Dietary habits among men and women in West Greenland: follow-up on the ACCEPT birth cohort

Sex differences in the association between plasma polyunsaturated fatty acids levels and moderate-to-severe plaque psoriasis severity: a cross-sectional and longitudinal study

BACKGROUND

Psoriasis is a chronic inflammatory skin disease with metabolic abnormalities serving as important contributors for pathogenesis and progression. Polyunsaturated fatty acids (PUFAs) have been found to be associated with human diseases, including psoriasis. However, differences and controversies exist regarding their content and roles.

METHODS

Plasma PUFAs concentrations were measured in 296 patients with moderate-to-severe plaque psoriasis from the Shanghai Psoriasis Effectiveness Evaluation CoHort. Disease severity was assessed using Clinician-Reported Outcomes (ClinROs), including Psoriasis Area and Severity Index (PASI), Body Surface Area (BSA) and Physician Global Assessment (PGA), as well as Patient-Reported Outcomes (PROs), including Patient Global Assessment (PtGA) and Dermatology Life Quality Index (DLQI). Multivariate generalized linear regression models (GLMs), subgroup and interaction analysis, and restricted cubic spline were used to estimate the cross-sectional associations between PUFAs concentrations and disease severity. Longitudinal assessments of PASI scores and PASI response were conducted at a 12-week follow-up. Associations between baseline plasma PUFAs levels and prospective PASI scores or PASI response were assessed using multivariate GLMs or logistic regression models.

RESULTS

Males suffered severer psoriasis and presented lower plasma docosahexaenoic acid (DHA) and arachidonic acid (ARA) levels compared to females. Among males, plasma eicosadienoic acid (EDA) level was positively associated with PASI, BSA and PGA scores, while total Omega-3 PUFAs and/or eicosapentaenoic acid (EPA) levels exhibited non-linear associations with PASI and/or BSA scores. α-Linolenic acid (ALA) was negatively, whereas ARA was positively, associated with DLQI scores. In females, Omega-3 PUFAs, including EPA, DHA, and total Omega-3 PUFAs, showed inverse associations with PASI and BSA scores. Longitudinally, plasma total Omega-6 PUFAs were positively associated with the likelihood of achieving PASI 100 at 12 weeks in males. In females, concentrations of dohomo-γ-linolenic acid were prospectively associated with an increase in PASI scores, and DHA was associated with the likelihood of achieving PASI 75 and PASI 90 decline.

CONCLUSIONS

Sex differences cross-sectionally exist in disease severity and plasma PUFAs levels. The association between PUFAs and psoriasis severity also varies cross-sectionally and longitudinally between males and females. Sex differences should be considered when studying the function and clinical application of PUFAs in psoriasis.

Assessment of exposure to perfluorinated industrial substances and risk of immune suppression in Greenland and its global context: a mixed-methods study

BACKGROUND

Perfluoroalkyl substances (PFASs) are ubiquitous global contaminants that do not readily biodegrade and are therefore routinely found worldwide in wildlife, humans, and the environment. There is a paucity of global assessments to understand regional and continental differences in exposure to PFASs and the associated health risks, including those for Indigenous Arctic communities who consume high trophic marine diets. We aimed to estimate the long-term exposure of dietary PFASs from consumption of polar bear and ringed seal meat and establish its association with blood serum concentrations of PFASs in Inuit in Ittoqoortoormiit (Scoresby Sound), East Greenland. We also aimed to assess the risk of immune suppression on the basis of European Food Safety Authority (EFSA) thresholds for weekly intake and blood serum concentrations of PFASs. Last, we conducted a worldwide risk assessment based on blood concentrations of PFASs emphasising Arctic exposure in a global context.

METHODS

In this mixed-methods study, we conducted interviews to compare dietary exposure of PFASs in anonymous, non-pregnant, Inuit adults (aged ≥18 years) from full-time or part-time hunter families in Ittoqoortoormiit, East Greenland with ESFA toxic threshold values for tolerable weekly intake of the four most immunotoxic PFASs (∑4PFAS; perfluorooctanoic acid, perfluorononanoic acid, perfluorohexanesulfonic acid, and perfluorooctane sulfonate). Independent hospital staff from the local hospital randomly selected participants using simple randomisation using a telephone directory. Blood serum concentrations were then compared with EFSA risk categories: low (0·7-9·5 ng/mL), moderate (>9·5-17·5 ng/mL), high (>17·5-31·9 ng/mL), and severe (>31·9 ng/mL). We also reviewed the available scientific literature of ∑4PFAS concentrations in human blood to place the Inuit dataset in a broader global context.

FINDINGS

Between Sept 21, and Oct 2, 2015, 22 participants were enrolled in the study, of which 12 were male and ten were female. Sex data were obtained from personal social security numbers and options were male or female. As a result of a subsistence diet high in marine mammal muscle, 322 (92%) of 350 people in the Ittoqoortoormiit cohort exceeded the established immunotoxic thresholds of ∑4PFASs set by EFSA's tolerable weekly intake of 4·4 ng/kg, and 301 (86%) were in the most severe risk category (>31·9 ng/mL) based on blood serum concentrations. This Inuit cohort had the highest non-occupational long-term exposure to PFASs worldwide despite their remote location relative to industrial sources. Using country-wide average values across global studies, we found that blood serum concentrations of PFASs in populations from European countries, North America, the Arctic, and Australia were generally higher than those in South America, Africa, and mainland Asia, with the highest concentrations found in people from USA, Canada, Greenland, Faroe Islands, Denmark, Iceland, Norway, Sweden, the UK, Spain, Poland, and Australia. These high exposure countries all fall within the EFSA moderate-risk and high-risk categories.

INTERPRETATION

PFAS contamination of the environment and human populations occurs worldwide. This pollution not only poses substantial risks for immune system adverse events but also cardiovascular, cancerous, and reproductive endpoints. Data on such PFAS exposure is scarce in numerous countries. Therefore, it is important to also map out the exposure in these countries to enable a thorough global assessment of exposure and risks.

FUNDING

Danish Cooperation for Environment in the Arctic.

Persistent organic pollutant exposures among Greenlandic adults in relation to lifestyle and diet: New data from the ACCEPT cohort

High concentrations of persistent organic pollutants (POPs) in blood of the Greenlandic population are well known. The exposure is mainly through traditional food intake, including marine mammals and seabirds. The present study aimed to follow up on POP concentrations (organochlorine pesticides, polychlorinated biphenyls, per- and polyfluoroalkyl substances, and halogenated flame retardants (HFRs)) and relations to lifestyle and diet of the mothers included in the Greenlandic ACCEPT cohort (3-5 years after inclusion in 2013-15) and to include the children's fathers. This new data collection in 2019-20 included blood samples for measurement of POP concentrations and lifestyle and food frequency questionnaires from 101 mothers and 76 fathers aged 24-55 years living in Nuuk, Sisimiut, and Ilulissat, Greenland. The mothers' intra-individual median percentage decrease in POP concentrations from inclusion to this follow-up (3-5 years later) was 16-58%, except for mirex (0% change). Median concentrations of POPs were 1.4-4.6 times higher in fathers than in mothers. The POPs differed by residential town with generally higher concentrations in Ilulissat compared to Sisimiut and Nuuk. We report, for the first time, novel HFRs in human samples from Greenland. However, concentrations were low and only dechlorane plus (with its anti-isomer) was detected in >50% of the samples. Most POPs correlated positively with age and n-3/n-6 fatty acid ratio. The lipophilic POPs correlated positively with the percentage of life lived in Greenland, whereas few POPs correlated positively with BMI, income (personal and household), education, and alcohol intake. The POPs generally associated positively with the intake of marine mammals, seabirds, and dried fish, while few POPs associated positively with Greenlandic fish intake. In contrast, POPs generally associated negatively with imported meat products intake. The study findings may be of interest for future dietary recommendations in Greenland. We discuss the potential explanations for the findings and suggestions for future research.

Prenatal exposure to persistent organic pollutants and metals and problematic child behavior at 3-5 years of age: a Greenlandic cohort study

High levels of persistent organic pollutants (POPs) and heavy metals are found in Arctic populations. POP and heavy metals are linked to impaired cognitive development. This study examined associations between prenatal POP and metals exposure and problematic child behavior using the Strength and Difficulties Questionnaire (SDQ). POPs and metals were measured in 102 pregnant Greenlandic women. During follow-up at 3–5 years, parents answered an assisted questionnaire including children’s SDQ scores. Associations were analyzed using linear and logistic regression analyses and adjusted for maternal plasma cotinine, educational level and age at delivery. In the adjusted analyses, the medium tertile of hexachlorobenzene (β = 3.06, p = 0.010), β-hexachlorocyclohexane (β = 3.58, p = 0.004) and trans-nonachlor (β = 2.06, p = 0.082) were positively associated with SDQ scores. The continuous cis-nonachlor (OR = 1.09, p = 0.079), dichloro-diphenyl-dichloroethylene (OR = 1.01, p = 0.077), trans-nonachlor (OR = 1.01, p = 0.091), and sum Organochlorine-Pesticides (OR = 1.00, p = 0.094) were positively associated with abnormal SDQ score and the continuous mirex (OR = 1.28, p = 0.096), oxychlordane (OR = 1.04, p = 0.066), and trans-nonachlor (OR = 1.02, p = 0.071) with abnormal hyperactivity score. We found no consistent evidence of associations between polychlorinated biphenyls, perfluoroalkylated substances and heavy metals and problematic behavior. Prenatal organochlorine pesticide exposure associated significantly with problematic behavior in 3–5 year old children.