Erythrocyte Membrane Polyunsaturated Fatty Acids Are Associated with Incidence of Metabolic Syndrome in Middle-Aged and Elderly People-An 8.8-Year Prospective Study.

BACKGROUND: The total and specific types of polyunsaturated fatty acids (PUFAs) related to metabolic syndrome (MetS) remain inconsistent. OBJECTIVE: We assessed the association of erythrocyte n-3 and n-6 PUFAs with MetS and the components of MetS in a cohort population. METHODS: This prospective analysis included 2754 participants (aged 40-75 y) from the Guangzhou Nutrition and Health Study (2008-2019) in China. Erythrocyte PUFAs at baseline were measured using gas chromatography. MetS was assessed every 3 y according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria. Multivariable Cox proportional hazard models were used to evaluate HRs and 95% CIs. RESULTS: We identified 716 incident cases of MetS. The primary analyses showed that the HRs (95% CIs) of MetS (tertile 3 versus 1) were 0.67 (0.56, 0.80) for n-3 PUFAs and 0.70 (0.58, 0.85) for n-6 PUFAs (all Ps trend <0.001). The secondary outcomes showed that, higher erythrocyte very-long-chain (VLC) PUFAs [20:3n-3, docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), arachidonic acid (ARA), and 22:4n-6], but lower α-linolenic acid (ALA) and γ-linolenic acid (GLA), tended to be associated with lower incidences of MetS and its components; among individual MetS components, the associations of PUFAs were more pronounced for hypertriglyceridemia (HTG) and hypertension, followed by low high-density lipoproten (HDL) cholesterol. Significantly higher concentrations of n-3 PUFAs (total, DPA, and DHA) and n-6 PUFAs (total, ARA, and 22:4) were observed in participants with improved (versus progressed) status of MetS (all Ps trend ≤0.003). CONCLUSION: This study reveals that higher erythrocyte VLC n-3 and n-6 PUFAs, but lower 18-carbon PUFAs (ALA and GLA), are associated with lower risks of MetS components (HTG, hypertension, and low HDL cholesterol) and thereby lower MetS incidence in Chinese adults.

Erythrocyte membrane n-3 polyunsaturated fatty acids are inversely associated with the presence and progression of nonalcoholic fatty liver disease in Chinese adults: a prospective study.

PURPOSE: Previous studies have shown that high-dose supplementation with n-3 polyunsaturated fatty acids (PUFAs) may benefit patients with nonalcoholic fatty liver disease (NAFLD), but the association of n-3 PUFAs with NAFLD among individuals with normal diets is only speculative. We investigated the cross-sectional and prospective associations between n-3 PUFAs and NAFLD in Chinese adults. METHODS: This community-based prospective study included 3049 men and women (40-75 years) in Guangzhou, China, whose participants completed an NAFLD ultrasound evaluation and erythrocyte PUFA tests. A total of 2660 participants underwent the second NAFLD evaluation approximately 3 years later. α-Linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocytes were measured by gas chromatography. RESULTS: After adjusting for potential confounders, we observed inverse associations between DHA, DHA + EPA, total n-3 PUFAs and the presence of NAFLD in the cross-sectional analysis. The adjusted odds ratios (95% confidence interval) of NAFLD for the highest (vs. lowest) tertile were 0.74 (0.61, 0.90) for DHA, 0.82 (0.67, 1.00) for EPA, 0.73 (0.60, 0.88) for DHA + EPA and 0.74 (0.61, 0.91) for total n-3 PUFAs  (all P values≤0.05). Over the average 3.12 years of follow-up, higher levels of DHA was associated with an improvement of NAFLD. The hazard ratio of improved NAFLD for the highest tertile was 1.18 (95% CI 1.09, 1.33) for DHA. Pathway analyses showed that favorable associations may be mediated by improvements in inflammatory markers (e.g., interleukin 1 beta and tumor necrosis factor alpha-like). CONCLUSIONS: Erythrocyte membrane n-3 PUFAs are inversely associated with the presence and progression of NAFLD in Chinese adults. TRIAL REGISTRATIONS: ClinicalTrials.gov NCT03179657.

Association between erythrocyte fatty acids in de novo lipogenesis pathway and DXA-derived body fat and trunk fat distribution in Chinese adults: a prospective study.

PURPOSE: Higher levels of fatty acids (FAs) in the de novo lipogenesis (DNL) pathway might be associated with higher levels of fat mass (FM), while limited evidence is available from the general population. We aimed to examine the associations between DNL-FAs and body fat and fat distribution in a general population of Chinese adults. METHODS: This community-based prospective cohort study included 3,075 participants (68% women) aged 40-75 years in urban Guangzhou, China. We measured erythrocyte DNL-FAs composition (including C16:0, C16:1n-7, C18:0, and C18:1n-9) at baseline and %FM over the total body (TB), trunk, limbs, android (A) and gynoid (G) regions after 3.2 years and 6.3 years of follow-up, respectively. RESULTS: Generally, higher proportions of individual erythrocyte DNL-FAs and their combined index were positively associated with adipose indices in the multivariable cross-sectional and longitudinal analyses. The cross-sectional percentage mean differences in quartile 4 (vs. 1) of the DNL index were 3.43% (TB), 4.56% (trunk), and 2.67% (A/G ratio) (all P trends < 0.01). The corresponding values in longitudinal changes of adipose indices were 1.40% (TB), 1.78% (trunk), and 1.32% (A) (all P trends < 0.05). The above associations tended to be more pronounced in the trunk and android area than the limbs and gynoid area. CONCLUSIONS: Erythrocyte DNL-FAs may contribute to an increase in total body fat in Chinese adults, particularly FM distributed in trunk and abdominal regions.

Erythrocyte Saturated Fatty Acids and Incident Type 2 Diabetes in Chinese Men and Women: A Prospective Cohort Study.

The association between circulating saturated fatty acids (SFAs) and incident type 2 diabetes (T2D) is reported in Western populations with inconsistent results, while evidence from Asian populations is scarce. We aimed to examine the associations between erythrocyte SFAs and incident T2D in a Chinese population. Between 2008 and 2013, a total of 2683 participants, aged 40⁻75 years, free of diabetes were included in the present analyses. Incident T2D cases were ascertained during follow-up visits. Gas chromatography was used to measure erythrocyte fatty acids at baseline. The Cox proportional hazards model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs). During 13,508 person years of follow-up, 216 T2D cases were identified. Compared with the first quartile, multivariable-adjusted HRs (95% CIs) of the fourth quartile were 1.20 (0.82⁻1.76; p = 0.242) for myristic acid (14-carbon tail, zero double bonds; 14:0), 0.69 (0.48⁻0.99; p = 0.080) for palmitic acid (16:0), 1.49 (1.02⁻2.19; p = 0.047) for stearic acid (18:0), 1.46 (1.00⁻2.12; p = 0.035) for arachidic acid (20:0), 1.48 (0.99⁻2.22; p = 0.061) for behenic acid (22:0), and 1.08 (0.74⁻1.56; p = 0.913) for lignoceric acid (24:0). Our findings indicate that individual erythrocyte SFAs are associated with T2D in different directions, with 18:0 and 20:0 SFAs positively associated with the risk, whereas no convincing inverse association for 16:0 SFAs.

Alternate Mediterranean diet score is positively associated with skeletal muscle mass index in middle-aged adults.

Researches have suggested Mediterranean diet might lower the risk of chronic diseases, but data on skeletal muscle mass (SMM) are limited. This community-based cross-sectional study examined the association between the alternate Mediterranean diet score (aMDS) and SMM in 2230 females and 1059 males aged 40-75 years in Guangzhou, China. General information and habitual dietary information were assessed in face-to-face interviews conducted during 2008-2010 and 3 years later. The aMDS was calculated by summing the dichotomous points for the items of higher intakes of whole grain, vegetables, fruits, legumes, nuts, fish and ratio of MUFA:SFA, lower red meat and moderate ethanol consumption. The SMM of the whole body, limbs, arms and legs were measured using dual-energy X-ray absorptiometry during 2011-2013. After adjusting for potential covariates, higher aMDS was positively associated with skeletal muscle mass index (SMI, SMM/height2, kg/m2) at all of the studied sites in males (all P trend<0·05). The multiple covariate-adjusted SMI means were 2·70 % (whole body), 2·65 % (limbs), 2·50 % (arms) and 2·70 % (legs) higher in the high (v. low) category aMDS in males (all P<0·05). In females, the corresponding values were 1·35 % (P trend=0·03), 1·05, 0·52 and 1·20 %, (P trend>0·05). Age-stratified analyses showed that the favourable associations tended to be more pronounced in the younger subjects aged less than the medians of 59·2 and 62·2 years in females and males (P interaction>0·10). In conclusion, the aMDS shows protective associations with SMM in Chinese adults, particularly in male and younger subjects.