Magda Gasull

Findings and limitations of previous studies on persistent organic pollutants (POPs) and pancreatic cancer risk support conducting further research in prospective cohorts. We conducted a prospective case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Participants were 513 pancreatic cancer cases and 1020 matched controls. Concentrations of 22 POPs were measured in plasma collected at baseline. Some associations were observed at higher concentrations of p, p’-DDT, trans-nonachlor, β-hexachlorocyclohexane and the sum of six organochlorine pesticides and of 16 POPs. The odds ratio (OR) for the upper quartile of trans-nonachlor was 1.55 (95% confidence interval 1.06-2.26; P for trend = 0.025). Associations were stronger in the groups predefined as most valid (participants having fasted >6 h, with microscopic diagnostic confirmation, normal weight, and never smokers), and as most relevant (follow-up ≥10 years). Among participants having fasted >6 h, the ORs were relevant for 10 of 11 exposures. Higher ORs were also observed among cases with microscopic confirmation than in cases with a clinical diagnosis, and among normal-weight participants than in the rest of participants. Among participants with a follow-up ≥10 years, estimates were higher than in participants with a shorter follow-up (for trans-nonachlor: OR = 2.14, 1.01 to 4.53, P for trend = 0.035). Overall, trans-nonachlor, three PCBs and the two sums of POPs were the exposures most clearly associated with pancreatic cancer risk. Individually or in combination, most of the 22 POPs analysed did not or only moderately increased the risk of pancreatic cancer.

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.