Background Overweight and obesity are on the rise all over the world and are related to a variety of chronic diseases. There is a lack of such research on the population aged 18-35. Objective To explore the trends of overweight and obesity in adults aged 18-35 from 1989 to 2018 and the epidemiological characteristics in 2018. Methods A total of 22425 adults aged 18-35 enrolled in the China Health and Nutrition Survey in 1989, 1991, 1993, 1997, 2000, 2004, 2006, 2009, 2011, 2015, and 2018 were selected as study subjects. Overweight and obesity were judged in accordance with WST 428-2013 Determination of adult weight. The trend analysis of body mass index (BMI) level adopted a general linear model, and the trend analysis of overweight and obesity rate adopted a chi-square test for trend. A joinpoint regression model was used to calculate the average annual percentage change (AAPC) and annual percentage change (APC). A log-binomial regression model was used to analyze the relationship between socioeconomic factors and overweight/obesity, and a model with sex stratification was also constructed. Results In the period of 1989–2018, the BMI, overweight rate, and obesity rate of adults aged 18-35 all showed an upward trend. The BMI increased from (21.3±2.3) kg·m⁻² to (23.3±4.0) kg·m⁻², and the rate of overweight and obesity increased from 12.1% to 36.8%. The results of joinpoint regression model showed that 2000 was a joinpoint, and the APCs of overweight rates of 1989–2000 and 2000–2018 were 4.1% and 2.4% respectively (P < 0.05), and the APCs of obesity rates were 15.2% and 7.5% respectively (P < 0.05). From 1989 to 2018, the overweight rate increased at an average annual rate of 3.1% (AAPC=3.1%, 95%CI: 2.4%-3.7%, P<0.05), and the obesity rate increased at an average annual rate of 10.3% (AAPC=10.3%, 95%CI: 7.6%-13.2%, P<0.05). The overweight and obesity rates of men, the 25-35 age group, and northerners were 49.5%, 38.7%, and 45.4% respectively. About 52.6% of men aged 25-35 were overweight and obese. The results of log-binomial regression analysis showed that the risks of overweight and obesity were lower in women (with men as reference, RR=0.54, 95%CI: 0.44-0.65) and in southerners (with northerners as reference, RR=0.74, 95%CI: 0.61-0.91), but was higher in the 25-35 year old group (with the 18-24 year old group as reference, RR=1.41, 95%CI: 1.07-1.87). After stratification by sex, the results of log-binomial regression analysis showed that compared with men aged 18-34, men aged 25-35 had an increased risk of overweight and obesity (RR=1.50, 95%CI: 1.04-2.14), and compared with women in the north, women in the south had a lower risk of overweight and obesity (RR=0.63, 95%CI: 0.46-0.87). Conclusion The problem of overweight and obesity of Chinese adults aged 18-35 is serious. We should give priority to intervene and prevent the overweight and obesity of men, people aged 25-35, and northerners, especially men aged 25-35.

Background Global dietary magnesium insufficiency is widespread and seriously harmful to human health. There are few studies on dietary magnesium intake in China, and associated dietary intervention lacks scientific support. Objective To explore the dietary magnesium intake level and food sources of Chinese adults aged 18-64 in 2018, and to identify the problems of dietary magnesium intake. Methods A total of 9181 residents in the 2018 "China Health and Nutrition Survey" were selected as the study subjects. Types and intake of food collected from consecutive 3-day 24-hour dietary recalls and by household condiment weighing and counting method. The average daily dietary magnesium intake and the composition of main food sources were calculated using the food composition table. Multiple logistic regression was used to analyze the relationship between socioeconomic factors and insufficient dietary magnesium intake. Results In 2018, the daily intake of magnesium in P₅₀ (P₂₅, P₇₅) of adults aged 18-64 in 15 provinces (autonomous regions and municipalities) of China was 252.28 (196.25, 326.27) mg. The proportion of residents with insufficient dietary magnesium intake was 60.9%. The proportions of women, adults aged 18-49, urban residents, southern region residents, and western regions residents with insufficient dietary magnesium intake were 66.4%, 63.4%, 62.4%, 65.2%, and 68.3%, respectively. The results of multiple logistic regression analysis showed that the risks of insufficient dietary magnesium intake were 64.6%, 24.6%, and 43.6% higher in women, urban residents, and southern region residents than those in men, rural residents, and northern region residents, respectively (OR=1.646, 95%CI: 1.509-1.794; OR=1.246, 95%CI: 1.126-1.379; OR=1.436, 95%CI: 1.311-1.573); the risk of insufficient dietary magnesium intake in residents aged 50-64 was 15.7% lower than that in residents aged 18-49 (OR=0.843, 95%CI: 0.771-0.921); the risks of insufficient magnesium intake in residents in middle and western areas were 1.202 times and 1.590 times of that in residents in eastern area (OR=1.202, 95%CI: 1.079-1.340; OR=1.590, 95%CI: 1.424-1.776). The effect of education level and income level on magnesium intake insufficiency was not observed (P>0.05). In addition, 41.4% of dietary magnesium of the subjects came from cereals and products (ranking first in food sources), and only 2.4% from dark vegetables with rich magnesium content (ranking sixth place). The top six dietary magnesium sources of men and women were the same. The proportion of dietary magnesium from cereals and products was 6.3% higher in rural residents than in urban residents, and 9.3% higher in residents living in northern regions than those in southern regions. The proportion of dietary magnesium from livestock meat and products was 1.3% higher in the 18-49 age group than in the 50-64 age group, 0.9% higher in urban residents than in rural residents, and 1.6% higher in western region residents than in eastern region residents. Conclusion The dietary magnesium intake of Chinese residents is generally insufficient, and the source of dietary magnesium is irrational. Women, residents aged 18-49, residents in southern, middle, and western areas are high-risk populations of dietary magnesium insufficiency. Chinese residents are encouraged to eat more dark vegetables and whole grain food; women should improve their dietary quality and intake diverse magnesium-rich food; southern region residents and urban residents should increase the intake of whole grains and avoid over refining food; residents aged 18-49, urban residents, and those in western regions should adjust their dietary structure and reduce meat intake.

Background Magnesium is an important nutrient, and participates in most metabolic processes. Many studies show an association between dietary magnesium intakes and nutrition-related diseases such as diabetes. However, the data of dietary magnesium intakes and secular trends among the whole life cycle of Chinese residents are not available. Objective To investigate the dietary magnesium intakes and associated secular trends over the past three decades in residents of all ages and China, to identify the high-risk residents of magnesium deficiency and plan nutritional interventions, and provide basic data support for the revision of dietary magnesium reference intake. Method The data came from the 10 rounds of the "China Health and Nutrition Survey" from 1991 to 2018, and the participants with complete sociodemographic and dietary data wereselected. The median intakes, insufficient rates, and secular trends of dietary magnesium intakes were analyzed in different survey years. Analysis of multiple linear regression was used to analyze the annual change characteristics of dietary magnesium intakes controlling gender, age, education, urban-rural stratum, and north-south region. Wilcoxon trend test was used to analyze the secular trends of dietary magnesium intakes in different characteristic groups. The trends of insufficient rate were analyzed by Cochran-Armitage trend test among different characteristic groups. Results A total of 127169 residents were included in the present study. The medians of dietary magnesium intakes in 1991, 1993, 1997, 2000, 2004, 2006, 2009, 2011, 2015, and 2018 were 283.70, 283.38, 304.26, 285.50, 283.64, 275.49, 267.92, 242.93, 240.51, and 238.89 mg·d⁻¹, respectively, showing a significant downward trend (F=2931.81, P<0.001). Dietary magnesium intakes showed significant differences in gender, age, education level, income level, urban-rural stratum, and north-south region in almost all survey years, except that there was no significant difference among different income groups in 1991. Insufficient rate of dietary magnesium intake showed a significant upward trend (Z=62.62, P<0.001), approximate 60% of Chinese residents consumed insufficient magnesium. The insufficient rate was 53.94% for male and 65.35% for female, and the insufficient rate in the 14-17 age group was as high as 71.29%. Conclusion The dietary magnesium intake shows a significant downward trend and insufficient intake of dietary magnesium is prevalent among Chinese population. It is necessary to observe the high-risk population and conduct relevant nutritional interventions, as well as to further assess the recommended intake of magnesium.

Background Magnesium plays an important physiological role in human, but the association between dietary magnesium intake and the risk of hypertension is unclear. Few studies have reported the dose-response relationship in Chinese population. Objective To analyze the relationship between dietary magnesium intake and the risk of hypertension in Chinese adults aged 18-64 years, and to explore the dose-response relationship. Methods A total of 13082 adults aged 18-64 years who participated in at least two rounds of the China Health and Nutrition Survey (CHNS) from 2000 to 2018 were selected. Dietary data were obtained by consecutive 3-day 24-hour dietary recall and weighting & bookkeeping method. Blood pressure was measured with a standard mercury sphygmomanometer. Hypertension was diagnosed when systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg, or self-reported hypertension history or using antihypertensive drugs. The mean of dietary magnesium intake in all survey years (excluding the last survey) was used as the dietary magnesium intake of the subject, and the mean of dietary magnesium intake was divided into 5 equal groups. Cox proportional risk model with adjustments for socio-demographic factors, body mass index (BMI), smoking and drinking, sleep time, physical activity, and dietary factors, was used to analyze the association between dietary magnesium intake and the risk of hypertension. A sensitivity analysis was conducted by excluding baseline diabetes patients and adjusting for baseline blood pressure. In addition, a restricted cubic spline model was used to analyze the dose-response relationship between them. Results In this study, male participants accounted for 47.70%, and those aged 18-44 years accounted for 72.47%. The mean follow-up time was 12.56 years and the prevalence of hypertension was 13.86%. Dietary magnesium intake was inversely associated with the risk of hypertension at the 4^th quintile (median 333.56 mg·d⁻¹) and the 5^th quintile (median 420.07 mg·d⁻¹) compared with the 1^st quintile (median 189.06 mg·d^–1), and the hazard risk (HR) values and associated 95%CIs were 0.81 (0.67-0.97) and 0.81 (0.66-0.99) respectively. After eliminating baseline diabetes and adjusting baseline blood pressure, dietary magnesium intake remained negatively associated with the risk of hypertension, which was consistent with the population-wide HR. The association between dietary magnesium intake and the risk of hypertension was non-linear (χ²=11.07, P=0.01). When dietary magnesium intake was higher than 339 mg·d⁻¹, the risk of hypertension decreased, and the HR value was the lowest in 375-418 mg·d⁻¹ (HR=0.65, 95%CI: 0.45-0.94), and then gradually tended to 1. There was no statistically significant association at 467 mg·d⁻¹ and above. Conclusion Magnesium intake in the range of 339-467 mg·d⁻¹ is negatively associated with the risk of hypertension in Chinese adults, presenting a U-shaped dose-response relationship.

Background At present, domestic and foreign studies on the association between dietary magnesium and diabetes risk are not consistent, and there are relatively few prospective studies in China and the study population is relatively limited. Objective To explore the association between dietary magnesium intake and diabetes risk in Chinese adults in 15 provinces (autonomous regions, municipalities), and to provide a scientific basis for revising dietary magnesium intake reference for Chinese residents. Methods A total of 8061 adults aged 18-64 who participated in at least two follow-up surveys in the China Health and Nutrition Survey in 2009, 2015, and 2018, had complete survey data, and did not report diabetes at baseline were selected as subjects. Food consumption data were collected from 3-day 24-hour dietary recalls and by weighing household cooking oil and condiments. The average daily dietary magnesium intake was calculated based on the food composition table. Multiple Cox proportional risk regression model and restricted cubic spline (RCS) model were used to analyze the association and dose-response relationship between dietary magnesium intake and diabetes risk. Diabetes was defined according to the Chinese Guidelines for the Prevention and Treatment of Type 2 Diabetes (2020 edition). Results A total of 47237.46 person-years were followed up, with an average follow-up of 5.86 years. Among 8061 subjects, the incidence rate was 8.86%. Compared with those in the top quintile of magnesium intake (Q5), those with lower dietary magnesium intake were more likely to be female, have higher income, higher education, live in urban areas, and have lower intakes of energy, dietary fiber, and dietary calcium. After adjusting for demographic characteristics, lifestyle, and dietary factors, compared with adults in the lowest quintile of dietary magnesium intake, the results of Cox proportional risk regression model showed that the second (median: 220.96 mg·d⁻¹), third (median: 263.01 mg·d⁻¹), and fourth (median: 312.33mg·d⁻¹) quintile dietary magnesium intake reduced the risk of diabetes by 45% (HR=0.55, 95%CI: 0.43-0.71), 39% (HR=0.61, 95%CI: 0.47-0.78), and 34% (HR=0.66, 95%CI: 0.51-0.78), respectively. The results of RCS analysis showed that dietary magnesium intake and the risk of diabetes were U-shaped overall. Taking the 5th percentile magnesium intake as reference, when dietary magnesium intake was lower than 240 mg·d⁻¹, the risk of diabetes gradually decreased with the increase of magnesium intake; the risk was the lowest at 240 mg·d⁻¹, followed by a slight increase in risk at 240-400 mg·d⁻¹; and no statistical difference presented in the association between dietary magnesium and diabetes risk after 650 mg·d⁻¹. Conclusion The study findings suggest an association between dietary magnesium intake and diebetes risk. The association is negative and non-linear when dietary magnesium intake is below 240 mg·d⁻¹.

Background Diabetes is a major contributor to global burden of disease. The role of magnesium in the prevention of diabetes has aroused concern. However, the research results on the impact of dietary magnesium on the risk of diabetes are hitherto inconsistent. Objective To evaluate the association between dietary magnesium intake and the risk of diabetes through a systematic review. Methods PubMed, Web of Science, China National Knowledge Infrastructure, Wanfang databases were searched for prospective studies that contained risk estimates for magnesium intake-associated diabetes and were published from January 1, 2000 to December 31, 2021. Two researchers independently screened the literature according to a set of pre-prepared inclusion and exclusion criteria, extracted the data according to an unified data extraction table, and evaluated the quality of included articles with Newcastle-Ottawa Scale (NOS). R 4.0.3 software and Stata SE16.0 software were used for meta-analysis and subgroup meta-analysis, and Higgins I² statistics were used to test the heterogeneity of the included studies. The sources of heterogeneity were analyzed by univariate meta regression. Results A total of 14 articles involving 17 prospective cohort studies (1065267 participants and 40506 patients with diabetes) were included in the study. The NOS scores ranged from 8 to 9, with an average of 8.6, indicating that the included studies were classified as being high quality. The highest quintile of magnesium intake group reduced the risk of diabetes by 22% (RR=0.78, 95%CI: 0.73-0.82) compared with the lowest quintile group. This association was not substantially modified by geographic region, sex, or follow-up length. The highest quintile of dietary magnesium intake in the Americas and Asia were associated with 22% and 26% reductions in the risk of type 2 diabetes respectively compared with the lowest quintile group (the Americas, RR=0.78, 95%CI: 0.73-0.84; Asia, RR=0.74, 95%CI: 0.63-0.88); The highest quintile of dietary magnesium intake in female, male and without gender stratified were associated with 22%, 19% and 46% reductions in the risk of type 2 diabetes respectively compared with the lowest quintile group (Female RR=0.78, 95%CI: 0.73-0.84; Male RR=0.81, 95%CI: 0.74-0.89; Both RR=0.54, 95%CI: 0.42-0.68); Compared with the lowest quintile groups, the groups with the highest quintile of dietary magnesium intake with a follow-up time of less than 10 years and more than 10 years reduced the risk of type 2 diabetes by 26% and 20% respectively (≤10 years, RR=0.74, 95%CI: 0.65-0.83; ＞10 years, RR=0.80, 95%CI: 0.75-0.85). After adjusting for hypertension, the highest quintile of dietary magnesium intake group reduced the risk of type 2 diabetes by 20% compared with the lowest quintile group (RR=0.80, 95%CI: 0.74-0.85). The year of publication (P<0.05) or the sex of the subjects (P<0.05) may be the source of heterogeneity by meta regression test. The results of Egger’s test for funnel plot asymmetry suggested publication bias. Conclusion The combined data supports a role for high magnesium intake in reducing the risk of type 2 diabetes. Because it is difficult to separate the effect of magnesium intake on diabetes risk from other factors, large-scale and clinical randomized controlled trials are needed to directly assess the impact of magnesium on the incidence rate of diabetes.