An LDLR missense variant poses high risk of familial hypercholesterolemia in 30% of Greenlanders and offers potential of early cardiovascular disease intervention.

The common Arctic-specific LDLR p.G137S variant was recently shown to be associated with elevated lipid levels. Motivated by this, we aimed to investigate the effect of p.G137S on metabolic health and cardiovascular disease risk among Greenlanders to quantify its impact on the population. In a population-based Greenlandic cohort (n = 5,063), we tested for associations between the p.G137S variant and metabolic health traits as well as cardiovascular disease risk based on registry data. In addition, we explored the variant's impact on plasma NMR measured lipoprotein concentration and composition in another Greenlandic cohort (n = 1,629); 29.5% of the individuals in the cohort carried at least one copy of the p.G137S risk allele. Furthermore, 25.4% of the heterozygous and 54.7% of the homozygous carriers had high levels (>4.9 mmol/L) of serum LDL cholesterol, which is above the diagnostic level for familial hypercholesterolemia (FH). Moreover, p.G137S was associated with an overall atherosclerotic lipid profile, and increased risk of ischemic heart disease (HR [95% CI], 1.51 [1.18-1.92], p = 0.00096), peripheral artery disease (1.69 [1.01-2.82], p = 0.046), and coronary operations (1.78 [1.21-2.62], p = 0.0035). Due to its high frequency and large effect sizes, p.G137S has a marked population-level impact, increasing the risk of FH and cardiovascular disease for up to 30% of the Greenlandic population. Thus, p.G137S is a potential marker for early intervention in Arctic populations.

Loss of Sucrase-Isomaltase Function Increases Acetate Levels and Improves Metabolic Health in Greenlandic Cohorts.

BACKGROUND & AIMS: The sucrase-isomaltase (SI) c.273_274delAG loss-of-function variant is common in Arctic populations and causes congenital sucrase-isomaltase deficiency, which is an inability to break down and absorb sucrose and isomaltose. Children with this condition experience gastrointestinal symptoms when dietary sucrose is introduced. We aimed to describe the health of adults with sucrase-isomaltase deficiency. METHODS: The association between c.273_274delAG and phenotypes related to metabolic health was assessed in 2 cohorts of Greenlandic adults (n = 4922 and n = 1629). A sucrase-isomaltase knockout (Sis-KO) mouse model was used to further elucidate the findings. RESULTS: Homozygous carriers of the variant had a markedly healthier metabolic profile than the remaining population, including lower body mass index (ß [standard error], -2.0 [0.5] kg/m2; P = 3.1 × 10-5), body weight (-4.8 [1.4] kg; P = 5.1 × 10-4), fat percentage (-3.3% [1.0%]; P = 3.7 × 10-4), fasting triglyceride (-0.27 [0.07] mmol/L; P = 2.3 × 10-6), and remnant cholesterol (-0.11 [0.03] mmol/L; P = 4.2 × 10-5). Further analyses suggested that this was likely mediated partly by higher circulating levels of acetate observed in homozygous carriers (ß [standard error], 0.056 [0.002] mmol/L; P = 2.1 × 10-26), and partly by reduced sucrose uptake, but not lower caloric intake. These findings were verified in Sis-KO mice, which, compared with wild-type mice, were leaner on a sucrose-containing diet, despite similar caloric intake, had significantly higher plasma acetate levels in response to a sucrose gavage, and had lower plasma glucose level in response to a sucrose-tolerance test. CONCLUSIONS: These results suggest that sucrase-isomaltase constitutes a promising drug target for improvement of metabolic health, and that the health benefits are mediated by reduced dietary sucrose uptake and possibly also by higher levels of circulating acetate.

Omega-3 fatty acids and risk of cardiovascular disease in Inuit: First prospective cohort study.

BACKGROUND AND AIMS: No prospective study have ever assessed if marine n-3 polyunsaturated fatty acids protect Inuit against cardiovascular disease as claimed. It is highly relevant as cardiovascular disease (CVD) incidence rates are rising concurrent with a westernization of diet. We aimed to assess the association between blood cell membrane phospholipid content of eicosapentaenoic acid and docosahexaenoic acid (EPA + DHA) on CVD risk in Inuit. METHODS: We used data from a cohort of adult Greenlanders with follow-up in national registers. The main outcome was fatal and non-fatal CVD incidence among participants without previous CVD. The continuous effect of EPA + DHA was calculated as incidence rate ratios (IRRs) using Poisson regression with age as time scale, adjusting for age, sex, genetic admixture, lifestyle and dietary risk factors. RESULTS: Out of 3095 eligible participants, 2924 were included. During a median follow-up of 9.7 years, 216 had their first CVD event (8.3 events/1000 person years). No association between EPA + DHA and CVD risk was seen, with IRR = 0.99 per percentage point EPA + DHA increase (95% CI: 0.95-1.03, p = 0.59). No association was seen with risk of ischemic heart disease (IHD) (IRR = 1.03, 95% CI: 0.97-1.09) and stroke (IRR = 0.98, 95% CI: 0.93-1.03) as separate outcomes or for intake of EPA and DHA. CONCLUSIONS: We can exclude that the CVD risk reduction is larger than 21% for individuals at the 75% EPA + DHA percentile compared to the 25% percentile. We need a larger sample size and/or longer follow-up to detect smaller effects and associations with IHD and/or stroke.

Marine Oil Supplements for Arthritis Pain: A Systematic Review and Meta-Analysis of Randomized Trials.

Arthritis patients often take fish oil supplements to alleviate symptoms, but limited evidence exists regarding their efficacy. The objective was to evaluate whether marine oil supplements reduce pain and/or improve other clinical outcomes in patients with arthritis. Six databases were searched systematically (24 February 2015). We included randomized trials of oral supplements of all marine oils compared with a control in arthritis patients. The internal validity was assessed using the Cochrane Risk of Bias tool and heterogeneity was explored using restricted maximum of likelihood (REML)-based meta-regression analysis. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to rate the overall quality of the evidence. Forty-two trials were included; 30 trials reported complete data on pain. The standardized mean difference (SMD) suggested a favorable effect (-0.24; 95% confidence interval, CI, -0.42 to -0.07; heterogeneity, I² = 63%. A significant effect was found in patients with rheumatoid arthritis (22 trials; -0.21; 95% CI, -0.42 to -0.004) and other or mixed diagnoses (3 trials; -0.63; 95% CI, -1.20 to -0.06), but not in osteoarthritis patients (5 trials; -0.17; 95% CI, -0.57-0.24). The evidence for using marine oil to alleviate pain in arthritis patients was overall of low quality, but of moderate quality in rheumatoid arthritis patients.