Elsevier

Environmental Pollution

Volume 243, Part A, December 2018, Pages 189-196
Environmental Pollution

Dietary patterns related to exposure to persistent organic pollutants based on the Ewha Birth and Growth Cohort

https://doi.org/10.1016/j.envpol.2018.08.072Get rights and content

Highlights

  • We identified dietary patterns related to blood POP levels in a general population of children.

  • Among various food groups, dairy products and shellfish/salted seafood were associated with multiple POPs.

  • Each dietary pattern accounted for 25.0% of total OCPs, 22.9% of dioxin-like PCBs, and 21.6% of marker PCBs in blood.

Abstract

Persistent organic pollutants (POPs) are endocrine disruptors that are typically ingested in food. Using data from the Ewha Birth and Growth Cohort study, we identified dietary patterns related to blood persistent organic pollutant (POP) levels in children. In total, 188 Korean children (95 boys and 93 girls) aged 7–9 years were included in this study. Daily food intake data derived from a semi-quantitative food-frequency questionnaire were grouped into 33 food groups. Dietary patterns were analyzed using the reduced rank regression method, with blood POP levels as dependent variables.

The marker polychlorinated biphenyl (PCB) pattern showed more weighted loading factors in the intake of shellfish/salted seafood, cheese, nuts and seeds, and total PCBs showed similar results. The dioxin-like PCB pattern was characterized by a higher intake of yogurt, beverages, and fruit and a lower intake of grain, seaweeds, and processed meat. Additionally, the total organochlorine pesticide (OCP) pattern showed positive factor loading values in shrimp and beverages, and negative factor loading values in seaweeds and processed meat. Each dietary pattern accounted for 25.0% of total OCPs, 22.9% of dioxin-like PCBs, 21.6% of marker PCBs, and 21.3% of total PCBs in blood. Dietary pattern scores were linearly related to blood POP levels, and this association remained after adjusting for sex, age, follow-up survey year, maternal educational level, body mass index, and total energy. Dietary patterns differed slightly among the individual POPs. Further studies are needed to develop an intervention strategy for children.

Introduction

Persistent organic pollutants (POPs) are artificially produced chemicals that are endocrine disruptors and are used in pesticides and industrial products. Lipophilic POPs accumulate up the food chain in the fatty tissue of living organisms and remain in the body for long periods due to their considerable half-lives (World Health Organization, 2010).

The toxicity and adverse health effects of POPs have been reported, leading many countries to ban and/or regulate their use (Ministry of Enviroment, 2013). In accordance with the Stockholm Convention, Korea enacted the Persistent Organic Pollutants Control Act in January 2007, and management and monitoring are ongoing. One study reported that the atmospheric dioxin level was 23% lower in 2009 (126.6 g I-TEQ/year) than in 2007 (164.5 g I-TEQ/year) (Ministry of Enviroment, 2013). Government policies and regulations have reduced exposure levels (Kim and Lee, 2010; Ministry of Environment, 2013; Malisch and Kotz, 2014), but POPs are still detected in blood samples and food. In Korea, the estimated POP exposure from foods, such as grains, fish, meat, and dairy products, was reported to be below the tolerable daily intake (Kim and Lee, 2010; Son et al., 2012), but low-dose sustained exposure is nevertheless reportedly associated with health risks (Lee et al., 2011), even in children (World Health Organization, 2010; Park et al., 2016a, Park et al., 2016b, Park et al., 2016c). Compared to adults, growing children are more susceptible to environmental pollutants (World Health Organization, 2010). Link et al. (2005) suggested the possibility that children should be monitored because they reflect normal environmental exposure more accurately than do adults and are not exposed to occupational pollutants.

Contaminated air, soil, and water are potential routes of exposure to POPs. Oral exposure through contaminated foods accounts for 90% of total exposure (Malisch and Kotz, 2014). Several major food groups, such as fish, meat, and dairy products, have high pollutant contents (Son et al., 2012; Zhou et al., 2012). Most risk assessment or monitoring studies have evaluated exposure to POPs in food. Although monitoring pollutant levels in food is important, there is also a need to explore the dietary patterns associated with POP levels to better understand pollutant exposure patterns. Dietary patterns can be analyzed in terms of their multiple dietary sources and expressed in terms of dietary pattern scores. There are two different approaches to the analysis of dietary patterns: a priori (e.g., the healthy eating index) and a posteriori (e.g., an exploratory statistical analysis of food intake data). A method that integrates these two approaches is that of reduced rank regression (RRR). This approach has causal advantages over other dietary pattern methods (e.g., principal component analysis, etc.) because dietary patterns are derived by reference to biomarkers as prior knowledge (Hoffmann et al., 2004). Although several studies have reported dietary patterns associated with POP exposure (Kvalem et al., 2009; Arisawa et al., 2011; Papadopoulou et al., 2014), there is a lack of evidence in children.

Under the assumption that POP exposure varies depending on the food intake pattern, we used RRR to identify the dietary patterns of children associated with the blood levels of several POP subtypes: total polychlorinated biphenyls (PCBs), marker PCBs, dioxin-like PCBs, and total organochlorine pesticides (OCPs). We also assessed whether the dietary pattern was consistently associated with blood levels of POPs after controlling for individual factors in children.

Section snippets

Study subjects

This study was performed using data from the Ewha Birth and Growth Cohort study in Korea. Detailed descriptions of the cohort composition and methodology are available elsewhere (Min et al., 2007; Lee et al., 2015). Briefly, the cohort was composed of mothers and their children, and the study began in 2001. The study focuses on preventive factors related to growth and disease susceptibility through long-term follow-up observations. The children are followed up at 3 and 5 years of age and

Results

Of the 188 subjects, 95 were boys (50.5%) and 21.5% had a mother with a low educational level. The mean BMI z-score was 0.28 (95% confidence interval (CI): 0.13–0.43), and the estimated daily total energy was 1580.25 kcal (95% CI: 1492.79–1667.72 kcal). The daily intakes of the 33 food groups are presented in Table 1.

Each individual POP dietary pattern explained more than 20% of the total variance of each POP level. The dietary pattern of total OCPs explained the highest percentage of variation

Discussion

Using data from a general population of children, we identified dietary patterns related to exposure to various POP subtypes. Different food groups were related to exposure to individual POPs, but dairy products and shellfish/salted seafood were associated with multiple POPs. The dietary pattern scores for the individual POPs were positively associated with the POP levels in blood, and each dietary pattern alone accounted for more than 20% of individual POP levels.

In the present study, the

Conclusions

In conclusion, our findings will provide useful information in regulating dietary exposure to environmental pollutants. Further studies should focus on developing a pollution-exposure intervention strategy for children. From a public health perspective, it may be necessary to examine the need for monitoring and regulating food preference in children, with an understanding of dietary patterns in children.

Conflicts of interest

None.

Funding

This work was supported by a grant (13162MFDS891) from the Ministry of Food and Drug Safety in 2013 and a grant (15162MFDS631) from the Ministry of Food and Drug Safety in 2015.

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