Associations between major dietary patterns and blood pressure among Southwest Chinese: A cross-sectional analysis based on the China Multi-Ethnic Cohort (CMEC) study.

BACKGROUND AND AIMS: In the less developed multi-ethnic regions (LEMRs) of Southwest China, the associations between dietary patterns and blood pressure (BP) values remain unclear. We aimed to investigate such associations and related effect modifiers. METHODS AND RESULTS: This study included 81,433 participants from the China Multi-Ethnic Cohort Study. Dietary intakes during the year before the interview were measured with the Quantitative Food Frequency Questionnaire. Three major dietary patterns that were highly in line with geographical and ethnic distributions of the study population, i.e., "Sichuan Basin," "Yunnan-Guizhou Plateau," and "Qinghai-Tibet Plateau," were derived using principal component factor analysis. The multilinear regression model combined with inverse probability of exposure weighting was used to estimate the associations between dietary patterns and BP values. Comparing the highest with the lowest quintiles, the Sichuan Basin dietary pattern (characterized by urban lifestyles) was associated with 2.67 mmHg lower systolic blood pressure (SBP) (95% CI: -3.07 to -2.27) and 0.89 mmHg lower diastolic blood pressure (95% CI: -1.12 to -0.65). In contrast, both the Yunnan-Guizhou Plateau (characterized by agricultural lifestyles) and the Qinghai-Tibet Plateau dietary patterns (characterized by nomadic lifestyles) showed positive associations with BP. In the stratified analysis, the associations between dietary patterns and SBP were significantly stronger in women than in men for all three kinds of dietary patterns. CONCLUSION: Both major dietary patterns and their associations with BP showed a substantial disparity in LEMRs of Southwest China. Dietary patterns in regions of higher socioeconomic status are more conducive to reducing the rising of BP, especially for women and urban residents, which might provide insights into the BP control in LEMRs of Southwest China.

Two a posteriori dietary patterns are associated with risks of hyperuricemia among adults in less-developed multiethnic regions in Southwest China.

Diet is a major determinant of hyperuricemia, but little is known about the association between diet and hyperuricemia in less-developed multiethnic regions (LMERs). This study aimed to assess the hypothesis that dietary patterns (including 2 a-priori and 3 a posteriori dietary patterns) are associated with hyperuricemia in LMERs. The 2 a priori dietary patterns were the Dietary Approaches to Stop Hypertension (DASH) and the alternative Mediterranean diet (aMED). We derived 3 a posteriori dietary patterns from the China Multi-Ethnic Cohort study by principal component factor analysis. Given that those dietary patterns had high geographic discrimination, they were named the Sichuan Basin (economically developed industrial region), Yunnan-Guizhou Plateau (agricultural region), and Qinghai-Tibet Plateau (nomadic region) dietary pattern, respectively. We performed a logistic regression model to investigate associations between dietary patterns and hyperuricemia with potential confounders identified by the directed acyclic graph. Comparing the highest with the lowest quintiles, the Sichuan Basin dietary pattern was positively associated with hyperuricemia, whereas the Yunnan-Guizhou Plateau dietary pattern showed an inverse association with hyperuricemia. For the Qinghai-Tibet Plateau dietary pattern, DASH, or aMED, our results did not show a significant association with hyperuricemia. The results were robust among stratified analyses and different analyzing strategies. The dietary patterns showed great diversity in Southwest China. Both DASH and aMED, which many studies widely recommended, did not show expected beneficial effects on preventing hyperuricemia. However, the plant-based protein dietary pattern in the Yunnan-Guizhou Plateau showed a beneficial association with the risk of hyperuricemia, which can provide insights for dietary guidance in LMERs.

The impacts of measurement errors on a dietary pattern analyses:a simulation study based on dietary data from the China Multi-Ethnic Cohort (CMEC) study.

BACKGROUND: Measurement error is a significant challenge in nutritional epidemiology research. Compared with traditional, isolated-nutrient research, dietary-pattern studies provide a more comprehensive approach to chronic disease prevention and have become popular in recent years. However, few studies have examined the impacts of measurement errors on dietary pattern analyses. OBJECTIVES: We investigated the impacts of measurement errors on the 2 most commonly used dietary pattern derivation methods: principal component factor analysis (PCFA) and K-means cluster analysis (KCA). METHODS: We conducted a simulation study by taking the dietary data collected in the China Multi-Ethnic Cohort study as the "true values" and adding linear measurement errors for each food group to consider both systematic and random errors. We investigated the impacts of measurement errors from 2 aspects: distortion of the derived dietary patterns and estimated associations between the dietary patterns and disease. RESULTS: For both systematic and random errors, larger measurement errors caused more serious distortion of dietary patterns derived by PCFA and KCA, with consistency rates ranging from 67.5% to 100% and from 13.4% to 88.4%, respectively. In addition, for both systematic and random errors, larger measurement errors caused greater attenuation effects on the association coefficients. For a beneficial association (coefficient, -0.5), the estimated coefficients ranged from -0.287 to -0.450 and from -0.231 to -0.394 in the PCFA and KCA, respectively. For a harmful association (coefficient, 0.5), the estimated coefficients ranged from 0.295 to 0.449 and from -0.003 to 0.373 in the PCFA and KCA, respectively. Dietary patterns derived by PCFA with factor loadings of low discrepancies and dietary patterns derived by KCA with small cluster sample sizes are more vulnerable to measurement error. CONCLUSIONS: Measurement errors could distort dietary patterns and attenuate the dietary pattern-disease association. The stability of dietary patterns under measurement errors differs when using PCFA and KCA.

Association of Dietary Approaches to Stop Hypertension diet and Mediterranean diet with blood pressure in less-developed ethnic minority regions.

OBJECTIVE: We aimed to investigate the association of Dietary Approaches to Stop Hypertension (DASH)-style diet and Mediterranean-style diet with blood pressure in less-developed ethnic minority regions (LMERs). DESIGN: Cross-sectional study. SETTING: Dietary intakes were assessed by a validated food frequency questionnaire. Dietary quality was assessed by the DASH-style diet score and the alternative Mediterranean-style diet (aMED) score. The association between dietary quality and blood pressure was evaluated using multivariate linear regression model. We further examined those associations in subgroups of blood pressure level. PARTICIPANTS: A total of 81433 adults from the China Multi-Ethnic Cohort (CMEC) study were included in this study. RESULTS: In the overall population, compared with the lowest quintile, the highest quintile of DASH-style diet score was negatively associated with systolic BP (coefficient: -2.78, 95% CI: -3.15 to -2.41; P-trend<0.001), while the highest quintile of aMED score had a weaker negative association with systolic BP (coefficient: -1.43, 95% CI: -1.81 to -1.05; P-trend<0.001). Both dietary indices also showed a weaker effect on diastolic BP (coefficient for DASH-style diet: -1.06, 95% CI: -1.30 to -0.82; coefficient for aMED: -0.43, 95% CI: -0.68 to -0.19). In the subgroup analysis, both dietary indices showed a stronger beneficial effect on systolic BP in the hypertension group than in either of the other subgroups. CONCLUSION: Our results indicated that the healthy diet originating from Western developed countries can also have beneficial effects on blood pressure in LEMRs. DASH-style diet may be a more appropriate recommendation than aMED as part of a dietary strategy to control blood pressure, especially in hypertensive patients.

Dietary Approaches to Stop Hypertension (DASH) diet, Mediterranean diet and blood lipid profiles in less-developed ethnic minority regions.

Different from developed countries, there is a paucity of research examining how the Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diets relate to lipids in less-developed ethnic minority regions (LEMR). A total of 83 081 participants from seven ethnic groups were retrieved from the baseline data of the China Multi-Ethnic Cohort study, which was conducted in less-developed Southwest China between May 2018 and September 2019. Multivariable linear regression models were then used to examine the associations of the DASH and alternative Mediterranean diet (AMED) scores, assessed by modified DASH score and AMED, as well as their components with total cholesterol (TC), LDL-cholesterol, HDL-cholesterol, TAG and TC/HDL-cholesterol. The DASH scores were negatively associated with TC, HDL-cholesterol and TAG. Comparing the highest quintiles with the lowest DASH scores, TC decreased 0·0708 (95 % CI -0·0923, -0·0493) mmol/l, HDL-cholesterol decreased 0·0380 (95 % CI -0·0462, -0·0299) mmol/l and TAG decreased 0·0668 (95 % CI -0·0994, -0·0341) mmol/l. The AMED scores were negatively associated with TC, LDL-cholesterol and HDL-cholesterol. Comparing the highest quintiles with the lowest AMED scores, TC decreased 0·0816 (95 % CI -0·1035, -0·0597) mmol/l, LDL-cholesterol decreased 0·0297 (95 % CI -0·0477, -0·0118) mmol/l and HDL-cholesterol decreased 0·0275 (95 % CI -0·0358, -0·0192) mmol/l. Although both the DASH diet and the Mediterranean diet were negatively associated with blood lipids, those associations showed different patterns in LEMR, particularly for TAG and HDL-cholesterol.

Dietary patterns and cardiometabolic risks in diverse less-developed ethnic minority regions: results from the China Multi-Ethnic Cohort (CMEC) Study.

Background In Western developed countries, food-based dietary patterns have been associated with the risk of cardiometabolic diseases, but little is known about such associations in less developed ethnic minority regions (LEMRs), where the cardiometabolic disease burden is growing rapidly and food patterns differ substantially. Methods Between May 2018 and September 2019, we recruited 99556 participants aged 30-79 years from the China Multi-Ethnic Cohort (CMEC) Study. We measured habitual dietary intake with validated food frequency questionnaire (FFQ) and then calculated dietary pattern scores for two of the most studied a priori dietary patterns, i.e., Dietary Approaches to Stop Hypertension (DASH) and alternative Mediterranean (aMED) style diets, and three a posteriori dietary patterns. Four cardiometabolic risks, including hypertension, diabetes, dyslipidaemia and metabolic syndrome (MetS), were newly diagnosed by medical examination and blood tests. We estimated adjusted odds ratios (OR) relating various dietary pattern scores to cardiometabolic risks using marginal structural models under the guidance of directed acyclic graphs. For the above associations, we further calculated the proportion mediated by overweight (PM) using regression-based mediation analysis for better public health implications. Findings The final study sample consisted of 68834 participants. Among them, we newly diagnosed 12803 hypertension, 3527 diabetes, 16342 hyperlipidaemia, and 8198 MetS cases. Overall, all 5 dietary patterns showed considerable associations with risks of hypertension and MetS. Comparing the highest with the lowest quintiles, the DASH score showed the strongest inverse associations with risks of hypertension (OR=0.74, 95% CI:0.70-0.79; PM=10%) and MetS (OR=0.79, 95% CI:0.74-0.85; PM=35%); conversely, scores of the localized a posteriori Yunnan-Guizhou plateau dietary pattern in LEMRs showed the strongest positive associations with risks of hypertension (OR=1.44, 95% CI:1.35-1.52; PM=10%) and MetS (OR=1.35, 95% CI:1.26-1.46; PM=33%), with all P values for trend <0.001. These associations were consistent in various subgroups defined by sex, age, smoking and physical activity, but with magnitudes that differed substantially across different ethnic regions and urbanicity. By investigating the single-component effects of dietary patterns, the dairy intake component contributed a major proportion to the beneficial effects of DASH (41.9% for hypertension and 100.5% for MetS). Interpretation Substantial socioeconomic status and ethnic disparities in diet quality and related cardiometabolic risks were seen in LEMRs, with hypertension being the top diet-related cardiometabolic risk. Our findings support that DASH provides superior dietary guidance compared to aMED for reducing cardiometabolic risks in LEMRs. In particular, the dairy intake encouraged by DASH may produce considerable beneficial effects. Funding This study was funded by the National Key R&D Program of China; full funding sources listed in the acknowledgements.