF, Mondello C, et al.

Carcinogenesis, 2015 Jun;36 Suppl 1(Suppl 1):S19-37.
PMID: 26106138 DOI: 10.1093/carcin/bgv029

Carcinogenesis is thought to be a multistep process, with clonal evolution playing a central role in the process. Clonal evolution involves the repeated 'selection and succession' of rare variant cells that acquire a growth advantage over the remaining cell population through the acquisition of 'driver mutations' enabling a selective advantage in a particular micro-environment. Clonal selection is the driving force behind tumorigenesis and possesses three basic requirements: (i) effective competitive proliferation of the variant clone when compared with its neighboring cells, (ii) acquisition of an indefinite capacity for self-renewal, and (iii) establishment of sufficiently high levels of genetic and epigenetic variability to permit the emergence of rare variants. However, several questions regarding the process of clonal evolution remain. Which cellular processes initiate carcinogenesis in the first place? To what extent are environmental carcinogens responsible for the initiation of clonal evolution? What are the roles of genotoxic and non-genotoxic carcinogens in carcinogenesis? What are the underlying mechanisms responsible for chemical carcinogen-induced cellular immortality? Here, we explore the possible mechanisms of cellular immortalization, the contribution of immortalization to tumorigenesis and the mechanisms by which chemical carcinogens may contribute to these processes.

Matched MeSH terms: Environmental Exposure/adverse effects
Fulltext Environmental air pollutants as risk factors for asthma among children seen in pediatric clinics in UKMMC, Kuala Lumpur

Idris IB, Ghazi HF, Zhie KH, Khairuman KA, Yahya SK, Abd Zaim FA, et al.

Ann Glob Health, 2016 6 22;82(1):202-8.
PMID: 27325078 DOI: 10.1016/j.aogh.2016.01.021

The prevalence of asthma is increasing, especially among children in Malaysia, with environmental factors as one of the main preventable contributors. The aim of this study was to determine the association between environmental air pollutants and the occurrence of asthma among children seen in pediatric clinics in Universiti Kebangsaan Malaysia Medical Center (UKMMC), Kuala Lumpur. An unmatched case control study among children who attended the pediatric clinic was carried out from May to August 2015. A total of 223 children who were diagnosed with asthma (105 cases) and who did not have asthma (118 controls) were included in this study. Their parents or caregivers were interviewed using questionnaires modified from the International Study of Asthma and Allergies in Childhood. Data obtained were analyzed using SPSS software version 20. There was a higher risk of asthma in those who had carpet at home (OR = 2.15 CI [1.25-3.68]), those who lived within 200 m of heavy traffic (OR = 1.72 CI [1.01-2.93]), and those who were exposed to lorry fumes (OR = 2.61. CI [1.38-4.93]). Environmental air pollutants increased the risk of asthma among children in Malaysia. Exposure to congested roads, lorry fumes, and indoor carpet were associated with asthma among children in this study. Parents or caretakers of children with asthma should be given adequate education on the prevention of asthmatic attack among these children.
Study site: Paediatric clinic, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia

Matched MeSH terms: Environmental Exposure/adverse effects*
The Malaysian Medical Association's role in public health control for reduction of bird dropping hazards in Sarawak

Hock RH

Aust N Z J Public Health, 2009 Apr;33(2):194-5.
PMID: 19413867 DOI: 10.1111/j.1753-6405.2009.00370.x
Matched MeSH terms: Environmental Exposure/adverse effects
Risk factors for prostate cancer in Universiti Kebangsaan Malaysia Medical Centre: a case-control study

Subahir MN, Shah SA, Zainuddin ZM

Asian Pac J Cancer Prev, 2009;10(6):1015-20.
PMID: 20192575

INTRODUCTION: In Malaysia, prostate cancer is ranked 6th among male cancer and expected to increase in the future. Several factors have shown to be related to prostate cancer such as sociodemographic, lifestyle, diet, occupational exposure, medical and health status. This is the first time a similar study was conducted in Malaysia to recognize the risk factors for prostate cancer patients who came for treatment at University Kebangsaan Malaysia Medical Centre (UKMMC).
METHODS: Prostate cancer cases diagnosed between 2003 and 2008 which met with the inclusion criteria were included in the study. One hundred and twelfth (112) pairs of cases and controls matched by age and ethnicity were analysed. McNemar Odds Ratios (OR(M)) were calculated using McNemar Calculator software for univariate analysis while conditional logistic regression was used for multivariate analysis, both using SPSS version 12.0.
RESULTS: Most of the prostate cancer patients (68.8%) that came for treatment in UKMMC were above 70 years old. The majority were Chinese (50.0%) followed by Malay (46.4%) and Indian (3.6%). Multivariate analysis showed cases were more likely to have a first-degree relative with a history of cancer (OR= 3.77, 95% CI= 1.19-11.85), to have been exposed to pesticides (OR= 5.57, 95% CI= 1.75-17.78) and consumed more meat (OR= 12.23, 95% CI= 3.89-39.01). Significantly reduced risks of prostate cancer were noted among those consuming more vegetables (OR= 0.12, 95% CI= 0.02-0.84), more tomatoes (OR= 0.35, 95% CI= 0.13-0.93) and those who had frequent sexual intercourse (OR= 0.44, 95% CI= 0.19-0.96).
CONCLUSION: Some lifestyle and occupation factors are strong predictors of the occurrence of prostate cancer among patients in UKMMC. More importantly, with the identification of the potentially modifiable risk factors, proper public health intervention can be improved.

Matched MeSH terms: Environmental Exposure/adverse effects
Exposure assessment for trace elements from consumption of marine fish in Southeast Asia

Agusa T, Kunito T, Sudaryanto A, Monirith I, Kan-Atireklap S, Iwata H, et al.

Environ Pollut, 2007 Feb;145(3):766-77.
PMID: 16828209

Concentrations of 20 trace elements were determined in muscle and liver of 34 species of marine fish collected from coastal areas of Cambodia, Indonesia, Malaysia and Thailand. Large regional difference was observed in the levels of trace elements in liver of one fish family (Carangidae): the highest mean concentration was observed in fish from the Malaysian coastal waters for V, Cr, Zn, Pb and Bi and those from the Java Sea side of Indonesia for Sn and Hg. To assess the health risk to the Southeast Asian populations from consumption of fish, intake rates of trace elements were estimated. Some marine fish showed Hg levels higher than the guideline values by U.S. Environmental Protection Agency and Joint FAO/WHO Expert Committee on Food Additives (JECFA). This suggests that consumption of these fish may be hazardous to the people.

Matched MeSH terms: Environmental Exposure/adverse effects*
Fulltext Skin prick test reactivity to common airborne pollens and molds in allergic rhinitis patients

Wan Ishlah L, Gendeh BS

Med J Malaysia, 2005 Jun;60(2):194-200.
PMID: 16114160 MyJurnal

Allergic rhinitis is the single most common chronic allergic disease affecting an estimated four million people in Malaysia. House dust mites, grass pollens and fungal spores play has been identified to play a major role in the pathogenesis of allergic rhinitis. However, sensitization to pollen and spores in Malaysia is not well documented. On the basis of the results of an aerobiological survey of the common mold spores and pollens in the Klang Valley, twelve local extracts of molds and two local extracts of grass pollens were prepared by the Institute for Medical Research for this study. The study evaluated the prevalence of skin prick test (SPT) reactivity to the extracts of those airborne molds and pollens in allergic rhinitis patients in the Klang Valley. A total of 85 allergic rhinitis patients were recruited. All molds and grass pollens extracts tested, elicited positive response to SPT. Among the molds extracts, Fusarium was observed to have the highest prevalence of SPT reactivity (23.5%), followed by Aspergillus flavum (21.2%), Dreselera orysae (18.8%), Alternaria sp (17.6%), Curvularis eragrostidis (17.6%), Penicillium oxa (16.5%), Pestolotriopsis gtuepini (16.5%), Rhizopphus arrhi (16.5%), Aspergilluls nigus (15.3%). Penicillium choy (12.9%), Aspergillus fumigatus (11.8%), and Cladosporium sp (4.7%). In the grass pollen, the SPT reactivity to Ischaemum and Enilia is 14.1% and 5.9% respectively. However, the prevalence of SPT reactivity was not influenced by the age, sex, ethnicity, symptomatology and concurrent allergic condition. We have documented the prevalence of skin prick test reactivity to common molds and grass pollens in the Klang valley, which is comparable to the neighboring countries. Its prevalence in our allergic rhinitis patients suggests that it has a role in pathogenesis of allergic diseases. A larger representative sample involving multi-centric centers in Malaysia should be encouraged in the near future.

Study site: ENT
Department, Pusat Perubatan University Kebangsaan Malaysia
(PPUKM)

Matched MeSH terms: Environmental Exposure/adverse effects
Parental awareness and attitude towards environmental tobacco smoke exposure in children with respiratory illnesses

Hasniah AL, Tan YP, Nur Buhairah MA, Chan TW, Muhammad Nabil TI, Syed Zulkifli SZ

Public Health, 2016 08;137:182-4.
PMID: 26976490 DOI: 10.1016/j.puhe.2015.10.028
Matched MeSH terms: Environmental Exposure/adverse effects*
Fulltext Environmental immune disruptors, inflammation and cancer risk

Thompson PA, Khatami M, Baglole CJ, Sun J, Harris SA, Moon EY, et al.

Carcinogenesis, 2015 Jun;36 Suppl 1:S232-53.
PMID: 26106141 DOI: 10.1093/carcin/bgv038

An emerging area in environmental toxicology is the role that chemicals and chemical mixtures have on the cells of the human immune system. This is an important area of research that has been most widely pursued in relation to autoimmune diseases and allergy/asthma as opposed to cancer causation. This is despite the well-recognized role that innate and adaptive immunity play as essential factors in tumorigenesis. Here, we review the role that the innate immune cells of inflammatory responses play in tumorigenesis. Focus is placed on the molecules and pathways that have been mechanistically linked with tumor-associated inflammation. Within the context of chemically induced disturbances in immune function as co-factors in carcinogenesis, the evidence linking environmental toxicant exposures with perturbation in the balance between pro- and anti-inflammatory responses is reviewed. Reported effects of bisphenol A, atrazine, phthalates and other common toxicants on molecular and cellular targets involved in tumor-associated inflammation (e.g. cyclooxygenase/prostaglandin E2, nuclear factor kappa B, nitric oxide synthesis, cytokines and chemokines) are presented as example chemically mediated target molecule perturbations relevant to cancer. Commentary on areas of additional research including the need for innovation and integration of systems biology approaches to the study of environmental exposures and cancer causation are presented.

Matched MeSH terms: Environmental Exposure/adverse effects*
Blood lead levels of urban and rural Malaysian primary school children

Hashim JH, Hashim Z, Omar A, Shamsudin SB

Asia Pac J Public Health, 2000;12(2):65-70.
PMID: 11836921

The objective of this article is to study the influence of exposure and socio-economic variables on the blood lead level of Malaysian school children. Data on respirable lead and blood lead of 346 school children were obtained from Kuala Lumpur (urban), Kemaman (semi-urban) and Setiu (rural). Respirable lead and blood lead were highest for Kuala Lumpur (95 ng/m3 and 5.26 micrograms/dL) followed by Kemaman (27 ng/m3 and 2.81 micrograms/dL) and Setiu (15 ng/m3 and 2.49 micrograms/dL), and the differences were statistically significant. The percentage of school children with excessive blood lead of 10 micrograms/dL or greater was 6.36% overall, and highest for Kuala Lumpur (11.73%). Regression analyses show that urban children are at higher risk of exhibiting excessive blood lead levels. Kuala Lumpur's school children have a 25 times greater risk of having excessive blood lead levels when compared to Kemaman's and Setiu's school children. Respirable and blood lead were correlated (r = 0.999, p = 0.021). Urban school children acquire higher blood lead levels than their rural and semi-urban counterparts, even after controlling for age, sex, parents' education and income levels. In conclusion, it is time that lead in the Malaysian environment and population be monitored closely, especially its temporal and spatial variability. Only then can a comprehensive preventive strategy be implemented.

Matched MeSH terms: Environmental Exposure/adverse effects
Lead exposure in the lead-acid storage battery manufacturing and PVC compounding industries

Ho SF, Sam CT, Embi GB

Occup Med (Lond), 1998 Sep;48(6):369-73.
PMID: 10024732

This study was conducted as part of the Human Exposure Assessment Location (HEAL) Project which comes under the United Nations Environment Programme/World Health Organisation (UNEP/WHO) Global environmental Monitoring System (GEMS). The objective of the study was to evaluate workers' exposure to lead in industries with the highest exposure. All subjects were interviewed about their occupational and smoking histories, the use of personal protective equipment and personal hygiene. The contribution of a dietary source of lead intake from specified foods known to contain lead locally and personal air sampling for lead were assessed. A total of 61 workers from two PVC compounding and 50 workers from two lead acid battery manufacturing plants were studied together with 111 matched controls. In the PVC compounding plants the mean lead-in-air level was 0.0357 mg/m3, with the highest levels occurring during the pouring and mixing operations. This was lower than the mean lead-in-air level of 0.0886 mg/m3 in the lead battery manufacturing plants where the highest exposure was in the loading of lead ingots into milling machines. Workers in lead battery manufacturing had significantly higher mean blood lead than the PVC workers (means, 32.51 and 23.91 mcg/100 ml respectively), but there was poor correlation with lead-in-air levels. Among the lead workers, the Malays had significantly higher blood lead levels than the Chinese (mean blood levels were 33.03 and 25.35 mcg/100 ml respectively) although there was no significant difference between the two ethnic groups in the control group. There were no significant differences between the exposed and control group in terms of dietary intake of specified local foods known to contain lead. However, Malays consumed significantly more fish than the Chinese did. There were no ethnic differences in the hours of overtime work, number of years of exposure, usage of gloves and respirators and smoking habits. Among the Malays, 94.3% eat with their hands compared with 9.2% of the Chinese. Workers who ate with bare hands at least once a week had higher blood lead levels after adjusting for lead-in-air levels (mean blood lead was 30.2 and 26.4 mcg/100 ml respectively). The study indicated that the higher blood lead levels observed in the Malay workers might have been due to their higher exposure and eating with bare hands.

Matched MeSH terms: Environmental Exposure/adverse effects
Assessment of health risks and individuals' willingness to participate in drinking water management at flood-prone Pahang River Basin, Malaysia

Alam L, Rahman LF, Ahmed MF, Bari MA, Masud MM, Mokhtar MB

Environ Geochem Health, 2021 May;43(5):2049-2063.
PMID: 33389458 DOI: 10.1007/s10653-020-00783-0

Rivers, the main source of the domestic water supply in Malaysia, have been threatened by frequent flooding in recent years. This study aims to assess human health risks associated with exposure to concentrated heavy metals in a flood-prone region of Malaysia and investigate the affected individuals' willingness to participate in managing water resources. Hazard indices and cancer risks associated with water contamination by heavy metals have been assessed following the method prescribed by the US Environmental Protection Agency. Yearly data of heavy metal contamination (Cd, Cr, Pb, Zn, Fe), water quality parameters (DO, BOD, COD, pH), and climatic information (annual rainfall, annual temperature) have been collected from the Department of Environment and Meteorological Department of Malaysia, respectively. The inductively coupled plasma mass spectrometry technique has been used by the department of environment for analyzing heavy metal concentration in river water samples. In this study, data from a stratified random sample of households in the affected region were analyzed, using partial least squares structural equation modeling, to predict the link between individuals' perceptions and attitudes about water resources and their willingness to engage in water management program. The health risk estimation indicated that the hazard index values were below the acceptable limit, representing no non-carcinogenic risk to adults and children residing in the study area via oral intake and dermal adsorption of water. However, the calculated value for cancer risk signified possible carcinogenic risks associated with Pb and Cd. In general, contamination due to pollution and flooding tends to increase in the basin region, and appropriate management is needed. The results identified perceived water quality as a significant factor influencing people's attitudes toward involvement in water management programs. As in many developing countries, there is no legal provision guaranteeing public representation in water management in Malaysia. The conclusion discusses the importance of these for the literature and for informing future policy actions.

Matched MeSH terms: Environmental Exposure/adverse effects
Fulltext Molecular Mechanisms of Stress-Responsive Changes in Collagen and Elastin Networks in Skin

Aziz J, Shezali H, Radzi Z, Yahya NA, Abu Kassim NH, Czernuszka J, et al.

Skin Pharmacol Physiol, 2016;29(4):190-203.
PMID: 27434176 DOI: 10.1159/000447017

Collagen and elastin networks make up the majority of the extracellular matrix in many organs, such as the skin. The mechanisms which are involved in the maintenance of homeostatic equilibrium of these networks are numerous, involving the regulation of genetic expression, growth factor secretion, signalling pathways, secondary messaging systems, and ion channel activity. However, many factors are capable of disrupting these pathways, which leads to an imbalance of homeostatic equilibrium. Ultimately, this leads to changes in the physical nature of skin, both functionally and cosmetically. Although various factors have been identified, including carcinogenesis, ultraviolet exposure, and mechanical stretching of skin, it was discovered that many of them affect similar components of regulatory pathways, such as fibroblasts, lysyl oxidase, and fibronectin. Additionally, it was discovered that the various regulatory pathways intersect with each other at various stages instead of working independently of each other. This review paper proposes a model which elucidates how these molecular pathways intersect with one another, and how various internal and external factors can disrupt these pathways, ultimately leading to a disruption in collagen and elastin networks.

Matched MeSH terms: Environmental Exposure/adverse effects
Fulltext Current Concepts of Neurodegenerative Mechanisms in Alzheimer's Disease

Magalingam KB, Radhakrishnan A, Ping NS, Haleagrahara N

Biomed Res Int, 2018;2018:3740461.
PMID: 29707568 DOI: 10.1155/2018/3740461

Neurodegenerative diseases are hereditary or sporadic conditions that result in the progressive loss of the structure and function of neurons as well as neuronal death. Although a range of diseases lie under this umbrella term, Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative diseases that affect a large population around the globe. Alzheimer's disease is characterized by the abnormal accumulation of extracellular amyloid-β plaques and intraneuronal neurofibrillary tangles in brain regions and manifests as a type of dementia in aged individuals that results in memory loss, multiple cognitive abnormalities, and intellectual disabilities that interfere with quality of life. Since the discovery of AD, a wealth of new information has emerged that delineates the causes, mechanisms of disease, and potential therapeutic agents, but an effective remedy to cure the diseases has not been identified yet. This could be because of the complexity of the disease process, as it involves various contributing factors that include environmental factors and genetic predispositions. This review summarizes the current understanding on neurodegenerative mechanisms that lead to the emergence of the pathology of AD.

Matched MeSH terms: Environmental Exposure/adverse effects

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