Background

The body burden of metals and persistent organic pollutants (POPs) is particularly high in populations that rely on fish and other marine species for sustenance. This exposure has been associated with an increased risk of type 2 diabetes, but results remain contrasted.

Objective

We studied this association in two Indigenous populations of northern Québec (Canada) with markedly different prevalences of diabetes and levels of exposure to POPs and mercury.

Methods

As part of health surveys conducted in 2004–2009, diabetes prevalence and glucose metabolism (glucose, insulin, HOMA-IR, HOMA-B) in non-diabetic fasting adults were assessed using similar protocols in two populations: Inuit from Nunavik (n = 877) and Cree from Eeyou Istchee territory (n = 780). Blood mercury, plasma polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides/metabolites and polybrominated diphenylethers (PBDEs) levels were measured in samples collected at the time of examination. Logistic and linear regressions and restricted cubic splines analyses were conducted adjusting for sex, age, waist circumference, smoking and omega-3 fatty acid content in plasma phospholipids.

Results

Diabetes prevalence was higher in Cree (20%) than in Inuit (7%), whereas environmental exposure was 2 to 3-fold greater in Inuit than in Cree participants. In the range of exposure common to the two populations, we observed similar linear increases in the risk of diabetes with increasing contaminant exposure. Among Cree participants, fasting glucose was positively associated with plasma PBDE level, and HOMA-B negatively associated with concentrations of ∑PCBs, dichlorodiphenyldichloroethylene, PBDEs and ∑OC pesticides. Among Inuit participants, a trend towards reduced insulin secretion was observed in association with most contaminants, but the relation was nonlinear (greater reduction at intermediate levels of exposure). A significant increase in fasting glucose levels was observed at elevated blood mercury levels (>16 μg/L).

Conclusion

The observed association between POPs exposure and diabetes risk in the two populations studied should be confirmed using prospective design. Our results suggest the need for additional research on the physiopathological process through which POPs exposure may induce type 2 diabetes in these Indigenous populations.

中文翻译：

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在两个加拿大土著居民中，持久性有机污染物和汞的暴露与葡萄糖代谢之间的关联。

背景

在依靠鱼类和其他海洋物种为生的人群中，金属和持久性有机污染物（POPs）的身体负担特别高。这种接触与2型糖尿病的风险增加有关，但结果仍然相反。

目的

我们在魁北克北部（加拿大）的两个土著人群中研究了这种关联，这些人群的糖尿病患病率以及持久性有机污染物和汞的暴露水平明显不同。

方法

作为2004-2009年进行的健康调查的一部分，对两个人群中的非糖尿病禁食成年人的糖尿病患病率和葡萄糖代谢（葡萄糖，胰岛素，HOMA-IR，HOMA-B）进行了评估：来自努纳维克的因纽特人（n = 877）和来自Eeyou Istchee领土的Cree（n = 780）。在检查时采集的样本中测量了血液中的汞，血浆中的多氯联苯（PCBs），有机氯（OC）农药/代谢物和多溴联苯醚（PBDEs）的水平。进行了逻辑和线性回归以及受限三次样条分析，以调整血浆磷脂中的性别，年龄，腰围，吸烟和omega-3脂肪酸含量。

结果

Cree（20％）的糖尿病患病率高于因纽特人（7％），而因纽特人的环境暴露要比Cree参与者高2至3倍。在两个人群共有的暴露范围内，我们观察到随着污染物暴露的增加，糖尿病风险呈线性相似的增加。在Cree参与者中，空腹血糖与血浆PBDE水平呈正相关，而HOMA-B与∑PCBs，二氯二苯基二氯乙烯，PBDEs和∑OC农药的浓度呈负相关。在因纽特人参加者中，观察到与大多数污染物相关的胰岛素分泌减少的趋势，但这种关系是非线性的（在中等暴露水平下会更大程度减少）。在血汞水平升高（> 16μg/ L）时，空腹血糖水平显着增加。

结论

在这两个研究人群中，POPs暴露与糖尿病风险之间观察到的相关性应使用前瞻性设计予以证实。我们的结果表明，需要对生理病理过程进行进一步的研究，通过这些过程，POPs的暴露可能会在这些土著人群中诱发2型糖尿病。