Publications by authors named "Hing Man Chan"

Indoor air quality is an important determinant for the health of children and youth, but the conditions within Indigenous communities are understudied. We collaborated with Kanehsatake First Nation in Quebec, Canada, to address this gap using a community-based participatory research approach. Levels of key indoor air indicators, including particulate matter (PM), CO, and relative humidity, were measured in 31 randomly selected households between June 2021 and January 2022.

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  • Brain pericytes can change into multiple cell types after injury, but different subsets might have varied abilities to do so based on their characteristics.
  • Using an ischemic stroke model and advanced techniques like single-cell RNA sequencing, researchers identified two main pericyte subpopulations (NG2 and Tbx18) that respond differently to brain injury: NG2 pericytes are more likely to turn into neurons, while Tbx18 pericytes can become endothelial cells, fibroblasts, and microglia.
  • Additionally, by manipulating AMP-dependent kinase (AMPK) activity, the study found ways to enhance the conversion of pericytes into functional neurons, implying that targeted treatments could improve neuron formation from pericytes after
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  • China has experienced a rapid shift in dietary habits, prompting a review to examine different eating patterns among its population and their health impacts.
  • The analysis of 130 studies involving over 900,000 participants identified six key dietary patterns, such as Traditional Whole-Grain, Plant-Based, and Western diets, and linked them to various health outcomes.
  • Healthier dietary patterns, particularly the Plant-Based and Traditional Whole-Grain diets, were associated with lower risks of diseases like cardiovascular issues, diabetes, and obesity, highlighting the importance of promoting these diets for better public health in China.
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  • Understanding the dietary habits of First Nations is essential for tackling health disparities, with history affecting their food practices and health for generations.
  • Indigenous peoples on reserves are not included in Canada’s dietary surveys, prompting a study that evaluates First Nations adults' diet quality using HEFI-2019 and C-HEI 2007 across ninety-two communities.
  • Results showed low adherence to dietary guidelines (HEFI-2019 score of 35/80 and C-HEI 2007 score of 49/100), with factors like age, education, and traditional food intake significantly impacting diet quality.
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Glyoxalase 1 (Glo1) is an essential enzyme to detoxify methylglyoxal (MGO), a cytotoxic byproduct of glycolysis. Accumulating studies have shown an important role of Glo1 in regulating cortical development and neurogenesis, potentially contributing to the pathogenesis of autism spectrum disorder (ASD) when impaired. We have previously shown that prenatal exposure to non-apoptotic low-dose methylmercury (MeHg), an environmental pollutant, induces premature cortical neurogenesis and ASD-like behaviors in a rodent model.

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  • In 2016, the first global map of n3 PUFA (Omega-3) levels was created using the Omega-3 Index (O3I), which measures the percentage of EPA and DHA in red blood cell membranes.
  • The current study updated this map by including new data from studies conducted after 1999, resulting in a comprehensive analysis of 342,864 subjects across 48 countries.
  • Overall, most countries had low to very low O3I levels, with some notable improvements or declines compared to the 2016 map, highlighting specific countries that showed changes in their Omega-3 status.
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Indigenous peoples in Canada are disproportionately exposed to environmental contaminants and may face elevated health risks related to their unique cultural, spiritual, and economic relationships with the land, including the use of traditional food systems. However, to date, institutionalized approaches to assess risks to human and ecological health from contaminants have not been well developed or implemented with Indigenous community contexts in mind. There is regulatory interest in developing new approach methods for risk assessment, and thus an opportunity to increase their relevance to Indigenous communities in which they will be ultimately applied.

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Toenails are a common monitoring tool for arsenic exposure, but the risk of external contamination of toenails has cast doubt on its usefulness. The main objective of this study is to investigate the micro-distribution of arsenic through the dorsoventral plane of nail clippings to understand endogenous vs exogenous sources. We used laser-ablation inductively coupled plasma mass spectrometry to measure arsenic through a dorsoventral cross-section of the nail plate collected from reference (N = 17) and exposed individuals (N = 35).

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Fetal development is one of the most sensitive windows to methylmercury (MeHg) toxicity. Laboratory and epidemiological studies have shown a dose-response relationship between fetal MeHg exposure and neuro performance in different life stages from infants to adults. In addition, MeHg exposure has been reported to be associated with disorders in endoderm-derived organs, such as morphological changes in liver cells and pancreatic cell dysfunctions.

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Aberrant neurodevelopment is a core deficit of autism spectrum disorder (ASD). Here we ask whether a non-genetic factor, prenatal exposure to the environmental pollutant methylmercury (MeHg), is a contributing factor in ASD onset. We showed that adult mice prenatally exposed to non-apoptotic MeHg exhibited key ASD characteristics, including impaired communication, reduced sociability, and increased restrictive repetitive behaviors, whereas in the embryonic cortex, prenatal MeHg exposure caused premature neuronal differentiation.

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Background/objectives: The body burden of mercury in humans can be measured through hair or blood biomarkers. To compare results from different studies, it is often required to convert mercury in hair to an equivalent level in blood, using a default hair:blood ratio of 250:1 by the World Health Organization (WHO). However, the actual ratio may vary within and between populations.

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Climate change is already impacting the North American Great Lakes ecosystem and understanding the relationship between climate events and public health, such as waterborne acute gastrointestinal illnesses (AGIs), can help inform needed adaptive capacity for drinking water systems (DWSs). In this study, we assessed a harmonized binational dataset for the effects of extreme precipitation events (≥90th percentile) and preceding dry periods, source water turbidity, total coliforms, and protozoan AGIs - cryptosporidiosis and giardiasis - in the populations served by four DWSs that source surface water from Lake Ontario (Hamilton and Toronto, Ontario, Canada) and Lake Michigan (Green Bay and Milwaukee, Wisconsin, USA) from January 2009 through August 2014. We used distributed lag non-linear Poisson regression models adjusted for seasonality and found extreme precipitation weeks preceded by dry periods increased the relative risk of protozoan AGI after 1 and 3-5 weeks in three of the four cities, although only statistically significant in two.

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A multi-stage sampling strategy selected 1387 on-reserve First Nations adults in Ontario. Foods from a 24-hour dietary recall were assigned to the 100 most common food groups for men and women. Nutrients from market foods (MF) and traditional foods (TF) harvested from the wild as well as MF costs were assigned based on the proportions of total grams consumed.

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Background: Global concerns of methylmercury (MeHg) exposure have been raised, especially on its effects on pregnant women. Recent epidemiological studies have revealed associations between maternal blood/hair MeHg concentrations, adverse pregnancy outcomes, and developmental deficits. However, the underlying mechanisms remain unclear.

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Objective: We previously examined the associations between dietary dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs) intake from fish consumption and type 2 diabetes (T2D) prevalence in Ontario and Manitoba. This study aims to further explore the relationship in a regionally representative sample of First Nations adults living on-reserve across Canada.

Methods: Dietary, health and lifestyle data collected by the cross-sectional First Nations Food, Nutrition and Environment Study (2008-2018) were analyzed.

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Objective: Our objective is to describe self-reported health status, prevalence of diabetes and obesity and their associations in participants from the First Nations Food, Nutrition and Environment Study (FNFNES) in order to identify possible correlates of health in First Nations adults.

Methods: FNFNES is a participatory study with First Nations Peoples living on reserve lands south of the 60 parallel. Health and diabetes were self-reported, and prevalence of obesity was evaluated.

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Objectives: Pharmaceuticals are emerging contaminants in the environment. Little has been published about the presence of pharmaceuticals in waterbodies nearby or on reserve land of First Nations in Canada. The objectives of this study were to (1) quantify the level of pharmaceuticals in First Nations' surface waters, (2) calculate the human health risks of the mixtures found, and (3) measure the exposure to pharmaceuticals in First Nations' drinking water where source water was highly contaminated.

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Objectives: The First Nations Food, Nutrition and Environment Study (FNFNES), a community-based participatory research project, measured the levels of metals of health concern and the levels of metals that have operational guidance (OG) and aesthetic objectives (AO) in drinking water of First Nations (FN) south of the 60 parallel.

Methods: Both stagnant (first draw) and flushed tap water samples were collected from participating households in 91 FN representing 11 ecozones. The concentrations of metals were quantified and compared to Health Canada's Guidelines for Canadian Drinking Water Quality (GCDWQ).

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Objective: The primary objective of this participatory study was to assess the current body burden of mercury among First Nations adults.

Methods: The First Nations Food, Nutrition and Environment Study (2008-2018) collected regionally representative data from First Nations adults living on reserves south of the 60 parallel. Mercury was analyzed in hair as a preferred biomarker for prolonged exposure.

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Objectives: First Nations may have a higher risk of contaminant exposure from the consumption of traditional foods. The objective of this study was to measure concentrations of metals and organochlorines in traditional foods commonly consumed by First Nations in Canada and estimate the risk from dietary exposure.

Methods: Data were collected from the participatory First Nations Food, Nutrition and Environment Study (2008-2018).

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Objective: To investigate the relationships between fish/seafood consumption patterns and food security status among First Nations (FN) communities in Canada. We estimated the contribution of fish/seafood to daily nutrient requirements. Barriers to traditional food (TF) access including fish were summarized.

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Objective: To describe the prevalence of food insecurity in First Nations households across Canada while identifying barriers and enablers to traditional food (TF) consumption.

Methods: The First Nations Food, Nutrition and Environment Study is a cross-Canada participatory study of on-reserve First Nations from 2008 to 2018. The Household Food Security Survey Module was used to capture income-related challenges experienced by First Nations households.

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Objective: Assess the diet quality of First Nations adults in Canada using percentage energy from traditional foods (TF) and ultra-processed products (UPP), food portions from the 2007 Eating Well with Canada's Food Guide - First Nations, Inuit and Métis (EWCFG-FNIM) and a Healthy Eating Index (HEI).

Methods: Data collection for this participatory research occurred in 92 First Nations reserves across Canada from 2008 to 2016. Percent daily energy intakes were estimated from 24-hour recalls for TF and NOVA food categories.

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