ABSTRACT
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.
ABSTRACT
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.