The burden of disease of three food-associated heavy metals in clusters in the Danish population - Towards targeted public health strategies.

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• The burden of disease from methylmercury, cadmium and inorganic arsenic exposure in some Danish subpopulations with certain dietary and lifestyle patterns and sociodemographics may be increased.

Introduction

The authors state that lifestyle and sociodemographics might impact dietary patterns, and consequently, human exposure to chemical hazards in foods, and correlated human health effects. The objective was to classify Danish population cohorts into clusters via dietary, lifestyle and sociodemographic indicators, and determine which had an increased disease burden due to methylmercury (MeHg), cadmium (Cd), and inorganic arsenic (iAs) exposure.

Methods

This study involved cluster analysis and chemical risk assessment. Secondary analysis of a cohort study was conducted via collating dietary and lifestyle patterns from Danish national survey data. The extracted dataset included 3946 participants, 80 food groups, and four lifestyle and demographic variables. Metal concentration data were derived from Danish food surveillance data. Population clusters classified subjects with similar dietary and lifestyle patterns, using self-organising maps (SOMs). Dietary exposure to MeHg, Cd and iAs in each cluster was conducted via risk assessment. Furthermore, disease burden was estimated in disability-adjusted life years (DALYs), using 2-D Monte Carlo simulation to account for uncertainty from variability.

Results

SOMs rendered 12 population clusters with distinct features. Human exposure to the metals differed between clusters, primarily driven by fish, seafood, and cereal consumption. A high proportion of females of childbearing age, 33-41 years, respectively, were in the two highest ranking disease burden clusters due to HeMg (i.e, clusters 5 and 6). Five clusters yielded an estimated burden >20 DALYs per 100,000 population per annum.

The highest estimated disease burdens for each metal (mainly urban dwellers) were as follows:

• . MeHg exposure: cluster 6 (highest overall burden); 47.30 DALYs/100,000, 54% female, 41 years (mean age), 74kg (mean body weight), 89% non-smokers, 59% further education, 95% moderate-very high physical activity level;
• iAs exposure: cluster 1, 10.7 DALYs/100,000, 49% female, 8 years old, 31kg, 89% non-smokers, 61% further education, 92% moderate-very high physical activity level;
• Cd exposure: cluster 8, 0.15 DALYs/100,000, 49% female, 59 years, 77kg, 84% non-smokers, 28% further education, 94% moderate-very high physical activity level.

Conclusion

Certain Danish subpopulations held a greater disease burden due to MeHg, Cd and iAs dietary exposure. MeHg bore the highest burden. Clusters of highly educated, urban dwelling, females with seemingly healthy dietary patterns and moderate to high physical activity had the highest burden due to metal exposure. MeHg exposure in women of childbearing age substantially contributed to the total disease burden due to the risk of adverse effects on the foetus.

• Practitioners and clients need to be informed of the risks of human exposure to methylmercury, cadmium and inorganic arsenic through dietary and lifestyle patterns and sociodemographics, particularly in certain subpopulations.
• Practitioners should educate themselves and their clients regarding the foods which may pose a higher risk to these metals, namely fish, seafood and cereal as cited by the authors.
• The results of the study may contribute to public health and food safety strategies aimed at the most affected cohorts exposed to these chemical contaminants.

• Future studies could investigate other metals and chemical hazards.
• Continuous surveillance of dietary and lifestyle exposure from multiple heavy metals and other chemical contaminants should be prioritised to inform public health and food safety.
• Dietary and lifestyle habit interventions could assess the possibility to reduce the risk of methylmercury, cadmium, inorganic arsenic exposure, and exposure from other metals.