Cardiac autonomic activity and blood pressure among Nunavik Inuit adults exposed to environmental mercury: a cross-sectional study

Valera, Béatriz; Dewailly, Éric; Poirier, Paul

doi:10.1186/1476-069x-7-29

Cited by 66 publications

(70 citation statements)

References 41 publications

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“…Regarding studies conducted in adults, we have previously reported a positive association between mercury and SBP and PP in a smaller group of only 205 Inuit adults Ն40 years of age with valid Holter data. 22 However, in the current study including more adults Ն40 years of age, as well as younger adults, we obtained consistent results. Our results are also in accordance with those published by Fillion et al 12 They observed that individuals with higher hair mercury levels had higher risk of increased SBP.…”

Section: Discussionsupporting

confidence: 74%

Environmental Mercury Exposure and Blood Pressure Among Nunavik Inuit Adults

2009

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Abstract-Epidemiological evidence suggests a negative impact of methylmercury on the cardiovascular system, but findings regarding the effect on blood pressure (BP) are not consistent. We aimed to study the impact of mercury levels on BP among Nunavik Inuit adults. The health survey Qanuippitaa? was conducted in Nunavik (northern Quebec, Canada), and data were obtained from 732 Inuit Ն18 years of age. Anthropometric blood samples, as well as systolic BP and diastolic BP, were assessed. Pulse pressure (systolic BPϪdiastolic BP) was calculated. Mercury blood concentration was used as a biomarker of recent exposure. Simple relations between mercury and BP parameters were studied by using the Pearson correlation, whereas multiple regressions were performed to control for confounders.

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Section: Discussionsupporting

confidence: 74%

Environmental Mercury Exposure and Blood Pressure Among Nunavik Inuit Adults

2009

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“…Also, in addition to the HRV traditional risk factors (age, sex, obesity, insulin sensitivity [measured as HOMA-IR], cholesterol [HDL and LDL-cholesterol] and triglycerides levels, smoking habits, alcohol consumption, physical activity, menopausal status and socioeconomic status), we considered the impact of mercury exposure. These results are particularly important since mercury has been associated with decreased HRV in populations with a high mercury intake, including the Inuit from Nunavik (22)(23)(24). However, no impact of mercury on resting HR was observed in this population (unpublished observations) and in other studies (22,24), which suggests that fish consumption may offer some protection regarding resting HR even in highly mercury-exposed populations.…”

Section: Discussionmentioning

confidence: 49%

“…Fish and marine mammals accumulate high quantities of mercury that has been associated with decreased HRV in adults (22)(23)(24). Since it is important for Inuit to know the risks and benefits of the traditional diet, we aimed to assess the impact of n-3 PUFAs on HRV and resting HR taking into account potential confounding factors.…”

Section: Introductionmentioning

confidence: 99%

Influence of n-3 fatty acids on cardiac autonomic activity among Nunavik Inuit adults

Valera¹,

Dewailly

Anassour-Laouan-Sidi³

et al. 2011

International Journal of Circumpolar Health

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Objectives. Inuit from Nunavik (northern Quebec) consume large amounts of fish and marine mammals, which are important sources of n-3 polyunsaturated fatty acids (n-3 PUFAs). These substances have a beneficial impact on heart rate (HR) and heart rate variability (HRV). However, it is unknown if this beneficial impact remains significant in populations with high mercury exposure. The study assessed the impact of n-3 PUFAs (Docosahexaenoic [DHA] and Eicosapentaenoic acid [EPA]) on resting HR and HRV among Nunavik Inuit adults considering mercury and other potential confounders. Study design. Cross-sectional study employing clinical measurements. Methods. Complete data were collected among 181 adults ≥40 years old (109 women and 72 men) living in the 14 coastal villages of Nunavik. Several indices of HRV were derived from a 2-hour Holter monitoring assessment. n-3 PUFAs levels were measured in membrane erythrocytes. Simple linear regression was used to analyse the relationship between n-3 PUFAs levels and resting HR and HRV parameters while multiple linear regressions were carried out to control for confounders. Results. In the overall analyses, EPA was associated with SDANN (β=0.07, p=0.04) and LF norm (β=-1.84, p=0.03) after adjusting for confounders. Among women, DHA was associated with resting HR (β=-1.40, p=0.03) while EPA was associated with SDNN (β=0.08, p=0.03), SDANN (β=0.09, p=0.02) and resting HR (β=-2.61, p=0.002). No significant association was observed in men. Conclusions. These results suggest a beneficial impact of n-3 PUFAs on resting HR and HRV among Nunavik Inuit women.

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“…Grandjean et al (2004) did not observe an influence of methyl mercury exposure on blood pressure and heart rate in children, but they described an influence of methyl mercury on the cardiac autonomic activity. The other studies summarised in the table as well as those not cited in the table like Valera et al (2008; and Fillion et al (2006) also do not provide a consistent result on the influence of methyl mercury exposure on blood pressure. Some of these studies investigated only small numbers of patients, others did not adequately control for the influence of fish intake e.g.…”

Section: Study Locationmentioning

confidence: 81%

Collate the literature on toxicity data on mercury in experimental animals and humans (Part I – Data on organic mercury)

Hassauer

Kaiser

Schneider

et al. 2012

EFSA Supporting Publications

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It was the scope of this project to collate, compile and summarise the scientific literature on the toxicity of methyl mercury, inorganic mercury and total mercury in humans and experimental animals published since 2002 and not evaluated in former JECFA risk assessments. Epidemiological data on MeHg toxicity confirmed former findings on an association between prenatal exposure and developmental neurotoxicity. Recent findings also support an influence of methyl mercury on the cardiovascular and immune system. Existing epidemiological data reveal several shortcomings limiting their suitability for risk assessment. Developmental neurotoxicity seems to be the most critical effect of MeHg in animals. A LOAEL of 0.01 mg/kg b.w. per day has been reported in young mice for locomotor activity exposed in utero. Rats seem to be less sensitive towards this endpoint: a NOAEL of 0.04 mg/kg b.w. per day has been reported in this species for locomotor activity. Systemic effects other than neurotoxicity have been mostly observed at higher doses than those producing neurotoxicity. No qualified epidemiological data appropriate for the evaluation of the toxicity of inorganic mercury after oral intake have been identified due to several limitations of the studies, e.g. small study group, insufficient control for confounders, inadequate exposure assessment. Toxicological studies in experimental animals widely confirmed former findings with respect to the target organs (neuro-, liver-, kidney-, immune-and reproductive toxicity, oxidative stress). The animal studies indicate that there might be relevant toxicological effects (developmental toxicity, liver toxicity) of inorganic mercury at dose levels similar or below the BMDL 10 value used for the derivation of the existing PTWI. However, due to some limitations of the studies no final conclusions can be drawn from these studies and the findings need further confirmation.

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Cardiac autonomic activity and blood pressure among Nunavik Inuit adults exposed to environmental mercury: a cross-sectional study

Cited by 66 publications

References 41 publications

Environmental Mercury Exposure and Blood Pressure Among Nunavik Inuit Adults

Environmental Mercury Exposure and Blood Pressure Among Nunavik Inuit Adults

Influence of n-3 fatty acids on cardiac autonomic activity among Nunavik Inuit adults

Collate the literature on toxicity data on mercury in experimental animals and humans (Part I – Data on organic mercury)

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