Magda Gasull

Number of Persistent Organic Pollutants Detected at High Concentrations in Blood Samples of the United States Population.

Human exposure to environmental chemicals as persistent organic pollutants (POPs) is usually assessed considering each pollutant individually, with little attention to concentrations of mixtures in individuals or social groups. Yet, it may be relatively common for humans to have low and high concentrations of numerous POPs. The study objectives were to analyze the number of POPs detected per person at high concentrations in the U.S. population, and the associations between such type of indicators and socioeconomic factors as gender, race / ethnicity, education, and poverty level. From 91 POPs analyzed in serum samples of 4,739 individuals in three subsamples of the National Health and Nutrition Examination Survey (NHANES) 2003–2004 (the last period with valid updated individual data for the compounds considered in the present study), we computed the number of POPs whose serum concentrations were above selected cutoff points. POPs included were 13 organochlorine compounds (OCs), 10 polybrominated diphenyl ethers (PBDEs), the polybrominated biphenyl (PBB) 153, 38 polychlorinated biphenyls (PCBs), 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs), and 12 perfluorinated compounds (PFCs). Over 13% of participants had ≥10 of the 37 most detected POPs each at a concentration in the top decile (P90). Over 30% of subjects with total toxic equivalency (TEQ) ≥P75, had ≥10 of 24 POPs not included in TEQ calculations at concentrations ≥P90. Compared to non-Hispanic whites, the adjusted odds ratio of having ≥10 of the 37 POPs at P90 was 9.2 for non-Hispanic blacks and 0.18 for Mexican Americans. Poverty, body mass index, age, and gender were also independently associated with having ≥10 POPs in the top decile. More than one tenth of the US population may have ≥10 POPs each at concentrations in the top decile. Such pattern is nine times more frequent in Non-Hispanic blacks and four times less frequent in Mexican Americans than in non-Hispanic whites.

Commentary: A step towards more comprehensive analyses of life course effects of mixtures of environmental factors

et al. Correcting serum concentrations of organochlorine compounds by lipids: alternatives to the organochlorine/total lipids ratio. Evaluation of total lipids using enzymatic methods for the normalization of persistent organic pollutant levels in serum.

Sociodemographic factors influencing participation in the Barcelona Health Survey study on serum concentrations of persistent organic pollutants

BACKGROUND Little is known about factors affecting participation in population-based biomonitoring studies. We analyzed socioeconomic factors influencing participation in the Barcelona Health Survey (BHS) study on the distribution of serum concentrations of persistent organic pollutants (POPs). METHODS After completing the BHS personal interview at home participants aged >or=15 years were invited to donate blood. Conducted on a different date and location, the POPs study included additional questions, blood extraction, and a brief physical examination. Factors influencing participation were analyzed by logistic regression. RESULTS Of 523 BHS participants that we contacted to participate in the study, 231 (44%) participated; they were broadly representative of the city population regarding sex, birth place, body mass index (BMI), employment status and occupational social class. Participants in the POPs study had higher educational level and family income. Controlling for confounders, participation was slightly higher among women than men (odds ratio [OR]=1.38, p=0.02), and lower among the youngest and oldest subjects (p=0.002), with a strong and monotonic trend of increasing participation with increasing educational level (p<0.001) (OR for university level vs. no studies=4.58, 95% CI: 2.3-9.3). CONCLUSIONS Although participation was somewhat low, participants were similar to the city population regarding sex, BMI, birth place, employment, and occupational social class. Health surveys that integrate environmental biomarkers should invest specific resources to encourage participation of the youngest and oldest individuals, and of those with more disadvantaged socioeconomic position (particularly, citizens with lowest education).

Contamination from endocrine disrupters of the general population at low and high concentrations.

Analyses of the concentrations of a given environmental compound usually show that most citizens have much lower concentrations than a certain minority, whose members have high body concentrations. Surveys of human exposure to chemicals do not usually integrate the number of chemical compounds detected per person and the concentration of each compound. This leaves untested relevant exposure situations, for example, whether individuals with low concentrations of some compounds have high concentrations of the other compounds. On scientific grounds, it is puzzling that this possibility, arithmetically and conceptually rather simple, has seldom if ever been tested in studies based on a representative sample of the general population. A study based on a representative sample of the general population of Catalonia (Spain) (Porta, Pumarega, & Gasull, 2012), which integrated the number of compounds detected per person and the concentration of each compound, found that more than half of the population had concentrations in the top quartile of 1 or more of the 19 persistent toxic substances (PTS) (pesticides and polychlorinated biphenyls) analyzed. Significant subgroups of the population accumulated PTS mixtures at high concentrations. For instance, 48% of women 60-74 years had concentrations of 6 or more PTS in the top quartile; half of the entire population had levels of 1-5 PTS above 500 ng/g, and less than 4% of citizens had all PTS in the lowest quartile. Thus, PTS concentrations appear low in most of the population only when each individual compound is looked at separately. It is not accurate to state that most of the population has low concentrations of PTS. The assessment of mixture effects must address the fact that most individuals are contaminated by PTS mixtures made of compounds at both low and high concentrations.

Blood Concentrations of Persistent Organic Pollutants and Unhealthy Metabolic Phenotypes in Normal-Weight, Overweight, and Obese Individuals

Factors underlying metabolic phenotypes, such as the metabolically healthy but obese phenotype, remain unclear. Differences in metabolic phenotypes-particularly, among individuals with a similar body mass index-could be related to concentrations of persistent organic pollutants (POPs). To our knowledge, no studies have analyzed POPs and metabolic phenotypes in normal-weight persons. We investigated the relationships between serum concentrations of POPs and metabolic phenotypes in 860 normal-weight, overweight, and obese participants in the 2002 Catalan Health Interview Survey (Spain). POP concentrations were significantly higher in metabolically unhealthy than in metabolically healthy individuals. In models adjusting for body mass index and other confounders, hexachlorobenzene, β-hexachlorocyclohexane, and polychlorinated biphenyls were associated with the unhealthy metabolic phenotype and metabolic syndrome. Among normal-weight individuals, the adjusted prevalence ratio of having an unhealthy phenotype for the upper category of the sum of orders of the 6 mentioned POPs (all individually associated with metabolic phenotypes) was 4.1 (95% confidence interval: 1.7, 10.0). Among overweight and obese individuals, the corresponding prevalence ratio for the sum of polychlorinated biphenyls was 1.4 (95% confidence interval: 1.0, 1.8). Our results supported the hypothesis that POP concentrations are associated with unhealthy metabolic phenotypes, not only in obese and overweight individuals but also (and probably more strongly) in normal-weight individuals.

Citizens’ perceptions of the presence and health risks of synthetic chemicals in food: results of an online survey in Spain

OBJECTIVE To explore factors influencing perceptions and viewpoints on the responsibility for the presence of toxic substances in food, on enforcement of laws and regulations that control human exposure to toxic substances in food, and on the effectiveness of such regulations. METHODS An online survey was completed by 740 individuals from several parts of Spain (median age, 47 years; 67% were women; 70% had completed university studies). RESULTS Over 87% of respondents said that it was possible that throughout their lives they could have accumulated in their body toxic substances potentially dangerous to their health. The attribution of the responsibility for toxic substances in food to a larger number of social groups was more frequent among respondents who consulted information about the problem more often (odds ratio [OR]: 1.92), who correctly identified factors that increase the likelihood of toxic substances in food being harmful to human health (OR: 2.86), who better knew the health problems that may be caused by such substances (OR: 2.48), and who recognised more food groups that tend to have concentrations of toxic substances potentially harmful to health (OR: 2.92) (all p values <0.001). Women were 65% less likely than men to answer that regulations on toxic substances in food are effective (p<0.001); and so were participants who identified more food groups with potentially toxic concentrations. CONCLUSIONS Among study participants there was a widespread scepticism and distrust towards the enforcement and effectiveness of laws and regulations that in Spain aim to control human exposure to toxic substances in food.

Self-rated health and chronic conditions are associated with blood concentrations of persistent organic pollutants in the general population of Catalonia, Spain

BACKGROUND Self-rated health (SRH) is a powerful predictor of mortality, morbidity, and need for health services. SRH generally increases with educational level, and decreases with age, number of chronic conditions, and body mass index (BMI). Because human concentrations of most persistent organic pollutants (POPs) also vary by age, education, and BMI, and because of the physiological and clinical effects of POPs, we hypothesized that body concentrations of POPs are inversely associated with SRH. OBJECTIVES To analyze the relation between serum concentrations of POPs and SRH in the general population of Catalonia, Spain, taking into account sociodemographic factors and BMI, as well as chronic health conditions and mental disorders, measured by the General Health Questionnaire-12 (GHQ-12). METHODS POP serum concentrations were measured by gas chromatography with electron-capture detection in 919 participants of the Catalan Health Interview Survey. RESULTS Individuals with higher concentrations of POPs had significantly poorer SRH; e.g., the median concentration of HCB in subjects with poor SRH was twice as high as in subjects with excellent SRH (366 ng/g vs. 169 ng/g, respectively; p-value<0.001). In crude models and in models adjusted for sex and BMI, the POPs-SRH association was often dose-dependent, and the likelihood of poor or regular SRH was 2 to 4-times higher in subjects with POP concentrations in the top quartile. In models adjusted for age or for chronic conditions virtually all ORs were near unity. No associations were found between POP levels and GHQ-12. CONCLUSIONS Individuals with higher concentrations of POPs had significantly poorer SRH, an association likely due to age and chronic conditions, but not to sex, education, social class, BMI, or mental disorders.