The relationship between dietary exposure to persistent organic pollutants from fish consumption and type 2 diabetes among First Nations in Canada

Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) dietary exposure is associated with an increased risk of type 2 diabetes in the European prospective investigation into cancer and nutrition (EPIC) cohort

AIMS/HYPOTHESIS

The aim of the present study was to investigate the association between dietary exposures to dioxins, dioxin-like polychlorinated biphenyls (DL-PCBs) and non-dioxin-like polychlorinated biphenyls (NDL-PCBs) and the incidence of type 2 diabetes mellitus (T2DM) in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

METHODS

This prospective cohort study with a median 11.7 years of follow-up, included 318,416 individuals recruited in 21 centers in eight countries. Dietary intake of dioxins and PCBs was calculated by combining EPIC food consumption data with food contamination data from the European Food Safety Authority (EFSA). To identify incident cases of T2DM, a thorough review of various sources including self-reported information, linkage to primary and secondary care registers, drug registers, hospital admissions, and mortality data was conducted. Associations between dietary intake of dioxins and PCBs and T2DM were evaluated using multivariable Cox regressions.

RESULTS

Higher T2DM risk was observed for higher estimated dietary intake of non-dioxin-like PCBs (NDL-PCBs; HR per 1 SD increment = 1.03 [95 %CI 1.01;1.04], and HR (Q4vs Q1) = 1.15 [1.08;1.22], P-trend < 0.001). The results were consistent in analyses stratified by gender, body mass index, country, median follow-up, or self-reported hypertension and hyperlipidemia, as well as when adjusting for fat intake. No consistent association was observed between dioxins+DL-PCBs intake and T2DM risk.

CONCLUSION / INTERPRETATION

Results obtained in this large European prospective study indicate a positive and linear association between dietary intake of NDL-PCBs and risk of T2DM. This association remained consistent across various stratified and sensitivity analyses. Further studies are warranted to better understand the biological mechanisms underlying this association.

Measurement of diet quality among First Nations peoples in Canada and associations with health: a scoping review

BACKGROUND

Given the increasing number and the diversity of dietary quality indices used for research, and the differences between settings, there is a need to identify valid indices of dietary quality in different contexts and populations and to identify their associations with health-related outcomes.

OBJECTIVES

The primary objective of this scoping review is to identify the tools used in determining dietary quality among First Nations and to describe the changes in diet. The second objective is to describe the associations identified in studies that have measured the relationship between health and dietary quality among First Nations; and the third objective is to identify factors associated with diet quality.

METHODS

PubMed, Embase, CINAHL, Global Health, and Web of Science were searched from inception to June 2021 and updated in February 2022. Articles were included if the research subjects were First Nations, or if articles reported disaggregated subset data for First Nations. Eligible studies focused on nutrition and diet and were published in English or French.

RESULTS

A total of 151 articles were included in the analysis. Studies used several indicators to measure if individuals adhered to dietary guidelines. Traditional food consumption was frequently used as an indicator of diet quality (n = 96). The consumption of store-bought foods was used as an indicator in 28 studies. Some studies used other diet quality indicators such as the Healthy Eating Index (n = 5) and ultra-processed food "NOVA" classification (n = 6). A trend for decreasing traditional food intake over time was apparent, alongside an increase in store-bought food intake. This trend was accompanied with declining health status, including the increased prevalence of overweight and obesity, diabetes, metabolic diseases, and dental caries.

CONCLUSION

This scoping review showed that diet quality among First Nations is improved when traditional foods are consumed. Reduced diet quality was associated with increased risk of noncommunicable diseases.

Polychlorinated Biphenyls (PCBs) in the Environment: Occupational and Exposure Events, Effects on Human Health and Fertility

In the last decade or so, polychlorinated biphenyls (PCBs) garnered renewed attention in the scientific community due to new evidence pointing at their continued presence in the environment and workplaces and the potential human risks related to their presence. PCBs move from the environment to humans through different routes; the dominant pathway is the ingestion of contaminated foods (fish, seafood and dairy products), followed by inhalation (both indoor and outdoor air), and, to a lesser extent, dust ingestion and dermal contact. Numerous studies reported the environmental and occupational exposure to these pollutants, deriving from building materials (flame-retardants, plasticizers, paints, caulking compounds, sealants, fluorescent light ballasts, etc.) and electrical equipment. The highest PCBs contaminations were detected in e-waste recycling sites, suggesting the need for the implementation of remediation strategies of such polluted areas to safeguard the health of workers and local populations. Furthermore, a significant correlation between PCB exposure and increased blood PCB concentrations was observed in people working in PCB-contaminated workplaces. Several epidemiological studies suggest that environmental and occupational exposure to high concentrations of PCBs is associated with different health outcomes, such as neuropsychological and neurobehavioral deficits, dementia, immune system dysfunctions, cardiovascular diseases and cancer. In addition, recent studies indicate that PCBs bioaccumulation can reduce fertility, with harmful effects on the reproductive system that can be passed to offspring. In the near future, further studies are needed to assess the real effects of PCBs exposure at low concentrations for prolonged exposure in workplaces and specific indoor environments.

Levels of metals and persistent organic pollutants in traditional foods consumed by First Nations living on-reserve in Canada

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). Traditional food samples were collected by community members and concentrations of metals and organochlorines were measured. The population-weighted mean daily contaminant intake from traditional food items was estimated. Hazard quotients (HQs) were calculated by dividing contaminant intake with the toxicological reference values (TRVs).

Results

A total of 2061 food samples (different parts and organs) from 221 species were collected. The highest concentrations of cadmium were found in the kidneys of land mammals: moose kidney was the most significant contributor to intake. The meat of land mammals and birds had the highest lead concentrations and were the most significant contributors to intake. Arsenic was highest in seaweed, and prawn was the most significant contributor. Mercury and methyl mercury were highest in harp seal meat, with walleye/pickerel contributing most to intake. Harp seal meat also had the highest p,p′-DDE and PCB concentrations, and ooligan grease and salmon were the most significant contributors to intake. The percentage of adults eating traditional food who exceeded the TRVs was 1.9% for cadmium, 3.7% for lead, 13.6% for arsenic, 0.7% for mercury, and 0% for p,p′-DDE and PCBs. All median HQs, and most 95th percentile HQs, were less than 1.

Conclusion

These results can be used as a baseline of contaminant levels and exposure in traditional foods for future monitoring programs and to support risk assessment programs.

Supplementary Information

The online version contains supplementary material available at 10.17269/s41997-021-00495-7.

Associations of health status and diabetes among First Nations Peoples living on-reserve in Canada

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 60th parallel. Health and diabetes were self-reported, and prevalence of obesity was evaluated. Socio-demographic and lifestyle factors and traditional food (TF) activities were investigated for associations with health parameters.

RESULTS

High prevalence rates of overweight/obesity (78-91%) and diabetes (19% age-standardized prevalence) were found. Smoking rates were high and physical activity was low. In multivariable analyses, obesity was associated with region, income source, age, gender, smoking and self-reported health; diabetes and lesser self-reported health were associated with obesity and lower education. Diabetes was strongly associated with lesser self-reported health and weakly associated with being a smoker.

CONCLUSION

We have identified possible correlates of health in this population that can help to better understand the underlying concerns and identify solutions for First Nations and their partners. We urge governments and First Nations to address the systemic problems identified with a holistic ecosystem approach that takes into consideration the financial and physical access to food, particularly TF, and the facilitation of improved health behaviour. New mechanisms co-developed with First Nations leadership should focus on supporting sustainable, culturally safe and healthy lifestyles and closing the gaps in nutrition and food insecurity.

The First Nations Food, Nutrition and Environment Study (2008-2018)-rationale, design, methods and lessons learned

OBJECTIVE

To describe the rationale, the participatory nature of the methodology, and the lessons learned during the First Nations Food, Nutrition and Environment Study (FNFNES), a community-based participatory research project implemented in eight Assembly of First Nations regions, which includes the entirety of Canada south of the 60th parallel.

METHODS

FNFNES respected the First Nations principles of Ownership, Control, Access and Possession (OCAP®) ( https://fnigc.ca/ocap ). A random sampling strategy based on an ecosystem framework comprising 11 ecozones was adopted to collect representative nutritional and environmental health results for all First Nations adults living on-reserve south of the 60th parallel. Data collection occurred during the fall months from 2008 to 2016. Respective First Nations were involved in the planning and implementation of data collection for the five principal components: household interviews, tap water sampling for metals, surface water sampling for pharmaceuticals, hair sampling for mercury, and traditional food sampling for contaminants.

RESULTS

A total of 6487 adults from 92 First Nations participated in the Study (participation rate 78%). A higher percentage of females (66%) participated than males (34%). The average age of males and females was similar (44 and 45 years, respectively). This study offers a novel body of coherent and regionally representative evidence on the human dimension of the ongoing environmental degradation affecting First Nations.

CONCLUSION

FNFNES serves as a good example of participatory research. We encourage public health professionals to develop policy and programs building on the participatory dimension of the research as well as on its results. The information collected by the FNFNES is also important for community empowerment, environmental stewardship and the general promotion of good health by and for First Nations peoples in Canada.

Can scientists and knowledge keepers sit comfortably together? An Indigenous physician's reflections on a decade of participatory research into First Nations nutrition, environment and health

The author, an Indigenous physician, offers his reflections on the history of scientific research with Indigenous People and its past role in ethical breaches and excesses of colonialism, as a backdrop to the relatively recent advances in collaborative, community-based participatory research involving First Nations and Inuit in Canada. The First Nations Food, Nutrition and Environment Study (2008-2018), introduced in this Special Issue, is presented as an example of an ethical space that was sustained for a decade to collaboratively develop new knowledge by First Nations and scientists working together, respectfully and inspired by shared interest. A short overview of twelve articles of the Special Issue is provided and characterized as creating a previously inaccessible picture of the modern diets of First Nations, along with the suite of environmental factors that are present in food and water in and around communities. Ultimately, the author hopes that Canadian society can set the table with Indigenous Peoples and respectfully set opinions onto each other and do this over and over again. With Canada already being a multicultural and pluralistic society, adding Indigenous realities into the mix only respects and honours the Indigenous roots of this country.