Obesity-Associated Dyslipidemia Is Moderated by Habitual Intake of Marine-Derived n-3 Polyunsaturated Fatty Acids in Yup'ik Alaska Native People: A Cross-Sectional Mediation-Moderation Analysis.

BACKGROUND: Obesity leads to insulin resistance, altered lipoprotein metabolism, dyslipidemia, and cardiovascular disease. The relationship between long-term intake of n-3 polyunsaturated fatty acids (n-3 PUFAs) and prevention of cardiometabolic disease remains unresolved. OBJECTIVES: The aim of this study was to explore direct and indirect pathways between adiposity and dyslipidemia, and the degree to which n-3 PUFAs moderate adiposity-induced dyslipidemia in a population with highly variable n-3 PUFA intake from marine foods. METHODS: In total, 571 Yup'ik Alaska Native adults (18-87 y) were enrolled in this cross-sectional study. The red blood cell (RBC) nitrogen isotope ratio (15N/14N, or NIR) was used as a validated objective measure of n-3 PUFA intake. EPA and DHA were measured in RBCs. Insulin sensitivity and resistance were estimated by the HOMA2 method. Mediation analysis was conducted to evaluate the contribution of the indirect causal path between adiposity and dyslipidemia mediated through insulin resistance. Moderation analysis was used to assess the influence of dietary n-3 PUFAs on the direct and indirect paths between adiposity and dyslipidemia. Outcomes of primary interest included plasma total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), non-HDL-C, and triglycerides (TG). RESULTS: In this Yup'ik study population, we found that up to 21.6% of the total effects of adiposity on plasma TG, HDL-C, and non-HDL-C are mediated through measures of insulin resistance or sensitivity. Moreover, RBC DHA and EPA moderated the positive association between waist circumference (WC) and TC or non-HDL-C, whereas only DHA moderated the positive association between WC and TG. However, the indirect path between WC and plasma lipids was not significantly moderated by dietary n-3 PUFAs. CONCLUSIONS: Intake of n-3 PUFAs may independently reduce dyslipidemia through the direct path resulting from excess adiposity in Yup'ik adults. NIR moderation effects suggest that additional nutrients contained in n-3 PUFA-rich foods may also reduce dyslipidemia.

Habitual Intake of Marine-Derived n-3 PUFAs is Inversely Associated with a Cardiometabolic Inflammatory Profile in Yup'ik Alaska Native People.

BACKGROUND: The relationship between dietary n-3 PUFAs and the prevention of cardiometabolic diseases, including type 2 diabetes, is unresolved. Examination of the association between n-3 PUFAs and chronic low-grade inflammation in a population where many individuals have had an extremely high intake of marine mammals and fish throughout their lifespan may provide important clues regarding the impact of n-3 PUFAs on health. OBJECTIVES: The aim of this study was to explore associations between concentrations of n-3 PUFAs resulting from habitual intake of natural food sources high in fish and marine mammals with immune biomarkers of metabolic inflammation and parameters of glucose regulation. METHODS: A total of 569 Yup'ik Alaska Native adults (18-87 years old) were enrolled in this cross-sectional study between December 2016 and November 2019. The RBC nitrogen isotope ratio (NIR; 15N/14N) was used as a validated measure of n-3 PUFA intake to select 165 participant samples from the first and fourth quartiles of n-3 PUFA intakes. Outcomes included 38 pro- and anti-inflammatory cytokines and 8 measures of glucose homeostasis associated with type 2 diabetes risks. These outcomes were evaluated for their associations with direct measurements of EPA, DHA, and arachidonic acid in RBCs. ANALYSIS: Linear regression was used to detect significant relationships with cytokines and n-3 PUFAs, adiposity, and glucose-related variables. RESULTS: The DHA concentration in RBC membranes was inversely associated with IL-6 (ß = -0.0066; P < 0.001); EPA was inversely associated with TNFα (ß = -0.4925; P < 0.001); and the NIR was inversely associated with Monocyte chemoattractant protein-1 (MCP-1) (ß = -0.8345; P < 0.001) and IL-10 (ß = -1.2868; P < 0.001). CONCLUSIONS: Habitual intake of marine mammals and fish rich in n-3 PUFAs in this study population of Yup'ik Alaska Native adults is associated with reduced systemic inflammation, which may contribute to the low prevalence of diseases in which inflammation plays an important role.

Investigation of setmelanotide, an MC4R agonist, for obesity in individuals with Smith-Magenis syndrome.

BACKGROUND: Smith Magenis Syndrome (SMS) is a rare genetic disorder caused by RAI1 haploinsufficiency. Obesity in people with SMS is believed partially due to dysfunction of the proximal melanocortin 4 receptor (MC4R) pathway. We therefore studied effects of treatment with the MC4R agonist setmelanotide on obesity and hunger, as well as metabolic, cardiac and safety, in individuals with SMS. METHODS: People with SMS received once-daily setmelanotide injections, with the dose titrated bi-weekly to a maximum of 3 mg over ∼1 month; and a full-dose treatment duration of 3mo. The primary outcome was percent change in body weight. Secondary outcomes included hunger, waist circumference, body composition, and safety. RESULTS: 12 individuals, ages 11-39 y, enrolled and 10 completed the full-dose treatment phase. Mean percent change in body weight at end-treatment was - 0.28 % [(95 % CI, -2.1 % to 1.5 %; n = 12; P = 0.66]. Participants experienced a significant decrease in total cholesterol associated with a significant decrease in HDL-cholesterol and a trend for lower LDL-cholesterol. Self-reported hunger was reduced at end-treatment (p = 0.011). All participants reported adverse events (AEs), most commonly injection-site reactions and skin hyperpigmentation. No AEs led to withdrawal or death. CONCLUSIONS: In this trial, setmelanotide did not significantly reduce body weight in participants with SMS. Participants reported significant differences in hunger, but such self-reports are difficult to interpret without a placebo-treated group. The changes in lipid profiles require further investigation. Results of this study do not suggest that dysfunction of the proximal MC4R pathway is the main etiology for obesity in people with SMS.

Circannual growth in Wisconsin children and adolescents: Identifying optimal periods of obesity prevention.

BACKGROUND: Recent studies suggest kids tend to gain the most weight in summer, but schools are chastised for supporting obesogenic environments. Conclusions on circannual weight gain are hampered by infrequent body mass index (BMI) measurements, and guidance is limited on the optimal timeframe for paediatric weight interventions. OBJECTIVES: This study characterized circannual trends in BMI in Wisconsin children and adolescents and identified sociodemographic differences in excess weight gain. METHODS: An observational study was used to pool data from 2010 to 2015 to examine circannual BMI z-score trends for Marshfield Clinic patients age 3 to 17 years. Daily 0.20, 0.50, and 0.80 quantiles of BMI z-score were estimated, stratified by gender, race, and age. RESULTS: BMI z-scores increased July to September, followed by a decrease in October to December, and another increase to decrease cycle beginning in February. For adolescents, the summer increase in BMI was greater among those in the upper BMI z-score quantile relative to those in the lower quantile (+0.15 units vs +0.04 units). This pattern was opposite in children. CONCLUSIONS: BMI increased most rapidly in late summer. This growth persisted through autumn in adolescents who were larger, suggesting weight management support may be beneficial for kids who are overweight at the start of the school year.

Associations of sleep patterns with metabolic syndrome indices, body composition, and energy intake in children and adolescents.

BACKGROUND: Self-reported short sleep duration is associated with greater risk for metabolic syndrome (MetS), obesity, and higher energy intake (EI). However, studies of these associations in children using objective methods are sparse. OBJECTIVES: The study aims to determine the associations for sleep patterns with MetS indices, body composition, and EI using objective measures in children. METHODS: Free-living sleep and physical activity were measured in 125 children (aged 8-17 years, BMI z = 0.57 ± 1.0, 55% female) using wrist-worn actigraphs for 14 nights. Blood pressure, fasting blood levels of lipids, insulin, glucose, waist circumference, and body composition (dual-energy X-ray absorptiometry [DXA]) were obtained during outpatient visits. EI was assessed during an ad libitum buffet meal. RESULTS: Later weekday and weekend bedtimes were associated with higher systolic blood pressure (Ps < 0.05). Sleep duration and bedtime were not significantly associated with other components of MetS, body composition, or EI. Short sleepers (duration less than 7 hours) consumed a greater percentage of carbohydrates than those with adequate (greater than or equal to 7 hours) sleep (P < 0.05). CONCLUSION: Indicators of sleep duration were variably associated with children's eating patterns and risk for chronic disease. Prospective data are needed to determine whether these indicators of sleep quality represent unique or shared risk factors for poor health outcomes.